Ca^(2+)/H_2O_2降解水中孔雀石绿

Degradation of Malachite Green in Aqueous Solution by Ca^(2+)/H_2O_2

在中性条件下,研究了Ca2++H2O2降解水中孔雀石绿(MG)过程.结果表明,加入Ca2+明显促进了MG降解,可使其脱色率由20%升至98%.随着H2O2加入量的增加,MG的脱色率在最初的10min内显著上升,当H2O2/Ca2+(摩尔比)>5时,2h后Ca2++H2O2降解MG脱色率均能达到98%.随着温度的升高,MG的脱色率显著上升.抗氧化剂(抗坏血酸)的加入抑制了Ca2++H2O2降解MG,当抗坏血酸浓度达到1mg/L时,降解率为0,说明在Ca2++H2O2降解MG体系中存在着氧化作用.在避光和光助条件下,加入Ca2+均能明显缩短MG的降解时间,说明Ca2+对其降解有催化作用.

The degradation of malachite green （MG） solution （4 mg/L） was improved by Ca^2＋/H2O2 at pH 7.0. Its oxidation was carried out at different H2O2 concentrations, temperatures and Ca^2＋ concentrations. The results showed that the decolorization rate of MG was promoted from 20% to 98% by adding Ca^2＋. The higher the concentration of H2O2, the higher the degradation rate of MG in early 10 rain. When the molar ratio of H2O2 to Ca^2＋ was more than 5, the decolorization rate could reach 98% in 2 h. The higher the temperature, the higher the decolorization rate. Moreover, when ascorbic acid as oxidation inhibitor （Vc） was added, the improvement of decolorization rate was restrained. When the concentration of ascorbic acid was I mg/L, the degradation rate of MG was 0. So the oxidative activation existed in the system of Ca^2＋/H2O2. Under both conditions of darkness and sunlight catalysis oxidations, the degradable time was shortened by adding Ca^2＋, indicating that the degradation of MG was catalyzed by Ca^2＋.