摘要
重金属铬(VI)污染已成为严重的环境问题，研发高效的吸附材料成为当前研究的热点。本文将壳聚糖与稀土进行复合，通过反相乳液交联法和静电纺丝法两种不同的方法，制备了壳聚糖/稀土复合微球和壳聚糖/稀土纤维膜两种不同形态结构的复合材料。通过吸附试验发现，上述两种吸附材料对水中重金属铬(VI)离子表现出较高的吸附能力。具体内容如下：
（1）采用壳聚糖，稀土硝酸钇为制备材料，通过反相乳液交联法制备了壳聚糖/稀土复合微球。选用稀土硝酸钇，壳聚糖，聚乙烯醇为原料，采用静电纺丝的方法制备壳聚糖/稀土复合纤维。并用扫描电镜、红外光谱、透射电镜、X射线衍射等物化表征进行分析。
（2）深入研究了复合材料对水中重金属铬(VI)离子的吸附性能，考查了稀土无机盐的掺杂量、溶液的pH值、剂量、铬(VI)离子的初始浓度、共存阴离子等各项因素对吸附效果的影响，同时比较了两种复合材料的形态结构对铬(VI)离子的吸附性能影响。得到如下结论：酸性条件有利于壳聚糖/稀土复合材料对铬(VI)离子的吸附；单位质量的壳聚糖/稀土复合微球的吸附容量与比复合纤维膜吸附容量高，产生的原因可能是复合微球中有效成分稀土和壳聚糖的含量较多，可以更好的对水中的重金属中铬(VI)离子进行吸附。
（3）通过对吸附行为的研究发现：吸附实验数据可以很好的用Langmuir吸附等温线方程进行拟合。吸附动力学研究表明，拟二级动力学方程对壳聚糖/稀土复合材料去除水中重金属铬(VI)离子的拟合效果较好。探讨了不同温度条件下复合材料对铬(VI)离子吸附的热力学参数，结果表明，壳聚糖/稀土复合材料对铬(VI)离子的吸附过程为吸热反应，反应过程可以自发进行。将壳聚糖/稀土复合材料对重金属铬(VI)离子的吸附能力与其他吸附材料进行比较，发现复合材料具有较高的吸附量。
（4）通过X射线光电子能谱和红外光谱分别测定了两种形态结构的壳聚糖/稀土复合材料吸附前后的元素和功能基团的变化，对吸附机理进行了深入的探讨。阐明了壳聚糖/稀土复合材料对水中的铬(VI)离子的吸附机理，其主要是通过复合材料表面功能基团协同作用的结果，并伴有螯合作用的发生，为复合材料的脱附提供了理论依据。
（5）吸附再生循环研究表明：壳聚糖/稀土复合微球经过3次吸附-解吸后，仍然保持了一定的吸附能力，可以多次循环使用。复合纤维膜经过洗涤解吸后，力学性能下降明显，因而无法多次循环使用。
Heavy metal chromium(VI) pollution is considered a serious environmental pollutantthus aroused widespread concern. it is found a new adsorbent composite material can bedeveloped by chitosan with rare earth element which having the ability to remove Cr(VI) ions.In common case, the absorbent property of chitosan/rare earth compound is related to its ownmorphology. In this research two different methods i.e., w/o and electrospinning, are used totwo differently morphological adsorbents that is chitosan/rare earth microsphere andchitosan/rare earth membrane. Both of the two composite show good adsorbent performancesafter chromium(VI) adsorption. The detailed research contents are outlined as follows:
（1）The chitosan/rare earth microsphere composite is developed by w/o method usedchitosan and rare earth yttrium nitrate. And the other method is used chitosan, rare earthyttrium nitrate and polyvinyl alcohol as preparation materials to make a electrospun fibrousmembrane. The chemical, structural and morphology characteristics of the composites aredetermined by transmission electron microscope (SEM), fourier infrared spectrum (FTIR),X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectronspectroscopy(XPS) method.
