research article nanofiltration in transforming...

Research ArticleNanofiltration in Transforming Surface Water intoHealthy Water Comparison with Reverse Osmosis

L D Naidu1 S Saravanan1 M Chidambaram2 Mukesh Goel3

Ashutosh Das3 and J Sarat Chandra Babu1

1Department of Chemical Engineering National Institute of Technology Tiruchirappalli 15 India2Department of Chemical Engineering Indian Institute of Technology Madras Chennai India3Center for Environmental Engineering PRIST University Thanjavur India

Correspondence should be addressed to L D Naidu ldnaidugmailcom

Received 7 April 2015 Revised 12 May 2015 Accepted 18 May 2015

Academic Editor Stefan I Voicu

Copyright copy 2015 L D Naidu et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The natural surface water especially available through rivers is the main source of healthy water for the living beings throughoutthe world from ancient days as it consists of all essential minerals With the advent of industrialization gradually even the mostprominent rivers have been polluted in all parts of the world Although there are lots of technologies nanofiltration (NF) has beenchosen to transform river water into healthy water due to its unique advantages of retaining optimum TDS (with essential mineralsrequired for human body) consuming of lower energy and no usage of any chemicals The prominent parameters of surface waterand macromicrominerals of treated water have been analyzed It is shown that NF is better in producing healthy water with highflux by consuming low energy

1 Introduction

In early days of industrialization the artificially produceddemineralized or distilled or deionized or reverse osmosiswater had extensive industrial uses rather than domesticapplications [1] It was clear from the very beginning thatdesalinated or demineralized water must be enriched withsome minerals such as calcium carbonate or limestone tomake it suitable as drinking water This will also improve thetaste [2 3]

The intake of our daily exclusive drinking water of 15ndash3 liters should contain some of the above minerals in sucha way that the TDS should be 100ndash500 ppm (healthy water)to ensure good health The optimum TDS has been decidedon the basis of good organoleptic characteristics reducedcorrosive nature and thirst-quenching properties of water[4ndash6] Remineralization alone could not provide perfectcomposition of minerals for drinking water [7ndash9] So insteadof demineralizing and remineralizing it is better to come upwith robust new methods of purifying water at lower costwith less energy and at the same time minimizing the usage

of chemicals and the impact on the environment One ofsuch methods in recent times is nanofiltration (NF) fortransforming surface water into healthy water [10ndash12] NF isthe newly developed pressure-driven membrane process forliquid-phase separations and has substituted reverse osmosis(RO) in several applications owing to greater flux and lesserenergy utilization rates It is in fact termed as future technol-ogy for drinking water in 21st century This work was takenup to show the effectiveness of NF in providing the optimumTDS (100ndash500 ppm) in the permeate water as per the stan-dards of WHO

The results will also be comparedwith ROfiltration RO isbased upon the fundamental pursuit for balance and has hugeapplication in drinking water preparation especially fromsalty seawater

2 Materials and Methods

21 NF and RO Membrane The nanofiltration and thin filmcomposite (TFC) polyamide reverse osmosis membranes in

Hindawi Publishing CorporationJournal of ChemistryVolume 2015 Article ID 326869 6 pageshttpdxdoiorg1011552015326869

2 Journal of Chemistry

Table 1 Membranesrsquo characteristics

Manufacturer Permionics Pvt Ltd Vadodara IndiaMembrane type Thin film composite (TFC) polyamideConfiguration Spiral wound

Dimensions Length of 40 inches diameter of 24inches and an effective area of 25m2

Pure water flux 90 L(hsdotm2) at 552 bars of feedpressure and 25∘C temperature

NaCl salt rejection 994 for 32000mgL feedconcentration at the pH range of 2 to 11

Recommended appliedpressure 3ndash14 bars

Maximum appliedpressure 41 bars

Recommended appliedtemperature 2ndash45∘C

Table 2 Characteristics of Cauvery river water collected frominfiltration gallery

Parameters Respective valuespH 722Turbidity 0Chlorides 130mglitTotal hardness 220mglitPhosphates 943mglitNitrates 1343mglitSulphates 25mglitTotal dissolved solids 830mglit

a spiral wound configuration were procured from Permion-ics Pvt Ltd Vadodara India The detailed description ofthe membrane is presented in Table 1 Tetrasodium-EDTAhydrochloric acid and sodium bisulfate were used for mem-brane cleaning and were supplied by Precision scientific LtdTiruchirappalli India

