摘要
电极材料及其制备方法是影响电极涂层的表面结构,从而影响电极的电催化氧化性能的一个主要因素,本文以Ce、Y、La、Nd稀土元素和Mn元素掺杂的Ti/SnO_2-Sb改性电极的制备及性能评价为主要研究内容,以对氯苯酚(4-CP)为电化学氧化降解目标物,初步探讨了4-CP的电化学催化氧化降解转化机理,以及电极结构与电催化氧化活性之间的关系。
本文以溶胶凝胶法分别制备了Ti/SnO_2-Sb涂层电极,稀土掺杂Ti/SnO_2-Sb涂层电极和Mn掺杂Ti/SnO_2-Sb涂层电极。利用SEM、EDX、XRD、XPS等现代分析工具对电极的形貌、结构进行表征,利用电化学工作站,紫外可见分光光谱(UV-vis)和高效液相色谱(HPLC)对电极降解4-CP的机理过程进行了探讨,并确定了热处理温度,Sb、Mn和稀土掺杂比例等工艺条件。
实验研究表明,热处理温度为500℃时为Ti/SnO_2-Sb电极最佳制备温度;Sb、稀土元素和Mn的掺杂对SnO_2涂层电极的电催化活性都有一定的提高,其中稀土元素Ce、Y、La、Nd中La元素的掺杂表现的对4-CP降解优势最为明显;通过试验确定了Sb掺杂量在6%,La掺杂量在1.5%,Mn掺杂量在6%时,提高电极电催化活性效果相对最好;通过高效液相色谱对电极降解4-CP的机理过程分析如下:Ti/SnO_2-Sb电极和稀土掺杂的Ti/SnO_2-Sb电极电化学氧化作用将4-CP降解反应生成以对苯醌为主体的中间产物,最终对苯醌被进一步开环降解为丁烯二酸等物质,丁烯二酸等被进一步氧化降解,最终生成二氧化碳和水;Mn掺杂的Ti/SnO_2-Sb电极则将4-CP降解反应生成以邻苯醌为主体的中间产物,最终邻苯醌被进一步开环降解为丁烯二酸等物质,丁烯二酸等被进一步氧化降解,最终生成二氧化碳和水。
Surface structure of electrode coating is affected greatly by electrode materials and the preparation methods, thus it is a key effect factor to the electrocatalytic oxidation properties. In this paper, the preparation and performance evaluation of Mn, Ce, Y, La, Nd and other rare earth elements which doped into the Ti/SnO_2-Sb electrodes were discussed. At the same time, chlorophenol (4-CP) was selected as the target of electro-catalytic degradation. It was preliminary investigated the mechanism of electrochemical oxidation degradation and transformation, and the the relationship between the electro-catalytic properties and the electrode structure was discussed in detail.
In this paper, Sol-Gel method were employed to prepared Ti/SnO_2-Sb coated electrode, Mn doped Ti/SnO_2-Sb electrode and rare earth doped Ti/SnO_2-Sb coated electrode. SEM, EDX, XRD, XPS were used to characterize the morphology and structure of as-prepared electrode. Electrochemical workstation, UV-visible spectrophotometer (UV-vis) and high performance liquid chromatography (HPLC) were used to analyze the degradation process of 4-CP from the angle of mechnisam. Meanwhile, operating parameters, such as the heat treatment temperature, the doping ratio of Sb, Mn and rare earth element were defined.
Experimental results showed that, the optimal heat treatment temperature for the Ti/SnO_2-Sb electrode was 500℃. The electrocatalytic activity of SnO_2 coated electrode can be improved by doping Sb, Mn and rare earth elements,and the doping effect of rare earth elements, such as Ce, Y, La, Nd is better than the doping effect of Mn. In addition, La showed the best performance in the four rare earth elements. Sb doped percentage at 6%, La’s at 1.5%, and Mn’s at 6% is the best ratios for the catalytic activity of prepared electrode, inspectively. Based on the HPLC results the mechanism of degradating 4-CP was introduced as follow: P-benzoquinone was the main by-product during the raction process of 4-CP degradation using electrocatalytic Ti/SnO_2-Sb electrodes and rare earths doped Ti/SnO_2-Sb as electrodes. Finally, P-benzoquinone was degraded to maleic acid and other substances, which can be furtherly degradated into CO_2 and H2O. While Mn doped Ti/SnO_2-Sb electrodes degradate 4-CP into O-benzoquinone, which was as the main intermediate. Then O-benzoquinone was degraded to maleic acid and other substances, maleic acid and other substances are furtherly degradated and ultimately generated carbon dioxide and water.
