efficient absorption of antibiotic from aqueous solutions

Research ArticleEfficient Absorption of Antibiotic from AqueousSolutions over MnO

2SAMn Beads and Their In Situ

Regeneration by Heterogeneous Fenton-Like Reaction

Yu Luo1 Bo Bai12 HonglunWang2 Yourui Suo2 and Yiliang Yao1

1Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region Changrsquoan University Ministry of EducationXirsquoan 710054 China2State Key Laboratory of Plateau Ecology and Agriculture Qinghai University Xining 810016 China

Correspondence should be addressed to Bo Bai baibochina163com

Received 16 May 2017 Accepted 10 July 2017 Published 21 August 2017

Academic Editor Run Zhang

Copyright copy 2017 Yu Luo et al This is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Alginate has been extensively used as absorbents due to its excellent properties However the practical application of pure alginatehas been restricted since the saturated adsorbent hasweak physical structure and could not be regenerated easily In this study a low-cost and renewable composite MnO2alginateMn adsorbent has been prepared facilely for the absorptive removal of antibioticwastewater FE-SEM FTIR andXRDanalyseswere used to characterize the samplesThenorfloxacin (NOR)was used as an index ofantibioticsMore specifically the batch absorption efficiency of the adsorbentswas evaluated by pH contact timewith differentNORconcentration and the temperatureThus the performance of absorption kinetic dynamics and isotherm equations were estimatedfor the adsorptive removal process Parameters including Δ1198660 Δ1198670 and Δ1198780 were utilized to describe the feasible adsorptionprocess To regenerate the saturated absorptive sites of the adsorbent the heterogeneous Fenton-like reactions were trigged byintroduction ofH2O2The results showed that the in situ regenerating has exhibited an excellent recycling stabilityThe high activityand the simple fabrication of the adsorbents make them attractive for the treatment of wastewater containing refractory organiccompound and also provide fundamental basis and technology for further practical application

1 Introduction

Extensive usages of chemical antibiotics have played animportant role in the health care for human and animals [1]However about 50sim90 of ingested antibiotics are excretedinto domestic sewage without being metabolized due to theincomplete metabolism [2 3] As a result residual chemicalantibiotic has been frequently found in the ground and drink-ing waters which inevitably lead to some unfriendly environ-mental influences such as the effects of the toxicity to animal-cule and the threats to human health [4 5] In recent yearscompared with the traditional strategies for removal of toxicantibiotics from wastewater using absorptive approachesfor the highly efficient degradation of stable antibioticsfrom wastewater treatment systems has been regarded asmost efficient route owing to their interested features of sim-ple operation low budget nontoxicity and efficient removal

rate Particularly the application of low-cost regenerationand environmentally friendly adsorbent attracts much moreattentions For example some wastes for economic cropssuch as rice-bran [6] cacao-shell [7] maize-stalk [8] andpeanut-shell [9] have been widely used as adsorbents to dealwith various antibiotics wastewater Sodium alginate (SA)a natural polysaccharide extracted from seaweed and com-prised homopolymeric blocks of guluronate blocks andman-nuronate blocks was used extensively as supported adsor-bent owing to its advantages of biocompatibility low toxicproperties and budget and ease of gelation [10 11] Severalalginate-based adsorbents including alginate nanohybrids[12] alginate nanohydrogel [13] alginate fiber [14] alginatebead [15] and alginate film [16] have already been exploredfor organic pollution adsorption applications In contrastthe alginate beads have been more widely used than the fiber

HindawiJournal of NanomaterialsVolume 2017 Article ID 3174393 13 pageshttpsdoiorg10115520173174393

2 Journal of Nanomaterials

nanoparticles or film forms because of their simple fabrica-tion and recovery process controllable particle dimensionand excellent dispersion stability [17] Unfortunately practi-cal application of pure alginate bead as adsorbent has beenrestricted since the adsorbent hasweak physical structure andcould not be regenerated easily which needs extra processor complete replacement [18] Therefore the explorationof developing an effective and easy regeneration route foralginate bead is of particular significance in contemporaryindustry

The degradation of contaminated organism fromwastew-ater by traditional Fenton oxidation process using slurrysuspensions of iron oxide as catalysts is considered as anexpensive process since longer reaction times are usuallyrequired to entirely oxidize the pollutants due to theirinefficient hydroxyl radicalsrsquo concentration inside reactions[19ndash21] To overcome this dilemma utilizing an enrichmentmethod or prethickening adsorption way prior to the oxida-tion process has been ascertained that the removal efficiencyof pollutants through the Fenton-like reaction has beensignificantly increased Typically the embedding of Fe3O4nanoparticles of yeast has integrated biosorption propertiesfrom pure yeast cells under the Fenton performance fromFe3O4 nanoparticles resulting in the high-effective degrada-tion of cationic azo dye in wastewater treatment [22] Theenhanced efficiency of wastewater treatment is ascribed tothe successive and synergistic effect on yeast biosorption andFe3O4 nanoparticles over heterogeneous Fenton catalyzesperformance and regeneration process Compared with tra-ditional iron oxide Fenton catalysts MnO2 exhibit mostattractive transition metal oxides which predisposed to coor-dinate with oxidant forming the Fenton-like process reagentto remove the contaminates in water treatment Such kindof catalyst possessed intriguing features such as wideningoperative pH ranges and high positive catalyst performance[23] Furthermore researches prove that decomposition ofH2O2 can be catalyzed by MnO2 nanoparticles to generatereactive oxygen species like hydroxyl radicals carboxylradicals and single oxygen to remove organic pollutants[24ndash26] As a consequence the simultaneous utilizationof MnO2 and H2O2 has been considered as Fenton-likeprocess reagent to oxidize the low-biodegradable organismFor instance methylene blue [27] methyl orange [28] andazo dyes [29] have been removed using MnO2-involvedhybrid composite as a catalyst in heterogeneousMnO2H2O2Fenton-like system

Thus in this work novel absorbents MnO2alginateMn(MnO2SAMn) beads were first fabricated The adsorbentswere characterized by a scanning electronmicroscopy (SEM)Fourier transform infrared spectroscopy (FTIR) and powderX-ray diffraction (XRD) respectively Norfloxacin (NOR)frequently detected inwastewater and surfacewaterwith highconcentrations was used on purpose as an index of antibi-otics to evaluate the adsorption properties of MnO2SAMnbeads The detailed absorptive removal processes for NORantibiotic from aqueous solutions overMnO2SAMn beadswere investigated Afterward the in situ regeneration ofthe saturated MnO2SAMn absorbents was trigged byintroduction of H2O2 The possible mechanism for in situ

regenerating norfloxacin-loaded MnO2SAMn was dis-cussed

2 Experimental

21 Materials Sodium alginate (SA) with the purity 095was purchased from Sinopharm Chemical Reagent Co Ltd(Shanghai China) Norfloxacin (C16H18FN3O3) was pur-chased from Sigma-Aldrich Co Ltd (Shanghai China) andthe purity is 098The reagents in this experiment are analyti-cal grade with mass fraction purity 099 and used as receivedManganese sulfate (MnSO4) and potassium permanganate(KMnO4) were purchased from Tianjin Yonghao JingxiChemical Co Ltd (Tianjin China) Ethanol (C2H5OH)was purchased from Tianjin Fuyu Jingxi Chemical Co Ltd(Tianjin China) Distilled water (183MΩ cm) was used tomake required aqueous solutions

22 MnO2SAMn Beads Preparation MnO2 nanoparticleswere prepared via a hydrothermal method Typically 30ml02molsdotLminus1 MnSO4 solution was added dropwise into 30ml03M KMnO4 solution with continuous stirring for at least30min Then the mixture was treated at 180∘C with aTeflon-lined autocave for 10 h After cooling down to roomtemperature the suspension was centrifuged and washed theprecipitate with distilled water After that the precipitate wasdried at 60∘C in air for 6 h the finalMnO2 nanoparticles wereobtained The reaction equation is as follows

3MnSO4 + 2KMnO4 + 2H2O 997888rarr5MnO2 + 2H2SO4 + K2SO4

(1)

Subsequently 1000 g of MnO2 nanoparticles was dis-persed into 50ml of 25 (w) sodium alginate solutions at29815 K with continuous stirring for 2 h After that thesodium alginate solution was dropped into MnSO4 solution(005mgL) with a peristaltic pump After the hydrogel beadswere stored at 4∘C for 10 h to form MnO2SAMn hydrogelbeads the obtained hydrogels were finally washed and storedat 4∘C until use

23 Adsorbents Characterization The morphology of theMnO2SAMn adsorbent was observed by a scanning elec-tron microscopy (SEM Hitachi S-4800 Japan) Elementcontent and line-scanning analysis were investigated byenergy-dispersive spectroscopy (EDS) analysis To studythe chemical structures Fourier transform infrared spectra(FTIR BiO-RAD FTS135 America) of the adsorbents weremonitored by a Bio-Rad FTS135 spectrometer in the range500ndash4500 cmminus1 using KBr And the crystal phase was investi-gated by powder X-ray diffraction (XRD Rigaku DMAX-3Cdiffractometer Japan) patterns which were conducted on XPert Pro diffractometer at a scanning rate of 100 permin usingCu K120572 radiations (120582 = 015418)

24 Adsorption Experiments In a typical run the exper-iment was conducted in 200mL conical flasks containing100mL of the desired NOR concentration at pH 4 Since

Journal of Nanomaterials 3

the adsorbents were primarily responsible for the adsorption20 gsdotLminus1MnO2SAMnadsorbentswere added in eachflaskThen the solution was stirred using a magnetic stirrer for85min 5ml samples in solution were picked up at regularintervals to centrifuge in order to separate the absorbentsfrom the liquid and then the supernatant was analyzed bya wavelength of 273 nm using an Evolution 201 ultraviolet-vis (Jenway Cambridge UK) spectrophotometer to confirmthe residual concentration of NOR and the loading efficiencyAfter that the samples were immediately reverted to the flaskThe adsorption capacity (119876119890 mgsdotgminus1) and loading efficiency(120578 ) of NOR were determined as follows

120578 = (1198620 minus 119862119890)1198620 times 100

119876119890 = (1198620 minus 119862119890) times 119881119898 (2)

where 1198620 (mgsdotLminus1) and 119862119890 (mgsdotLminus1) are the NOR concen-tration before and after adsorption respectively 119881 (L) isthe volume of the solution and 119898 (g) is the weight of theabsorbent

25 In Situ Regeneration of Absorbents Typically in anadsorptive removal process 100mL 10mgsdotLminus1 NOR aqueoussolution was conducted in conical flask and 20 gsdotLminus1 ofMnO2SAMn adsorbents was used as the absorbents thenanalyzing the supernatant of the solution to determine theNOR loading efficiency when the adsorption equilibriumfinished After that the solution was added by 5mL 1 (wv)H2O2 and irradiated for 4 h using two ultraviolet lamps fixeddirectly above the flaskThen the absorbentswere collected bycentrifugation washed thoroughly and dried to be reused inthe next run Another cycle of sorption-regeneration processwas repeated in the same manner as mentioned above