22 Surface Water Characteristics Surface water was pro-cured from the nearby legendary Cauvery river one of theprominent rivers in south India In Table 2 the characteristicof the raw surface water is given

23 Nanofiltration Pilot Plant System Description The frontview and the schematic representation of the membrane pilotsystem are shown in Figures 1 and 2 respectively It consistsof mainly spiral wound membrane module incorporatingthin film composite nanofiltration (TFC-NF)membranewithan inlet pressure of 10 bars for the process of nanofiltrationinside the fiber-reinforced plastic (FRP) cylindrical pressurevessels with the dimensions of 2510158401015840 diametertimes 2110158401015840 length (thesize of each of the modules) A feed tank of 25 L capacity (SS-316) was used for storage and supply of feed to the nanofiltra-tion module A high pressure pump capable of maintaininga pressure of 100 bars was installed for transporting the feedliquid A 2 HP single-phase motor runs the respective pumpA restricting needle valve was provided at the concentrate

Figure 1 Front view of the NF and RO membrane process pilotplant

4 2

NF membrane 1

Permeate

(1) Pressure indicator(2) Valve

(3) Storage tank(4) Pump

212

Rete

ntat

e

3

Figure 2 Schematic representation of the nanofiltration (NF)membrane pilot plant

outlet to pressurize the feed liquid to the desired valueand the respective pressure indicated by a provided pressuregauge Permeate and concentrate flow rates weremeasured byRotameters All the accessories were connected by 0510158401015840 outerdiameter stainless steel-316 piping in high pressure regionwhereas low pressure outlets were made of PVC braidedtubing

24 Experimental Procedure and Sampling Twenty-five litersof the feed was poured into the feed tank after thoroughlycleaning the membrane system and then wetted with thedeionized water A high pressure pump was employed totransport the feed to spiral wound membrane moduleThe retentate flow rate was maintained constant (10 Lmin)throughout the experimental runs to ensure identical hydro-dynamic conditions inside the membrane module Feedpressure was varied from 0 to 7 bars by keeping the feed TDSconcentration constant Flux wasmeasured by collecting per-meate in a measuring jar for a period of 2-3min About 300ndash400mL of permeate was collected for each pressure increasefor a thorough analysis Experiments were repeated twice

Journal of Chemistry 3

with every feed sample for ensuring reproducibility of thepermeate characteristics

25 Analytical Methods The feed and permeate of thenanofiltration processes were analyzed for TDS by TDS scanmeter chlorides were analyzed by titration method pH wasanalyzed by digital pHmeter and TOCwas analyzed by TOCanalyzer The feed water conductivity measured by conduc-tivity meter and the permeate conductivity had been mea-sured by online instrumentation Nitrate phosphate and sul-phate presented in the water samples were analyzed with DR890 colorimeter (Hach USA) Before testing any water sam-ples 10mL of distilled water is taken in the colorimeter andtested for its zero value

26 Flux and Percent Rejection Thepercent rejection (119877) ofTDS can be calculated as given by Rautenbach and Albrecht[13]

119877 = (1minus119862

119901

119862

119891

)times 100 (1)

where 119862119891and 119862

119901are the concentrations of a TDS (ppm) or

particular component in the feed and permeate The waterflux (119869) (in L(m2 h)) can be calculated as

119869 (Lmh) = 119881119860 times 119905

(2)

where 119881 is the volume of permeate collected (L) 119860 is themembrane area (m2) and 119905 is time (h)

27 Power Consumption Power consumption is a major fac-tor in membrane separation process Power consumption iscalculated as shown below

119875 =

119876 sdot 119901

120578

(3)

where 119875 is power consumed by feed pump or high pressurepump kW 119876 is flow rate of permeate or retentate m3sec 119901is pressure applied within the spiral wound module kPa and120578 is efficiency of the pump

3 Results and Discussion

Membrane performance will be influenced by the variationof the feed pressure and percent rejection of TDS chloridesof the surface water [14 15] Moreover the permeate TOChas been observed with the variation of pressure as it is veryimportant parameter for surface water evaluation Permeateflux percent rejection of TDS and chlorides and powerconsumption were compared for NF and RO membrane

