超声辅助电催化氧化降解水杨酸的研究庄琳懿

2552006　10　　四　川　环　境SICHUANENVIRONMENT　　Vol.25,No.5October　2006··:2006-03-31:(20010247004):(1979-),,,2004。。庄琳懿1,马　前1,宋卫峰2,倪亚明1(1.、、,　200092;2.,　510090)　　:通过对水杨酸降解的UV扫描吸收光谱的研究表明,在水杨酸的电催化氧化和超声辅助电催化氧化降解过程中,都有吸收紫外光的中间体生成,对吸光度峰值随降解反应时间的变化关系进行非线性最小二乘法拟合(NLSF),发现其衰减均符合表观一级反应动力学规律;而COD值的衰减也都符合表观一级反应动力学规律。GC-MS检测到水杨酸超声辅助电催化氧化降解60min后,有中间产物甲酸、乙酸、苯酚,认为是水杨酸在·OH的作用下,开环氧化降解生成乙酸和甲酸等小分子有机物,最后降解为二氧化碳和水。　　:;;;;:X703.1　　　　:A　　　　:1001-3644(2006)05-0004-05StudyontheUltrasound-assistedElectro-catalyticOxidationofSalicylicAcidinWaterZHUANGLin-yi1,MAQian1,SONGWei-feng2,NIYa-ming1(1.DepartmentofChemistry,SchoolofLifeScience&Technology,StateKeyLaboratoryofPollutionControlandResourceReuse,TongjiUniversity,Shanghai200092,China;2.SchoolofEnvironmentalScience&Engineering,GuangdongUniversityofTechnology,Guangzhou510090,China)　　Abstract:Theelectro-catalyticoxidationandultrasound-assistedelectro-catalyticoxidationwereusedrespectivelytothedegradationofsalicylicacid.ThroughUVscanningspectra,itcanbeprovedsomeintermediatesthatcanabsorbtheUVlightwereproducedinthedegradationreaction.TheabsorbancepeakvariedwithreactiontimeandtherelationshipwasprocessedbyNLSF.Theresultsshowedthatthereductionsofrelativeabsorbancepeakofthesolutionstreatedbythetwowaysbothmetthepseudofirst-orderreactionkinetics.Theintermediateformicacid,aceticacidandphenolweredetectedbyGC-MSafter60minofthedegradation.Itprovedthatsalicylicacidwasfirstdegradedintosmall-sizeorganiccompoundsbyhydroxylradicals,andfinallyintocarbondioxideandwater.Keywords:Electro-catalyticoxidation;ultrasound;salicylicacid;intermediate;mechanism　　,,,,,[1]。,、,、,,,/H2O2/O2[2],,TiO2,[3],[1]TiO2,,。TiO2,[4]。TiO2,[5],TiO2[6]。,Al2O3[7],[8]、[9],。,·OH[10,11]、O3[12]、H2O2[13]DOI:10.14034/j.cnki.schj.2006.05.002,,,,。、[14],[15]。,,,[16]。,、,[17]。[18],。,[19,20]、[21]、[22]。,[23,24]。,,,。1　实验部分1.1　(AR,),(AR,),(AR,),(AR,)。1.2　　　(200mL)11.SnO2/Sb2O5/Ti;2.Ti;3.;4.pH;5.;6.1　Fig.1　Experimentalsystemforultrasound-assistedcatalyticelectrolysis,。,2.0mL,COD,pH。1.3　1.3.1　COD值的测定,、、,5.15%,102%[25]。30min,140℃。1.3.2　UV分光光度扫描分析UVLambdaBio40UV(PE)。2mL10mL,2mL10-2mol/LNaOH,,pH10.3。2mL10.0g/LNa2SO4,λ=200～400nmUV,UV。6nm/s。1.3.3　GC-MS分析200mL,50mL3,,0.5mL,GC-MS。GC-MSFinniganVoy-ager-。HP-INNOWax(30m×0.25mm,0.25μm),50℃(2min)～250℃(10min),15℃/min。0.5μL,(He)1.0mL/min,15∶1。EI,70eV,200℃;400V,100mA。35～500amu,0.5/。NIST。2　结果与讨论2.1　(SA)f=20kHz,27.1W/cm2,pH10.0,Na2SO4CNa2SO4=10.0g/L,i=5mA/cm2,T=20℃,120min,COD。COD2。　　2,COD(NLSF),,55:2　CODFig.2　VariationinCODvalueduringECOandUSECOprocessesofSACOD,1。