纳米TiO2光催化转化下有机氯农药与AgNO3的光谱特性研究

以TiCl4为原料,利用水解法制备了锐钛矿型纳米TiO2。研究了α,β,γ,δ-六六六(BHC)、滴滴涕、狄氏剂、三氯杀螨醇、七氯等含氯农药在纳米TiO2的悬浮体系和紫外光的作用下的降解行为。由于C—Cl键能的关系,不同有机氯农药的光降解效率有很大的不同,其降解率为三氯杀螨醇>狄氏剂>滴滴涕>七氯的降解率,而对六六六的异构体,其降解率顺序为-αBHC>-γBHC>-δBHC>-βBHC。研究了Cl-在聚乙烯醇表面活性剂溶液中生成氯化银溶胶在260 nm左右的吸光光谱特性,通过有机氯转化为无机氯离子(Cl-)以及Cl-浓度与氯化银溶胶吸光值之间的线性关系的方式,实现有机氯农药含量的间接测定。

Spectrum Study of Organochlorine Pesticides after Nano TiO2 Photocatalytic Degradation in AgNO3 Medium

A study on a nano anatase TiO2 production from the hydrolysis of TiCl4 was presented. In the nano TiO2 suspending medium, the photocatalytic behaviors for some organochlorine pesticides including alpha, beta, gamma, delta-BHC, DDT, dieldrin, dicofol and agroceres were compared and studied under UV irradiation in the air. Owing to structural difference of C--Cl in the molecule, the degradation efficiencies for the organochlorine pesticides presented an obvious difference with the order of dicofol>dieldrin> DDT>agroceres and alpha-BHC>gamma-BHC>delta-BHC>beta-BHC. Accordingly, the nano TiO2 material was applied as a photocatalyzer, which catalyzed transformation of organochlorine pesticide to chlorine ion. Nanoparticle of silver chloride with a maximal absorbance at the wavelength of 260 nm were prepared in the surfactant polyvinyl alcohol solution. Organochlorine pesticides could be determined according to the concentration of silver chloride.