TiO2/Mg(OH)2复合材料对有机污水中甲基橙的光催化降解动力学的研究
来源:汇意旅游网
第13卷第2期 2014年6月 材料与 冶金学报 VoL 13 No.2 Journal of Materials and Metallurgy June 2014 TiO2/Mg(OH)2复合材料对有机污水中甲基橙的 光催化降解动力学的研究 李婷,孟波,邢鹏飞 (东北大学材料与冶金学院,沈阳110004) 摘要:采用溶胶一凝胶法制备了纳米TiO:,并以TiO 和镁盐溶液为前驱物用氨气鼓泡法制得了 TiO:/Mg(OH):复合材料.利用氢氧化镁在水溶液中较强的吸附能力和TiO:对有机物的催化降解作用,研究 TiO /Mg(OH):复合材料对有机污水中的甲基橙暗反应吸附规律和光反应催化降解性能.结果表明:当 TiO2/Mg(OH)2加入量为1 g・L 时,在可见光下照射180 min后,对有机污水中含20 mg・L 的甲基橙的降解 率达到98.00%,同时在同等条件下选用国家标准(3O mg・L 亚甲基蓝溶液)作为参照时,降解率可达 99.20%.TiO /Mg(OH) 复合材料对污水中甲基橙的催化降解反应较好地符合Langmuir动力学模型,可用一 级反应动力学方程进行描述. 关键词:动力学;TiO /Mg(OH):复合材料;光催化;降解;甲基橙 中图分类号:X 788 文献标识码:A 文章编号:1671—6620(2014)02-0085-07 Kinetics of photocatalytic degradation of methyl orange in organic waste water by magnesium hydroxide/titanium dioxide composite material Li Ting,Meng Bo,Xing Pengfei (School ofMaterials&Metallurgy,Northeastern University,Shenyang 110004,China) Abstract:In this paper,TiO2 nanometer powder was prepared by sol—gel method,and TiO2/Mg(OH)2 composite material was prepared by the ammonia bubbfing method with nanometer titanium dioxide as the precumor. Mg(oH)2 has a strong adsorption efect in a liquid,and TiO2 has a high degradaiton eicfiency to organic matter in waste water.TiO2/Mg(OH)2 composite materila was used to deal、Ⅳith the orgaicn waste water.The dark reaction adsorption and the photocatalytic degradation for the methyl orange were researched.The result showed that:when 1 g・L~TiO2/Mg(OH)2 composite materila was put in a methyl orange solution,and the solution was exposed 1 80 min under visible light,the degradation rate of methyl orange in solution reached 98%.The degradation regularity obeyed the Langmuir Dynamic Model,and the photocatlytaic oxidation reaction of the methyl orange with TiO2/Mg(OH)2 composite materilas can be descirbed with the first order reaction ̄neitcs equation. Key words:kinetics;TiO2/Mg(OH)2 composite mateirl;photaocatalytic;degraatdion;methyl orange 快速的工业化发展给人们的生活带来各种各 样便利,同时也造成了严重的环境污染,随着人类 环保意识的觉醒以及环保标准的提高,控制环境 污染问题已成为全球关注的焦点.自1972年 Fuijisima和Honda 报道了TiO 电极光电解水 能,被广泛地应用于环境保护、污水处理等诸多领 域.纳米TiO,在光照的条件下能够产生强氧化性 的光生空穴,该光生空穴能彻底降解几乎所有的 有机物,并最终生成H 0、CO 等无机小分子.由 于其光催化活性高、自身化学稳定性好和清洁无 毒,已成为最具潜力的半导体光催化材料 .相 关研究发现光催化剂表面吸附有机物的能力是影 现象后,半导体光催化的研究引起了广泛的关注. 作为一种高效光催化剂,纳米TiO 具有催化活性 高、稳定性好、能耗低以及无二次污染等优良性 收稿日期:2013.10-21. 基金项目:国家自然科学基金资助项目(51074043). 响降解效率的一个重要因素,将光催化剂负载于 作者简介:李婷(199O一),女,东北大学硕士研究生,E—mail:litingmengbo@163.com;邢鹏飞(1966一),东北大学教授,博士生 导师. 