3 Results and Discussion

31 Characterization of MnO2SAMn Beads An estimatedformation pathway of MnO2SAMn beads is shown inScheme 1

In this work sodium alginate was dissolved ahead indistilled water with magnetic stirring for 10 h to get a homo-geneous expansive solution which would intertwine eachtogether forming a three-dimensional network through cova-lent and noncovalent interactions like hydrogen bond elec-trostatic interactions and van der Waals forces [30 31] Thenthe MnO2 nanoparticles were introduced into the solutiongradually with continuous stirring during the intertwinedprocesses Thus the expansive solution of sodium alginatewould provide a certain possibility for MnO2 nanoparti-cles uniformly dispersing and embedding into the polymernetwork to obtain MnO2SA gel solution After that thecompositewas dropwise injected intoMnSO4 solutionWhenMnO2SA gel droplets were immersed intoMnSO4 aqueoussolution MnO2SAMn hydrogel beads were achieved dueto the ionic cross-linking interactions between carboxyl

COONa COONa

COONa

COONa

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

HO

HO

NaOOC NaOOC

O O OO

O O

OO

OOO

OOO

OO

minus minusminus

minus

minus

minus

minus

minus

Dissolved in water(sodium alginate)

Sodium alginate

(alginate)

Adding Mn2 nanoparticles

Drop-wise injectedin MnS4 solution

MnS4 solution

Gelation

－Ｈ2+－Ｈ2+

－Ｈ2+

－Ｈ2+

－Ｈ2+－Ｈ2+

－Ｈ2+

－Ｈ2+

－Ｈ2+

－Ｈ2+

Mn2 nanoparticles

Mn2alginateMn

Hydrogen bond

Scheme 1Mechanism for the formation ofMnO2SAMnhydrogelbeads

group of the alginate chains and Mn2+ by chelation andcovalent and noncovalent forces It was conceivable that theimpregnation ofMnO2 nanoparticles is an effective approachto enhance the physicochemical properties of hydrogel beadsand the physical MnO2SAMn hydrogel beads acquiredwould be comprised of water MnO2 Mn2+ ions and alginatewith abundant free carboxyl groups and hydroxyl groups

Based on the previous analysis we can infer that algi-nate molecule MnO2 nanoparticles and Mn2+ ions havehad their own extremely important contribution for theformation of MnO2SAMn hydrogel beads respectivelyFor the alginate material the physical cross-linked prop-erty of the alginate polymer chains have assembled thedispersive MnO2 nanoparticles into hydrogel beads helpingto fabricate the uniform and scattered spherical alginategel microspheres Besides the generated alginate hydrogelshave reserved sufficiently original groups including hydroxyland carboxyl groups on the surface of alginate substrateswhich can be used for capturing the chemical antibioticscompound from aqueous solutions by covalent and nonco-valent forces And thus the enrichment or preconcentrationadsorption of chemical antibiotics compound prior to theheterogeneous oxidation process could be fulfilled As for theMnO2 nanoparticles they have acted as the inner skeleton tostrengthen themechanical stability ofMnO2SAMn hydro-gel beads Also the MnO2 nanoparticles within the innerand surface of MnO2SAMn hydrogel beads can provideabundant catalytic active sites for the heterogeneous Fenton-like reaction speeding up the degradation rate of norfloxacinantibiotics Owing to the fact that coordination for divalentions is permitted by the structure of guluronate blocks ofalginate the ample Mn2+ ions within the system hereby have


Tans

mitt

ance

()

594670

117814101636

1740

3429

523

716

3429

1426

16321163

2854

2925

(a) pure AB

3428

2854

2925

Wavenumber (＝Ｇminus1)4000 3500 3000 2500 2000 1500 1000 500

(b) pure Mn2

(c) Mn2SAMn

Figure 1 FTIR spectra of (a) AB (b)MnO2 and (c)MnO2SAMnbeads

functioned as a cross-linking agent to help to form alginatehydrogels in solution by binding solely with guluronateblocks from polymer chains By these means one polymerguluronate block could form junctions with the adjacentpolymer guluronate chains and finally the MnO2SAMnbeads with complicated cross-linking hydrogel and uniqueegg-box shape were constructed successfully [32]

To examine the chemical bonding structure and possibleinteractions of the MnO2SAMn beads FTIR analysiswas employed to detect the chemical bonds transformationin parallel to MnO2 pure alginate hydrogel beads andMnO2SAMn beads For the alginate hydrogel beads inFigure 1(a) the peaks at 3428 2925 2854 1632 1426and 1163 cmminus1 are ascribed to the -OH -CH2- -CH3 theasymmetric and symmetric stretching vibration of -COOHand -CO vibrations respectively [33ndash37] In the case of theMnO2 nanoparticles in Figure 1(b) the peak at 3429 cmminus1is mainly generated by -OH of the water molecule adheringto the surface of MnO2 nanoparticles which indicates thatthe surface of synthesized MnO2 nanoparticles has suffi-cient hydroxyl groups [38] The two peaks around 716 and523 cmminus1 are aroused by Mn-O-Mn and Mn-O stretchingvibration [39 40] In the FTIR spectrum of MnO2SAMnbeads (Figure 1(c)) the characteristic adsorption peaks ofpure alginate hydrogel beads and MnO2 were approximatelymaintained or even stronger Moreover an original peak at1740 cmminus1 probably caused by the absorption vibrations of thendashCOOH in alginate molecule [41 42] However the peaks at3428 cmminus1 1632 cmminus1 1426 cmminus1 and 1163 cmminus1 of pure algi-nate hydrogel beads and 3429 cmminus1 716 cmminus1 and 523 cmminus1of MnO2 were changed to 3429 cmminus1 1636 cmminus1 1410 cmminus11178 cmminus1 670 cmminus1 and 594 cmminus1 in MnO2SAMn beadsrespectively These changes implied that the alginate networkand MnO2Mn in the MnO2SAMn hydrogel beads werelinked with the strong intermolecular forces of hydrogenbonding and chelation between Mn and hydroxyl groupscarboxyl groups and such linkages resulted in forming astable three-dimensional network

Optical photographs and FE-SEM images of MnO2SAMn beads are presented in Figure 2 respectively Figure 2(a)indicates that the surface ofMnO2SAMnhydrogel beads ina gel state is smooth and the bead has a black spherical shapewith a diameter approximately 20 plusmn 02mm simultaneouslythe average diameter after freezing drying is about 15 plusmn02mmThe shrinkage of the MnO2SAMn hydrogel beadsindicated that the obtained hydrogel beads have a definiteadsorption capacity for water molecule Theoretically thewater-holding capacity (WHC) can be calculated as follows

WHC (mg) = 120588119882 times 119881119882 = 120588119882 times 43120587 (119877eq3 minus 1198771198893) (3)

where 120588119882 is the density of water 119881119882 is the volume ofMnO2SAMn hydrogel beads and 119877eq and 119877119889 are theradius of the gelatinous beads (eq) and dried (119889) beads Aftercalculation its water-holding capacitywas theoretically about7327mgsdotbeadminus1

Figure 2(b) is the SEM photograph of a freezing driedMnO2SAMn hydrogel bead It shows that the surface ofMnO2SAMn hydrogel bead is relatively sags and crestswith small concave depressions on the reason should beattributed to two cases For the one side it is due torough shrinkage of MnO2SAMn hydrogels over completefreezing drying process For another side it is due to theimpregnation of MnO2 nanoparticles into alginate hydro-gel beads in the aqueous solution Figures 2(c) and 2(d)show that the local surface magnified and cross sectionmagnified SEM photographs of samples The photographsindicated that the MnO2 nanoparticles with an average sizeof 200 plusmn 20 120583m widths and 4000 plusmn 20 120583m length weresuccessfully embedded onin the three-dimensional cross-linked alginate hydrogel beads heterogeneously and deeplydue to the intermolecular forces of hydrogen bond betweenMnO2 nanoparticles and alginate polymers and the chelationbetween Mn2+ ions and hydroxyl carboxyl groups Brieflythe stable and tight MnO2SAMn hydrogel beads wereacquired with abundant carboxyl and hydroxyl groups forNOR adsorption

The distribution of elements of selected MnO2SAMnzone was further investigated by EDS analysis and line-scanning The experimental results were shown in Figure 3As shown in Figure 3(a) the EDS analysis of MnO2SAMnbeads inferred that C O and Mn elementals were the maincomponents with weight percentage of 4410 2636 and2954 respectively confirming the purity ofMnO2SAMnmaterials Moreover from the graph in Figure 3(b) the line-scanning for selected surface zone of MnO2SAMn beadpresented high homogeneity that during the area withMnO2impregnation the intensities of Mn and O are notable muchstronger than C while in the other area the intensitiesof C O and Mn trended towards stable values Theseresults further prove the successful immobilization of MnO2nanoparticles onin the SA beads and lead to an enhancementof amount of available adsorptionregeneration sites

The structural characterization of MnO2SAMn beadsare further determined by powder X-ray diffraction technol-ogy The typical XRD analyses are shown in Figure 4 The


(a) (b)

(c) (d)

Figure 2 (a) Photograph of MnO2SAMn hydrogels in equilibrium gel state (left) and dried state (right) (b c) SEM photographs ofMnO2SAMn and surface of MnO2SAMn and (d) cross section of MnO2SAMn

2636 2954 4410 100

C

Mn

O

Total

Element content ()

(a)

Relat

ive i

nten

sity

(au

)

COMn

00 01 02 03 04 05 06 07 08 09 10

Distance (lowast10 Ｇ)

10 Ｇ

(b)

Figure 3 Element content (a) and selected zone line-scanning analysis for C O and Mn elements of MnO2SAMn beads (b)

diffraction of alginate gel beads (Figure 4(c)) shows typicalpeaks around 131∘ and 206∘ [43] Moreover in Figure 4(b)the composites had similar diffraction peaks at 2120579 = 287∘374∘ 410∘ 428∘ 567∘ and 594∘ giving an index to a 120573-MnO2 phase [44] Therefore Figure 4(a) exhibits the XRD

pattern of MnO2SAMn hydrogel bead including both thediffraction peaks of MnO2 nanoparticles and alginate gelbeads correspondingly And the successful impregnating ofMnO2 onin the MnO2SAMn beads was confirmed sinceno further impurities peaks were found


10 20 30 40 50 60 70 80

(c) pure AB

Inte

nsity

(au

)

127∘

203∘

206∘131∘

287∘

287∘

374∘

374∘428∘

428∘

410∘

410∘

567∘

594∘

594∘567∘

2 (∘)

(b) pure Mn2

(a) Mn2SAMn

Figure 4 XRD patterns of (a) MnO2 SAMn beads (b) MnO2nanoparticals (c) pure alginate bead

32 Adsorptive Removal of NOR Antibiotic from AqueousSolutions In this study the applications of MnO2SAMnbeads were evaluated by the adsorptive removal of NORcompound from the simulated solution using batch reactorThe parameters of the adsorptive removal process deter-mined in the experiments were pH (2ndash10) NOR concentra-tion (2ndash30mgsdotLminus1) contact time (0ndash85min) and tempera-ture (28815ndash31815 K) In addition parameters of adsorptivekinetic and thermodynamic were utilized to confirm effi-ciency for the adsorptive removal process

