Characterization of dissolved organic matter from surface waters with low to high dissolved organic carbon and the related disinfection byproduct formation potential

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    Journal of Hazardous Materials 271 (2014) 228235

    Contents lists available at ScienceDirect

    Journal of Hazardous Materials

    journa l homepage: www.e lsev ier .com/ locate / jhazmat

    haracterization of dissolved organic matter from surface waters withow to high dissolved organic carbon and the related disinfectionyproduct formation potential

    ngzhen Lia,b, Xu Zhaoa,, Ran Maoa, Huijuan Liua, Jiuhui Qua

    State key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085,hinaChina Academy of Urban Planning and Design, Beijing 100044, China

    i g h l i g h t s

    The DBPFP of source waters did notcorrelate with the DOC value.SUVA didnt represent the potentialto form DBP in low-aromatic waters.The Hi fraction played an importantrole in DBPFP for waters.Phenolic hydroxyl group tended toform TCM and TCAA during chlorina-tion.Carboxyl and alcoholic hydroxylgroups tended to form DCAA andBr-DBP.

    g r a p h i c a l a b s t r a c t

    The characterization of DBP precursors from three sourcewaters in China revealed that theDBPFP did notcorrelatewith theDOC value. TheHo fractionmainly contained phenolic hydroxyl and conjugated doublebonds which were reactive with chlorine to produce DBP, especially TCM and TCAA. The Hi fraction maycontainmore amino, carboxyl and alcoholic hydroxyl groups,which had the great potential to formDCAAand Br-DBP during chlorination.

    r t i c l e i n f o

    rticle history:eceived 24 November 2013eceived in revised form 27 January 2014ccepted 7 February 2014vailable online 16 February 2014

    eywords:isinfection byproductissolved organic carbon

    a b s t r a c t

    In this study, the disinfection byproduct formation potential (DBPFP) of three surface waters with thedissolved organic carbon (DOC) content of 2.5, 5.2, and 7.9mg/L was investigated. The formation anddistribution of trihalomethanes and haloacetic acids were evaluated. Samples collected from three sur-face waters in China were fractionated based on molecular weight and hydrophobicity. The raw watercontaining more hydrophobic (Ho) fraction exhibited higher formation potentials of haloacetic acid andtrihalomethane. The DBPFP of the surface waters did not correlate with the DOC value. The values ofDBPFP per DOC were correlated with the specific ultraviolet absorbance (SUVA) for Ho and Hi fractions.The obtained results suggested that SUVA cannot reveal the ability of reactive sites to form disinfectionydrophobicityhlorination

    byproducts for waters with few aromatic structures. Combined with the analysis of FTIR and nuclearmagnetic resonance spectra of the raw waters and the corresponding fractions, it was concluded thatthe Ho fraction with phenolic hydroxyl and conjugated double bonds was responsible for the production

    of trichloromethanes and trichpotential to form dichloroacet

    Corresponding author. Tel.: +86 10 62849160; fax: +86 10 62849160.E-mail addresses: liangzhen403@sina.com (A. Li), zhaoxu@rcees.ac.cn (X. Zhao), jdmrr

    ttp://dx.doi.org/10.1016/j.jhazmat.2014.02.009304-3894/ 2014 Published by Elsevier B.V.loroacetic acids. The Hi fraction with amino and carboxyl groups had theic acids and chlorinated trihalomethanes.

    2014 Published by Elsevier B.V.

    @163.com (R. Mao), hjliu@rcees.ac.cn (H. Liu), jhqu@rcees.ac.cn (J. Qu).

    dx.doi.org/10.1016/j.jhazmat.2014.02.009http://www.sciencedirect.com/science/journal/03043894http://www.elsevier.com/locate/jhazmathttp://crossmark.crossref.org/dialog/?doi=10.1016/j.jhazmat.2014.02.009&domain=pdfmailto:liangzhen403@sina.commailto:zhaoxu@rcees.ac.cnmailto:jdmrr@163.commailto:hjliu@rcees.ac.cnmailto:jhqu@rcees.ac.cndx.doi.org/10.1016/j.jhazmat.2014.02.009

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    A. Li et al. / Journal of Hazard

    . Introduction

    It is recognized that dissolved organic matter (DOM) is therincipal precursor of disinfection byproducts (DBPs) in the chlo-ination treatment [1,2]. Trihalomethanes (THMs) and haloaceticcids (HAAs) are the two major groups of DBPs, which are poten-ially carcinogenic [3,4]. Therefore, it is important tounderstand theelationship between the characteristics of DOM and DBPs yields.