引文
[1]张春杨,王香玲,张壮志.高浓度有机污水生物处理方法研究进展[J].安徽农业科学, 2007, 35(31): 10007-10009.
[2]陈旭东,李朝霞,孟令尧.高浓度有机废水处理技术研究进展[J].河北化工, 2008, 12(03): 71-73.
[3]吴为中,冯叶成,王建龙.不动杆菌(Acinetobacter sp.)降解4-氯酚的特性及机制研究[J].环境科学,2008, 29(11): 3186-3188.
[4]姜元臻,韦朝海,任源,等.活性炭纤维催化臭氧氧化去除废水中4-氯酚的分析[A].中国化学会.第四届全国环境化学学术大会论文汇编[C].南京:中国化学会, 2007, 457-458.
[5]冯凯,邱木清.生物法处理染料废水的研究与进展[J].工业水处理, 2009, 29(2): 19-21.
[6]杨立新.生物法在我国轻工业有机废水处理中的应用与进展[J].鞍山钢铁学院学报, 2001, 24(4): 251-255.
[7]信欣,王焰新,叶芝祥,等.生物强化技术处理高盐有机废水[J].水处理技术, 2008, 34(8): 66-70.
[8]王香爱.我国微生物法水处理技术的研究进展[J].化工科技, 2009, 17(2): 50-54.
[9]施国键,乔俊莲,郑广宏,等.电化学氧化处理生物难降解有机废水的研究进展[J].化工环保, 2009, 29(4): 326-330.
[10]刘海音,周春丽,张强.有机废水生物处理及综合利用技术的研究进展[J].安徽农业科学, 2009, 37(16): 7630-7631.
[11]杨晓丽.高浓度有机废水的生化处理研究[J].化学工业与工程技术, 2008, 29 (3): 35-37.
[12]吴跃辉,吴少林,刘元隆,等.工业有机废水高级处理的方法与技术[J].江西化工, 2003, 47(16): 21-25.
[13] Sohn YS, Smith YR, Misra M, et al. Electrochemically assisted photocatalytic degradation of methyl orange using anodized titanium dioxide nanotubes [J]. Applied Catalysis B: Environmental, 2008, 84: 372-378.
[14] Feng Y, Cui YH, Liu J, et al. Factors affecting the electro-catalytic characteristics of Eu doped SnO2/Sb electrode [J]. Journal of Hazardous Materials, 2010, 178: 29-34.
[15] Cui YH, Feng YJ, Liu ZQ. Influence of rare earths doping on the structure and electro-catalytic performance of Ti/Sb-SnO2 electrodes [J]. Electrochimica Acta, 2009, 54: 4903-4909.
[16] Chen X, Yao P, Wang D, et al. Antimony and cerium co-doped tin oxide electrodes for pollutant degradation [J]. Chemical Engineering Journal, 2009, 147: 412-415.
[17]王倩.电-催化湿式氧化处理苯酚废水的协同作用研究[D].上海:同济大学环境科学与工程学院, 2008.
[18]许涛,宋国勇.难降解有机废水的高级氧化技术[J].辽宁城乡环境科技, 2005, 25(3): 44-46.
[19]蒋永生,唐华龙.超声波在废水处理中的应用研究现状[J].重庆工商大学学报(自然科学版), 2005, 22(1): 25-29.
[20]芮延年,王明娣,刘鑫培,等.高浓度、难降解有机污水超声裂解处理关键技术的研究[J].苏州大学学报(工科版), 2006, 26(4): 1-6.
[21] Park KW, Han SB, Lee JM. Photo(UV)-enhanced performance of Pt-TiO2 nanostructure electrode for methanol oxidation [J]. Electrochemistry Communications, 2007, 9: 1578-1581.
[22]肖小明,李洪青,邹华生.超声波降解有机污染物的研究与发展[J].环境科学与技术, 2003, 26(1): 84-86.
[23]周军,金奇庭.电解法处理废水的研究进展[J].水处理技术, 2000, 26(3): 728-731.
[24]申哲民,雷阳明,贾金平,等. PbO2电极氧化有机废水的研究[J].高校化学工程学报, 2004, 18(1): 105-108.