321 Effect of pH in Solution The effect of pH is a signifi-cant factor in adsorptive removal process since it is closelyintegrated with the surface charge of the adsorbent andthe chemical structure of organic materials [45] Hereinparameters of theNOR adsorptive removal experiments wereperformed with 10mgL NOR 2mM H2O2 solution and20 gL adsorbent at 30∘C and the adsorption propertiesincluding removal efficiency and adsorptive removal capacitywere investigated by MnO2SAMn and pure AB respec-tively (Figure 5) The value of the maximumNOR adsorptiverate by catalyst MnO2SAMn beads is 983 while bycatalyst AB the value is 552 at pH40However with the pHof the solution (pH40ndash100) further increasing the efficiencyof NOR adsorption decreases from 983 to 372 and 552to 117 respectively The maximum adsorption capacitiesare 49mgg by catalyst MnO2SAMn beads and 28mggby AB beads individuallyThis observation gives the evidencethat MnO2 and Mn2+ ions can improve the NOR adsorptioncapacity in Fenton-like system

Such phenomenon is probably ascribed to the causesbelow For MnO2SAMn beads adsorbents their surface isapt to be adjusted at different pH since the pHpzc of MnO2 is225 [46] and the pHpzc of pure alginate bead is 42 For NORadsorbate each NOR molecule has two functional groupsincluding acid carboxyl and basic piperazine Therefore theacid-base equilibrium of the NOR molecule was inevitably

influenced by the solution pH More specifically the piper-azine group of the NOR exists as a protonated cation formin an acidic environment when pH is less than 6 On thecontrary a basic environment could cause a deprotonationwhen pH is greater than 9 Namely the NOR performsas deprotonated anion form at a basic environment Whilethe solution pH is varied from 6 to 9 the NOR exists aszwitterions form [47 48]

322 Effects of NOR Concentration Effects of adsorp-tion contact time with different initial NOR concentration(2ndash30mgsdotLminus1) were carried out for 85min at 30∘C with20 gsdotLminus1 adsorbent and 2mM H2O2 in pH 4 solution inFigures 5(b) and 5(c) Figure 5(b) showed that the kinetics ofNOR included two stages of behaviors during the adsorptionprocess a fast adsorption period over a short time followedby a slower adsorption period for a longer time In the firststage it is due to the adsorptive sites on the MnO2SAMnadsorbent surface through the initial period of adsorptionbehavior For the second stage adsorption rate was prob-ably by the molecular-repulsive interactions between NORmolecule on the absorbent surface and the solution As timegoes on some adsorbed NORmolecules were desorbed fromthe adsorbent dispersing to the bulk phase again Equilib-rium adsorption capacity increased notably from 993 to9685mgsdotgminus1 with the increasing of NOR concentration vary-ing from 2 to 30mgsdotLminus1 Such phenomenon can be probablycontributed to the strong interactions of driving force amongNOR ions during high concentration From Figure 5(c)it indicates that a lower initial NOR concentration resultsin a higher adsorption efficiency With NOR concentrationvarying from 2 to 30mgsdotLminus1 the final degradation of NOR byMnO2SAMn beads and pure AB beads at 85min decreasesfrom 993 to 579 and from 461 to 115 respectivelyThe NOR removal efficiency and adsorption capacity byMnO2SAMn beads are higher than those values by pureAB beads These results indicate that MnO2SAMn beadshave more abundant adsorption sites than pure AB beads

323 Kinetics of NOR The kinetics is significant for theremoval efficiency since it can provide the mechanism ofadsorption process For the reason that the adsorbate res-idence time is controlled by the kinetics removal rate ofthe adsorption is so important that the design parametersof the process can be better optimized Therefore predictingremoval rate in which adsorption behavior occurs is consid-ered as the most significant element for the design of theadsorptive removal process [49]

To study the adsorption mechanism linearized adsorp-tive kinetic equation is utilized to find the adsorption kineticsof NOR adsorbed by theMnO2SAMn hydrogel beads [50]The pseudo-first-order equation is as follows

ln (119876119890 minus 119876119905) = ln119876119890 minus 1198961 times 119905 (4)

where 119876119890 and 119876119905 represent the amount of NOR adsorbed onthe adsorbent at the equilibrium and at time 119905 separately 1198961(minminus1) is rate coefficient for the pseudo-first-order


1 2 3 4 5 6 7 8 9 10 11 12 13minus20

0

20

40

60

80

100

(C) AB loading capacity(D) AB removal efficiency

minus20

minus10

0

10

20

30

40

50

NHN N

FO

NN

O

H

H

F

N N

COOHFO

H

H

pH

(A)

(B)

(C)

(D)

NOR cation form

NOR zwitterion NOR anion form

(

)

Qe

2（52（5

2（5

(A) Mn2SAMn capacity(B) Mn2SAMn efficiency

minusminus

+

+

(ＧＡmiddotＡminus

1)

(a)

0 10 20 30 40 50 60 70 80 900

102030405060708090

100

Time (min)

C0 = 30ＧＡmiddotminus1






Qe


1)

(b)

0 10

10

20

20

30

30

40 50 60 70 80 90 1000

5

15

25

Loading efficiency ()

pure ABMn2SAMn beads

Initi

al N

OR

conc

entr

atio

n (m

gmiddotminus1)

(c)

Figure 5 Effects of (a) pH [NOR] = 10mgsdotLminus1 (b) and (c) contact time and initial NOR concentration pH= 4 Reaction conditions [catalyst]= 20 gsdotLminus1 [H2O2] = 2mM 119879 = 30∘C

Table 1 Kinetic adsorption parameters of different initial concentration of NOR

1198620(mgsdotLminus1) 119876exp(mgsdotgminus1) Pseudo-first-order Pseudo-second-order119876cal(mgsdotgminus1) 1198961minminus1 1198772 119876cal(mgsdotgminus1) 1198962(gsdotmgminus1sdotminminus1) 1198772

20 9933 10057 0088 0955 10135 0097 099850 24530 24965 0081 0963 25026 0039 0996100 48523 50481 0065 0961 49485 0020 0994150 64799 65527 0090 0988 66100 0015 0996200 73691 74191 0100 0989 75190 0013 0997300 86779 87914 0087 0910 88455 0011 0997

The pseudo-second-order equation is as follows [51 52]rdquo119905119876119905 =

11198962 times 1198762119890 +

119905119876119890 (5)

where119876119890 and119876119905 are the capacities at equilibrium and at time119905 (s) respectively 1198962 (gsdotmgminus1sdotminminus1) is rate coefficient for the

second-order equationThefitted curves for both two kineticsare presented in Figure 6 curve-fitting data and correlationparameters are shown in Table 1

Figure 6 shows the plots of two kinetics of NOR adsorp-tion onMnO2SAMnwith variedNOR concentrationsTherate coefficients and correlation coefficient for adsorption


0 5 10 15 20 25 30 35 40minus2

minus1

0

1

2

3

4

5

Time (min)

ln(Q

eminusQ

t)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(a)

0 10 20 30 40 50 60 70 80 900

2

4

6

8

10

Time (min)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(tQ

t) (m

inmiddotgmiddotＧ

Ａminus1)

(b)

Figure 6 Pseudo-first-order (a) and pseudo-second-order (b) adsorption kinetics for adsorption of NOR onto MnO2SAMn at differentinitial NOR concentrations at reaction conditions [catalyst] = 20 gsdotLminus1 [H2O2] = 2mM pH = 4 119879 = 30∘C

were simulated and summarized in Table 1 Table 1 revealedthat the practical adsorption amount values (119876exp) disagreewith the theoretical values (119876cal) although the constant values(1198772) for the pseudo-first and pseudo-second equations werein the range of 0910sim0989 and 0994sim0998 respectivelyHowever the values of correlation coefficient (1198772) for thepseudo-second-order are much closer to 10 than the valuesfor pseudo-first-order confirming that the adsorption pro-cess of MnO2SAMn hydrogel beads for simulated NOR-solution fits the pseudo-second-order equation better

324 Isothermal andThermodynamic Experiments of Adsorp-tion Thermodynamic experiments onNORadsorptionwereinvestigated in a temperature range of 15∘C to 45∘C withpH 4 10mgsdotLminus1 NOR 20 gsdotLminus1 adsorbent and 2mM H2O2solution In order to study whether the adsorption processmight take place spontaneously parameters including thechanges of enthalpy (Δ1198670) the entropy (Δ1198780) and the Gibbsfree energy (Δ1198660) associated with adsorptive removal processwere calculated as follows

ln119870119889 = minusΔ1198670

119877 times 119879 +Δ1198780119877

119870119889 = 119876119890119862119890 Δ1198660 = minus119877 times 119879 times ln119870119889

(6)

where 119870119889 and 119879 (K) are the equilibrium adsorption constantand temperature respectively Constant119877 (8314 Jsdotmolminus1sdotKminus1)is the ideal-gas coefficient In addition parameters Δ1198670 andΔ1198780 are obtained from the plots of ln119870119889 versus 1119879

Table 2 Adsorption thermodynamic parameters of NOR byMnO2SAMn beads

TemperatureK Δ1198660kJsdotmolminus1 Δ1198670kJsdotmolminus1 Δ1198780Jsdotmolminus1sdotKminus128815 minus024

2052 888729815 minus27130815 minus87631815 minus684

Table 2 exhibits the data of Δ1198660 Δ1198670 and Δ1198780 for theadsorptive removal process From Table 2 the negative Δ1198660indicates that at temperature ranging from 15 to 45∘C thespontaneous nature of adsorption occurs relatively easier at35∘C Considering Δ1198660 is in the range minus20 to 0 kJsdotmolminus1the processes are dominated by the physical adsorption [5354] Moreover the positive Δ1198670 (2052 kJsdotmolminus1) reveals thatsuch adsorptive removal process is the result of endothermicnature of adsorption and physical interactions includingvan der Waals interactions hydrogen-bonding forces andelectrostatic force [54] Furthermore the positive value ofΔ1198780 (8887 kJsdotmolminus1) confirms that excellent affinity of NORmolecule towards adsorbent and randomness increases at thesolid-liquid interface at 15ndash45∘C [55]

The Langmuir Freundlich and Dubinin-Radushkevichisotherms are selected to describe how adsorbents interactwith adsorbate during the adsorption behavior The Lang-muir isotherm assumes that uniform adsorptive processoccurs with the monolayer at the adsorbent surface [56]While the Freundlichmodel is an empirical expression whichdescribes the multilayer sorption behaviors that occurred inthe heterogeneous system [57] Compared with the isothermequations above Dubinin-Radushkevich isotherm model is


Table 3 Adsorption thermodynamic parameters of NOR by MnO2SAMn beads

TemperatureK Langmuir isotherm model119876119898mgsdotgminus1 119887Lsdotmgminus1 119877119871 1198772

28815 1732 054 048ndash006 0978229815 1481 055 047ndash006 0982430815 2499 040 056ndash008 0970931815 3081 029 063ndash010 09787

TemperatureK Freundlich isotherm model119870119865Lsdotgminus1 119899 1198772

28815 676 282 0976329815 719 351 0981330815 757 457 0969731815 700 339 09778

TemperatureK Dubinin-Radushkevich isotherm model119876119898mgsdotgminus1 119896DRkJ2sdotmol2 119864kJsdotmolminus1 1198772