    To understand the composition of DOM in surface water, DOMas been isolated and fractionated by ultrafiltration and resin frac-ionation according to the molecular weight and physicochemicalroperties [59]. The hydrophobic fraction with large moleculareight DOM was found to be the most important source of DBPsrecursors [8,10]. Hydrophilic fraction may also contribute sub-tantially to the formation of DBPs especially in waters with lowumic component [11]. Moreover, it was found that the character-stics of natural organic matter (NOM) in surface water dependedn climate, geological conditions and surrounding watersheds1214]. Although some studies were performed to characterizeOM in several source waters [12,14,15], little information wasocused on the composition and characteristics of DBPs precur-ors in different regions of China, especially for the individualtructure of DBPs precursors in waters with high concentration ofromide.A different formation trend of THMs and HAAs in the chlori-

    ation treatment was reported [3,16]. The presence of bromiden DOM also had an effect on the formation and distributionf THMs and HAAs during the chlorination process [8,17]. Sev-ral researchers have tried to correlate water quality parameters,uch as dissolved organic carbon (DOC) and specific ultravioletbsorbance divided by dissolved organic carbon (SUVA) to disin-ection byproduct formation potential (DBPFP) of DOM [3,10,18].UVA has been found to be a good indicator for quantifying NOMeactivity in DBPs formation [3,7]. By contrast, Ates et al. reportedhat SUVA did not correlate well with the formation and species ofBPs in waters with low DOC content [11]. Thus, it was requiredhat an integrated analytical approach to elucidate the chemicalomposition and physical structures of DBPs precursors.

    The primary aim of this research was to compare the char-cteristics of DBPs precursors from three water sources in Chinaontaining low to high DOC levels. The effectiveness of SUVA valuen predicting DBPs formation with different bromide, SUVA andOC levels was investigated. The raw waters and the correspond-ng fractions were examined for their associated functional groupsy three dimensional excitation-emissionmatrix (3DEEM) fluores-ence, fourier transform infrared (FT-IR) and 13C nuclear magneticesonance (13C NMR) spectra analysis. Relationship between thetructures of DBPs precursors and DBPs species was explored.

    . Materials and methods

    .1. Raw water sampling

    The rawwaterswere collected from three potablewater sourcesetweenOctober2011and July2012. Thewater sourceswereas fol-ows:Miyun Reservoir (Beijing (BJ), northern China),Weishan LakeXuzhou (XZ), east China), and Hongze Lake (Lianyungang (LYG),ast China). Sampleswere collected in 25 Lplastic bottles anddeliv-red to the laboratory. After being filtrated by a pre-rinsed 0.45mlass fiber filters, the samples were stored in the dark at 4 C..2. Resin and membrane separation of the DOC fractions

    NOMwas fractionated into five fractions using a stirred ultrafil-ration cell device (Model 8200, Amicon, Millipore) with nominalaterials 271 (2014) 228235 229

    molecular weight cutoffs of 3, 10, 30, and 100kDa regenerated cel-lulose membranes (PL, 63.5mm, Millipore). Experiments followedtheproceduredescribedbyKitis et al. (2002).Meanwhile, NOMwasalso fractionated by resin fractionation. The filtered NOMwas acid-ified to pH2 using 6M sulfuric acid and then passed throughDAX-8resin followed by XAD-4 resin, in accordance with the method ofAiken et al. (1992). Effluent from the XAD-4 resin was collectedand named as the hydrophilic (Hi) fraction. The hydrophobic (Ho)and transphilic (Hs) fractions were retained by DAX-8 and XAD-4 resin (Supelco, Bellefonte, PA, USA) respectively. These fractionswere eluted with 0.1M sodium hydroxide in the reverse direction.The Ho and Hs fractions were concentrated again on the MSC-Hcation exchange resin obtained from J&K in order to remove thesalt of the Ho and Hs fractions. Each NOM fraction was diluted tooriginal state with ultrapure water and the pH value was adjustedto be 7.00.2 using H2SO4 or NaOH. The DOC concentration andthe UV absorbance at 254nm (UV254) of each NOM fraction weremeasured.

    2.3. DBPs formation potential

    Chlorination experiment was carried out according to the Stan-dard Method 5710 with modifications [19]. As described in theStandard Method 5710B, the reaction time for THMFP shouldbe 7 days. However, it is also described in 5710D that for somecompounds, such as brominated haloacetic acids, are not stableand can degrade during storage-either during a long reaction time,7daysmaybe too long for somecompounds. TheNaOCl stock solu-tion (20mg/mL as Cl2) was stored in aluminum foil-covered glassstoppedflask. Chlorine dosing solutionwas prepared from the dilu-tion of NaOCl stock solution (about 5mg/mL as Cl2). NaOH/KH2PO4buffer solutions (pH7.0) and chlorine dosing solutionwere injectedinto each sample. The chlorine dosewas determined by 4h prelim-inary demand tests on each sample according to Standard Method5710B [19]. After being dosed with chlorine, samples were storedat 252 C in the dark for 24h. Free chlorine residuals of the sam-plesweremeasured by anN,N-diethyl-p-phenylenediamine (DPD)titrimetricmethod [20]. After the addition of the sodiumsulfite intothe water samples, the concentrations of trihalomethanes forma-tion potential (THMFP) and haloacetic acids formation potential(HAAFP) were determined according to the procedure [21].

