TiO_(2)和稀硫酸改性TiO_(2)复合材料降解废水土霉素的对比研究

A comparative study on degradation of oxytetracycline wastewater by TiO_(2) and dilute sulfuric acid modified TiO_(2) composite materials

以钛酸四丁酯为前驱体、无水乙醇为分散剂,水热法合成纯TiO_(2),再加入稀H_(2)SO_(4)合成SO4^(2-)/TiO_(2)来降解废水中的土霉素.从废水中土霉素浓度、光催化剂投加量、pH、吸附时间等因素对土霉素降解率的影响,发现在相同的条件下,SO4^(2-)/TiO_(2)对废水土霉素的去除率远远大于纯TiO_(2)对土霉素的去除率.使用BET、XPS、TEM技术对SO4^(2-)/TiO_(2)复合材料进行表征分析,结果表明,SO4^(2-)成功修饰于TiO_(2)上,介孔(2~50 nm)体积占比增加,平均孔径和孔容量减小,比表面积增大,形成Ti—O—S键的双桥式配位的结构,使得氧原子处于缺电子状态,增加了表面酸性,有效阻止光生电子-空穴对复合,原来的禁带宽度从3.25 eV(纯TiO_(2))降低到3.09 eV(SO4^(2-)/TiO_(2)),提高了电子吸收阈值及光吸收范围,电子跃迁能力增强,增强了SO4^(2-)/TiO_(2)光催化性能.

This experiment studies on the oxytetracycline degradation of pure TiO_(2) synthesized under hydrothermal conditions with titanium tetrabutyl titanate as the precursor and anhydrous alcohol as dispersant and of SO4^(2-)/TiO_(2) synthesized by dilute H2SO4.The degradation rate of oxytetracycline in wastewater is influenced by factors such as the concentration of oxytetracycline,the dosing quantity of photocatalyst,pH,and adsorption time.It is found that the removal efficiency of SO4^(2-)/TiO_(2) to oxytetracycline is much higher than that of pure TiO_(2) under the same conditions.The properties of SO4^(2-)/TiO_(2) composites are characterized by BET,XPS,and TEM respectively.The result reveals that SO4^(2-) is successfully modified on TiO_(2),the volume ratio of mesoporous(2-50 nm)increases,the average pore diameter and volume decrease,and the specific surface area is expanded.The electron-deficient oxygen atom in the double-bridge Ti—O—S bond intensifies surface acidity,effectively preventing photoinduced electron hole pairs recombination.The original band gap is decreased from 3.25 eV(pure TiO_(2))to 3.09 eV(SO4^(2-)/TiO_(2)).The absorption threshold and light absorption range raises,electron transition ability is enhanced and the photocatalytic performance of SO4^(2-)/TiO_(2) is improved.