(2)The influence of the adulteration of rare earth, solution pH value, dosage, Cr(VI) ioninitial concentration, and co-ions were studied. In acidic solution, the chitosan/rare earthelement keeps a high adsorption capacities. Comparing the two different morphologicalcomposite, Cr(VI) ions in water can be effectively adsorbed by the fibrous membrane whichhas a high adsorption capacity, however, which adsorption capacity is slightly lower thanmicrosphere composite. This change may be attributed to the different the ratio of rare earthyttrium and chitosan is not the same. The microsphere composite contains more rare earthions, so more adsorption of water Cr(VI)ions can occur via electrostatic attraction.
(3) The adsorption data from the experiment can be fit well by Langmuir isotherm.Comparison the adsorption ability of chitosan/rare earth composite with that of othermaterials, it is found the composite has a high adsorbent amount. In addition, adsorptionkinetics of Cr(VI) ions is found to conform to pseudo-second order kinetics. Thethermomechanics constants of composite under different temperatures demonstrates theadsorbent process is a endothermic reaction.
(4)The changes of element and functional groups before and after the adsorption aremeasured by X-ray spectrometer and infrared spectrum. The mechanism domonstrates that theadsorption is attribute to electrostatic attraction coupled with chelation.
(5) Adsorption regeneration cycle research showed that chitosan/rare earth compositemicrospheres still keep some adsorption capacities after3adsorption-desorption cycles.Therefore it can effectively used. Meanwhile, the mechanics performance of fibrous is poorafter desorption, so it can't use repeatly.
引文
[1] Beaumont JJ, Sedman RM, Reynolds SD, et al. Cancer mortality in a Chinese population exposed tohexavalent chromium in drinking water [J]. Epidemiology,2008,19:12-23.
[2]马春梅.改性废弃稀土抛光粉对废水中铬离子的吸附性能研究[D]:[硕士学位论文],呼和浩特:内蒙古大学,2011:3.
[3] Yao H, Guo L, Jiang BH, et al. Oxidative stress and chromium(VI)carcinogenesis [J]. Pathol ToxicolOncol,2008,27:77–88.
[4] Wise SS, Holmes AL and Wise SJP. Particulate and soluble hexavalent chromium at cytotoxic andgenotoxic to human lung epithelial cells [J]. Mutat Res-Gen Tox En,2006,610:2-7.
[5] Russo P, Catassi A, Imperatori A, et al. Molecular mechanisms of hexavalent chromium-inducedapoptosis in human bronchoalveolar cells [J]. J Respir Cell Mol Biol,2005,33:589-600.
[6]戴树桂,岳贵春,王晓蓉.环境化学,116[M].北京:高等教育出版,1997.
[7]高洪阁,李白英.应用高硫煤燃烧产生的二氧化硫还原电镀废水中的六价铬离子[J].煤矿环境保护,2002,16(4):16-17.
[8] Gheju M and Balcu I. Removal of chromium from Cr(VI) polluted wastewaters by reduction withscrap iron and subsequent precipitation of resulted cations [J]. J Hazard Mater,2011(196):131-138.
[9] Fang ZQ, Qiu XQ, Huang RX, et al. Removal of chromium in electroplating wastewater by nanoscalezero-valent metal with synergistic effect of reduction and immobilization [J]. Desalination,2011,280:224-231.
[10]吴克明,石瑛,王俊等.离子交换树脂处理钢铁钝化含铬废水的研究[J].工业安全与环保,2005,31(4):22-23.
[11] W′ojcik G, Neagu V and Bunia I. Sorption studies of chromium(VI) onto new ion exchanger withtertiary amine, quaternary ammonium and ketone groups [J]. J Hazard Mater,2011,190:544-552.
[12]黄世臣,李熙英,王娟.高效吸附铬的菌株筛选及优化条件[J].东北林业大学学报,2010,38(4):105-106.