31 Effect of Pressure on Permeate Flux Figure 3 shows theeffects of applied pressure on permeate and concentrate fluxesas the pressure increasesThe permeate flux increases linearlywith increase of applied pressure which suggests that theremay be negligible concentration polarization As expectedthe concentrate flux is reduced as the pressure is increased

250

200

150

100

50

0

0 2 4 6 8

PermeateConcentrate

Flux

(Lm

h)

Pressure (kgcm2)

Figure 3 Fluxes of permeate and concentrate versus processpressure for nanofiltration

Flux

(Lm

h)

25

20

15

10

5

00 2 4 6 8

Pressure (kgcm2)

NFRO

Figure 4 Comparing permeate flux as a function of pressurebetween NF and RO

This indicated that the performance of membrane module isgood The permeate flux for both RO and NF is comparedin Figure 4 In both cases the permeate flux increaseslinearly with increase of applied pressure which suggests thatthere may be negligible concentration polarization for ROmembrane as well However it can be observed that permeateflux obtained was more in case of NF For the same pressure(3 bars) 204 Lmh of permeate flux was obtained during NFprocess whereas RO could facilitate only 84 Lmh This isbecause of the small pore size of RO membranes conse-quently yielding a higher pressure drop

32 TOC Rejections by Membrane The surface water TOCdata is presented in Figure 5 The permeate TOC reducedfrom 653mgL to 267mgL indicating a high removal of


0100200300400500600700

0 1 2 3 4 5 6 7 8

Perm

eate

TO

C

NFRO

Pressure (kgcm2)

Figure 5 Comparing permeate total organic carbon (TOC) as afunction of pressure between NF and RO

0

20

40

60

80

100

120

0 1 2 3 4 5 6 7 8

NFRO

Pressure (kgcm2)

Reje

ctio

n of

TD

S (

)

Figure 6 Comparing rejection of TDS as a function of pressurebetween NF and RO

organic compound using NF membrane These studies indi-cate greater potential of NF membranes compared to severalestablished treatments Higher retention of contaminants wasachieved Generally the TOC reduction would be merely 5ndash10 for conventional treatments [16] butNF has given higherreduction of 60Thiswill lead to decrease in toxic chemicalspresent in the water and hence their consumption SimilarlyRO treatment has yielded 63 TOC reduction

33 TDS and Chlorides Rejection byMembrane This removalof organic compound continued collectively with removalof inorganic ions (Figure 6) It can be seen from the figurethat the rejection of TDS increases with increase in appliedpressureThe increase was dominating till 3 bars because theion transport due to convection becomes significant com-pared to diffusion Thereafter the increase in rejection wasnegligible reaching a limiting value at 6 bars The maximumrejection of TDS by NF is found to be 70 from the feedwater TDS dropped from 451mgL to 135mgL It makes NFhighly suitable as potable water On the other hand quickelimination of TDS was observed for RO treatment as

0102030405060708090

NFRO

0 1 2 3 4 5 6 7 8Pressure (kgcm2)

Reje

ctio

n of

chlo

rides

()

Figure 7 Comparing rejection of chloride as a function ofpressure between NF and RO

the applied pressure increasing the rejection of TDS isincreased gradually and reached the steady value of 98rejection at 2 bars and it has remained the same although thepressure has increased TDS reduced to as low as 143mgLat the limiting value of 7 bars Although the RO processhas given higher TDS reduction such high reduction isundesirable to use as potable water A low TDS will forcethe salts in the body to come out of tissues and as the watercomes out through kidneys some of these minerals are lostto the body Considering these aspects NF performance isdeemed to be optimal and acceptable as potable water Thechloride removal data is shown in Figure 7 It can be seen that80 rejection was observed for RO while 72 rejection wasobserved for NF for the limiting pressure of 7 bars

34 Nitrates Sulphates and Phosphates Rejection by Mem-brane The nitrates sulphates and phosphates presence insurface water is one of the main problems related with thequality of the water Excess nitrates and phosphates canaccelerate eutrophication rendering surface water pollutedand undrinkable Figure 7 presents the effectiveness of NFin removing the nitrates sulphates and phosphates from thesurface water It can be seen that sulphate ion is maximallyrejected compared to phosphates and nitrates This could bebecause of higher hydration energy and charge associatedwith sulphate ions (Figure 8)

