Photochemical degradation of chromophoric dissolved organic matter

不知各位用的着否色谱图 chromatogram 色谱峰 chromatographic peak峰底 peak base峰高 h，peak height峰宽 W，peak width半高峰宽 Wh/2，peak width at half height峰面积 A，peak area拖尾峰 tailing area前伸峰 leading area假峰 ghost peak畸峰 distorted peak反峰 negative peak拐点 inflection point原点 origin斑点 spot区带 zone复班multiple spot区带脱尾 zone tailing基线 base line基线漂移 baseline drift基线噪声 N，baseline noise统计矩 moment一阶原点矩γ1，first origin moment二阶中心矩μ2，second central moment三阶中心矩μ3，third central moment液相色谱法 liquid chromatography，LC液液色谱法 liquid liquid chromatography，LLC液固色谱法liquid solid chromatography，LSC正相液相色谱法 normal phase liquidchromatography反相液相色谱法 reversed phase liquidchromatography，RPLC柱液相色谱法 liquid column chromatography高效液相色谱法 high performance liquidchromatography，HPLC尺寸排除色谱法 size exclusion chromatography，SEC凝胶过滤色谱法 gel filtration chromatography凝胶渗透色谱法 gel permeation chromatography，GPC亲和色谱法 affinity chromatography离子交换色谱法 ion exchange chromatography，IEC离子色谱法 ion chromatography离子抑制色谱法 ion suppression chromatography离子对色谱法 ion pair chromatography疏水作用色谱法 hydrophobic interactionchromatography制备液相色谱法 preparative liquid chromatography平面色谱法 planar chromatography纸色谱法paper chromatography薄层色谱法 thin layer chromatography，TLC高效薄层色谱法high performance thin layerchromatography，HPTLC浸渍薄层色谱法 impregnatedthin layerchromatography凝胶薄层色谱法 gel thin layer chromatography离子交换薄层色谱法 ion exchange thin layerchromatography制备薄层色谱法 preparative thin layerchromatography薄层棒色谱法 thin layer rod chromatography液相色谱仪 liquid chromatograph制备液相色谱仪 preparative liquid chromatograph凝胶渗透色谱仪 gel permeation chromatograph涂布器 spreader点样器 sample applicator色谱柱chromatographic column棒状色谱柱 monolith column monolith column微粒柱microparticle column填充毛细管柱 packed capillary column空心柱 open tubular column微径柱 microbore column混合柱 mixed column组合柱 coupled column预柱precolumn保护柱 guard column预饱和柱 presaturation column浓缩柱 concentrating column抑制柱 suppression column薄层板 thin layer plate浓缩区薄层板concentrating thin layer plate荧光薄层板 fluorescence thin layer plate反相薄层板 reversed phase thin layer plate梯度薄层板 gradient thin layer plate烧结板sintered plate展开室 development chamber 往复泵 reciprocating pump注射泵 syringe pump气动泵pneumatic pump蠕动泵 peristaltic pump检测器 detector微分检测器 differential detector积分检测器 integral detector总体性能检测器 bulk property detector溶质性能检测器 solute property detector(示差)折光率检测器 [differential] refractive indexdetector荧光检测器 fluorescence detector紫外可见光检测器 ultraviolet visible detector电化学检测器 electrochemical detector蒸发(激光)光散射检测器[laser] light scatteringdetector光密度计 densitometer薄层扫描仪 thin layer scanner柱后反应器 post-column reactor体积标记器 volume marker记录器 recorder积分仪 integrator馏分收集器 fraction collector工作站 work station固定相stationary phase固定液 stationary liquid载体 support柱填充剂 column packing化学键合相填充剂 chemically bonded phasepacking薄壳型填充剂 pellicular packing多孔型填充剂 porous packing吸附剂 adsorbent离子交换剂 ion exchanger基体 matrix载板 support plate粘合剂 binder流动相 mobile phase洗脱(淋洗)剂 eluant，eluent 展开剂 developer等水容剂 isohydric solvent改性剂 modifier显色剂 color [developing] agent死时间 t0，dead time保留时间 tR，retention time调整保留时间 t'R，adjusted retention time死体积 V0，dead volume保留体积 vR，retention volume调整保留体积v'R，adjusted retention volume柱外体积 Vext，extra-column volune粒间体积 V0，interstitial volume(多孔填充剂的)孔体积 VP，pore volume of porouspacking液相总体积 Vtol，total liquid volume洗脱体积 ve，elution volume流体力学体积 vh，hydrodynamic volume相对保留值 ri.s，relative retention value分离因子α，separation factor流动相迁移距离 dm，mobile phase migrationdistance流动相前沿mobile phase front溶质迁移距离 ds，solute migration distance比移值 Rf，Rf value高比移值 hRf，high Rf value相对比移值 Ri.s，relative Rf value保留常数值Rm，Rm value板效能 plate efficiency折合板高 hr，reduced plate height分离度R，resolution液相载荷量 liquid phase loading离子交换容量 ion exchange capacity 负载容量 loading capacity渗透极限 permeability limit排除极限 Vh，max，exclusion limit拖尾因子 T，tailing factor柱外效应 extra-column effect管壁效应wall effect间隔臂效应 spacer arm effect边缘效应 edge effect斑点定位法localization of spot放射自显影法 autoradiography原位定量 in situ quantitation生物自显影法 bioautography归一法 normalization method内标法 internal standard method外标法 external standard method叠加法 addition method普适校准(曲线、函数) calibration function or curve谱带扩展(加宽) band broadening(分离作用的)校准函数或校准曲线 universalcalibration function or curve [of separation]加宽校正 broadening correction加宽校正因子 broadeningcorrection factor溶剂强度参数ε0，solvent strength parameter洗脱序列eluotropic series洗脱(淋洗) elution等度洗脱 gradient elution梯度洗脱 gradient elution(再)循环洗脱 recycling elution线性溶剂强度洗脱 linear solvent strength gradient程序溶剂 programmed solvent程序压力 programmed pressure程序流速programmed flow展开 development上行展开 ascending development下行展开descending development双向展开 two dimensional development环形展开 circular development离心展开 centrifugal development向心展开 centripetal development径向展开 radial development多次展开 multiple development分步展开 stepwise development连续展开 continuous development梯度展开 gradient development匀浆填充 slurry packing停流进样 stop-flow injection阀进样 valve injection柱上富集on-column enrichment流出液 eluate柱上检测 on-column detection柱寿命 columnlife柱流失 column bleeding显谱 visualization活化 activation反冲 back flushing 脱气 degassing沟流 channeling过载 overloading。

