聚苯胺/TiO_2复合材料对U(Ⅵ)吸附性能的研究

Adsorption Ability of Polyaniline/TiO_2 Composite for U(Ⅵ)in Aqueous Solution

采用溶胶-凝胶法合成二氧化钛(TiO2),并将苯胺聚合在TiO2表面制备了聚苯胺(PANI)/TiO2复合材料(PANI/TiO2)。使用FT-IR、TGA和XPS表征了制备的TiO2、PANI和PANI/TiO2的表面功能基团、热稳定性和表面元素组成。研究了溶液pH值、吸附时间、U(Ⅵ)浓度和温度等因素对TiO2、PANI和PANI/TiO2吸附U(Ⅵ)的影响,探讨了3种材料对U(Ⅵ)的吸附动力学、等温线和热力学性质。FT-IR、TGA和XPS表征结果表明,成功制备了PANI/TiO2复合材料。TiO2、PANI和PANI/TiO2吸附U(Ⅵ)的最佳pH值分别为5.0、4.5和5.0;吸附过程均符合Langmuir吸附等温模型和准二级吸附方程,TiO2、PANI和PANI/TiO2的单层饱和吸附量分别为11.49、22.41、43.29mg/g;3种吸附剂对U(Ⅵ)的吸附过程均为自发的吸热过程。同时,PANI/TiO2具有较好的循环使用性能,第5次使用时,吸附量仅降低了15.4%。

Polyaniline（PANI）/TiO2 was synthesized via polymerization of aniline on the surface of TiO2 which was prepared by a sol-gel method.And the surface functional groups,thermal stability and surface elemental composition of TiO2,PANI and PANI/TiO2 were characterized by FT-IR,TGA and XPS.Effects of pH,contacting time,initial U（Ⅵ）concentration,temperature on the U（Ⅵ）adsorption were investigated and optimized by static batch experiments.The results of FT-IR,TGA and XPS indicatethat PANI/TiO2 composite is successfully prepared.The optimum pH value for U（Ⅵ）adsorption on TiO2,PANI and PANI/TiO2 is 5.0,4.5 and 5.0,respectively.The adsorption isotherms and kinetics as well as the thermodynamics were studied using various models.The results show that the adsorption processes are fitted well to the Langmuir and pseudo-second order equations.In addition,the monolayer adsorption capacity of TiO2,PANI and PANI/TiO2 is 11.49,22.41 and 43.29 mg/g,respectively.The adsorption processes of TiO2,PANI and PANI/TiO2 for U（Ⅵ）are spontaneous and endothermic in nature.And,the PANI/TiO2 composite shows excellent reusability,whose adsorption capacity only decreases by 15.4% when it is used at the fifth time.