[13] Raichur AM and Jyoti BM. Adsorption of Cr(VI) onto mixed rare earth oxides[J]. Sep Purif Technol,2001,24:121-127.
[14] O'Connell DW, Birkinshaw C and O'Dwyer TF. Heavy metal adsorbents prepared from themodification of cellulose: A review [J]. Bioresour Technol,2008,99:6709-6724.
[15]黄玉洁,张焕祯.改性人造沸石处理含铬(VI)地下水的实验研究[J].环境工程,2012,30(4):1-3.
[16]杨慧芬,张伟娜,胡瑞娟.十六烷基三甲基溴化铵改性沸石对水中Cr(VI)的吸附去除率[J].硅酸盐学报,2011,11(38):2143-2147.
[17]陈彰旭,郑炳云,傅明连等.纳米羟基磷灰石对模拟含铬废水中Cr6+的吸附研究[J].山东理工大学学报,2010,24(5):20-22.
[18] Wen Y, Tang ZR, Chen Y, et al. Adsorption of Cr(VI) from aqueous solutions using chitosan-coated flyash composite as biosorbent [J]. Chem Eng J,2011,175:110-116.
[19] Veli S and Akyüz B. Adsorption of copper and zinc from aqueous solutions by using natural clay[J]. JHazard Mater,2007,149:226-233.
[20] Rajendra S. Eco-friendly and morphologically-controlled synthesis of porous CeO2microstructure andits application in water purification[J]. J colloid Interface Sci,2010,348(2):600-607.
[21]杨秋菊,孔凡茂.纳米ZrO2和Fe2O3在处理含铬(VI)废水中的应用[J].水处理技术,2008,34(3):60-62.
[22]李彬,宁平,金建琼等.稀土吸附剂处理含铬微污染水研究[J].水处理技术,2006,32(4):43-52.
[23] Recillas S, Colón J, Casals E, et al. Chromium(VI) adsorption on cerium oxide nanoparticles andmorphology changes during the process[J]. J Hazard Mater,2010,184(1-3):425-431.
[24] Zhou JB, Wu PX, Dang Z, et al. Polymeric Fe/Zr pillared montmorillonite for the removal of Cr(VI)from aqueous solutions[J]. Chem Eng J,2010,162:1035-1044.
[25] Chen SH, Yue QY, Gao BY, et al. Equilibrium and kinetic adsorption study of the adsorptive removalof Cr(VI)using modified wheat residue [J]. J Colloid Interface Sci,2010,349:256-264.
[26] Chen S, Yue Q, Gao B, et al. Adsorption of hexavalent chromium from aqueous solution by modifiedcorn stalk: a fixed-bed column study [J]. Bioresour Technol,2012,113:114-120.
[27] Cui H, Fu M, Yu S, et al. Reduction and removal of Cr(VI) from aqueous solutions using modifiedbyproducts of beer production [J]. J Hazard Mater,2011,186(2-3):1625-1631.
[28] Aydin YA and Aksoy ND. Adsorption of chromium on chitosan: Optimization, kinetics andthermodynamics [J]. Chem Eng J,2009,151:188-194.
[29] Kousalya GN, Gandhi MR and Meenakshi S. Sorption of chromium(VI) using modified forms ofchitosan beads [J]. Int J Biol Macromol,2010,47:308-315.
[30] Sankararamakrishnan N, Dixit A, Iyengar L, et al. Removal of hexavalent chromium using a novelcross linked xanthated chitosan [J]. Bioresource Technol,2006,97:2377-2382.
[31] Khezami L and Capart R. Removal of chromium(VI) from aqueous solution by activated carbons:Kinetic and equilibrium studies [J]. J Hazard Mater,2005,123:223-231.
[32] Karthikeyan T, Rajgopal S, and Miranda LR. Chromium(VI) adsorption from aqueous solution byHevea Brasilinesis sawdust activated carbon [J]. J Hazard Mater,2005,124:192-199.