Simultaneous photocatalytic reduction of Cr(VI)and oxidation of phenol over monoclinic BiVO 4under visible light irradiationBaoping Xie a ,Hanxia Zhang a ,Peixiang Cai a ,Rongliang Qiu b ,Ya Xiong a,*a School of Chemistry and Chemical Engineering,Zhongshan University,Guangzhou 510275,PR China bSchool of Environmental Science and Engineering,Zhongshan University,Guangzhou 510275,PR ChinaReceived 31March 2005;received in revised form 25August 2005;accepted 29August 2005Available online 16November 2005AbstractBiVO 4powder with monoclinic structure was prepared and used as a visible-light catalyst simultaneously for the photooxidation of phenol and the photoreduction of Cr(VI).The photocatalytic efficiency was found to be rather low for either single phenol solution or single Cr(VI)solution.However,the photocatalytic reduction of Cr(VI)and photocatalytic oxidation of phenol proceed more rapidly for the coexistence system of phenol and Cr(VI)than for the single process,showing synergetic effect between the oxidation and reduction reactions.For the simultaneous pho-tocatalytic reduction–oxidation process,the first-order kinetic constant of phenol degradation was 0.0314min À1,being about six times higher than that for the photocatalytic process of single phenol.This result reveals the feasibility of using Cr(VI)as the electron scavenger of m BiVO 4-mediated photocatalytic process of phenol degradation,and gives us an enlightenment to employ other semiconductor with a better visible light response but with a more positive band edge to efficiently degrade organic pollutants.This is the first report for simultaneous photocatalytic reduction of Cr(VI)and removal of phenol under visible light irradiation using photocatalyst m BiVO 4.Ó2005Elsevier Ltd.All rights reserved.Keywords:Photocatalysis;Visible light;BiVO 4;Cr(VI);Phenol1.IntroductionThe increased pollution of water and air by industrial wastes demands the application of modern pollution control technologies.The semiconductor photocatalytic degradation of harmful substrates is a comparativelynew method for the removal of pollutants from water (Legrini et al.,1993;Hoffmann et al.,1995).This photo-catalytic method is based on the reactive properties of electron–hole pairs generated in the semiconductor par-ticles under illumination with light of energy greater than the semiconductor bandgap.TiO 2has universally been recognized as one of the better photocatalysts in heterogeneous photocatalysis (Choi et al.,2000;Lee and Choi,2002).However,the driving of TiO 2-based photocatalytic processes need costly UV light and its practical application is limited as well (Yu et al.,1997;0045-6535/$-see front matter Ó2005Elsevier Ltd.All rights reserved.doi:10.1016/j.chemosphere.2005.08.064*Corresponding author.Tel.:+862084115556;fax:+862084112245.E-mail address:cesxya@ (Y.Xiong).Chemosphere 63(2006)956–963/locate/chemosphereRay and Beenackes,1998).Therefore,recently much attention has been paid to develop visible light response catalysts(Zou et al.,2001;Oshikiri et al.,2002).The motivation of these developments mainly stems from the utilization of the cheap solar energy.Monoclinic BiVO4(for short,m BiVO4)is one of these investigated visible-light catalysts.It possesses a bandgap of2.3–2.4eV,which is smaller than that of the TiO2photocatalyst(3.2eV)and shows well absorp-tion for visible light.However,most of researches for m BiVO4have been directed towards the ability of split-ting water into O2,only a few studies are associated with the removal of organic contaminants(Kudo et al.,1999; Tokunaga et al.,2001;Kohtani et al.,2002,2003).This is because,although m BiVO4possesses a valence band edge(ca.+2.4V vs.NHE)with a high oxidation activity for organic pollutants under visible light,its conduction band edge is located at ca.0V vs.NHE(pH0),thus,its photogenerated electrons cannot easily be captured by O2in air.Therefore,it is necessary tofind a suitable elec-tron scavenger with a higher redox potential in order to facilitate the m BiVO4-driven photooxidation of organic pollutants.Chromium(VI)is a frequent contaminant in waste-waters arising from industrial processes such as electro-plating,leather tanning and paint making.Its removal from wastewaters is of crucial importance because it is harmful to biological systems and can easily get into the food chains.One of the most preferred methods to treat Cr(VI)in water is the transformation to the less noxious Cr(III).Furthermore,Cr(III)can be precipi-tated in neutral or alkaline solutions as Cr(OH)3and removed as a solid waste.Thus,the conventional meth-ods of Cr(VI)elimination from aqueous phase are based on the reduction to the trivalent state by reaction with strong reducing agent at acid pH,followed by Cr(III) hydroxide formation in alkaline medium.However, among other problems,this method is not suitable for the elimination of dilute Cr(VI)solutions and requires expensive use of chemicals(Khalil et al.,1998).Consid-ering that the redox potential of Cr(VI)is+1.33V vs. NHE(pH0)for acidic condition(Ku and Jung,2001), higher than the conduction band potential of m BiVO4, it is thermodynamically possible that Cr(VI)will capture photoexcited conduction band electrons of semiconduc-tor and will be reduced to Cr(III).This possibility stim-ulated us to use Cr(VI)as the photogenerated electron scavenger in the process of m BiVO4-driven photocata-lytic oxidation of organic pollutants.Moreover,it is expected that Cr(VI)as an electron scavenger not only can increase the photocatalytic efficiency of organic pol-lution oxidation but also Cr(VI)can be reduced to the less toxic Cr(III).Phenol and its derivatives are widely used as raw materials in many petrochemical,chemical and pharma-ceutical industries.At present,the importance of phenol is proved by its ever-increasing production that reached 1900million kg in1995in the USA alone(Fortuny et al.,1998).Wastewaters that may contain many phe-nolic compounds from the industries mentioned above are highly toxic to most aquatic life.Therefore,the removal of phenol from wastewater is of environmental interest.In the present contribution,we will address the enhancement issue on the photocatalytic activity of m BiVO4towards the degradation of phenol by employ-ing Cr(VI)as both a photogenerated electron scavenger of m BiVO4and an inorganic pollutant.Aside from fun-damental considerations,the main incentive for the con-tribution is to approach the feasibility of applying the semiconductor with a higher conduction band edge to wastewater treatment using m BiVO4as an example, and at the same time,to investigate the efficiency of simultaneous photocatalytic reduction of Cr(VI)and oxidation of organic pollutant over m BiVO4under visi-ble light irradiation.2.Experimental section2.1.MaterialAnalytical grade K2Cr2O7was used to prepare Cr(VI)solution.HNO3or NaOH was used to set the correct pH value.Phenol was prepared by dissolving the solids in deionized water.Phenol and all other chem-icals used were of analytical reagent grade.2.2.Preparation and characterization of mBiVO4The m BiVO4powder was prepared using a reported aqueous process(Kohtani et al.,2002).Aqueous Bi(NO3)3Æ5H2O(0.4M)and NH4VO3(0.4M)solutions containing HNO3were prepared separately.After these two100ml solutions mixed with a Bi:V=1:1stoichiom-etric ratio,7.5g of urea was added.The mixed solution was then stirred magnetically at363K for6h.Thefinal products werefiltrated to obtain solid matter,and then sintered15min in an oven at450°C.The prepared photocatalyst was characterized by sev-eral instrumental analysis techniques.BET surface area measurement was carried out by N2adsorption at 77K using an ASAP2010volumetric adsorption ana-lyzer(Micromeritics Instrument Corp.,USA).X-ray dif-fraction(XRD)was obtained using D/Max-IIIA Diffratometer(Rigaku Corporation,Japan)with Radia-tion of Cu target(K/1,k=1.54056nm).Scanning electron microscopy(SEM)was performed on gold-coated samples using a JSM-6330F-mode Field Emis-sion Scanning Electron Microscope(JEOL,Japan). Diffuse reflectance spectrum was recorded with a UV-PC3101PC spectrophotometer(SHIMASZU,Japan)B.Xie et al./Chemosphere63(2006)956–963957with an integrating sphere(Specular Reflectance ATT.5-DEG)and BaSO4as a white standard.2.3.Experimental procedurePhotocatalytic irradiations were carried out in a 60ml cylindrical reactor,irradiated from the side, using a middle-pressure Xenon arc lamp(XHA150 W)equipped with a cut-offglassfilter transmitting k>400nm