28815 738 021 167 0905229815 582 019 169 0904630815 867 018 172 0896531815 1016 016 174 08962

used to distinguish the adsorptionmechanics as chemical andphysical adsorption of NOR [58]

The Langmuir equation has the following form

119876119890 = 119876max times 119887 times 1198621198901 + 119887 times 119862119890 (7)

where 119862119890 (mgsdotLminus1) and 119876max (mgsdotgminus1) are the equilibriumNOR concentration and maximum adsorptive capacity and119887 (Lsdotmgminus1) is the coefficient of adsorption

Moreover the Freundlich isotherm equation is as follows

119876119890 = 119870119891 times 1198621198901119899 (8)

where 119870119891 and 119899 are the constants indicating the adsorptioncapacity and adsorption intensity respectively

Additionally a dimensionless constant (119877119871) can reflectthe significant performance of Langmuir and is given by

119877119871 = 11 + 119887 times 1198620 (9)

where the coefficient 119877119871 implies the type of isotherm basedon the following ranges 119877119871 = 0 irreversible 0 lt 119877119871 lt 1favorable 119877119871 = 1 linear 119877119871 gt 1 unfavorable [59]

Furthermore the Dubinin-Radushkevich isothermmodel for the linear form is

ln119876119890 = ln119876119898 minus 119896DR times 1205762 (10)

120576 = 119877 times 119879 times ln(1 + ( 1119862119890)) (11)

119864 = 1radic2 times 119896DR (12)

where 119896DR (molsdotJminus1) is the constant related to the mean freeenergy of adsorption 120576 is Polanyi potential which can be

calculated from (11) Constant 119877 (Jsdotmolminus1sdotKminus1) and 119879 (K) arethe gas constant and absolute temperature119864 (kJsdotmolminus1) is themean energy of the adsorption

The simulated data on the basis of the aforementionedmodels are shown in Table 3 It reveals the determinedcoefficient constant for the two isotherm models at differenttemperature The result proves that the Langmuir modelbetter fits the practical values of MnO2SAMn beads FromTable 3 we can find that the Langmuir constant119876119898 indicatingthe maximum adsorption capacity of MnO2SAMn beadswas increased while the values of b indicating the energy ofthe adsorption were decreased with increasing temperaturetill 45∘C And the values of 119877119871 range within 006ndash063 for dif-ferent initial NOR concentrations at different temperaturesThese phenomena once again confirm that the adsorption forNOR on MnO2SAMn beads was favorable

Freundlich model could not explain the adsorptionbehavior as the Langmuir theory did since the constant 1198772was lower than the values in LangmuirmodelTheFreundlichconstant 119899 ranged from 228 to 457 at different temperaturesalso revealing that the adsorption was favorable [60] Itconfirmed that values of 119870119865 increased with the temperatureof the solution up to 30815 K proving that high NORadsorption capacity easily occurred at relatively temperature

FromTable 3 it can be seen that the values ofmean energy119864 simulated are all smaller than 2 kJsdotmolminus1 confirming thatthe adsorption of NOR by MnO2SAMn absorbent wasdominated by physical adsorption during the process [61]

33 Regeneration of NOR-Loaded MnO2SAMn by Het-erogeneous Fenton-Like Reaction The migration of NORantibiotics from aqueous solutions have been achieved byabsorptive enrichment or preconcentration approach overMnO2SAMn beads Then the regeneration of the sat-urated absorptive sites by subsequent destruction of the


1 2 3 4 1 2 3 470

75

80

85

90

95

100

Rem

oval

effici

ency

()

as adsorbent

adsorption

Rem

oval

effici

ency

()

Cycle time

SA as adsorbent

20

30

40

50

60

70

80

after （22UV light

Mn2SAMn

Figure 7 Reuse of the in situ regenerated alginate andMnO2SAMn hydrogel beads Reaction conditions [NOR]= 10mgsdotLminus1 [catalyst] = 20 gsdotLminus1 pH = 4 119879 = 30∘C

adsorbed organic NOR pollutants are extremely crucial forthe economic cost In the present study the reuse andregeneration of saturated absorbent were performed by trig-ging UV assisted-heterogeneous Fenton-like reaction Theexperimental results were shown in Figure 7

Figure 7 showed the reuse performance of in situ regen-erated alginate andMnO2SAMnThe cycling properties ofalginate and MnO2SAMn used for catalytic reaction wereevaluated at [NOR] = 10mgsdotLminus1 [catalyst] = 20 gsdotLminus1 pH =4 and 119879 = 30∘C In Figure 7 the removal rate of pure ABafter UVH2O2 regeneration over four cycles was apparentlydropped from 58 to 35 This contributed to the fact thatthe removal ofNOR in solution by pure alginate beadsmainlydepended on the adsorption properties Herein it is wellknown that decomposition of H2O2 could be catalyzed byUV radiation to create oxidizing radicals The significantmechanisms include thatNORandH2O2molecules occupiedthe bare active sites on the surface of the alginate thenNOR was removed by the oxidizing radicals created by thedecomposition of H2O2 and dissolved into the solutionsimilar results were acquired by Tunc et al [62] AlthoughNOR in solution could be removed by the pure alginatebeads in the UVH2O2 system the adsorbed NOR couldblock the activated sites and decrease catalytic efficiency onthe surface of the alginate towards the H2O2 decomposition[63] However compared with the pure alginate beads theMnO2SAMnhas achieved a higher removal rate in theUV-Fenton-like system The removal rate of MnO2SAMn was98 95 91 and 86 respectively (Figure 7) It indicatedthat the MnO2SAMn catalyst retained excellent activityand stability after recycle for four timesThis probably can beattributed to the effects of alginate adsorption property UVphotolysis and MnO2Mn-triggered heterogeneous Fenton-like oxidation Comparing with pure alginate beads theMnO2Mn-triggered heterogeneous Fenton-like oxidationprocess directs an ascendant position for the contributor

during regeneration process The phenomena give a firmevidence that MnO2SAMn catalyst can be reused at leastfour times without losing much effectiveness to remove NORpollutant which is significant in practical and long-termapplications

For UVFenton-like reaction system ∙OH HOO∙ and1O2 were generated by decomposition of H2O2 and theycan powerfully and nonselectively oxidize or destroy themolecules structure of organic pollutants [64] Neverthelessorganic pollutant as NOR can be removed from aqueoussolutions only theywere adsorbed on the catalyst surface [65]Based on this assumption possible formationmechanism forin situ regenerating NOR-loadedMnO2SAMn is proposedto be a process of adsorption-decomposition-desorptionFirstly H2O2 and NOR are adsorbed on the catalyst surfacesecondly under UV irradiation photolysis and MnO2Mn-triggered heterogeneous Fenton-like oxidation H2O2 isdecomposed into ∙OH HOO∙ and 1O2 radicals ((13)ndash(21))Part of the newly generated radicals diffuses on the surfaceand reacts directly with the adsorbed NOR molecules anddecompose them into small organic molecules and inorganicsubstances And the other radicals are desorbed from thesurface dispersed into the solution and decomposed theNOR in the solution Finally the degraded small unitsof NOR are desorbed from the catalyst surface and enterinto the solution recovering the active potential site of thecatalyst surface Therefore MnO2SAMn could be in situregenerated for the next catalytic reaction

Mn2+ +H2O2 997888rarr ∙OH +Mn3+ +OHminus (13)

H2O2 + ∙OH 997888rarr HOO∙ +H2O (14)

Mn3+ +HOO∙ 997888rarr Mn2+ +H+ +O2 (15)

∙OH +HOO∙ 997888rarr H2O +O2 (16)

HOO∙ 997888rarr H+ +O2∙minus (17)

O2∙minus + ∙OH 997888rarr 1O2 +OHminus (18)

O2∙minus +HOO∙ 997888rarr 1O2 +HOOminus (19)

HOO ∙ +HOO∙ 997888rarr 1O2 +H2O2 (20)

1O2 + organic contaminants 997888rarr CO2 +H2O (21)

4 Conclusions

In this study the present research attempted to develop asimple and ecofriendly approach to prepare a superabsorbentcomposite material via the modification of alginate hydrogelbeads impregnating with MnO2 nanoparticles The abun-dant hydroxyl radicals and hydroperoxyl radicals derivedfrom H2O2 and distinctive chemicalphysical performanceinherited from alginate have guaranteed the strengthenedMnO2SAMn composites with enhanced NOR adsorptionand pH sensitivity FE-SEM photographs displayed that thecatalyst has a surface of relative sags and crests with smallconcave depressions And FTIR analysis confirmed that the


composites have abundant carboxyl and hydroxyl groups foradsorption The batch experiment was investigated by pHcontact time with different initial NOR concentration andtemperature Moreover the performance of kinetic dynamicsand the kinetic data revealed that the adsorption ofNORontoMnO2SAMn fitted pseudo-second-order kinetic modelwhen compared with the pseudo-first-order kinetic equationconfirming the rate determining step dominated by thechemical forces of attraction The adsorption process wasevaluated by Langmuir isotherm equation and Freundlichisotherm model and it was found that the adsorptionfollowed Langmuir isotherm equation well This revealedthat the adsorption process obeyed the monolayer sorp-tion process Thermodynamic parameters such as negativevalue of Δ1198660 indicated the spontaneous adsorption processMore importantly the in situ regenerating tests justifiedthe excellent recycling stability reusability and renewableability This study confirmed that NOR-containing solutionsdemonstrated high removal efficiency in the heterogeneousFenton-like process over MnO2SAMn the high activityof MnO2SAMn and their simple preparation make themattractive for the treatment of antibiotics in wastewatertreatment and provide fundamental basis and technology forfurther practical application

Conflicts of Interest

The authors declare that they have no potential or actualconflicts of interest pertaining to this submission

Acknowledgments

This work was financially supported by National Natural Sci-ence Foundation of China (no 21176031) Shanxi ProvincialNatural Science Foundation of China (no 2015JM2071) andFundamental Research Funds for the Central Universities(no 310829165027 no 310829162014 and no 310829175001)

References

[1] C G Daughton and T A Ternes ldquoPharmaceuticals andpersonal care products in the environment agents of subtlechangerdquo Environmental Health Perspectives vol 107 no 6 pp907ndash938 1999

[2] M Gros M Petrovic A Ginebreda and D Barcelo ldquoRemovalof pharmaceuticals during wastewater treatment and environ-mental risk assessment using hazard indexesrdquo EnvironmentInternational vol 36 no 1 pp 15ndash26 2010

[3] R Alexy A Scholl T Kumpel and K KummererWhat DoWeKnow about Antibiotics in the Environmentvol 63 SpringerBerlin Germany 2004

[4] Y-J Lee S-E Lee D S Lee and Y-H Kim ldquoRisk assessmentof human antibiotics in Korean aquatic environmentrdquo Environ-mental Toxicology and Pharmacology vol 26 no 2 pp 216ndash2212008

[5] P T P Hoa S Managaki N Nakada et al ldquoAntibiotic con-tamination and occurrence of antibiotic-resistant bacteria inaquatic environments of northern Vietnamrdquo Science of the TotalEnvironment vol 409 no 15 pp 2894ndash2901 2011