35 Power Consumption Figure 9 compares the energy con-sumption of RO andNF filtration It can be noted that 21 Lmhcan be obtained at 200W in case of NF but the same flux wasobtained at 448W in case of RO system Besides the electric-ity consumption is always on the higher side for RO mem-brane [17] Hence the electrical power consumption in caseof RO system is more than two times that of NF for the sameflow rate Thus NF not only gives potable water but also givesin an energy efficient way

4 Conclusions

It was found that nanofiltration is effective in providingrequired TDS from the surface water (Cauvery river water)


100

90

80

70

60

50

40

30

20

10

0

Nitrates Sulphates Phosphates

Reje

ctio

n (

)

NFRO

Figure 8 rejection of nitrates sulphates and phosphates usingNF and RO

25

20

15

10

5

0

0 100 200 300 400 500

Electricity consumption (W)

Flux

(Lm

h)

NFRO

Figure 9 Comparison of RO and NF electricity consumption forsame permeate flux

and makes it as potable water The experimental results haveshown that increasing the applied pressure resulted in anincrease of TDS rejection from surface water Although itseems to be the NF cannot reduce the total TDS but thefact is that it is only more effective as far as potable wateris concerned since in potable water it is a must that someminerals should be dissolved in water as per the standards ofWHO otherwise it is harmful for health A reduction in TDSfrom 451mgL to 135mgL was observed during NF processSo in an economic and health perspective to produce potablewater theNF is the best Additionally electricity consumptionwas found to be low in case of NF making it apposite forpotablewater In fact in future wewould like to comeupwithan operation of nanofiltration using renewable energy thusfurther reducing the energy consumption

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

The authors thank MHRD (Ministry of Human ResourceDevelopment) Government of India for providing financialsupport through their institute National Institute of Technol-ogy Trichy (in the form of seedmoney for research scholars)

References

[1] M L Fornasero R NMarenchino and C L Pagliero ldquoDeacid-ification of soybean oil combining solvent extraction andmem-brane technologyrdquo Advances in Materials Science and Engineer-ing vol 2013 Article ID 646343 5 pages 2013

[2] S Sobana and R C Panda ldquoIdentification modelling andcontrol of continuous reverse osmosis desalination system areviewrdquo Separation Science and Technology vol 46 no 4 pp551ndash560 2011

[3] N A SaniW J Lau andA F Ismail ldquoPolyphenylsulfone-basedsolvent resistant nanofiltration (SRNF) membrane incorpo-rated with copper-135-benzenetricarboxylate (Cu-BTC) nano-particles for methanol separationrdquo RSC Advances vol 5 no 17pp 13000ndash13010 2015

[4] European Union ldquoCouncil Directive 9883EC of 3 November1998 on the quality of water intended for human consumptionrdquoOfficial Journal of the European Communities vol L330 pp 32ndash54 1998

[5] P Garzon andM J Eisenberg ldquoVariation in themineral contentof commercially available bottledwaters implications for healthand diseaserdquo The American Journal of Medicine vol 105 no 2pp 125ndash130 1998

[6] B van der Bruggen and C Vandecasteele ldquoRemoval of pollu-tants from surface water and groundwater by nanofiltrationoverview of possible applications in the drinking water indus-tryrdquo Environmental Pollution vol 122 no 3 pp 435ndash445 2003

[7] M A Shannon P W Bohn M Elimelech J G Georgiadis BJ Marıas and A M Mayes ldquoScience and technology for waterpurification in the coming decadesrdquo Nature vol 452 no 7185pp 301ndash310 2008

[8] M A Montgomery andM Elimelech ldquoWater and sanitation indeveloping countries including health in the equationrdquo Envi-ronmental Science and Technology vol 41 no 1 pp 17ndash24 2007

[9] A Orecki M Tomaszewska K Karakulski and A WMorawski ldquoSurface water treatment by the nanofiltrationmethodrdquo Desalination vol 162 no 1ndash3 pp 47ndash54 2004