and a water jacket to remove infrared light. Air or nitrogenflow was employed in all cases to pro-duce a homogenous suspension of the catalysts in the solution.For all photocatalytic runs,a fresh solution (40ml)containing0.1mM K2Cr2O7or/and0.1mM phenol was adjusted to the desired pH,and the catalyst was suspended at1g lÀ1concentration.Prior to irradia-tion,suspensions were ultrasonicated for10min and magnetically stirred for20min in the dark at room tem-perature to ensure substrate-surface equilibration.Adsorption tests were performed in a shaker at25°C for2h.Photocatalyst(0.2g)was added into a200ml solution containing Cr(VI)or/and phenol.After2h in dark,phenol and Cr(VI)concentrations in the aqueous phase were measured.2.4.Analytical methodsAfter the run,the samples were separated from m BiVO4by centrifugation and furtherfiltered through a Millipore Millex250.45l m membranefilter.The Cr(VI)concentration in the resulting solution was deter-mined colorimetrically at540nm using diphenylcarbaz-ide as color agent(Editorial Board of Environment Protection Bureau of China,2002).Phenol concentra-tion was determined colorimetrically at510nm using 4-aminoantipyrine as color agent.Total organic carbon (TOC)was determined using a TOC-V CSH analyzer (SHIMASZU,Japan).The generation ofÅOH was determined using a recently reported method(Liu et al.,2004).A40ml aqueous solution of benzene and m BiVO4was mixed thoroughly and transferred into the cylindrical reactor. The concentration of benzene was1mM in the solution and the catalyst was suspended at1g lÀ1concentration. Different amounts of H2O2were added into the aqueous solution.Then the aqueous solution was irradiated for 30min using the same Xenon arc lamp.The control experiments without m BiVO4and in dark were carried out in parallel.After the run,the samples were separated from m BiVO4and the phenol concentrations were ana-lyzed.According to Liu et al.Õs report,ÅOH-mediated oxidation of benzene forms phenol with nearly100% yield and the phenol concentration represented the con-centration ofÅOH photoproduction.The point of zero charge of m BiVO4was determined by mass titration(Subramanian et al.,1988).Various amounts of m BiVO4powder were added to40ml fresh water and the resulting pH values were measured after 24h of equilibration.The containers of m BiVO4/water were sealed and placed on a shaker for24h,which was found to be sufficient to allow for an equilibrium pH of the mix solution to be attained.3.Results and discussion3.1.Characterization of mBiVO4BiVO4mainly possesses three crystal forms,zircon structure with tetragonal system,scheelite structure with monoclinic and tetragonal systems(Kudo et al.,1999). Only m BiVO4shows well visible light response.To investigate the crystal structure of the prepared BiVO4 in our experiment,the XRD of the BiVO4was mea-sured.The prepared BiVO4is phase pure and shows an excellent match with the published JCPDS data (JCPDSfile no:14-688)for m BiVO4.It possesses a BET surface area of3.1m2gÀ1and an average grain size of about200–300nm,as presented in Fig.1.In contrast to TiO2,the m BiVO4shows obvious absorption in visi-ble light region up to about550nm according to the observed result of its diffuse reflection spectra.The bandgap of the compound is about2.3eV through esti-mated from the absorption edge,consistent with the reported value(Kudo et al.,1999;Tokunaga et al., 2001).3.2.Dark adsorption of phenol and Cr(VI)on mBiVO4 surfaceSince the photoassisted degradation occurs predomi-nantly on the photocatalyst surface,adsorption is an important process in affecting photocatalyticdegrada-Fig.1.SEM image for m BiVO4.958 B.Xie et al./Chemosphere63(2006)956–963tion rate,therefore the adsorption performance towards phenol and Cr(VI)from aqueous solution on m BiVO4 particles was investigated.Plots of the adsorption iso-therms of phenol and Cr(VI)on m BiVO4particles are illustrated in Fig.2.As can be seen from thisfigure, no obvious adsorption of phenol was observed on the m BiVO4surface.This result is consistent with the reported data(Kohtani et al.,2003).The adsorption iso-therms of Cr(VI)at pH1.5,4.0and7.0show a type of parabolic-shape.The parabolic shape of the isotherms means that there is no strong competition between the solvent and the adsorbate to occupy the adsorbent sur-face sites,according to Giles et alÕs view(Giles et al., 1974).The experimental data of the Cr(VI)adsorption on m BiVO4wasfitted with the Langmuir equation.Thefit-ted Langmuir adsorption constants of the Cr(VI) adsorption are4.0±0.3l gÀ1at pH1.5,2.3±0.2l gÀ1 at pH4.0and0.6±0.1l gÀ1at pH7.0.The Langmuir adsorption constant at pH1.5is about5.6times higher than that at pH7.0.This fact indicates that adsorption of Cr(VI)on m BiVO4was intensively dependent on pH of the solution and a lower pH value was beneficial to the adsorption.In the Cr(VI)–phenol mixture system, the similar result of the adsorption was observed,indi-cating that phenol did not interact with the adsorption of Cr(VI).The suitable charge distribution on m BiVO4could explain no adsorption of phenol and the effect of pH on the Cr(VI)adsorption.According to the result of mass titration,the point of zero charge of m BiVO4is at pH2.7.This denotes the m BiVO4surface is positively charged below pH2.7,which favored the adsorption ofCr(VI),i.e.Cr2O2À7,while the m BiVO4surface is nega-tively charged over pH 2.7,which unbenefited the adsorption of Cr(VI).For hydrophobic phenol,the sur-face of m BiVO4with charge prohibits its movement to it and consequently rejects the adsorption.3.3.Photocatalytic performs of mBiVO43.3.1.Photocatalytic oxidation for single substrate: phenolKohtani et al.(2003)investigated the photocatalytic oxidation of phenol using BiVO4under irradiation from the solar simulator in alkaline solution.In this section, m BiVO4was tested as a photocatalyst for photooxida-tion of phenol in acidic solution under visible light irra-diation.Fig.3shows the photocatalytic efficiency for phenol photooxidation with single substrates.As can be noticed from the curve A of thisfigure,phenol could be oxidized by m BiVO4-mediated photocatalytic process in air-saturated acidic solution without added electron scavengers.At the end of a3-h photocatalytic run,the degradation of phenol reached52.0%and TOC removal was8.8%.However,the reaction is still very slow from the viewpoint of practical application.Thisfigure also shows that phenol was degraded slightly using N2as theflowing gas(curve B)and implies that the photoox-idation scarcely occurred either in the absence of photo-catalyst or when the dispersion was purged with N2gas.The photocatalytic kinetics of many organic com-pounds has often been modeled to the Langmuir–Hin-shelwood equation.However,the initial concentration of phenol was very low and the adsorption of phenol on m BiVO4was not observed according to the result of the previous section.Therefore,Langmuir–Hinshel-wood equation in this experiment can simplify to the first-order reaction kinetics.Thisfirst-order kinetics was confirmed by the linear transforms,and a rather low rate constant,0.0045minÀ1(R=0.9951),was obtained byfitting the transformed equation with the experimental data in Fig.3,curve A.B.Xie et al./Chemosphere63(2006)956–963959For semiconductor photocatalysis,a frequently dis-cussed issue is the oxidative pathway,i.e.,direct holeattack or/andÅOH radical oxidation.Fig.4shows thephotoproduction ofÅOH in various experimental condi-tions.It can be seen from thisfigure that noÅOH wasproduced in dark or under visible light without the addi-tion of m BiVO4.Moreover,noÅOH was determinedthough the benzene solution with m BiVO4but withoutH2O2was irradiated under visible light.Only whenH2O2was added to the photocatalytic system,significant ÅOH was observed and the amount ofÅOH was increased along with the amount of H2O2.Thus we can confirmindirectly that the m BiVO4-mediated degradation ofphenol in the absence of H2O2was performed by thedirect hole attack,other than byÅOH radical oxidation.At the same time,based on the fact ofÅOH absence inthe phenol and m BiVO4system,it was suggested thatthe photogenerated electrons of m BiVO4were capturedby oxygen molecule not through route of Eq.(1),possi-ble through route of Eq.