[33] Zhou HL, Chen YF. Effect of acidic surface functional groups on Cr(VI) removal by activated carbonfrom aqueous solution [J]. Rare Metals,2010,29(3):333-338.
[34] Tang C, Zhang R, Wen S, et al. Adsorption of hexavalent chromium from aqueous solution onraw and modified activated carbon [J]. Water Environ Res,2009,81(7):728-734.
[35] Batista AC, Villanueva ER, Amorim RVS, et al. Chromium (VI) ion adsorption features ofchitosan film and its chitosan/zeolite conjugate13X film [J]. Molecules,2011,16:3569-3579.
[36] Pandey S and Mishra SB. Organic-inorganic hybrid of chitosan/organoclay bionanocompositesfor hexavalent chromium uptake [J]. J Colloid Interface Sci,2011,361:509-520.
[37]王琼生,万清黎.粘土-壳聚糖复合吸附剂吸附铬(VI)离子性能的研究[J].福建师范大学学报(自然科学版),2006,22(2):62-67.
[38]蒋挺大.甲壳素[M].北京:化学工业出版社,2001.
[39]姚瑞华.基于镧系金属改性壳聚糖的脱氟新技术研究[D]:[博士学位论文].青岛:中国海洋大学2009.
[40] Gandhi MR, Viswanathan N and Meenakshi S. Preparation and application of alumina/chitosanbiocomposite [J]. Int J Biol Macromol2010,47:146-154.
[41] Aneesh PK, Prathish KP, Kala R, and et al. Lanthanum carbonate incorporated chitosan microparticlesfor phosphate collection[J]. Reac Funct Polym,2009:69714-718.
[42] Viswanathana N and Meenakshib S. Development of chitosan supported zirconium(IV)tungstophosphate composite for fluoride removal. J Hazard Mater,2010,176:459-465.
[43] Bansiwal A, Thakrea D, Labhshetwara N, and et al. Fluoride removal using lanthanum incorporatedchitosan beads[J]. Colloid Surface B, Biointerfaces,2009,74:216-224.
[44]唐珊珊.高分子/无机纳米材料的制备及物性研究[D]:[硕士学位论文],长春:东北师范大学,2007.
[45] Sang YM, Li FS. Heavy metal-contaminated groundwater treatment by a novel nanofiber membrane[J]. Desalination,2008,223(1-3):349-360.
[46] Kar P and Misra M. Use of keratin fiber for separation of heavy metals from water[J]. J Chem TechnolBiotechnol,2004,79(11):1313-1319.
[47] Haider S and Park SY. Preparation of the electrospun chitosan nanofibers and their applications to theadsorption of Cu(II) and Pb(II) ions from an aqueous solution[J]. J Membrane Sci,2009,328,90-96.
[48] Horzum N, Boyac E, VS Y AE, et al. Sorption efficiency of chitosan nanofibers toward metal ionsat low concentrations [J]. Biomacromol,2010,11(12):3301-3308.
[1]林英光,皮丕辉,郑大锋等.水合氧化铈铝柱撑锂皂石对氟的吸附性能研究[J].中国环境科学,2010,30(1):52-57.
[2]欧阳通.稀土材料氢氧化铈吸附水中亚砷酸与砷酸阴离子的特性效果[J].环境科学,2004,25:43-46.
[3]杨磊,赵文岩,马静静等.粉煤灰负载铈吸附剂的制备研究[J].稀土,2009,30(6):83-86.
[4]王国建,王东田,陈霞等.吸附法除氟技术的原理与方法[J].环境科学与管理.2008,33(8):121-124.
[5]焦中志,张昱,杨敏等.稀土铈基无机吸附剂对氟的吸附性能[J].环境化学.2002,21(4):366-370.
[6] Hideaki I, Junji N, Yuzuru I, et al，Anion Adsorption Behavior of Rare Earth Oxide Hydrates[J]. TheChemical Society of Japan,1987,(5):1807-1813.