[6] D Kalderis D Koutoulakis P Paraskeva et al ldquoAdsorption ofpolluting substances on activated carbons prepared from ricehusk and sugarcane bagasserdquoChemical Engineering Journal vol144 no 1 pp 42ndash50 2008

[7] A Obuge and M Evbuomwan ldquoAdsorption of methylene blueonto activated carbon impregnated with KOH using cocoashellrdquo Journal of Engineering Research vol 2 pp 11ndash18 2014

[8] B Xu C Wang Q L Hao Q Z Jia G J Li and Y WangldquoCatalytic pyrolsis characteristics and kinetics of cotton stalkrdquoChinese Journal of Bioprocess Engineering vol 7 pp 21ndash26 2009

[9] Y Liu X Sun and B Li ldquoAdsorption of Hg2+ and Cd2+ byethylenediamine modified peanut shellsrdquo Carbohydrate Poly-mers vol 81 no 2 pp 335ndash339 2010

[10] L V de Souza Santos A M Meireles and L C LangeldquoDegradation of antibiotics norfloxacin by Fenton UV andUVH2O2rdquo Journal of Environmental Management vol 154 pp 8ndash12 2015

[11] J H Sun J L Feng S H Shi Y Q Pi M K Song and Y ShildquoDegradation of the antibiotic sulfamonomethoxine sodium inaqueous solution by photo-Fenton oxidationrdquo Chinese ScienceBulletin vol 57 no 5 pp 558ndash564 2012

[12] G Zelmanov and R Semiat ldquoIron(3) oxide-based nanoparticlesas catalysts in advanced organic aqueous oxidationrdquo WaterResearch vol 42 no 1-2 pp 492ndash498 2008

[13] M Goncalves P Figueira D Maciel et al ldquoPH-sensitiveLaponitedoxorubicinalginate nanohybrids with improvedanticancer efficacyrdquo Acta Biomaterialia vol 10 no 1 pp 300ndash307 2014

[14] H J Lim H D Ghim J H Choi H Y Chung and J OLim ldquoControlled release of BMP-2 from alginate nanohydrogelsenhanced osteogenic differentiation of human bone marrowstromal cellsrdquoMacromolecular Research vol 18 no 8 pp 787ndash792 2010

[15] RMWadowsky S Laus T Libert S J States andGD EhrlichldquoInhibition of PCR-based assay for Bordetella pertussis by usingcalcium alginate fiber and aluminum shaft components of anasopharyngeal swabrdquo Journal of Clinical Microbiology vol 32no 4 pp 1054ndash1057 1994

[16] J A Rowley G Madlambayan and D J Mooney ldquoAlginatehydrogels as synthetic extracellular matrix materialsrdquo Biomate-rials vol 20 no 1 pp 45ndash53 1999

[17] M Oussalah S Caillet S Salmieri L Saucier and M LacroixldquoAntimicrobial effects of alginate-based film containing essen-tial oils for the preservation of whole beef musclerdquo Journal ofFood Protection vol 69 no 10 pp 2364ndash2369 2006

[18] V N Tirtom A Dincer S Becerik T Aydemir and ACelik ldquoComparative adsorption of Ni(II) and Cd(II) ions onepichlorohydrin crosslinked chitosan-clay composite beads inaqueous solutionrdquo Chemical Engineering Journal vol 197 pp379ndash386 2012

[19] N M Mahmoodi ldquoBinary catalyst system dye degradationusing photocatalysisrdquo Fibers and Polymers vol 15 no 2 pp273ndash280 2014

[20] T Yuranova O Enea E Mielczarski J Mielczarski P Albersand J Kiwi ldquoFenton immobilized photo-assisted catalysisthrough a FeC structured fabricrdquo Applied Catalysis B Environ-mental vol 49 no 1 pp 39ndash50 2004

[21] M B Kasiri H Aleboyeh and A Aleboyeh ldquoDegradation ofacid blue 74 using Fe-ZSM5 zeolite as a heterogeneous photo-Fenton catalystrdquoApplied Catalysis B Environmental vol 84 no1-2 pp 9ndash15 2008


[22] R Song B Bai G L Puma H Wang and Y Suo ldquoBiosorptionof azo dyes by raspberry-like Fe3O4yeast magnetic micro-spheres and their efficient regeneration using heterogeneousFenton-like catalytic processes over an up-flow packed reactorrdquoReaction Kinetics Mechanisms and Catalysis vol 115 pp 547ndash562 2015

[23] J Fei Y Cui X Yan et al ldquoControlled preparation of MnO2hierarchical hollow nanostructures and their application inwater treatmentrdquo Advanced Materials vol 20 no 3 pp 452ndash456 2008

[24] M Fukushima K Tatsumi and K Morimoto ldquoInfluence ofiron(III) and humic acid on the photodegradation of pen-tachlorophenolrdquo Environmental Toxicology and Chemistry vol19 no 7 pp 1711ndash1716 2000

[25] H N Alyea ldquoChlorine from KMnO4 + HClrdquo Journal of Chem-ical Education vol 46 no 3 p A218 1969

[26] S B Kanungo K M Parida and B R Sant ldquoStudies onMnO2-III The kinetics and the mechanism for the catalyticdecomposition of H2O2 over different crystalline modificationsofMnO2rdquo Electrochimica Acta vol 26 no 8 pp 1157ndash1167 1981

[27] Z Cai D Zhang L Gu et al ldquoMnO2 nanosheets as ahigh-efficiency electrocatalyst for H2O2 reduction in alkalinemediumrdquo RSC Advances vol 6 no 4 pp 2546ndash2551 2016

[28] Y Li J Qu F Gao et al ldquoIn situ fabrication ofMn3O4 decoratedgraphene oxide as a synergistic catalyst for degradation ofmethylene bluerdquo Applied Catalysis B Environmental vol 162pp 268ndash274 2015

[29] H Y He J F Huang L Y Cao and J PWu ldquoPhotodegradationof methyl orange aqueous on MnWO4 powder under differentlight resources and initial pHrdquo Desalination vol 252 no 1ndash3pp 66ndash70 2010

[30] A A Pandit R A Pawar and D R Shinde ldquoColloidal MnO2catalysed degradation of two azo dyes methyl red and methylorange from aqueous mediumrdquo International Journal of Scienceand Research vol 4 pp 1119ndash1122 2013

[31] X-W Shi Y-M Du L-P Sun J-H Yang X-H Wang andX-L Su ldquoIonically crosslinked alginatecarboxymethyl chitinbeads for oral delivery of protein drugsrdquo MacromolecularBioscience vol 5 no 9 pp 881ndash889 2005

[32] P Degen S Leick and H Rehage ldquoMsechanical stability ofionotropic alginate beadsrdquo Zeitschrift fur Physikalische Chemievol 223 no 9 pp 1079ndash1090 2009

[33] G T Grant E RMorris D A Rees P J C Smith andDThomldquoBiological interactions between polysaccharides and divalentcations the egg-boxmodelrdquo FEBS Letters vol 32 no 1 pp 195ndash198 1973

[34] Y Dong W Dong Y Cao Z Han and Z Ding ldquoPreparationand catalytic activity of Fe alginate gel beads for oxidativedegradation of azo dyes under visible light irradiationrdquoCatalysisToday vol 175 no 1 pp 346ndash355 2011

[35] S K Papageorgiou E P Kouvelos E P Favvas A A Sapa-lidis G E Romanos and F K Katsaros ldquoMetal-carboxylateinteractions in metal-alginate complexes studied with FTIRspectroscopyrdquo Carbohydrate Research vol 345 no 4 pp 469ndash473 2010

[36] T KokuboM HanakawaM Kawashita et al ldquoApatite-formingability of alginate fibers treated with calcium hydroxide solu-tionrdquo Journal of Materials Science Materials inMedicine vol 15no 9 pp 1007ndash1012 2004

[37] C Prabhu S Wanjari S Gawande et al ldquoImmobilization ofcarbonic anhydrase enriched microorganism on biopolymer

based materialsrdquo Journal of Molecular Catalysis B Enzymaticvol 60 no 1-2 pp 13ndash21 2009

[38] T Tripathy and R P Singh ldquoCharacterization of poly-acrylamide-grafted sodium alginate a novel polymeric floccu-lantrdquo Journal of Applied Polymer Science vol 81 no 13 pp 3296ndash3308 2001

[39] M Nakayama M Shamoto and A Kamimura ldquoSurfactant-induced electrodeposition of layered manganese oxide withlarge interlayer space for catalytic oxidation of phenolrdquo Chem-istry of Materials vol 22 no 21 pp 5887ndash5894 2010

[40] S Liang F Teng G Bulgan R Zong and Y Zhu ldquoEffect ofphase structure of MnO2 nanorod catalyst on the activity forCO oxidationrdquo Journal of Physical Chemistry C vol 112 no 14pp 5307ndash5315 2008

[41] A Vazquez-Olmos R Redon G Rodrıguez-Gattorno et alldquoOne-step synthesis of Mn3O4 nanoparticles structural andmagnetic studyrdquo Journal of Colloid and Interface Science vol291 no 1 pp 175ndash180 2005

[42] D Sannino V Vaiano L A Isupova and P Ciambelli ldquoHetero-geneous photo-fenton oxidation of organic pollutants on struc-tured catalystsrdquo Journal of Advanced Oxidation Technologiesvol 15 no 2 pp 1224ndash1226 2012

[43] J Zhou and L Zhang ldquoStructure and properties of blendmembranes prepared from cellulose and alginate inNaOHureaaqueous solutionrdquo Journal of Polymer Science Part B PolymerPhysics vol 39 no 4 pp 451ndash458

[44] H L A El-Mohdy ldquoRadiation-induced degradation of sodiumalginate and its plant growth promotion effectrdquoArabian Journalof Chemistry vol 10 pp S431ndashS438 2017

[45] S K Das J Bhowal A R Das and A K Guha ldquoAdsorptionbehavior of rhodamine B on Rhizopus oryzae biomassrdquo Lang-muir vol 22 no 17 pp 7265ndash7272 2006

[46] J W Murray ldquoThe surface chemistry of hydrous manganesedioxiderdquo Journal of Colloid and Interface Science vol 46 no 3pp 357ndash371 1974

[47] P Zhang H Li S Yao and W Wang ldquoEffects of pH andpolarity on the excited states of norfloxacin and its 41015840-N-acetylderivative a steady-state and time-resolved studyrdquo ScienceChina Chemistry vol 57 no 3 pp 409ndash416 2014

[48] S K Swaina T Patnaik P C Patnaik U Jha and R KDey ldquoDevelopment of new alginate entrapped Fe(III)ndashZr(IV)binary mixed oxide for removal of fluoride from water bodiesrdquoChemical Engineering Journal vol 215-216 pp 763ndash771 2013

[49] A M Raichur and M J Basu ldquoAdsorption of fluoride ontomixed rare earth oxidesrdquo Separation and Purification Technol-ogy vol 24 no 1-2 pp 121ndash127 2001

[50] Y SHoAdsorption ofHeavyMetals fromWaste Streams by PeatUniversity of Birmingham 1995