(2)O2þ2Hþþ2eÀ!2ÅOHð1ÞO2þ4Hþþ4eÀ!2H2Oð2Þ3.3.2.Photocatalytic reduction for single substrate:Cr(VI)Photocatalytic reduction of Cr(VI)on TiO2has been studied by several research groups(Schrank et al.,2002;Testa et al.,2004).Most of these reduc-tions were carried out under UV irradiation,rarely under visible light irradiation.Fig.5shows the visible light-driven catalytic reduction of Cr(VI)on m BiVO4 at different pH for60min run.As can be seen in this figure,Cr(VI)could be reduced very slowly without additional hole scavengers.And moreover this reduc-tion was considerably dependent on the pH.The reduc-tion rates of Cr(VI)increased with decreasing solution pH and the trend of change was more obvious at around pH2.7.For example,the reduction efficiency of Cr(VI)at pH1.5was12.1%including5.2%adsorp-tion for60min run while the reduction of Cr(VI)was not observed basically at pH7.0.In addition,we still tested the visible light-driven catalytic reduction of Cr(VI)using m BiVO4under an N2flow,the result shows that no significant reduction of Cr(VI)was occurred under any pH.Generally,the mechanism of photocatalytic Cr(VI) reduction is well described by the capture of photo-excited conduction band electrons followed by the one-electron reduction reaction(Testa et al.,2001),and the final result of this reduction process can be simply pre-sented with Eq.(3)(Khalil et al.,1998):Cr2O2À7þ14Hþþ6eÀðconduction bandÞ!2Cr3þ7H2Oð3ÞAccording to this mechanism,in order to realize the photoreduction of Cr(VI),the conduction band of the semiconductor photocatalyst must be more negative than the reduction potential of Cr(VI)(Chen and Ray, 2001).Therefore,the energy level of the bottom of the conduction band is a measure of the reduction strength of the photogenerated electrons.Because the conduction band edge of m BiVO4is at ca.0V vs.NHE(pH0), according to the Nernstian Equation:E CBðVÞ¼0–0:059pHðat25 CÞð4Þthe positions of the conduction band of m BiVO4at pH 1.5and pH7.0are calculated to beÀ0.09V and À0.4V,respectively.The calculated result suggests the photocatalytic reduction seems to be favored at high pH.This calculation result contradicted the above experiment observation if only mBiVO4was consid-960 B.Xie et al./Chemosphere63(2006)956–963ered,however,the reduction potential of Cr(VI)also changed as pH.For example,the reduction potential of Cr(VI)is1.1V at pH1.5while it is only0.4V at pH7.0(Chen and Ray,2001).Thus,the difference of reduction potential,the driving force of the reduction reaction,between Cr(VI)and the conduction band of m BiVO4is 1.19V at pH 1.5and0.8V at pH7.0. Apparently,decreasing pH is still beneficial to Cr(VI) reduction.Besides,the obvious change of the reduction effi-ciency of Cr(VI)at about pH2.7might be associated with the surface charge of m BiVO4particles.According to the previous result,the m BiVO4surface is electro-positive below pH2.7,which favored the adsorption of Cr(VI),and the m BiVO4surface is electronegative over pH 2.7,which unfavored the adsorption of Cr(VI).Thus,surface charge of m BiVO4can partly be accounted for the decreasing of reduction efficiency of Cr(VI)on m BiVO4as the increasing of pH.In the viewpoint of the surface charge,the Cr(VI)reduction was suggested to be performed at pH<2.7.In this experiment,all the following run solutions were adopted to pH1.5.3.3.3.Photocatalytic reactions for Cr(VI)and phenol mixtureThe above experiments indicate that the m BiVO4-mediated photocatalytic degradation efficiency of single phenol in air-saturated was not satisfied since O2was not a suitable scavenger of photogenerated electrons for m BiVO4.In this section,Cr(VI)was chosen to serve as the electron scavenger to inhibit the recombination of electrons and holes.Curve A in Fig.6presents the dependence of photo-catalytic degradation efficiency of phenol on Cr(VI)con-centration at pH1.5.It can be seen that the efficiency rapidly increased with the increase of Cr(VI)concentra-tion,indicating a strong promoting effect of Cr(VI)to the degradation of phenol.For example,the addition of0.1mM Cr(VI)leaded to an2.3-time increase of the degradation efficiency for a60-min run,compared with that in the absence of Cr(VI).A kinetics constant k of 0.0314minÀ1(R=0.9832)towards phenol removal for a3-h run at this condition was also obtained by thefit of the data in Fig.7(A)using the kinetic equation of thefirst-order reaction.The kinetic constant was about six times higher than that with single phenol.Moreover, TOC determination showed the degradation extent of phenol was obviously increased also due to addition of Cr(VI).For example,the TOC removal efficiency of phenol–Cr(VI)system reached as high as59.0%for a 3-h run,being50.0%higher than that of single phenol. These increases of the degradation efficiency and extent confirmed that Cr(VI)is an efficient photogenerated electron scavenger for m BiVO4because no homoge-neous reaction between Cr(VI)and phenol was observed at this experimental condition as m BiVO4was not added.Theoretically,in this photoelectrochemical process the number of charges involved in the reduction by con-duction-band electrons and oxidation by valence-band holes must be equal,thus,one can expect that the pro-moting effect is mutual,i.e.,the presence of phenol also should enhance the photocatalytic degradation of Cr(VI).It can be seen from curve B in Fig.6that the promoting effect was directly proportional to the phenol concentration.At pH1.5,0.4mM phenol speeded up the rate of the reaction more efficiently than0.1mM phenol did.When the concentration of phenol was more than0.4mM,the Cr(VI)could be reduced almost com-pletely by photocatalytic process under visible light irra-diation within60min of reaction time while only about 13.0%reduction was reached in the absence of phenol as hole scavenge.This mutual promoting effect provides an important support using m BiVO4as a visible-light cata-lyst for efficient simultaneous removal of phenol and Cr(VI)by photocatalytic oxidation and reduction, respectively,in the same system.The selection of airflow agitation aroused an issue about other effect of air except for speeding mass trans-ferring,because the influence of dissolved oxygen on the photocatalytic reduction rate of Cr(VI)on TiO2is con-troversial at present(Chen and Ray,2001).In order to response this question,a comparative investigation of simultaneous photodegradation of Cr(VI)and phenol in the presence of either air or nitrogenflow was performed.Fig.7also gives the photocatalytic efficiencies for degradation of phenol and reduction of Cr(VI)using m BiVO4in the presence of air or N2.It can be pointed out that the photocatalytic efficiencies for degradation of phenol and reduction of Cr(VI)were about100%in the presence of N2at the end of the experiment,similarB.Xie et al./Chemosphere63(2006)956–963961to those obtained in airflow.These results seemed to be different from that in the above single photocatalytic oxidation of phenol or single photocatalytic reduction of Cr(VI).This discrepancy can be interpreted as fol-lows:Cr(VI)has high reduction driving force for acidic conditions compared with O2,thus,the reduction of Cr(VI)dominated the scavenge of the photogenerated electrons while the effect of the dissolved oxygen on the scavenge is negligible in the coexistence system of Cr(VI)and air.In other words,the airflow,similar to N2flow,only plays a role in speeding mass transferring.4.ConclusionsBiVO4powder with monoclinic structure was employed as a visible-light catalyst for the simultaneous removal of phenol and Cr(VI).Although the photocata-lytic efficiency was found to be rather low for either sin-gle phenol solution or single Cr(VI)solution,the considerable enhancement of the photocatalytic effi-ciency was observed for Cr(VI)–phenol mixture solu-tion.This enhancement effect can be attributed to a mutual promoting effect of simultaneous photocatalytic phenol oxidation and Cr(VI)reduction.This result not only reveals the feasibility of using Cr(VI)as the electron scavenger of m BiVO4-mediated photocatalytic process, but also gives us an enlightenment to employ other semi-conductor with a better visible light response but with a more positive band edge to efficiently degrade organic pollutants and to directly apply sunlight to photocata-lytic decontamination for actual wastewater containing organic and inorganic species.AcknowledgementsThis work was supported by NSF of China (20277046and29977030),NSF(04009713)of Guang-dong Province and Foundation of the Education Minis-try for the Returned Scholar from Abroad(4105483). 