[7] Mao XP, Guo GJ, Huang JF, et al. A novel method to prepare chitosan powder and its application incellulase immobilization [J]. J Chem Technol Biot,2006,81(2):189-195.
[8] Shi W, Zhang FB and Zhang GL. Adsorption of bilirubin with polylysine carrying chitosan-coatednylon affinity membranes [J]. J Chromatogr B,2005,819(2):301-306.
[9]乌建敏.光度法测定甲壳低聚糖的平均相对分子质量[J].化学世界,2001,6:293-295.
[10] Li JL. Pan JL and Zhang LG. Culture of hepatocytes on fruetose-modified chitosan scaffold[J].Biomateriais,2003,24(13):2317-2322.
[11] Yao R, Meng F, Zhang L, et al. DefYSVidatiSR Sf [ateV YsiRg ReSdy iY-mSdifed chitSsaR[J]. JHazard Mater.165:454-460.
[12] Zimmermann AC, Mecab A, Fagundes T et al.2010. Adsorption of Cr(VI) using Fe-crosslinkedchitosan complex (Ch-Fe)[J]. Hazard. Mater,2009,179:192–196.
[13]钟伟华,壳聚糖蒙脱土杂化微球的制备及吸附性能研究[D]:[硕士学位论文].广州:华南师范大学,2007.
[14]李海虹,吴晶.盐酸小蘖碱壳聚糖缓释微球[J].化学世界,278-281.
[15]察冬梅,刘明军,孙小梅等.壳聚糖磁性微球对偶氮品红的吸附[J].中南民族大学学报(自然科学版),2011,30(4):36-40.
[16]王怀玉,董利民,昝青峰等.乳化交联法制备壳聚糖微球粘连原因分析[J].功能材料,2007,38:1923-1925.
[17]吴佳林,郑少琼,刘森,秦春英.静电纺丝制备复合纳米纤维方法的研究进展[J],合成纤维,2009,2:9-12.
[18] Hedi SG, Phillip G, Kris S. Protective textile materials based on electrospun nanofibers [J]. Journal ofAdvanced Materials,2002,34:44-55.
[19] Doshi J, Reneker DH. Electrospinning Process and Applications of Electrospun Fibers [J]. JElectrostatics,1995,35(2/3):151-160.
[20] Haider S, Park SY. Preparation of the electrospun chitosan nanofibers and their applications to theadsorption of Cu(II) and Pb(II) ions from an aqueous solution [J]. J Memb Sci,2009,328(1-2):90-96.
[21] Hunley MT, Long TE. Electrospinning Functional Nanoscale Fibers: A Perspective for the Future [J].Polym Int,2008,57(3):385-389.
[22] Sundaramurthi D, Vasanthan KS, Kuppan P and et al. Electrospun nanostructured chitosan-poly(vinylalcohol) scaffolds: a biomimetic extracellular matrix as dermal substitute[J]. Biomed Mater,2012,7(4):8.
[23] Min B M, Lee S W, Lim J N, et al. Chitin and Chitosan Nanofibers: Electrospinning of Chitin andDeacetylation of Chitin Nanofibers [J]. Polymer,2004,45(21):7137-7142.
[24] Son B, Yeom BY, Song SH, et al. Antibacterial electrospun chitosan/poly (vinyl alcohol) nanofiberscontaining silver nitrate and titanium dioxide [J]. J Appl Polym Sci,2009(6):2892-2899.
[25] Homayoni H, Ravandi SAH, Valizadeh M. Electrospinning of chitosan nanofibers: processingoptimization [J]. Carbohydr Polym,2009,77(3):656-661.
[26] Deitzel JM, Kleinmeyer JD, Harris D, et al. The Effect of Processing Variables on the Morphology ofElectrospun Nanofibers and Textiles [J]. Polymer,2001,42(1):261-272.
[27]蒋挺大.甲壳素[M].北京:化学工业出版社,2001.