[25]施国键,乔俊莲,郑广宏,等.电化学氧化处理生物难降解有机废水的研究进展[J].化工环保, 2009, 29(4): 326-330.
[26]张招贤.钛电极学导论[M].北京:冶金工业出版社, 2008, 87-88.
[27]张招贤.钛电极学导论[M].北京:冶金工业出版社, 2008, 90-92.
[28] Yi Q, Li L, Yu W, et al. Hydrothermal synthesis of titanium-supported PtIrRu/Ti electrode and its electrocatalytic activity [J]. Journal of Alloys and Compounds, 2008, 466: 52-58.
[29] Yang X, Zou R, Huo F, et al. Preparation and characterization of Ti/SnO2-Sb2O3-Nb2O5/PbO2 thin film as electrode material for the degradation of phenol [J]. Journal of Hazardous Materials, 2009, 164: 367-373.
[30]杨耀辉.铈掺杂Ti/Sn-Sb阳极制备及催化氧化苯酚研究[D].辽宁:大连理工大学, 2009.
[31]方宁,贾金平,钟登杰,等.掺硼金刚石薄膜电极在水处理中应用的研究进展[J].环境污染与防治, 2007, 29(9): 708-712.
[32] Langeloth M, Chiku M, Einaga Y. Anodic stripping voltammetry of zinc at boron-doped diamond electrodes in ammonia buffer solution [J]. Electrochimica Acta, 2010, 55: 2824-2828.
[33]刘峰斌,汪家道,刘兵,等.掺硼金刚石薄膜的电化学性能[J].功能材料与器件学报, 2005, 11(3): 295-298.
[34]张招贤,张建华. IrO2/Ta2O5涂层钛电极电化学性能的研究[J].广东有色金属学报, 2004, 14(2): 98-100.
[35] Cestarolli DT, De Andrade AR. Electrochemical and morphological properties of Ti/Ru0.3Pb(0.7-x)TixO2-coated electrodes [J]. Electrochimica Acta, 2003, 48(2): 4137-4142.
[36] Wang X, Tang D, Zhou J. Microstructure, morphology and electrochemical property of RuO270SnO230mol% and RuO230SnO270mol% coatings [J]. Journal of Alloys and Compounds, 2007, 430: 60-66.
[37] Zhang L, Tian DB, Zhu JJ. Direct electrochemistry and electrochemical catalysis of myoglobin-TiO2 coated multiwalled carbon nanotubes modified electrode [J]. Bioelectrochemistry, 2008, 74: 157-163.
[38] Yao P, Chen X, Wu H, et al. Active Ti/SnO2 anodes for pollutants oxidation prepared using chemical vapor deposition [J]. Surface & Coatings Technology, 2008, 202: 3850-3855.
[39]梁镇海,张福元,樊彩梅,等.钛基二氧化锡电极的制备及性能研究[J].稀有金属材料与工程, 2007, 36(2): 278-281.
[40] Marti CA, Battisti AD, Ferro S, et al. Removal of the Pesticide Methamidophos from Aqueous Solutions by Electrooxidation using Pb/PbO2, Ti/SnO2, and Si/BDD Electrodes [J]. Environmental Science & Technology, 2008, 42: 6929-6935.
[41] Ardizzone S, Bianchi CL, Borgese L, et al. Physico-chemical characterization of IrO2-SnO2 sol-gel nanopowders for electrochemical applications [J]. Journal of Applied Electrochemistry, 2009, 39(11): 2093-2105.
[42] Li M, Feng CP, Zhang ZY, et al. Efficient electrochemical reduction of nitrate to nitrogen using Ti/IrO2-Pt anode and different cathodes [J]. Electrochimica Acta, 2009, 54(20): 4600-4606.
[43] Guglielmi M, Menegazzo E, Paolizzi M, et al. Sol-gel deposited Sb-doped tin oxide films [J]. Journal of Sol-Gel Science and Technology, 1998, 13(1-3): 679-683.
[44] Putz J, Ganz D, Gasparro G, et al. Influence of the heating rate on the microstructure and on macroscopic properties of sol-gel SnO2: Sb coatings [J]. Journal of Sol-Gel Science and Technology, 1998, 13(1-3): 1005-1010.
[45]李家亮,姜洪义,牛金叶等.透明导电氧化物薄膜的研究现状及展望[J].现代技术陶瓷, 2006, 27(1): 19-23.