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专业英语absorption 吸收absolute leth al dose,LD100绝对致死量absolute humi dity 绝对湿度acid depositi on 酸沉降acid rain 酸雨activated slu dge process 活性污泥法active transp ort 主动运输acute toxicit y test 急性毒性试验acceptabledaily intake,ADI 每天容许摄入量accumulation蓄积作用activated carbon 活性碳adenine腺嘌呤additional joint action相加作用administer 给药、染毒aerobic digestion 有氧消化aerosol 气溶胶afforestation绿化allergic reaction 变态反应air 空气air analysis空气分析air-borne pollutant 空气传播污染物air cleaner空气净化器air contaminant 空气污染物air current气流airflow rate气流速度air humidity气湿air ionization 空气离子化air monitoritoring 大气监测air pollution 大气污染airpollutant大气污染物air pollutionindex 大气污染指数air pollutionsurveillancesystem 大气污染监测系统air pollutionlegislation大气污染法规air pressure气压air purification 大气自净作用air quality standard 大气质量标准air sampler 空气采样器air sanitatio n 空气卫生air sterili zation 空气消毒air temperatu re 气温air temperatu re inversion 逆温air velocit y 空气流速alkalinity 碱度alum 明矾aluminium sul fate 硫酸铝Ames test Am es试验ammonia-chlorine process氯胺消毒法ammonia-nirtiter-nitrates三氮anaerobic digestion 无氧消化anemogram风速计anion synthetic detergent阴离子合成洗涤剂antagonism 拮抗试验antergy 对抗作用argyria 银质沉着病artificial illumination 人工照明arsenic 砷artesian aquifer 承压含水层artesian fountain 自流泉artesian well自流井atmosphere compositions 大气组成automobile exhaust 汽车尾气available chlorine 有效氯back-line study 本底调查bacteriological examinationof water水质细菌学检验base-pair substitution 碱基置换benzo(a)pyrene 苯并（a）芘benzene hexachloride,BHC六六六binign tumor 良性肿瘤bioactivation 生物活化bioassay生物鉴定biochemical oxygen demand生化需氧量biodetoxication 生物解毒/生物灭活作用biogeochemicaldisease 生物地球化学性地方病biological fi lter 生物滤池biological ha lf-life 生物半减期biological tr eatment 生物处理biomembrane粘液生物膜biosphere 生物圈biotoxin 生物毒素biotransformat ion 生物转化biotransport 生物转运black-foot disease 黑脚病blank test空白试验bleaching powder 漂白粉blood/gas partition coefficient 血/气分配系数blood-brain barrier 血脑屏障blood placental barrier血-胎盘屏障burning furnace 焚烧炉carcinoma 恶性肿瘤cadmium 镉calcium hypochlorite 漂白粉精cancer 癌carbon monoxide 一氧化碳carbon monoxide poisoning一氧化碳中毒carbon tetrachloride 四氯化碳carcinogenicity 致癌性carcinogenesis致癌作用centralized water supply集中式给水chemical carcinenesis 化学致癌作用chemical carcinogen 化学致癌物chemicalteratogen 化学致畸物chemical mutagen 化学诱变物chemical oxygen consumption 化学耗氧量chemical oxygen demand 化学需氧量chlorination氯化作用chlorinator加氯器chlorine ammonia treatment氯胺处理chlorine content 含氯量chlorine dema nd 需氯量chlorine dosa ge 加氯量chlorine pois oning 氯中毒chlorine resi dual 余氯chlorobenzen e 氯苯chloroform 氯仿chlorophenotha ne,DDT 滴滴涕chromosome ab erration 染色体畸变chronic abstr icted respira tory disease 慢性阻塞性呼吸道疾病chronic toxicity test 慢性毒性试验cilia 纤毛clarification澄清、净化cloth filter布滤器coagulation混凝coagulant 混凝剂coagulation aids 助凝剂cocarcinogen促癌物coeffient ofnatural illumination 自然照度系数coliforms group 大肠菌群collection water supply system 集中式供水系统colorimeter比色计compost 堆肥comprehensiveutilization综合利用conjugation reaction 结合反应consumer 消费者conversion转化cretinism克汀病cyanide 氰化物cytosine 胞嘧啶cumulative coefficient 蓄积系数damp control 防潮daylighting自然采光decomposer 分解者defluoridation除氟degradation reaction 降解反应delayed toxiceffect 迟发性毒作用dental caries龋齿dental fluorosis 氟骨症deport 输送desalination 淡化（除盐）desertificatio n 沙漠化detoxication 解毒作用direct carcin ogen 直接致癌物direct mutage n 直接致突变物distribution 分布disinfection 消毒dissolved oxy gen 溶解氧distllation蒸馏diversity fac tor 不均匀系数DNA repair修复DNA synthesis合成dominant lethal mutationtest 显性致死突变试验dose-effect relationship剂量效应关系dose-responserelationship剂量-反应关系dust 粉尘或尘ecosystem 生态系统ecological balance 生态平衡ecosphere 生态圈effective temperature 有效温度effective size 有效粒径electrodialysis 电渗析法embryotoxicity胚胎毒性endemia 地方病endemic goiter 地方性甲状腺肿endemic fluorosis 地方性氟中毒energy flow能量流动environmentaldeterioration 环境恶化environmentaldisruption环境失调environmentalecology 环境生态学environmentalhealth standard 环境卫生标准environmentalhealth criteria 环境卫生基准environmentalhygiene 环境卫生学environmentalmonitoring环境监测environmentalpollution环境污染environmental program 环境规划environmental protection agency 环境保护局environmenta l quality st andard 环境质量标准environmental quality eva luation 环境质量评价essential ele ments 必需元素eutrophication 富营养化facilitated d iffusion 易化扩散falling dust 降尘fecal innocence treatment粪便无害化处理ferric sulfate 硫酸铁ferric trichloride 三氯化铁ferrous sulfate 硫酸亚铁filtration 过滤fluoride 氟化物fluorine 氟food chain食物链fog 雾forward mutation 正向突变frameshift mutation 移码突变free residualchlorine 游离余氯fume 烟functional accumulation 功能蓄积gene mutation基因突变genotoxic carcinogen 遗传毒性致癌物goitrogen 致甲状腺肿物质green houseeffects 温室效应green housegases 温室气体groundwater地下水guanine 鸟嘌呤hazard 危害heating 采暖heat control 降温hexavalent chromium 六价铬high risk population 高危险人群hospital sewage treatment医院污水处理humic substance /humus 腐殖质hydrocarbons碳氢化合物hygienic stan dard for dom estic drinkin g water 生活饮用水卫生标准idiosyncratic reaction 特异体质反应immediate tox ic effect 速发毒性反应impervious be d 不透水层indirect carc inogen 间接致癌物indirect muta gen 间接致突变物infrared ray 红外线inhalable particulate,IP可吸入颗粒物initiating stage 启动阶段interhalogens卤间化合物iodine deficiency disorder,IDD 碘缺乏病ionosphere电离层irreversibletoxic effect不可逆毒作用Itai-Itai disease 痛痛病Keshan disease 克山病Kashin-Beck disease 大骨节病landfill 填埋lead 铅Legionnaire’s disease 军团病lethal dose,LD 致死剂量lethal concentration,LC 致死浓度50% lethal dose,LD50 半数致死量lighting coefficient 采光系数local toxiceffect 局部毒作用London smog伦敦型烟雾long-term exposure 长期暴露long-term test 长期试验Los Angelessmog 洛杉矶烟雾manganess 锰marsh gas fermentation 沼气发酵mass-spectrometry 质谱分析法material accumulation 物质蓄积material cycle 物质循环maximal tolerance dose,LD0最大耐受量maximum allowable concentr ation,MAC 最高容许浓度median lethal dose 半数致死剂量/浓度mercury 汞metabolic act ivation 代谢活化metabolic tra nsformation代谢转化metabolic sat uration 代谢饱和metaboism 代谢metabolite 代谢产物metal compoun ds 金属化合物mesosphere 电离层methemoglobinemia 正铁血红蛋白血症micronucleus微核minimal effect level 最小有作用剂量minimal lethal dose 最小致死量minamata disease 水俣病mixed function oxidase,MFO混合功能氧化酶mono-oxygenase单氧酶molecular pollutant 分子状污染物municipal refuse 城市垃圾mutagenesis致突变作用mutant 突变体mutagen 致突变物（诱变物）mutagenicty致突变性mutation 突变neurotoxicity神经毒性nitrogen oxides 氮氧化物nitrate 硝酸盐noise protection 防噪声non-genotoxiccarcinogen非遗传毒性致癌物oligodynamicaction 微动作用oncogene 癌基因oxidation 氧化oxidation pond 氧化塘ozone 臭氧ozone depletion 臭氧层耗竭ozone layer臭氧层particulate pollutant 粒子状污染物particle matter,PM 颗粒物percolating w ater 渗滤水pervious bed 透水层persistent or ganic polluta nts(pops) 持续有机污染物pesticide 杀虫剂phagocytosis 吞噬photochemical reaction 光化学反应photochemical smog 光化学烟雾piankton 浮游生物pinocytosis吞饮pollutant standard index,PSI 污染物标准指数polyaluminiumchloride 羟基/碱式氯化铝polyacrylamide,PAA 聚丙烯酰胺point mutation 点突变polychlorinated biphenyls,PCB 多氯联polycyclic Aromatic hydrocarbons,PAH 多环芳烃precarcinogen前致癌物primary environment 原生环境primary pollutant 一次污染物rimary treatment 物理处理/一级处理producer 生产者progressing stage 进展阶段progression进展promoter 促进剂promoting stage 促进阶段promutagen 促诱变物proximate carcinogen 近致癌物pro-oncogene原癌基因public nuisance 公害pulmonary macrophages 肺巨噬细胞purification净化rapid filter快滤池red tide 红潮refuse burner垃圾焚烧炉relative humidity 相对湿度removal of hardness 软化/除硬removal of taste and odo r 除嗅味reversible to xic effect可逆毒作用risk assessme nt 危险度评估reverse osmos is 反渗透法reversional m utation 回复突变sand filtrati on 砂滤sanitary and anti-epidemi c station 卫生防疫站sanitary prot ection of wa ter source水源卫生防护sanitary regulation 卫生法规sarcoma 肉瘤saturated humidity 饱和湿度secondary environment 次生环境secondary pollution 二次污染secondary pollutant 二次污染物secondary treatment 二级处理/生物处理sedimentation沉淀selection ofwater source 水源选择selenium 硒separate water supply 分散式给水septic tank化粪池sewage works污水处理厂sewage irrigation 污水灌溉sick buildingsyndrome,SBS不良建筑物综合症silver 银simple diffusion 简单扩散skeletal fluorosis 氟骨症slow filter慢滤池smog 烟雾self-purification 自净作用soil pollution 土壤污染somatic mutation 体细胞突变SOS chromotest SOS显色试验spectrophotometer 分光光度计septic tand化粪池spontaneous mutation 自发突变storage depot 贮存库stratosphere 平流层stabilization pond 稳定塘subacute toxi city test 亚急性毒性试验subchronic to xicity test 亚慢性毒性试验sun radiation 太阳辐射susceptible p opulation 敏感人群suspending pa rticulate 飘尘sulphur dioxi de 二氧化硫surface water地面水synergistic joint action协同作用systemic toxic effect 全身毒作用target organ靶器官terate 畸胎teratology 畸胎学teratogenic effect 致畸作用teratogenicity致畸性temperature inversion 气温temperature regulation 温度调节tertiary treatment 三级处理/深度处理total organiccarbon,TOC总有机碳total hardness 总硬度total dissolved solids 溶解性总固体total bacteria count 细菌总数tolerance 耐受性toxication 中毒toxicant 毒物toxicity 毒性transition 转换transversion颠换troposphere对流层toxico-dynamics 毒效学toxico-Kinetics 毒物代谢动力学tubidity 浑浊度tumor suppressorgene 抑癌基因unscheduled DNA synthesis,UDS 程序外DNA合成ultimate carcinogen 终致癌物ultraviolet r ay 紫外线visible light 可视线volatile orga nic compounds ,VOCs 挥发性有机物volatile phen olic compound s 挥发酚类waste disposa l 垃圾处理waste recycli ng 废物回收利用waste residue 废渣waste scaveng ing 废物清除wind 气流。