[10] Raman N Cheryan and N Rajagopalan ldquoConsider nanofiltra-tion for membrane separationrdquo Chemical Engineering Progressvol 90 pp 68ndash74 1994

[11] P Eriksson ldquoNanofiltration extends the range of membranefiltrationrdquo Environmental Progress vol 7 no 1 pp 58ndash61 1988

[12] R S Harisha K M Hosamani R S Keri S K Nataraj and TM Aminabhavi ldquoArsenic removal from drinking water usingthin film composite nanofiltration membranerdquo Desalinationvol 252 no 1ndash3 pp 75ndash80 2010

[13] R Rautenbach and R Albrecht Membrane Processes WileyChichester UK 1989


[14] S Sridhar A Kale and A A Khan ldquoReverse osmosis of ediblevegetable oil industry effluentrdquo Journal of Membrane Sciencevol 205 no 1-2 pp 83ndash90 2002

[15] M Pizzichini C Russo and C D Di Meo ldquoPurification of pulpand paper wastewater with membrane technology for waterreuse in a closed looprdquo Desalination vol 178 no 1ndash3 pp 351ndash359 2005

[16] R J Petersen ldquoComposite reverse osmosis and nanofiltrationmembranesrdquo Journal of Membrane Science vol 83 no 1 pp 81ndash150 1993

[17] I C Escobar S Hong and A Randall ldquoRemoval of assailableand biodegradable dissolved organic carbon by reverse osmosisand nanofiltration membranesrdquo Journal of Membrane Sciencevol 175 pp 1ndash17 2000

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Spectroscopy

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Table 1 Membranesrsquo characteristics

Manufacturer Permionics Pvt Ltd Vadodara IndiaMembrane type Thin film composite (TFC) polyamideConfiguration Spiral wound

Dimensions Length of 40 inches diameter of 24inches and an effective area of 25m2

Pure water flux 90 L(hsdotm2) at 552 bars of feedpressure and 25∘C temperature

NaCl salt rejection 994 for 32000mgL feedconcentration at the pH range of 2 to 11

Recommended appliedpressure 3ndash14 bars

Maximum appliedpressure 41 bars

Recommended appliedtemperature 2ndash45∘C

Table 2 Characteristics of Cauvery river water collected frominfiltration gallery

Parameters Respective valuespH 722Turbidity 0Chlorides 130mglitTotal hardness 220mglitPhosphates 943mglitNitrates 1343mglitSulphates 25mglitTotal dissolved solids 830mglit

a spiral wound configuration were procured from Permion-ics Pvt Ltd Vadodara India The detailed description ofthe membrane is presented in Table 1 Tetrasodium-EDTAhydrochloric acid and sodium bisulfate were used for mem-brane cleaning and were supplied by Precision scientific LtdTiruchirappalli India

22 Surface Water Characteristics Surface water was pro-cured from the nearby legendary Cauvery river one of theprominent rivers in south India In Table 2 the characteristicof the raw surface water is given

23 Nanofiltration Pilot Plant System Description The frontview and the schematic representation of the membrane pilotsystem are shown in Figures 1 and 2 respectively It consistsof mainly spiral wound membrane module incorporatingthin film composite nanofiltration (TFC-NF)membranewithan inlet pressure of 10 bars for the process of nanofiltrationinside the fiber-reinforced plastic (FRP) cylindrical pressurevessels with the dimensions of 2510158401015840 diametertimes 2110158401015840 length (thesize of each of the modules) A feed tank of 25 L capacity (SS-316) was used for storage and supply of feed to the nanofiltra-tion module A high pressure pump capable of maintaininga pressure of 100 bars was installed for transporting the feedliquid A 2 HP single-phase motor runs the respective pumpA restricting needle valve was provided at the concentrate

Figure 1 Front view of the NF and RO membrane process pilotplant

4 2

NF membrane 1

Permeate

(1) Pressure indicator(2) Valve

(3) Storage tank(4) Pump

212

Rete

ntat

e

3

Figure 2 Schematic representation of the nanofiltration (NF)membrane pilot plant

outlet to pressurize the feed liquid to the desired valueand the respective pressure indicated by a provided pressuregauge Permeate and concentrate flow rates weremeasured byRotameters All the accessories were connected by 0510158401015840 outerdiameter stainless steel-316 piping in high pressure regionwhereas low pressure outlets were made of PVC braidedtubing

