铁促双电极电化学氧化处理丙烯腈生产废水的研究

Electrochemical Oxidation of Dual Electrodes with Iron Promoting Used for the Treatment of Wastewater from Acrylonitrile Production

采用钛基二氧化锡(Ti/SnO2)和金属铁构成组合阳极,并以石墨为阴极,研究了铁促双电极电化学氧化处理丙烯腈生产废水的效果及反应过程的相关规律.结果表明,与传统电化学氧化相比,采用组合阳极的双电极氧化过程获得了更高的有机物去除率并提高了电流效率.在相同电压下,当不外加H2O2时,COD去除率比采用传统电化学氧化提高11.0%～13.8%,电流效率提高8.0%～15.0%,而当外加H2O2浓度为2200mg·L-1,且电压为4.0V时,COD去除率达74.6%,TOC去除率达67.9%.随着外加H2O2浓度的增加,COD和TOC去除率增加.反应初始阶段H2O2浓度较高而Fe2+浓度很低,随反应时间延长H2O2浓度迅速下降而Fe2+浓度则逐渐升高.反应过程中H2O2与Fe2+浓度变化速率与电压密切相关.H2O2初始浓度一定的情况下,阳极通电时间对电流效率影响显著.双电极电化学氧化对丙烯腈生产废水色度也具有良好的去除作用.铁促双电极电化学氧化为有机废水的处理提供了一个新的选择.

Effects and laws of electrochemical oxidation of dual electrodes with iron promoting for the treatment of wastewater from acrylonitrile production were investigated using Ti/SnO2 ＋ Fe as combined anodes and graphite as cathode. Compared with traditional electrochemical oxidation, the higher removal of organic pollutants and current efficiency were obtained via oxidation of dual electrodes. Through the process COD removal efficiency and current efficiency were enhanced by 11.0 %- 13.8 % and 8.0%- 15.0 % respectively, referred to the results from traditional electrochemical oxidation under conditions of the same voltage and no hydrogen peroxide added. With 2 200 mg·L^-1 hydrogen peroxide and voltage of 4.0 V, COD and TOC removal efficiencies increased to 74.6% and 67.9% respectively, and with the increase of hydrogen peroxide, both were enhanced obviously. During the initial reaction period, the higher hydrogen peroxide concentration and the lower Fe^2＋ concentration were detected, and with reaction time increased, hydrogen peroxide concentration decreased rapidly and Fe^2＋ concentration increased gradually. The voltage value had great effect on the concentrations of hydrogen peroxide and Fe^2＋, and the current efficiency was affected obviously by the time of current passed through iron anode under certain initial dosage of hydrogen peroxide. The better color removal was also obtained from electrochemical oxidation of dual electrodes. The electrochemical oxidation of dual electrodes with iron promoting presents a new alternative for the treatment of organic wastewater.