光异构反应释放氧离子英文回答：Heterogeneous photocatalysis is a process that involves the use of a photocatalyst to initiate a chemical reaction under light irradiation. This process is widely used in various applications, including environmental remediation, energy conversion, and organic synthesis. One of the key features of heterogeneous photocatalysis is the release of oxygen ions during the reaction.The release of oxygen ions in heterogeneous photocatalysis is primarily attributed to the oxidation of water molecules. In the presence of a suitable photocatalyst, such as titanium dioxide (TiO2), water molecules can be split into oxygen ions (O2-) and hydrogen ions (H+). This process is known as water oxidation and is a crucial step in the overall reaction.To illustrate this process, let's consider thephotocatalytic degradation of organic pollutants in water using TiO2 as the photocatalyst. When TiO2 is exposed to light, it absorbs photons and generates electron-hole pairs. The photogenerated holes (h+) on the surface of TiO2 can react with water molecules, leading to the formation of hydroxyl radicals (OH•) and oxygen ions (O2-):TiO2 + h+ + H2O → TiO2 + OH• + O2-。

光催化降解染料英文Title: Photocatalytic degradation of dyes: An effective approach for wastewater treatmentAbstract:The textile industry is one of the world's largest contributors to water pollution due to its extensive use of dyes. These dyes not only pose a threat to aquatic ecosystems but also have adverse effects on human health. Traditional wastewater treatment methods are often ineffective in removing dyes from wastewater, leading to their persistence in the environment. In recent years, researchers have turned their attention towards photocatalytic degradation as a promising approach for the efficient removal of dyes. This review aims to provide an in-depth analysis of the principles, mechanisms, and applications of photocatalytic degradation in the treatment of dye-containing wastewater. The efficiency of different photocatalysts, the influence of key parameters, and the challenges related to scaling up the process are discussed. Moreover, the potential use of advanced materials and emerging techniques are presented to further enhance the overall performance of photocatalysis in dye degradation. This review highlights the importance of photocatalytic degradation as an environmentally friendly and economically feasible method for wastewater treatment in the textile industry.1. Introduction:1.1 Background1.2 Importance of wastewater treatment in the textile industry1.3 Problem statement2. Dye degradation mechanisms:2.1 Photocatalysis principles2.2 Photocatalysts for dye degradation2.3 Key parameters affecting the photocatalytic process2.4 Mechanisms of dye degradation3. Photocatalysts for dye degradation:3.1 TiO2-based photocatalysts3.2 ZnO-based photocatalysts3.3 Other metal oxide photocatalysts3.4 Doped photocatalysts3.5 Nanostructured photocatalysts4. Key parameters influencing photocatalysis:4.1 Light source and intensity4.2 Catalyst concentration and loading4.3 pH and temperature4.4 Dye concentration and type4.5 Co-existing components5. Challenges and future prospects:5.1 Scale-up challenges5.2 Catalyst recovery and reuse5.3 Cost-effectiveness5.4 Integration with other treatment methods5.5 Advanced materials and techniques6. Applications and case studies:6.1 Photocatalytic degradation in textile wastewater treatment 6.2 Case studies on different dye classes6.3 Comparison with other wastewater treatment methods7. Conclusion:7.1 Summary and key findings7.2 Recommendations for future research7.3 Implications and benefits of photocatalytic degradationIn conclusion, photocatalytic degradation has emerged as a promising approach for effectively treating dye-containing wastewater in the textile industry. The principles, mechanisms, and applications of photocatalysis have been extensively investigated, and numerous case studies have demonstrated its effectiveness in dye degradation. However, efforts should be directed towards addressing the challenges associated with scaling up the process, catalyst recovery, and cost-effectiveness to ensure the practical implementation of photocatalytic degradation in large-scale wastewater treatment plants. The integration of advanced materials and emerging techniques holds great potential in further improving the efficiency and performance of photocatalysis. Therefore, future research should focus on developing innovative solutions to overcome these challenges and establish photocatalytic degradation as a sustainable and economically feasible method for wastewater treatment in the textile industry.。

