累托石催化草酸、柠檬酸光化学还原Cr(VI)的研究

Rectorite Catalyzed Photochemical Reduction of Chromium (VI) by Oxalate and Citrate in Aqueous Solutions

研究了重金属Cr(VI)在累托石矿物表面的吸附特性及在金属卤化物灯照射下,累托石对草酸、柠檬酸光化学转化Cr(VI)的影响.结果表明,Cr(VI)在累托石表面中的吸附量较小,其吸附符合Langmuir等温式.在250W金属卤化物灯照射的光反应体系中,累托石可以显著促进草酸、柠檬酸光化学还原Cr(VI),具有催化作用.累托石光催化还原去除Cr(VI)随着溶液pH值的减小而增加.在一定范围内,Cr(VI)的光化学还原率随累托石用量及草酸、柠檬酸的加入量的增加而增大.

The adsorption characteristics of Cr（VI） on the surface ofrectorite and the influence of rectorite on the photochemistry reduction of Cr （VI） by oxalate and citrate in the aqueous solutions are investigated. The results show that the adsorption of Cr（VI） on the surface of rectorite are small and fitted to the Langmuir equation. Rectoite can accelerate the Cr（VI） reduction by oxalate and citrate under the irradiation of 250 W metal halide lamp （λ ≥365 nm）. The ratio of Cr（VI） photoreduction is dependent on the pH, which decreases with increasing the pH values, and increases with increasing dosage of rectorite and concentrations of oxalate and citrate. Key words,