[46] Kotz R, Stucki S, Carcer B. Electrochemical waste water treatment using high overvoltage anodes. Part I: Physical and electrochemical properties of SnO2 anodes [J]. Journal of Applied Electrochemistry, 1991, 21(2): 14-20.
[47] Comninellis C. Electrochemical treatment of wastewater containing phenol [J]. Process Safety & Environmental Protection, 1992, 70: 219-224.
[48] Grimm F, Bessarabov D, Maier W, et al. Sol-gel film-preparation of novel electrodes for the electrocatalytic oxidation of organic pollutants in water [J]. Desalination, 1998, 115(3): 295-302.
[49] Li XY, Cui YH, Feng YJ, et al. Reaction pathways and mechanisms of the electrochemical degradation of phenol on different electrodes [J]. Water Research, 2005, 39(10): 1972-1981.
[50] He DL, Mho S. Electrocatalytic reactions of phenolic compounds at ferric ion co-doped SnO2: Sb5+ electrodes [J]. Journal of Electroanalytical Chemistry, 2004, 568(1-2): 19-27.
[51] Feng YJ, Cui YH, Wang JJ. Preparation and characterization of Dy doped Ti-base SnO2/Sb electro-catalytic electrodes [J]. Chinese Journal of Inorganic Chemistry, 2005, 21(6): 836- 841.
[52]李善评,付敬,胡振.稀土Y改性Ti/Sb2O5-SnO2电催化电极的制备及表征[J].山东大学学报(理学版), 2008, 43(9): 22-26.
[53] Triki M, Ksibi Z, Ghorbel A, et al. Preparation and characterization of CeO2-TiO2 support for Ru catalysts: Application in CWAO of p-hydroxybenzoic acid [J]. Microporous and Mesoporous Materials, 2009, 117: 431-435.
[54] Ai SY, Gao MN, Zhang W, et al. Preparation of Ce-PbO2 modified electrode and its application in detection of anilines [J]. Talanta, 2004, 62: 445-450.
[55] Yamamura H, Nishino H, Kakinuma K. Relationship between oxide-ion conductivity and dielectric relaxation in the Ln2Zr2O7 system having pyrochore-type compositions (Ln= Yb, Y, Gd, Eu, Sm, Nd, La) [J]. Journal of Physics and Chemistry of Solids, 2008, 69: 1711-1717.
[56] Santana MHP, De Faria LA. Oxygen and chlorine evolution on RuO2 +TiO2+CeO2+Nb2O5 mixed oxide electrodes [J]. Electrochimica Acta, 2006, 51: 3578-3585.
[57]王静,冯玉杰.溶胶-凝胶法制备稀土Gd掺杂SnO2电催化电极的实验研究[J].环境污染治理技术与设备, 2005, 6(7): 19-24.
[58]李善评,胡振,孙一鸣,等.新型钛基PbO2电极的制备及电催化性能研究[J].山东大学学报(工学版), 2007, 37(3): 109-113.
[59]吕彦玲,邵光杰,赵北龙,等.稀土镧掺杂MnO2电极的制备及性能研究[J].中国稀土学报, 2009, 27(5): 652-656.
[60]宋汶,肖代红,贺跃辉,等.稀土元素对AI-Cu-Mg-Ag合金显微组织影响的研究进展[J].中国有色金属学报, 2009, 19(8): 1355-1365.
[61]石富.稀土电解槽的研究现状及发展趋势[J].中国稀土学报, 2007, 25(1): 70-76.
[62]甄博如.电催化电极的制备及其用于难降解有机废水处理的研究[D].山东:山东大学, 2007.
[63]卞文娟,周明华,雷乐成.高压脉冲液相放电降解水中邻氯苯酚[J].化工学报, 2005, 56(1): 152-156.
[64]邹忠,李吉,丁凤其,等.稀土Eu掺杂对金属氧化物涂层阳极电催化性能的影响[J].中国有色金属学报, 2001, 11(1): 91-94.
[65]王运革,林纪筠,陈康宁.含稀土化合物的金属阳极涂层研究(I)[J].华东师范大学学报(自然科学版), 1995, 4: 60-64.
[66]杨建红.铝电解双极多室槽及功能电极材料的研究[D].长沙:中南工业大学, 1992.
[67]冯玉杰.电化学技术在环境工程中的应用[M].北京:化学工业出版社, 2002.