[28]聂莉,吴晓芳,伊萍等. CS中脱乙酞度测定方法的探讨[J].中国卫生检验杂志,2005,15(3):328-331.
[29]孙万成.优质CS的制备及脱乙酞度的测定方法比较[J].现代食品科技,2006,22(3):105-107.
[30]刘弈君,蒋英,封云芳等.用GPC研究CS氧化降解过程中的分子量及其分布[J].功能高分子学报,2004,17(4):671-674.
[31] Zhong HX, Ma YL, Cao XF, et al. Preparation and characterization of flowerlikeY2(OH)5NO3·1.5H2O and Y2O3aRd theiV effcieRt Ve SZa Sf CV(VI) fVS aUYeSYs sS YtiSR[J]. J PhysChem C,2009,113:3461-3466.
[1]国家环境保护局. GB7467-87，水质六价铬的测定碳酰二肼分光光度法[S].北京,1987:11-14
[2] Ajouyed O, Hurel C, Ammari M, et al. Sorption of Cr(VI) onto natural iron and aluminum(oxy)hydroxides: effects of pH, ionic strength and initial concentration[J]. J Hazard Mater,2010,174(1-3):616-622.
[3] Kousalya GN, Gandhi MR and Meenakshi S. SSVTtiSR Sf chVS iY (VI) YsiRg Sdifed fSV s Sfchitosan beads[J]. Int J of Bio Macrol,2010,47:308-315.
[4] Park D, Park JM. Mechanisms of the removal of hexavalent chromiumby biomaterials orbiomaterial-basedactivatedcarbons [J]. J Hazard Mater,2006,137:1254-1257.
[5] Zhong HX, Ma YL, Cao XF, et al. Preparation and characterization of flowerlikeY2(OH)5NO3·1.5H2O and Y2O3aRd theiV effcieRt Ve SZa Sf CV(VI) fVS aUYeSYs sS YtiSR[J]. J PhysChem C,2009,113:3461-3466.
[1]赵振国.吸附作用应用原理[M].北京:化学工业出版社,2005.17.
[2] Sarkar M, BenerjeeA, Pramanick PP, et al. Design and operation of operation of fixed bed lateritecolumn for the removal of fluoride from water[J]. Chem Eng J,2007(131):329-335.
[3] Haim D, Cil A, and David A. Kinetics of surfactant adsorption: the free energy approach[J]. CollidSurf A,2001(183):259-276.
[4]张莉平.特殊水质处技术[M].北京:化学工业出版社,2005,189.
[5]王九思.水处理化学[M].北京:化学工业出版社,2002,153-201.
[6]姚瑞华.基于镧系金属改性壳聚糖的脱氟新技术研究[D].[博士学位论文].青岛:中国海洋大学2009.
[7] Freundlich HZ. Uber die adsorption in l sungen[J]. J Phys Chem B,1906,57:385-470.
[8] Langmuir I. The constitution and fundamental properties of solids and liquids[J]. J Ame Chem Soc,1916,38:2221-2295.
[9] Kousalya GN, Gandhi MR and Meenakshi S. Sorption of chromium(VI) using modified forms ofchitosan beads[J]. Int J Biol Macromol,2010,47:308-315.
[10] Wen Y, Tang ZR, Chen Y, et al. Adsorption of Cr(VI) from aqueous solutions using chitosan-coated flyash composite as biosorbent[J]. Chem Eng J,2011,175:110-116.
[11] Gandhi MR, Viswanathan N, Meenakshi S. Preparation and application of alumina/chitosanbiocomposite[J]. Int J Biol Macromol,2010,47:146-154.
[12] Gandhi MR, Meenakshi S. Preparation and characterization of La(III) encapsulated silicagel/chitosan composite and its metal uptake studies[J]. J Hazard Mater,2012,203-204:29-37.