    Four THMs (CHCl3, CHBrCl2, CHBr2Cl, CHBr3) species wereextracted with hexane (HPLC Grade, Fisher, USA) and mea-sured according to the U.S EPA Method 551 [22]. Nine HAAs(monochloro-, monobromo-, dichloro-, bromochloro-, dibromo-,bromodichloro-, bromodichloro-, dibromochloro-, trichloro- andtribromoacetic acid) samples were extracted with methyl-tert-butyl ether (MTBE) (HPLC Grade, J.T. Baker, USA) followed bybeing derivatized with acidic methanol according to the US EPAmethod 552.3 [22]. 1, 2-dibromopropane (98.0%, GC, Fluka, USA)was served as the interval standard. Quantitative analysis wasconducted using a gas chromatograph (6890N, Agilent) with anelectron capture detector (ECD). The experiment conditions weregiven in the supporting information.

    2.4. Characterization of DBPs precursors

    The samples of DBPs precursors obtained through a freeze-drying treatment were analyzed for their structural and chemicalcharacteristics. KBr (FT-IR Grade, Aldrich Co., USA) wasmixedwiththe powder of DBPs precursors and the FT-IR spectra of the mix-ture were obtained with an IR spectrometer (Thermo Nicolet 5700,

    USA).

    3DEEM fluorescence spectra were recorded on a fluorescencespectrophotometer (model F-4500, Hitachi, Japan). 3DEEM spec-tra were obtained bymeasuring the emission spectra ranging from

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    80 to 550nm repeatedly at the excitation wavelengths from 220o 440nm. Blank samples of ultra-pure water were included in theorrection of inner filtering and Raman scattering of the fluores-ence spectra.

    The solid-state 13C NMR spectra were acquired using a crossolarizationmagic angle spinning (CPMAS) on a Bruker instrumentAVANCE III, 400MHz, Bruker, Germany)with a 4mmH/X/Y probe.3C CPMAS NMR was performed on 100200mg of the samplescontact time of 3ms, pulse delay of 1 s, spinning rate of 5000Hznd 20480 scans).The pH values of these water samples were measured by a

    H meter (720A, Thermo Orion, USA). Dissolved organic carbonDOC)wasmeasured by a TOC analyzer (Shimadzu, TOC-VCPH totalrganic carbon analyzer, Japan). Thewater sampleswerefiltered byhe membrane (0.45m Millipore Co., USA). UV was measured byspectrophotometer (Hitachi, U-3010 spectrophotometer, Japan).romide concentrations were measured using measured using ionhromatograph (IC, ICS-2000, Dionex, Sunnyvale, CA) equippedith an IonPac AS-19 anion column and an IonPac AG19 guardolumn.

    . Results and discussion

    .1. Fractionation analysis of BJ, LYG and XZ raw watersThe tested surface waters (BJ, LYG and XZ raw waters) wereollected from the drinking water sources with low to high DOCalues in China. The raw waters were fractionated by ultrafiltra-ion and resin fractionation according to the molecular weight and

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    ig. 1. DBPFP% distribution and DBPFP/DOC of the raw waters and corresponding fractiaters; (b) distribution of HAAFP% based on hydrophobicity and HAAFP/DOC of raw watf THMFP% and HAAFP% from the corresponding fractions.aterials 271 (2014) 228235

    physicochemical properties. As shown in Table S1 Table S1, DOC ofthe raw waters follows the order: XZ> LYG>BJ. SUVA values dif-fer from DOC values with the following rank order: LYG>XZ>BJ.Among them, XZ rawwater shows the highest bromide concentra-tion. Moreover, the Ho fraction is the most abundant of the DAXpartition-based groups. It is shown in Table S1 that the percentcontent of the hydrophobic carbon increases with the increase ofthe SUVA value. With the decrease of the SUVA levels, the per-centage of Hs and Hi fractions increases, indicating that Hi fractionbecomes an important fraction for the low SUVAwaters. There alsoexists a trend that the fraction with large molecular size has rel-atively high level of SUVA. Similar results were also reported byAtes et al., who observed that the natural waters with SUVA val-ues

  • A. Li et al. / Journal of Hazardous Materials 271 (2014) 228235 231

    3.02.52.01.51.00.50

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    (a)

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    DB

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    THMFP/DOC

    R2=0.9638

    HAAFP/DOC

    R2=0.9779

    SUVA (L/mg DOC-m)

    THMFP/DOC HAAFP/DOC

    3.02.52.01.51.00.50

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    SUVA (L/mg DOC-m)

    THMFP/DOC HAAFP/DOC

    3.02.52.01.51.00.50

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    R2=0.4168

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    ig. 2. The relationship between SUVA andDBPFP/DOC from the rawwaters and theractions; (d) the hydrophilic fractions.

    orresponding Hs and Hi fractions, but hydrophilic carbon alsolays an important role in the disinfection byproduct formationor the water samples with SUVA values

  • 232 A. Li et al. / Journal of Hazardous Materials 271 (2014) 228235

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    ig. 3. Fluorescene spectroscopy of BJ raw water and the fractions based on hydropydrophilic fraction.

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