材料与冶金学报 第13卷 图11不同初始浓度的甲基橙在90rain时刻的瞬时反应速率ri Fig.11 Reaction rate of diferent concentration of methyl orange(f=90 min) 由表3可见甲基橙的降解速率随着初始浓度 的增加而变大,将i/r对i/p。进行线性拟合,如 图l2所示. 动力学关系较好地遵守L—H模型.在Langmiur —Hinshelwood(L—H)动力学模型中有 1 1 1 1 了 由此可求=一+ ’ 出反应速率常数 0.167 mg・(L・arin)~,表观吸附平衡常数 光催化降解甲基橙的动力学方程为: ~一K=一0.0149 L・mg~. 一5.98073p0+402.70836 上述实验测定确定TiO /Mg(OH) 催化降解 有机污水中甲基橙溶液反应遵循一级反应动力 学.在Langmiur—Hinshelwood(L—H)动力学模 图12 1/r一1/p0关系曲线 Fig.12 Curve of1/p0 VS l/r 型中, ,: : d t一1+ 将上式积分得:。 ‘ 由图12得出1/r与1/p。的线性回归方程为: 1/r=一5.98073+402.70836/po,回归系数R = 0.99 634.1/r对1/p0线性关系显著,故 TiO /Mg(OH) 催化降解有机污水中甲基橙溶液 : + 当p /po=0.5的时候,可得到Ti0z/Mg(OH)2 催化降解甲基橙溶液反应的半衰期: 第2期 李 婷等:TiOz/Mg(OH)z复合材料对有机污水中甲基橙的光催化降解动力学的研究 91 Lett,2005,3(2):57—61 =0.5 +0.693 [4]quewx,ZhouY,LamYL,etalOptical andmicrostructural properties of sol—gel derived titania/organically modiifed 3 结 论 silane thin films[J].ThinSohdFilms,2000,358(1/2):16. [5]Fujishima A,Rao T N,Try D A.Titanium dioxide (1)以氨气鼓泡法制得TiO /Mg(OH):复合 photocatlaysis[J].Photoch C,2002,1(1):1—21. 材料光催化降解甲基橙反应速率随着甲基橙初始 [6]吴子豹,黄妙良,杨嫒嫒,等.负载型TiO 复合材料对甲 浓度的增加而增加. 基橙的吸附行为及光催化降解动力学[J].精细化工, 2007,24(1):21—26. (2)当有机污水中甲基橙溶液浓度为 (Wu Z B,Huang M L,Yang Y Y,et a1.Adsorption behavior and photocatalytic discoloration kinetics of methyl 20 mg/L时,光催化效率随复合粉体的加入量先 orange on supported TiO2 composite[J].Fine Chemicals, 增加后减小,在复合粉体为0.015 g左右时达到 2007,24(1):21-26.) 最优,在可见光照射条件下180 [7]金德宽,严群芳.TiO2凹土光催化降解活性深蓝K—R动 力学[J].实验室研究与探索,2011,30(11):194—204. TiO2/Mg(OH)2复合材料加入量为1 g/L时,有机 (Jin D K,Yan Q F.Dynamics of TiO2/attapulgite 污水中含20 mg/L的甲基橙的降解率达到 photocatalyst decolorizing reactive deep blue K—R[J]. Laboratory Research and Exploration,2011,30(I1):194 98.00%,用同样方法在同等条件下测得该复合催 —204.) 化剂对30 m#L的亚甲基蓝溶液的降解率达 [8]Chen Changlun,Li Xueliang,Zhao Dongbin.Adsoprtion 到99.20%. kinetic,thermodynamic and desorption studies of Th(IV)on oxiidzed Multiwall carbon nanotubes[J].Colloid and Surfaces (3)复合材料对甲基橙的吸附规律都符合 A:physicochem Eng Aspects,2007,302:449—454. Langmuir吸附等温模型,光催化反应符合一级动 [9]Lijina S H.Elicalm micro—tubes of graphitic carbon[J] 力学规律. Nature,1991,354:56. [1O]Kim S H,Ngo H H,shon H K.Adsorption and 参考文献: photocatalysis kinetics of herbicide onto titanium oxide and powdered activated carbon. Separation and Puriifcation [1]Fnijishima A,Honda K.Electrochemical photolysis ofwater at Technology,2008,58(3):335—342. a semiconductor electrode[J].Nature,1972,238(5358): [11]Peng F,Cai L F,Huang