[51] Y S Ho andGMcKay ldquoThe sorption of lead (II) on peatrdquoWaterResearch vol 33 pp 578ndash584 1999

[52] E Bulut M Ozacar and I A Sengil ldquoAdsorption of malachitegreen onto bentonite equilibrium and kinetic studies andprocess designrdquoMicroporous andMesoporousMaterials vol 115no 3 pp 234ndash246 2008

[53] T Qiu Y Zeng C Ye and H Tian ldquoAdsorption thermody-namics and kinetics of p-xylene on activated carbonrdquo Journalof Chemical and Engineering Data vol 57 no 5 pp 1551ndash15562012

[54] A A Jalil S Triwahyono M R Yaakob et al ldquoUtilization ofbivalve shell-treated Zea mays L (maize) husk leaf as a low-cost biosorbent for enhanced adsorption of malachite greenrdquoBioresource Technology vol 120 pp 218ndash224 2012


[55] R Sancha J Bajpai and A K Bajpai ldquoDesigning of fullers-earth-containing poly(vinyl alcohol)-g-poly(2- acrylamido-2-methyl-1-propanesulfonic acid) nanocomposites swelling anddeswelling behaviorsrdquo Journal of Applied Polymer Science vol118 no 2 pp 1230ndash1239 2010

[56] I Langmuir ldquoThe adsorption of gases on plane surfaces ofglassmica and platinumrdquoThe Journal of the AmericanChemicalSociety vol 40 no 9 pp 1361ndash1403 1918

[57] V Vimonses S Lei B Jin C W K Chow and C SaintldquoKinetic study and equilibrium isotherm analysis of Congo Redadsorption by claymaterialsrdquoChemical Engineering Journal vol148 no 2-3 pp 354ndash364 2009

[58] A A Ahmad B H Hameed and A L Ahmad ldquoEquilibriumand kinetics of disperse dye adsorption on activated carbon pre-pared from rattan sawdust by chemical activationrdquo InternationalConference Environmental Engineering 2008

[59] A Z M Badruddoza Z B Z Shawon W J D Tay K Hidajatand M S Uddin ldquoFe3O4cyclodextrin polymer nanocom-posites for selective heavy metals removal from industrialwastewaterrdquo Carbohydrate Polymers vol 91 no 1 pp 322ndash3322013

[60] Y Liu M Chen and H Yongmei ldquoStudy on the adsorptionof Cu(II) by EDTA functionalized Fe3O4 magnetic nano-particlesrdquo Chemical Engineering Journal vol 218 pp 46ndash542013

[61] J Ma F Yu L Zhou et al ldquoEnhanced adsorptive removal ofmethyl orange and methylene blue from aqueous solution byalkali-activated multiwalled carbon nanotubesrdquo ACS AppliedMaterials amp Interfaces vol 4 no 11 pp 5749ndash5760 2012

[62] S Tunc T Gurkan and O Duman ldquoOn-line spectrophoto-metric method for the determination of optimum operationparameters on the decolorization of Acid Red 66 and DirectBlue 71 from aqueous solution by Fenton processrdquo ChemicalEngineering Journal vol 181-182 pp 431ndash442 2012

[63] A Bach andR Semiat ldquoThe role of activated carbon as a catalystin GACiron oxideH2O2 oxidation processrdquo Desalination vol273 no 1 pp 57ndash63 2011

[64] W Zhang Z Yang X Wang Y Zhang X Wen and S YangldquoLarge-scale synthesis of 120573-MnO2 nanorods and their rapid andefficient catalytic oxidation of methylene blue dyerdquo CatalysisCommunications vol 7 no 6 pp 408ndash412 2006

[65] C Ye Y Bando G Shen and D Golberg ldquoThickness-dependent photocatalytic performance of ZnO nanoplateletsrdquoThe Journal of Physical Chemistry B vol 110 no 31 pp 15146ndash15151 2006

Submit your manuscripts athttpswwwhindawicom

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nanoparticles or film forms because of their simple fabrica-tion and recovery process controllable particle dimensionand excellent dispersion stability [17] Unfortunately practi-cal application of pure alginate bead as adsorbent has beenrestricted since the adsorbent hasweak physical structure andcould not be regenerated easily which needs extra processor complete replacement [18] Therefore the explorationof developing an effective and easy regeneration route foralginate bead is of particular significance in contemporaryindustry

The degradation of contaminated organism fromwastew-ater by traditional Fenton oxidation process using slurrysuspensions of iron oxide as catalysts is considered as anexpensive process since longer reaction times are usuallyrequired to entirely oxidize the pollutants due to theirinefficient hydroxyl radicalsrsquo concentration inside reactions[19ndash21] To overcome this dilemma utilizing an enrichmentmethod or prethickening adsorption way prior to the oxida-tion process has been ascertained that the removal efficiencyof pollutants through the Fenton-like reaction has beensignificantly increased Typically the embedding of Fe3O4nanoparticles of yeast has integrated biosorption propertiesfrom pure yeast cells under the Fenton performance fromFe3O4 nanoparticles resulting in the high-effective degrada-tion of cationic azo dye in wastewater treatment [22] Theenhanced efficiency of wastewater treatment is ascribed tothe successive and synergistic effect on yeast biosorption andFe3O4 nanoparticles over heterogeneous Fenton catalyzesperformance and regeneration process Compared with tra-ditional iron oxide Fenton catalysts MnO2 exhibit mostattractive transition metal oxides which predisposed to coor-dinate with oxidant forming the Fenton-like process reagentto remove the contaminates in water treatment Such kindof catalyst possessed intriguing features such as wideningoperative pH ranges and high positive catalyst performance[23] Furthermore researches prove that decomposition ofH2O2 can be catalyzed by MnO2 nanoparticles to generatereactive oxygen species like hydroxyl radicals carboxylradicals and single oxygen to remove organic pollutants[24ndash26] As a consequence the simultaneous utilizationof MnO2 and H2O2 has been considered as Fenton-likeprocess reagent to oxidize the low-biodegradable organismFor instance methylene blue [27] methyl orange [28] andazo dyes [29] have been removed using MnO2-involvedhybrid composite as a catalyst in heterogeneousMnO2H2O2Fenton-like system

Thus in this work novel absorbents MnO2alginateMn(MnO2SAMn) beads were first fabricated The adsorbentswere characterized by a scanning electronmicroscopy (SEM)Fourier transform infrared spectroscopy (FTIR) and powderX-ray diffraction (XRD) respectively Norfloxacin (NOR)frequently detected inwastewater and surfacewaterwith highconcentrations was used on purpose as an index of antibi-otics to evaluate the adsorption properties of MnO2SAMnbeads The detailed absorptive removal processes for NORantibiotic from aqueous solutions overMnO2SAMn beadswere investigated Afterward the in situ regeneration ofthe saturated MnO2SAMn absorbents was trigged byintroduction of H2O2 The possible mechanism for in situ

regenerating norfloxacin-loaded MnO2SAMn was dis-cussed

2 Experimental

21 Materials Sodium alginate (SA) with the purity 095was purchased from Sinopharm Chemical Reagent Co Ltd(Shanghai China) Norfloxacin (C16H18FN3O3) was pur-chased from Sigma-Aldrich Co Ltd (Shanghai China) andthe purity is 098The reagents in this experiment are analyti-cal grade with mass fraction purity 099 and used as receivedManganese sulfate (MnSO4) and potassium permanganate(KMnO4) were purchased from Tianjin Yonghao JingxiChemical Co Ltd (Tianjin China) Ethanol (C2H5OH)was purchased from Tianjin Fuyu Jingxi Chemical Co Ltd(Tianjin China) Distilled water (183MΩ cm) was used tomake required aqueous solutions

22 MnO2SAMn Beads Preparation MnO2 nanoparticleswere prepared via a hydrothermal method Typically 30ml02molsdotLminus1 MnSO4 solution was added dropwise into 30ml03M KMnO4 solution with continuous stirring for at least30min Then the mixture was treated at 180∘C with aTeflon-lined autocave for 10 h After cooling down to roomtemperature the suspension was centrifuged and washed theprecipitate with distilled water After that the precipitate wasdried at 60∘C in air for 6 h the finalMnO2 nanoparticles wereobtained The reaction equation is as follows

3MnSO4 + 2KMnO4 + 2H2O 997888rarr5MnO2 + 2H2SO4 + K2SO4

(1)

Subsequently 1000 g of MnO2 nanoparticles was dis-persed into 50ml of 25 (w) sodium alginate solutions at29815 K with continuous stirring for 2 h After that thesodium alginate solution was dropped into MnSO4 solution(005mgL) with a peristaltic pump After the hydrogel beadswere stored at 4∘C for 10 h to form MnO2SAMn hydrogelbeads the obtained hydrogels were finally washed and storedat 4∘C until use

23 Adsorbents Characterization The morphology of theMnO2SAMn adsorbent was observed by a scanning elec-tron microscopy (SEM Hitachi S-4800 Japan) Elementcontent and line-scanning analysis were investigated byenergy-dispersive spectroscopy (EDS) analysis To studythe chemical structures Fourier transform infrared spectra(FTIR BiO-RAD FTS135 America) of the adsorbents weremonitored by a Bio-Rad FTS135 spectrometer in the range500ndash4500 cmminus1 using KBr And the crystal phase was investi-gated by powder X-ray diffraction (XRD Rigaku DMAX-3Cdiffractometer Japan) patterns which were conducted on XPert Pro diffractometer at a scanning rate of 100 permin usingCu K120572 radiations (120582 = 015418)

24 Adsorption Experiments In a typical run the exper-iment was conducted in 200mL conical flasks containing100mL of the desired NOR concentration at pH 4 Since



120578 = (1198620 minus 119862119890)1198620 times 100

119876119890 = (1198620 minus 119862119890) times 119881119898 (2)






COONa COONa

COONa

COONa

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

HO

HO

NaOOC NaOOC

O O OO

O O

OO

OOO

OOO

OO

minus minusminus

minus

minus

minus

minus

minus


Sodium alginate

(alginate)



MnS4 solution

Gelation

－Ｈ2+－Ｈ2+

－Ｈ2+

－Ｈ2+

－Ｈ2+－Ｈ2+

－Ｈ2+

－Ｈ2+

－Ｈ2+

－Ｈ2+

Mn2 nanoparticles

Mn2alginateMn

Hydrogen bond





Tans

mitt

ance

()

594670

117814101636

1740

3429

523

716

3429

1426

16321163

2854

2925

(a) pure AB

3428

2854

2925


(b) pure Mn2

(c) Mn2SAMn











(a) (b)

(c) (d)


2636 2954 4410 100

C

Mn

O

Total

Element content ()

(a)

Relat

ive i

nten

sity

(au

)

COMn

00 01 02 03 04 05 06 07 08 09 10


10 Ｇ

(b)





10 20 30 40 50 60 70 80

(c) pure AB

Inte

nsity

(au

)

127∘

203∘

206∘131∘

287∘

287∘

374∘

374∘428∘

428∘

410∘

410∘

567∘

594∘

594∘567∘

2 (∘)