专利名称：PHOTOELECTROCHEMICALDETERMINATION OF CHEMICAL OXYGENDEMAND发明人：ZHAO, Huijun申请号：AU2004000438申请日：20040405公开号：WO04/088305P1公开日：20041014专利内容由知识产权出版社提供摘要：A method for determining chemical oxygen demand of a water sample comprises the steps of (a) applying a constant potential bias to a photoelectrochemical cell, having a photoactive working electrode (e.g. a layer of titanium dioxide nanoparticles coated on an inert conductive substrate) and a counter electrode, and containing a supporting electrolyte solution; (b) illuminating the working electrode with a light source and recording the background photocurrent produced at the working electrode from the supporting electrolyte solution; (c) adding a water sample, to be analysed, to the photoelectrochemical cell; (d) illuminating the working electrode with a light source and recording the total photoelectrocurrent produced with the sample; (e) determining the chemical oxygen demand according to the type (exhaustive or non-exhaustive) of degradation conditions employed. An apparatus for carrying out the method is also claimed.申请人：ZHAO, Huijun地址：AU,AU国籍：AU,AU代理机构：MISCHLEWSKI, Darryl 更多信息请下载全文后查看。

第35 1期2019 1 月无机 化 学学报CHINESE JOURNAL OF INORGANIC CHEMISTRYVol.35 No.1 43-49两个基于多金属氧簇和咪唑类化合物的有机-无机杂化物的合成及性质周欣叶晶王志花靳素荣！(武汉理工大学化学化工与生命科学学院，武汉430070)摘要：在室温条件下合成了2个多金属氧簇化合物(HbiBp)3(PM 〇i2〇4〇).biBp(l )和(HbiB)3(PM 〇i2〇4〇).biB(2)(biBp=苯并咪唑基苯酚，bid=苯并咪唑)&通过红外、元素分析和X 射线单晶衍射分析对2个化合物进行了表征。