L.Preparation ofnitrogen—doped 37—38. ittnaium dioxide wich visible—light photocatlaytic activity using [2]Zheng H L,Pan Y x,Xinag X Y.Oxidation of acidic dye a facile hydrothermal method[J].Jouma1 of Physics and Eosin Y by the solar photofenton processes[J].Journal of Chemistyr ofSolids,2008,69(7):1657—1664. Hazardous Materilas,2007,141(3):457—464. [12]Para S,Stanca S E,Guasaquilb I.Photocatalytic degradation of [3]Sakkas V A,Dimou A, Pitarakis K.TiO2 photocatalyzed atrazine using suspended and supported TiO2[J].Applied Catlaysis is B:Environmentla,2004,51:107—116. degradation of diazinon in an aqueous medium[J].Chem (上接84页) [45]Mizuno K,Todoroki H,Noda M,et a1.Effects ofM and Ca the microstructure of 14%Cr4%AI ODS ferritic stee1【J J. in ferrosliicon alloys for deoxidation on niclusion composiiton in Materilas Transactions.2010,51(5):1011—1O15. type 304 stainless steel[J].Iron and Steel—maker,2001,28 (8):93—101. [51]GuoAM,Li SR,Guo J,et a1.Effect ofzirconium addition onthe impact toughness ofthe heat affected zone in a high [46]Todoroki H,Inada S.Recent innovation and prospect in srtength low alloy pipehne steel [J]. Materials production technology of specilaty steels with high cleanliness Characterization,2008,59(2):134—139. [J]Bul1.Iron Steel Inst.,2003,8(2):575. [52]TrindadeV B,MeUo R S T,Payao J C,et a1.Influence of [47]陈家祥.钢铁冶金学(炼钢部分)[M].北京:冶金工业出 z1rCon1Um 0n nad toughness of low—alloy steel 版社,2009:14—15. weld metals[J].Journal of Materilas Engineering and (Chen Jiaxiang.The ferrous metallurgy(steelmaking)[M]. Performance,2006,15(3):284—289. Beijing:Metallurgical Industry Press,2009:14—15.) [53]Karasev A V,Suito H.Characteristics of fine oxide particles [48]Jiang z H,Li S J,Li Y.Thermodynamic calculation of produced by Ti/M(M Mg and Zr)complex deoxidation in inclusion formation in Mg——AI——Si——O system of430 stainless Fe一10 mass%Ni alloy[J].Isu International,2008,48 steel melts[J].Journal of Iron and Steel Research (11):1507—1516. International,2011,18(2):14—17. [54]Ohta H,Suito H.Characterisitcs of particle size distribution of [49] Sawai T,Wakoh M,Uesihma Y,et a1.Analysis of oxide deoxidation products with Mg,Zr,A1,Ca,Si/Mn and Me,/ dispersion during solidiifcation in Ti,Zr—deoxiidzed steel in Fe一10mass%Ni alloy[J].ISIJ International,2006,46 [J].ISIJ International,1992,32(1):169—173. (1):14—21. [5O] Isselin J,Kasada R,Kimura A,et a1.Effects ofZr addition on