(b) pure Mn2

(a) Mn2SAMn












1 2 3 4 5 6 7 8 9 10 11 12 13minus20

0

20

40

60

80

100


minus20

minus10

0

10

20

30

40

50

NHN N

FO

NN

O

H

H

F

N N

COOHFO

H

H

pH

(A)

(B)

(C)

(D)

NOR cation form


(

)

Qe

2（52（5

2（5


minusminus

+

+


1)

(a)

0 10 20 30 40 50 60 70 80 900

102030405060708090

100

Time (min)







Qe


1)

(b)

0 10

10

20

20

30

30

40 50 60 70 80 90 1000

5

15

25



Initi

al N

OR

conc

entr

atio

n (m

gmiddotminus1)

(c)




20 9933 10057 0088 0955 10135 0097 099850 24530 24965 0081 0963 25026 0039 0996100 48523 50481 0065 0961 49485 0020 0994150 64799 65527 0090 0988 66100 0015 0996200 73691 74191 0100 0989 75190 0013 0997300 86779 87914 0087 0910 88455 0011 0997


11198962 times 1198762119890 +

119905119876119890 (5)





0 5 10 15 20 25 30 35 40minus2

minus1

0

1

2

3

4

5

Time (min)

ln(Q

eminusQ

t)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(a)

0 10 20 30 40 50 60 70 80 900

2

4

6

8

10

Time (min)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(tQ

t) (m

inmiddotgmiddotＧ

Ａminus1)

(b)




ln119870119889 = minusΔ1198670

119877 times 119879 +Δ1198780119877


(6)












28815 676 282 0976329815 719 351 0981330815 757 457 0969731815 700 339 09778


28815 738 021 167 0905229815 582 019 169 0904630815 867 018 172 0896531815 1016 016 174 08962






119876119890 = 119870119891 times 1198621198901119899 (8)



119877119871 = 11 + 119887 times 1198620 (9)




120576 = 119877 times 119879 times ln(1 + ( 1119862119890)) (11)

119864 = 1radic2 times 119896DR (12)








1 2 3 4 1 2 3 470

75

80

85

90

95

100

Rem

oval

effici

ency

()

as adsorbent

adsorption

Rem

oval

effici

ency

()

Cycle time

SA as adsorbent

20

30

40

50

60

70

80

after （22UV light

Mn2SAMn







H2O2 + ∙OH 997888rarr HOO∙ +H2O (14)

Mn3+ +HOO∙ 997888rarr Mn2+ +H+ +O2 (15)

∙OH +HOO∙ 997888rarr H2O +O2 (16)




HOO ∙ +HOO∙ 997888rarr 1O2 +H2O2 (20)


4 Conclusions






Acknowledgments


References












































































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of




120578 = (1198620 minus 119862119890)1198620 times 100

119876119890 = (1198620 minus 119862119890) times 119881119898 (2)






COONa COONa

COONa

COONa

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

OH

HO

HO

NaOOC NaOOC

O O OO

O O

OO

OOO

OOO

OO

minus minusminus

minus

minus

minus

minus

minus


Sodium alginate

(alginate)



MnS4 solution

Gelation

－Ｈ2+－Ｈ2+

－Ｈ2+

－Ｈ2+

－Ｈ2+－Ｈ2+

－Ｈ2+

－Ｈ2+

－Ｈ2+

－Ｈ2+

Mn2 nanoparticles

Mn2alginateMn

Hydrogen bond





Tans

mitt

ance

()

594670

117814101636

1740

3429

523

716

3429

1426

16321163

2854

2925

(a) pure AB

3428

2854

2925


(b) pure Mn2

(c) Mn2SAMn











(a) (b)

(c) (d)


2636 2954 4410 100

C

Mn

O

Total

Element content ()

(a)

Relat

ive i

nten

sity

(au

)

COMn

00 01 02 03 04 05 06 07 08 09 10


10 Ｇ

(b)





10 20 30 40 50 60 70 80

(c) pure AB

Inte

nsity

(au

)

127∘

203∘

206∘131∘

287∘

287∘

374∘

374∘428∘

428∘

410∘

410∘

567∘

594∘

594∘567∘

2 (∘)

(b) pure Mn2

(a) Mn2SAMn












1 2 3 4 5 6 7 8 9 10 11 12 13minus20

0

20

40

60

80

100


minus20

minus10

0

10

20

30

40

50

NHN N

FO

NN

O

H

H

F

N N

COOHFO

H

H

pH

(A)

(B)

(C)

(D)

NOR cation form


(

)

Qe

2（52（5

2（5


minusminus

+

+


1)

(a)

0 10 20 30 40 50 60 70 80 900

102030405060708090

100

Time (min)







Qe


1)

(b)

0 10

10

20

20

30

30

40 50 60 70 80 90 1000

5

15

25



Initi

al N

OR

conc

entr

atio

n (m

gmiddotminus1)

(c)




20 9933 10057 0088 0955 10135 0097 099850 24530 24965 0081 0963 25026 0039 0996100 48523 50481 0065 0961 49485 0020 0994150 64799 65527 0090 0988 66100 0015 0996200 73691 74191 0100 0989 75190 0013 0997300 86779 87914 0087 0910 88455 0011 0997


11198962 times 1198762119890 +

119905119876119890 (5)





0 5 10 15 20 25 30 35 40minus2

minus1

0

1

2

3

4

5

Time (min)

ln(Q

eminusQ

t)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(a)

0 10 20 30 40 50 60 70 80 900

2

4

6

8

10

Time (min)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(tQ

t) (m

inmiddotgmiddotＧ

Ａminus1)

(b)




ln119870119889 = minusΔ1198670

119877 times 119879 +Δ1198780119877


(6)












28815 676 282 0976329815 719 351 0981330815 757 457 0969731815 700 339 09778


28815 738 021 167 0905229815 582 019 169 0904630815 867 018 172 0896531815 1016 016 174 08962






119876119890 = 119870119891 times 1198621198901119899 (8)



119877119871 = 11 + 119887 times 1198620 (9)




120576 = 119877 times 119879 times ln(1 + ( 1119862119890)) (11)

119864 = 1radic2 times 119896DR (12)








1 2 3 4 1 2 3 470

75

80

85

90

95

100

Rem

oval

effici

ency

()

as adsorbent

adsorption

Rem

oval

effici

ency

()

Cycle time

SA as adsorbent

20

30

40

50

60

70

80

after （22UV light

Mn2SAMn







H2O2 + ∙OH 997888rarr HOO∙ +H2O (14)

Mn3+ +HOO∙ 997888rarr Mn2+ +H+ +O2 (15)

∙OH +HOO∙ 997888rarr H2O +O2 (16)




HOO ∙ +HOO∙ 997888rarr 1O2 +H2O2 (20)


4 Conclusions






Acknowledgments


References












































































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of



Tans

mitt

ance

()

594670

117814101636

1740

3429

523

716

3429

1426

16321163

2854

2925

(a) pure AB

3428

2854

2925


(b) pure Mn2

(c) Mn2SAMn











(a) (b)

(c) (d)


2636 2954 4410 100

C

Mn

O

Total

Element content ()

(a)

Relat

ive i

nten

sity

(au

)

COMn

00 01 02 03 04 05 06 07 08 09 10


10 Ｇ

(b)





10 20 30 40 50 60 70 80

(c) pure AB

Inte

nsity

(au

)

127∘

203∘

206∘131∘

287∘

287∘

374∘

374∘428∘

428∘

410∘

410∘

567∘

594∘

594∘567∘

2 (∘)

(b) pure Mn2

(a) Mn2SAMn












1 2 3 4 5 6 7 8 9 10 11 12 13minus20

0

20

40

60

80

100


minus20

minus10

0

10

20

30

40

50

NHN N

FO

NN

O

H

H

F

N N

COOHFO

H

H

pH

(A)

(B)

(C)

(D)

NOR cation form


(

)

Qe

2（52（5

2（5


minusminus

+

+


1)

(a)

0 10 20 30 40 50 60 70 80 900

102030405060708090

100

Time (min)







Qe


1)

(b)

0 10

10

20

20

30

30

40 50 60 70 80 90 1000

5

15

25



Initi

al N

OR

conc

entr

atio

n (m

gmiddotminus1)

(c)




20 9933 10057 0088 0955 10135 0097 099850 24530 24965 0081 0963 25026 0039 0996100 48523 50481 0065 0961 49485 0020 0994150 64799 65527 0090 0988 66100 0015 0996200 73691 74191 0100 0989 75190 0013 0997300 86779 87914 0087 0910 88455 0011 0997


11198962 times 1198762119890 +

119905119876119890 (5)





0 5 10 15 20 25 30 35 40minus2

minus1

0

1

2

3

4

5

Time (min)

ln(Q

eminusQ

t)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(a)

0 10 20 30 40 50 60 70 80 900

2

4

6

8

10

Time (min)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(tQ

t) (m

inmiddotgmiddotＧ

Ａminus1)

(b)




ln119870119889 = minusΔ1198670

119877 times 119879 +Δ1198780119877


(6)












28815 676 282 0976329815 719 351 0981330815 757 457 0969731815 700 339 09778


28815 738 021 167 0905229815 582 019 169 0904630815 867 018 172 0896531815 1016 016 174 08962






119876119890 = 119870119891 times 1198621198901119899 (8)



119877119871 = 11 + 119887 times 1198620 (9)




120576 = 119877 times 119879 times ln(1 + ( 1119862119890)) (11)

119864 = 1radic2 times 119896DR (12)








1 2 3 4 1 2 3 470

75

80

85

90

95

100

Rem

oval

effici

ency

()

as adsorbent

adsorption

Rem

oval

effici

ency

()

Cycle time

SA as adsorbent

20

30

40

50

60

70

80

after （22UV light

Mn2SAMn







H2O2 + ∙OH 997888rarr HOO∙ +H2O (14)

Mn3+ +HOO∙ 997888rarr Mn2+ +H+ +O2 (15)

∙OH +HOO∙ 997888rarr H2O +O2 (16)




HOO ∙ +HOO∙ 997888rarr 1O2 +H2O2 (20)


4 Conclusions






Acknowledgments


References












































































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of



(a) (b)

(c) (d)


2636 2954 4410 100

C

Mn

O

Total

Element content ()

(a)

Relat

ive i

nten

sity

(au

)

COMn

00 01 02 03 04 05 06 07 08 09 10


10 Ｇ

(b)





10 20 30 40 50 60 70 80

(c) pure AB

Inte

nsity

(au

)

127∘

203∘

206∘131∘

287∘

287∘

374∘

374∘428∘

428∘

410∘

410∘

567∘

594∘

594∘567∘

2 (∘)

(b) pure Mn2

(a) Mn2SAMn












1 2 3 4 5 6 7 8 9 10 11 12 13minus20

0

20

40

60

80

100


minus20

minus10

0

10

20

30

40

50

NHN N

FO

NN

O

H

H

F

N N

COOHFO

H

H

pH

(A)

(B)

(C)

(D)

NOR cation form


(

)

Qe

2（52（5

2（5


minusminus

+

+


1)

(a)

0 10 20 30 40 50 60 70 80 900

102030405060708090

100

Time (min)







Qe


1)

(b)

0 10

10

20

20

30

30

40 50 60 70 80 90 1000

5

15

25



Initi

al N

OR

conc

entr

atio

n (m

gmiddotminus1)

