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pH对低温燃烧法合成钨酸铋光催化降解罗丹明B的影响
引用本文:余忠雄,向 垒,钟方龙,李彦文,莫测辉,蔡全英,黄献培,吴小莲,赵海明.pH对低温燃烧法合成钨酸铋光催化降解罗丹明B的影响[J].无机材料学报,2015,30(5):535-541.
作者姓名:余忠雄  向 垒  钟方龙  李彦文  莫测辉  蔡全英  黄献培  吴小莲  赵海明
作者单位:(暨南大学 1. 环境学院, 广东省高校水土环境毒害性污染物防治与生物修复重点实验室; 2. 生态学系, 广州 510632)
基金项目:国家自然科学基金(41173101, 41301337); 广东省自然科学基金重点项目(2011020003196); 广东省高校高层次人才项目; 东莞市科技计划项目(2012108102043)
摘    要:以低温燃烧法制备钨酸铋(LCM-Bi2WO6), 并表征了其晶体结构、形貌特征、等电点及紫外漫反射谱, 同时以染料罗丹明B(RhB)为目标污染物(25 mg/L, pH=4), 考察了所制备Bi2WO6的吸附性能和光催化性能, 并探讨了RhB溶液pH(1、4、7、10)及酸度调节剂成分(盐酸和硫酸)的影响。结果表明, 所制备Bi2WO6为正交相, 吸收极限波长为455 nm, 禁带宽度为2.72 eV, 晶格粒径为14.7 nm, 等电点为3.43; 其对RhB的吸附和光催化效果强于水热法制备Bi2WO6和二氧化钛(TiO2)。不同pH溶液中, LCM-Bi2WO6对RhB的吸附过程和光催化过程分别符合准二级动力学方程和一级动力学方程式, 且吸附平衡量(7.48~21.93 mg/g)和光催化速率常数(0.0197~0.1181 min-1)均随pH降低而增大。LCM-Bi2WO6对RhB的光催化降解主要由·OH所致。光催化过程中, RhB紫外可见光谱的蓝移现象揭示LCM-Bi2WO6可通过脱乙基-共轭显色基团断裂途径降解RhB。以H2SO4调节酸度时, SO42-离子可被Bi2WO6强吸附, 从而使得LCM-Bi2WO6对RhB的平衡吸附量(qe为6.03 mg/g)和光催化速率(kv为0.115 min-1)远小于HCl调节(qe为21.93 mg/g, kv为0.1181 min-1)时对RhB的平衡吸附量和光催化速率。

关 键 词:低温燃烧法  钨酸铋  光催化  pH  
收稿时间:2014-09-30
修稿时间:2014-11-30

Effects of Solution pH on Photocatalytic Degradation of Rhodamine B Using Bismuth Tungstate Prepared by Low-temperature Combustion Method
YU Zhong-Xiong,XIANG Lei,ZHONG Fang-Long,LI Yan-Wen,MO Ce-Hui,CAI Quan-Ying,HUANG Xian-Pei,WU Xiao-Lian,ZHAO Hai-Ming.Effects of Solution pH on Photocatalytic Degradation of Rhodamine B Using Bismuth Tungstate Prepared by Low-temperature Combustion Method[J].Journal of Inorganic Materials,2015,30(5):535-541.
Authors:YU Zhong-Xiong  XIANG Lei  ZHONG Fang-Long  LI Yan-Wen  MO Ce-Hui  CAI Quan-Ying  HUANG Xian-Pei  WU Xiao-Lian  ZHAO Hai-Ming
Affiliation:(1. School of Environment, Jinan University, Key Laboratory of Water/Soil Toxic Pollutants Control and Bioremediation of Guangdong Higher Education Institutions, Guangzhou 510632,China; 2. Department of Ecology, Jinan University, Guangzhou 510632, China)
Abstract:Bismuth tungstate (Bi2WO6) was synthesized by low-temperature combustion method (LCM) and characterized by diffuse reflectance spectroscope (DRS), X-ray diffraction (XRD), scanning electron microscope (SEM) and Zeta potential. The effects of solution pH and acidity regulator types on the photocatalytic degradation of RhB by LCM-Bi2WO6 were investigated. Results showed that LCM-Bi2WO6 was an orthorhombic crystal and its wavelength of maximum absorption, forbid bandwidth, lattice size and isoelectric point were 455 nm, 2.72 eV, 14.7 nm and 3.43, respectively. Stronger adsorption and photodegradation of RhB (25 mg/L, pH=4) using LCM-Bi2WO6 as photocatalyst was observed, compared with using TiO2 or Bi2WO6 prepared by hydrothermal method as photocatalyst. Adsorption and photodegradation of RhB by LCM-Bi2WO6 satisfied the pseudo-second-order kinetic equations and first order kinetic equations, respectively. Equilibrated adsorption capacity (7.48-21.93 mg/g) and photodegradation rate constants (0.0197-0.1181 min-1) of RhB by LCM-Bi2WO6 were positively related to solution pH. Photocatalytic degradation of RhB by LCM-Bi2WO6 was mainly triggered by free hydroxyl groups (·OH). Blue shifts of RhB ultraviolet-visible spectrum indicated its degradation through ethyl removal and conjugated groups break pathway. Weaker adsorption (qe=6.03 mg/g) and photodegradation (kv=0.115 min-1) of RhB by LCM-Bi2WO6 using H2SO4 as acidity regulator were observed compared with using HCl (qe=21.93 mg/g, kv=0.115 min-1) as acidity regulator, because of SO42- strong adsorption to LCM-Bi2WO6.
Keywords:low-temperature combustion method  Bi2WO6  photocatalysis  pH value  
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