化合物中多酸阴离子与有机组分通过氢 键、静电引力及！-!堆积作用形成一维链多金属氧簇化合物晶。

电化 研表化合物l 和2 有 氧化。

光催化研究结果显示化合物l 和化合物2对罗丹明B 和亚基蓝具有良好的光催化降解作用。

关键词：多金属氧酸盐（有机组分；晶体结构；光催化降解中图分类号：O ei-.ei^ 文献标识码：A文章编号：1001-4861(2019)01-0043-07DOI ： 10.11862/CJIC.2019.023Two Inorganic-Organic Hybrid Crystals Based on Polyoxometallatesand Imidazole Compounds: Syntheses and PropertiesZ H O U Xin Y E Jing W A N G Zhi-Hua JIN Su-Rong!(School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China)Abstract ： Two one-dimensional chain polyoxometallic cluster compounds connecting poly-acid anions withorganic components benzimidazolyl phenol(bidp) or benzimidazole(bid) by hydrogen bond, electros tatic attraction andstacking have been synthesized a t room temperature, which are (Hbidp)3(PMo 12O 4〇) • bidp (l) and (Hbid)3(PMo 12O 4〇)'bid (2), and they have been unequivocally characterized by IR spectroscopy, complete elemental analysis and single crystal X-ray diffraction. The cyclic voltammogran indicted that compounds land 2 have excellent redox properties. The photocatalytic performance of compounds land 2 were investigated with photodegradation of methylene blue (M B ) and rhodamine B (RhB) with U V irradiation. C C D C : 1458018, l; 1469803, 2.Keywords ： polyoxometalate; organic components; crystal structure; photocatalytic degradation多属氧酸 有 氧和氧原子，一 机，用多个氧原子与有机化合物有有机-化 & 和多样性，在、化、 有在用k 1-5】。

S S环境保护工程Environmental Protection Engineering由于藻类大多生活在水体表面，漂浮型纳米材料能够提高材料和藻细胞的有效接触，使光催化材料变得更具有针对性。

并且漂浮型纳米材料能够更有效地利用太阳光能，提高作用速度和除藻效果，而漂浮的特点使纳米材料更易于回收，减少纳米材料对生态环境产生的二次污染。

Wang等心％用简单的溶胶-凝胶法将F-Ce-Ti02负载在膨胀珍珠岩上用来去除铜绿微囊藻，在9 h光照后对藻的去除率达到98.1 %，并且制备出了 PDDA@NPT-EGC用来去除铜绿微囊藻及其所释放的藻毒素。

5结论与展望蓝藻水华问题日益严重，已经成为当今世界上许多国家的心腹大患，解决蓝藻水华问题迫在眉睫，但是目前已有的处理方法均有一些不足，限制了它们的大范围推广应用。

传统的粉末状纳米光催化材料因不易回收且在实际使用中存在巨大的隐患，使其应用也受到了一定限制，所以现有研究将其搭载固定在某个载体上，可以使其适用于不稳定复杂相体系。

而不同漂浮载体和负载方法也会对材料产生影响。

上述研究目前仍处于试验阶段，还需要进一步探索，笔者对已有的一些漂浮型纳米材料进行了总结，以期为今后的相关研究提供参考。

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