[13] Hu XJ, Wang JS, Liu YG, et al. Adsorption of chromium (VI) by ethylenediamine-modifiedcross-linked magnetic chitosan resin: Isotherms, kinetics and thermodynamics[J]. J Hazard Mater,2011,185:306-314.
[14] Batista AC, Villanueva ER, Amorim RV, et al. Chromium (VI) ion adsorption features of chitosan filmand its chitosan/zeolite conjugate13X film[J]. Molecules,2011,16:3569-3579.
[15] Zhong HX, Ma YL, Cao XF, et al. Preparation and characterization of flowerlikeY2(OH)5NO3·1.5H2O and Y2O3aRd theiV effcieRt Ve SZa Sf CV(VI) fVS aUYeSYs sS YtiSR[J]. J PhysChem C,2009,113:3461-3466.
[16] Karthikeyan T, Rajgopal S, and Miranda LR. Chromium(VI) adsorption from aqueous solution byHevea Brasilinesis sawdust activated carbon[J]. J Hazard Mater,2005,124:192-199.
[17] Recillas S, Colóna, Casals E, et al. Chromium(VI) adsorption on cerium oxide nanoparticles andmorphology changes during the process[J]. J Hazard Mater,2010,184:425-431.
[18] Liu SS, Chen YZ, Zhang LD, et al. Enhanced removal of trace Cr(VI) ions from aqueous solution bytitanium oxide–Ag composite adsorbents[J]. J Hazard Mater,2011,190:723-728.
[19] HO YS and Mckay G. A comparison of chemisorption kinetics models applied to pollutant removalonvarious sorbent[J]. Process Saf Environ Prot,1998(76):332-341.
[20] Rudzinski W and Panczyk T. Kinetics of isothermal adsorption on energetically heterogeneous solidsurfaces: a new theoretical description based on the statistical rate theory of interfacial transport[J]. JPhys Chem B,2000(104):9149-9162.
[21] Paria S, Khilar KC. A review on experimental studies of surfactant adsorption at thehydrophilicsolid-water interface[J], Adv Colloid Inerface Science.2004(110):75-95.
[22]冯孝庭,吸附分离技术[M].2000.化学工业出版社:3-14.
[23] Saiers JE, Hornberger GM and Liang L. First and second-order kinetics approaches for modeling thetransport of colloidal particles in porousmedia[J]. Water Resour Res,1994(30):2499-2506.
[24] Limusin G, Gaudet JP, Charlet LA, et al.Sorption isotherms: A review on physical bases, modeling andmeasurement[J]. Appl Geochem,2007(22):249-275.
[25] Kilislioglu A and Bilgin B. Thermodynamic and kinetic investigations of uranium adsorption onamberlite IR-118H resin[J]. Int J Appl Radiat Isotop,2003(5):155-160.
[26] Liu T, Zhao L, Sun D, et al. Entrapment of nanoscale zero-valent iron in chitoan beads for hexavalentchromium removal from wastewater[J]. J Hazard Mater,2010,184(1-3):724-730.
[27]林英光,皮丕辉,郑大锋等.水合氧化铈铝柱撑锂皂石对氟的吸附性能研究[J].中国环境科学,2010,30(1):52-57.
[28] Music S, Maljkovic M, Popovic S, et al. Formation of chromia from amorphous chromiumhydroxide[J]. Croat Chem Acta,1999,72:789-802.
[29] Xia L, McCreery RL.1998. Chemistry of a chromate conversion coating on aluminum alloyAA2024-T3probed by vibrational spectroscopy[J]. Electrochem Soc Interface,145:3083-3089.
[30] Bajpai J, Shrivastava R and Bajpai AK. Dynamic and equilibriumstudieson adsorptionofCr(VI)ionsontobinarybio-polymericbeadsofcrosslinked alginate andgelatin, Colloid Surf.2004(A236):81–90.
[31] Viswanathana N and Meenakshib S. Development of chitosan supported zirconium(IV)tungstophosphate composite for fluoride removal. J Hazard Mater,2010,176:459-465.