24 Experimental Procedure and Sampling Twenty-five litersof the feed was poured into the feed tank after thoroughlycleaning the membrane system and then wetted with thedeionized water A high pressure pump was employed totransport the feed to spiral wound membrane moduleThe retentate flow rate was maintained constant (10 Lmin)throughout the experimental runs to ensure identical hydro-dynamic conditions inside the membrane module Feedpressure was varied from 0 to 7 bars by keeping the feed TDSconcentration constant Flux wasmeasured by collecting per-meate in a measuring jar for a period of 2-3min About 300ndash400mL of permeate was collected for each pressure increasefor a thorough analysis Experiments were repeated twice





119877 = (1minus119862

119901

119862

119891

)times 100 (1)

where 119862119891and 119862



119869 (Lmh) = 119881119860 times 119905

(2)



119875 =

119876 sdot 119901

120578

(3)





250

200

150

100

50

0

0 2 4 6 8

PermeateConcentrate

Flux

(Lm

h)

Pressure (kgcm2)


Flux

(Lm

h)

25

20

15

10

5

00 2 4 6 8

Pressure (kgcm2)

NFRO





0100200300400500600700

0 1 2 3 4 5 6 7 8

Perm

eate

TO

C

NFRO

Pressure (kgcm2)


0

20

40

60

80

100

120

0 1 2 3 4 5 6 7 8

NFRO

Pressure (kgcm2)

Reje

ctio

n of

TD

S (

)




0102030405060708090

NFRO

0 1 2 3 4 5 6 7 8Pressure (kgcm2)

Reje

ctio

n of

chlo

rides

()





4 Conclusions



100

90

80

70

60

50

40

30

20

10

0


Reje

ctio

n (

)

NFRO


25

20

15

10

5

0

0 100 200 300 400 500


Flux

(Lm

h)

NFRO





Acknowledgment


References




























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





119877 = (1minus119862

119901

119862

119891

)times 100 (1)

where 119862119891and 119862



119869 (Lmh) = 119881119860 times 119905

(2)



119875 =

119876 sdot 119901

120578

(3)





250

200

150

100

50

0

0 2 4 6 8

PermeateConcentrate

Flux

(Lm

h)

Pressure (kgcm2)


Flux

(Lm

h)

25

20

15

10

5

00 2 4 6 8

Pressure (kgcm2)

NFRO





0100200300400500600700

0 1 2 3 4 5 6 7 8

Perm

eate

TO

C

NFRO

Pressure (kgcm2)


0

20

40

60

80

100

120

0 1 2 3 4 5 6 7 8

NFRO

Pressure (kgcm2)

Reje

ctio

n of

TD

S (

)




0102030405060708090

NFRO

0 1 2 3 4 5 6 7 8Pressure (kgcm2)

Reje

ctio

n of

chlo

rides

()





4 Conclusions



100

90

80

70

60

50

40

30

20

10

0


Reje

ctio

n (

)

NFRO


25

20

15

10

5

0

0 100 200 300 400 500


Flux

(Lm

h)

NFRO





Acknowledgment


References




























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


0100200300400500600700

0 1 2 3 4 5 6 7 8

Perm

eate

TO

C

NFRO

Pressure (kgcm2)


0

20

40

60

80

100

120

0 1 2 3 4 5 6 7 8

NFRO

Pressure (kgcm2)

Reje

ctio

n of

TD

S (

)




0102030405060708090

NFRO

0 1 2 3 4 5 6 7 8Pressure (kgcm2)

Reje

ctio

n of

chlo

rides

()





4 Conclusions



100

90

80

70

60

50

40

30

20

10

0


Reje

ctio

n (

)

NFRO


25

20

15

10

5

0

0 100 200 300 400 500


Flux

(Lm

h)

NFRO





Acknowledgment


References




























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


100

90

80

70

60

50

40

30

20

10

0


Reje

ctio

n (

)

NFRO


25

20

15

10

5

0

0 100 200 300 400 500


Flux

(Lm

h)

NFRO





Acknowledgment


References




























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article nanofiltration in transforming...

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