[68]孙志远,巩国樑,朱宁.掺硼金刚石薄膜电极电化学特性的研究[J].天津理工大学学报, 2008, 24(2): 22-24.
[69]王玉乾,王兵,孟祥钦.化学气相沉积法制备超纳米金刚石薄膜[J].材料导报, 2009, 23(7): 54-56.
[70]付志强,周家斌,王成彪,等.化学气相沉积法制备SiC/SiO2梯度复合涂层的热力学分析[J].材料工程, 2008, 13(5): 68-71.
[71] Correa LB, Comninellis C. Electrochemical oxidation of p-chlorophenol on SnO2-Sb2O5 based anodes for wastewater treatment [J]. Journal of Applied Electrochemistry, 2003, 33(1): 1211-1215.
[72]张乃东,李宁,彭永臻.涂膏热解法制备钛基Sn、Sb氧化物电极[J].物理化学学报. 2003, 19(2): 1154-1158.
[73]王茜.溶胶-凝胶(Sol-Gel)法的原理、工艺及其运用[J].河北化工, 2007, 30(4): 25-27.
[74]王焆,李晨,徐博.溶胶-凝胶法的基本原理、发展及应用现状[J]. 2006, 26(3): 273-277.
[75]王静,孙春峰,吴发超,等.稀土Gd掺杂SnO2-Sb涂层阳极电催化氧化甲基橙[J].化工环保, 2009, 29(1): 14-17.
[76] Lzquierdo R, Sacher E, Yelon A. X-ray photoelectron spectra of antimony oxides [J]. Applied Surface Science, 1989, 40(1-2): 175-177.
[77]郭金玲,沈岳年.用Scherrer公式计算晶粒度应注意的几个问题[J].内蒙古师范大学学报(自然科学汉文版), 2009, 38(3): 357-358.
[78]姚红军.用Ti/SnO2(Sb)电极电催化氧化硝基苯酚类废水的研究[D].上海:复旦大学, 2005.
[79]肖友军.含稀土La的镍基合金电镀及其析氢电催化行为研究[J].南方冶金学院学报, 2004, 25(1): 55-57.
[80] Wang YH, Chan KY, Li XY. Electrochemical degradation of 4-chlorophenol at nickel-antimony doped tin oxide electrode [J]. Chemosphere, 2006, 65(3): 1087-1093.
[81]胡吉明,孟惠民,张鉴清,等. Ti基IrO2+Ta2O5涂层阳极的析氧电催化活性[J].金属学报, 2001, 37(6): 628-632.
[82]皮运正,王建龙.臭氧氧化水中2,4,6-三氯酚的反应机理研究[J].环境科学学报, 2005, 25(12): 1619-1623.
[83] Detomaso A, Lopez A, Lovecchio G, et al. Practical Applications of the Fenton Reaction to the Removal of Chlorinated Aromatic Pollutants.Oxidative Degradation of 2,4-Dichlorophenol [J]. Research Articles, 2003, 10(6): 379-384.
[84] Lopez A, Mascolo G, Detomaso A, et al. Temperature activated degradation (mineralization) of 4-chloro-3-methyl phenol by Fenton's reagent [J]. Chemosphere, 2005, 59: 397-403.
[85]李善评,胡振,曹翰林.钕改性钛基SnO2/Sb电催化电极的制备及表征[J].中国稀土学报, 2008, 26(3): 291-297.
[86]崔玉虹,刘正乾,刘志刚,等. Ce掺杂钛基二氧化锡电极的制备及电催化性能研究[J].功能材料. 2004, 35(1): 2035-2039.
[87]崔玉虹,冯玉杰,刘峻峰.含Mn中间层钛基二氧化锡电催化电极的性能[J].材料研究学报, 2005, 19(1): 47-53.
[88]张翼,王磊,闫红娟,等.钕掺杂Ti基Sn-Sb涂层电极的制备及性能评价[J].中国稀土学报, 2007, 25(6): 760-764.
[89]王雅琼,顾彬,许文林,等. MnOx活性层制备条件对Ti/SnO2+Sb2O3/MnOx电极性能的影响[J].无机材料学报, 2006, 21(6): 1362-1366.
[90]徐海青,刘秀宁,王育乔,等.复合金属氧化物Sn-Sb-Mn/陶瓷粒子电极体系的电催化性能[J].物理化学学报. 2009, 25(5): 840-846.