1　CODTab.1　Thepseudo-first-orderrateconstantsofCODremovalduringSAdegradationprocessesk1,COD(min-1)(ECO)0.0078±0.0002(USECO)0.0125±0.0003　　1,,COD;,COD(k1,COD)。,,、[26],,。2.2　(SA)UV2.2.1　水杨酸的UV扫描吸收光谱UV3、4。　　3、4,(t=0)235nm298nm,。,。2.2.2　水杨酸的吸光度峰值变化(λ=298nm)λ=298nm3　Fig.3　UVabsorptionspectraduringtheelectro-catalyticoxidationofSA4　Fig.4　UVabsorptionspectraduringtheultrasound-assistedelectro-catalyticoxidationofSA()5。5　(λ=298nm)Fig.5　VariationinpeakabsorbanceduringSAdegradation　　5,,;,。6　　　　四川环境25(NLSF),,2。2　(λ=298nm)Tab.2　TheapparentdecreasingrateconstantsofpeakabsorbanceduringSAdegradationk1,SA(min-1)(ECO)0.0171±0.0007(0～15min)0.0078±0.0002(15～120min)(USECO)0.0169±0.0013　　2,,。,,。,(0～15min),;(15～120min),,。COD(1)。2.3　GC-MS60min(2.1),GC-MS(1.3.3),。2.3.1　水杨酸降解的中间产物GC-MS60min、、,6、78()。6　Fig.6　Themassspectrogramofformicacid(M=46)7　Fig.7　Themassspectrogramofaceticacid(M=60)8　Fig.8　Themassspectrogramofphenol(M=94)2.3.2　水杨酸的降解过程、、·OH,,;·OH,、[2,27]。·OH,,,、,。　　,1981Ramsay[28]2,6-·OH,pH=7,。2001pH=11,Ramsay·OH。,H2O2,pH,,·OH,,·OH,·OH,[29]。,,·OH9。9　·OHFig.9　ProposedreactionpathwaysofSAdecompositionbyhydroxylradicals75:3　结　论CODUV,(NLSF)COD,COD,0.00780.0125min-1。,COD(k1,COD)。UV(298nm),,。298nm,,,;GC-MS60min、、。:[1]　　,,　.TiO2[J].(),2005,13(1):93-96.[2]　ChristophKScheck,FritzHFrimmel.Degradationofphenolandsali-cylicacidbyultravioletradiation/hydrogenperoxide/oxygen[J].Wa-terResearch,1995,29(10):2346-2352.[3]　CSu,BYHong,CMTseng.Sol-gelpreparationandphotocatalysisoftitaniumdioxide[J].CatalysisToday,2004,96(3):119-126.[4]　　,,,.:[J].,2005,25(6):756-760.[5]　KChhor,JFBocquet,CColbeau-Justin.Comparativestudiesofphe-nolandsalicylicacidphotocatalyticdegradation:influenceofabsorbedoxygen[J].MaterialsChemistryandPhysics,2004,86(15):123-131.[6]　LevDavydov,EttireddyPReddy,PaulFrance,etal.Sonophotocat-alyticdestructionoforganiccontaminantsinaqueoussystemsonTiO2powders[J].AppliedCatalysisB:Environmental,2001,32(1～2):95-105.[7]　MathiasErnst,FranckLurot,Jean-ChristopheSchrotter.Catalytico-zonationofrefractoryorganicmodelcompoundsinaqueoussolutionbyaluminumoxide[J].AppliedCatalysisB:Environmental,2004,47(1):15-25.[8]　,,,.[J].,2005,6(1):62-67.[9]　MartaOtero,CarlosAGrande,AlirioERodrigues.Adsorptionofsali-cylicacidontopolymericadsorbentsandactivatedcharcoal[J].Reac-tiveandFunctionalPolymers,2004,60:203-213.[10]　AlexanderKraft,ManuelaStadelmann,ManfredBlaschke.Anodicoxi-dationwithdopeddiamondelectrodes:anewadvancedoxidationpro-cess,anewadvancedoxidationprocess[J].JournalofHazardousMa-terials,2003,103(3):247-261.[