(c)




20 9933 10057 0088 0955 10135 0097 099850 24530 24965 0081 0963 25026 0039 0996100 48523 50481 0065 0961 49485 0020 0994150 64799 65527 0090 0988 66100 0015 0996200 73691 74191 0100 0989 75190 0013 0997300 86779 87914 0087 0910 88455 0011 0997


11198962 times 1198762119890 +

119905119876119890 (5)





0 5 10 15 20 25 30 35 40minus2

minus1

0

1

2

3

4

5

Time (min)

ln(Q

eminusQ

t)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(a)

0 10 20 30 40 50 60 70 80 900

2

4

6

8

10

Time (min)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(tQ

t) (m

inmiddotgmiddotＧ

Ａminus1)

(b)




ln119870119889 = minusΔ1198670

119877 times 119879 +Δ1198780119877


(6)












28815 676 282 0976329815 719 351 0981330815 757 457 0969731815 700 339 09778


28815 738 021 167 0905229815 582 019 169 0904630815 867 018 172 0896531815 1016 016 174 08962






119876119890 = 119870119891 times 1198621198901119899 (8)



119877119871 = 11 + 119887 times 1198620 (9)




120576 = 119877 times 119879 times ln(1 + ( 1119862119890)) (11)

119864 = 1radic2 times 119896DR (12)








1 2 3 4 1 2 3 470

75

80

85

90

95

100

Rem

oval

effici

ency

()

as adsorbent

adsorption

Rem

oval

effici

ency

()

Cycle time

SA as adsorbent

20

30

40

50

60

70

80

after （22UV light

Mn2SAMn







H2O2 + ∙OH 997888rarr HOO∙ +H2O (14)

Mn3+ +HOO∙ 997888rarr Mn2+ +H+ +O2 (15)

∙OH +HOO∙ 997888rarr H2O +O2 (16)




HOO ∙ +HOO∙ 997888rarr 1O2 +H2O2 (20)


4 Conclusions






Acknowledgments


References












































































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of



10 20 30 40 50 60 70 80

(c) pure AB

Inte

nsity

(au

)

127∘

203∘

206∘131∘

287∘

287∘

374∘

374∘428∘

428∘

410∘

410∘

567∘

594∘

594∘567∘

2 (∘)

(b) pure Mn2

(a) Mn2SAMn












1 2 3 4 5 6 7 8 9 10 11 12 13minus20

0

20

40

60

80

100


minus20

minus10

0

10

20

30

40

50

NHN N

FO

NN

O

H

H

F

N N

COOHFO

H

H

pH

(A)

(B)

(C)

(D)

NOR cation form


(

)

Qe

2（52（5

2（5


minusminus

+

+


1)

(a)

0 10 20 30 40 50 60 70 80 900

102030405060708090

100

Time (min)







Qe


1)

(b)

0 10

10

20

20

30

30

40 50 60 70 80 90 1000

5

15

25



Initi

al N

OR

conc

entr

atio

n (m

gmiddotminus1)

(c)




20 9933 10057 0088 0955 10135 0097 099850 24530 24965 0081 0963 25026 0039 0996100 48523 50481 0065 0961 49485 0020 0994150 64799 65527 0090 0988 66100 0015 0996200 73691 74191 0100 0989 75190 0013 0997300 86779 87914 0087 0910 88455 0011 0997


11198962 times 1198762119890 +

119905119876119890 (5)





0 5 10 15 20 25 30 35 40minus2

minus1

0

1

2

3

4

5

Time (min)

ln(Q

eminusQ

t)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(a)

0 10 20 30 40 50 60 70 80 900

2

4

6

8

10

Time (min)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(tQ

t) (m

inmiddotgmiddotＧ

Ａminus1)

(b)




ln119870119889 = minusΔ1198670

119877 times 119879 +Δ1198780119877


(6)












28815 676 282 0976329815 719 351 0981330815 757 457 0969731815 700 339 09778


28815 738 021 167 0905229815 582 019 169 0904630815 867 018 172 0896531815 1016 016 174 08962






119876119890 = 119870119891 times 1198621198901119899 (8)



119877119871 = 11 + 119887 times 1198620 (9)




120576 = 119877 times 119879 times ln(1 + ( 1119862119890)) (11)

119864 = 1radic2 times 119896DR (12)








1 2 3 4 1 2 3 470

75

80

85

90

95

100

Rem

oval

effici

ency

()

as adsorbent

adsorption

Rem

oval

effici

ency

()

Cycle time

SA as adsorbent

20

30

40

50

60

70

80

after （22UV light

Mn2SAMn







H2O2 + ∙OH 997888rarr HOO∙ +H2O (14)

Mn3+ +HOO∙ 997888rarr Mn2+ +H+ +O2 (15)

∙OH +HOO∙ 997888rarr H2O +O2 (16)




HOO ∙ +HOO∙ 997888rarr 1O2 +H2O2 (20)


4 Conclusions






Acknowledgments


References












































































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of



1 2 3 4 5 6 7 8 9 10 11 12 13minus20

0

20

40

60

80

100


minus20

minus10

0

10

20

30

40

50

NHN N

FO

NN

O

H

H

F

N N

COOHFO

H

H

pH

(A)

(B)

(C)

(D)

NOR cation form


(

)

Qe

2（52（5

2（5


minusminus

+

+


1)

(a)

0 10 20 30 40 50 60 70 80 900

102030405060708090

100

Time (min)







Qe


1)

(b)

0 10

10

20

20

30

30

40 50 60 70 80 90 1000

5

15

25



Initi

al N

OR

conc

entr

atio

n (m

gmiddotminus1)

(c)




20 9933 10057 0088 0955 10135 0097 099850 24530 24965 0081 0963 25026 0039 0996100 48523 50481 0065 0961 49485 0020 0994150 64799 65527 0090 0988 66100 0015 0996200 73691 74191 0100 0989 75190 0013 0997300 86779 87914 0087 0910 88455 0011 0997


11198962 times 1198762119890 +

119905119876119890 (5)





0 5 10 15 20 25 30 35 40minus2

minus1

0

1

2

3

4

5

Time (min)

ln(Q

eminusQ

t)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(a)

0 10 20 30 40 50 60 70 80 900

2

4

6

8

10

Time (min)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(tQ

t) (m

inmiddotgmiddotＧ

Ａminus1)

(b)




ln119870119889 = minusΔ1198670

119877 times 119879 +Δ1198780119877


(6)












28815 676 282 0976329815 719 351 0981330815 757 457 0969731815 700 339 09778


28815 738 021 167 0905229815 582 019 169 0904630815 867 018 172 0896531815 1016 016 174 08962






119876119890 = 119870119891 times 1198621198901119899 (8)



119877119871 = 11 + 119887 times 1198620 (9)




120576 = 119877 times 119879 times ln(1 + ( 1119862119890)) (11)

119864 = 1radic2 times 119896DR (12)








1 2 3 4 1 2 3 470

75

80

85

90

95

100

Rem

oval

effici

ency

()

as adsorbent

adsorption

Rem

oval

effici

ency

()

Cycle time

SA as adsorbent

20

30

40

50

60

70

80

after （22UV light

Mn2SAMn







H2O2 + ∙OH 997888rarr HOO∙ +H2O (14)

Mn3+ +HOO∙ 997888rarr Mn2+ +H+ +O2 (15)

∙OH +HOO∙ 997888rarr H2O +O2 (16)




HOO ∙ +HOO∙ 997888rarr 1O2 +H2O2 (20)


4 Conclusions






Acknowledgments


References












































































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of



0 5 10 15 20 25 30 35 40minus2

minus1

0

1

2

3

4

5

Time (min)

ln(Q

eminusQ

t)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(a)

0 10 20 30 40 50 60 70 80 900

2

4

6

8

10

Time (min)

2mgmiddotminus1

5mgmiddotminus1

10 mgmiddotminus1

15 mgmiddotminus1

20 mgmiddotminus1

30mgmiddotminus1

(tQ

t) (m

inmiddotgmiddotＧ

Ａminus1)

(b)




ln119870119889 = minusΔ1198670

119877 times 119879 +Δ1198780119877


(6)












28815 676 282 0976329815 719 351 0981330815 757 457 0969731815 700 339 09778


28815 738 021 167 0905229815 582 019 169 0904630815 867 018 172 0896531815 1016 016 174 08962






119876119890 = 119870119891 times 1198621198901119899 (8)



119877119871 = 11 + 119887 times 1198620 (9)




120576 = 119877 times 119879 times ln(1 + ( 1119862119890)) (11)

119864 = 1radic2 times 119896DR (12)








1 2 3 4 1 2 3 470

75

80

85

90

95

100

Rem

oval

effici

ency

()

as adsorbent

adsorption

Rem

oval

effici

ency

()

Cycle time

SA as adsorbent

20

30

40

50

60

70

80

after （22UV light

Mn2SAMn







H2O2 + ∙OH 997888rarr HOO∙ +H2O (14)

Mn3+ +HOO∙ 997888rarr Mn2+ +H+ +O2 (15)

∙OH +HOO∙ 997888rarr H2O +O2 (16)




HOO ∙ +HOO∙ 997888rarr 1O2 +H2O2 (20)


4 Conclusions






Acknowledgments


References












































































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of







28815 676 282 0976329815 719 351 0981330815 757 457 0969731815 700 339 09778


28815 738 021 167 0905229815 582 019 169 0904630815 867 018 172 0896531815 1016 016 174 08962






119876119890 = 119870119891 times 1198621198901119899 (8)



119877119871 = 11 + 119887 times 1198620 (9)




120576 = 119877 times 119879 times ln(1 + ( 1119862119890)) (11)

119864 = 1radic2 times 119896DR (12)








1 2 3 4 1 2 3 470

75

80

85

90

95

100

Rem

oval

effici

ency

()

as adsorbent

adsorption

Rem

oval

effici

ency

()

Cycle time

SA as adsorbent

20

30

40

50

60

70

80

after （22UV light

Mn2SAMn







H2O2 + ∙OH 997888rarr HOO∙ +H2O (14)

Mn3+ +HOO∙ 997888rarr Mn2+ +H+ +O2 (15)

∙OH +HOO∙ 997888rarr H2O +O2 (16)




HOO ∙ +HOO∙ 997888rarr 1O2 +H2O2 (20)


4 Conclusions






Acknowledgments


References












































































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of



1 2 3 4 1 2 3 470

75

80

85

90

95

100

Rem

oval

effici

ency

()

as adsorbent

adsorption

Rem

oval

effici

ency

()

Cycle time

SA as adsorbent

20

30

40

50

60

70

80

after （22UV light

Mn2SAMn







H2O2 + ∙OH 997888rarr HOO∙ +H2O (14)

Mn3+ +HOO∙ 997888rarr Mn2+ +H+ +O2 (15)

∙OH +HOO∙ 997888rarr H2O +O2 (16)




HOO ∙ +HOO∙ 997888rarr 1O2 +H2O2 (20)


4 Conclusions






Acknowledgments


References












































































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of






Acknowledgments


References












































































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of
























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


efficient absorption of antibiotic from aqueous solutions

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