溶液浓差能驱动的逆电渗析有机废水氧化降解机理研究

Study on the mechanism of organic wastewater oxidation degradation with reverse electrodialysis powered by concentration gradient energy of solutions

将逆电渗析(RED)电极氧化还原反应作用于有机废水降解,可以达到利用低品位热氧化降解有机废水的目的.RED反应器阳极产生氧化反应生成的HClO及阳极表面直接电化学氧化反应对有机废水产生氧化降解作用,阴极发生电芬顿反应生成H_2O_2对有机废水产生氧化降解作用.为了验证溶液浓差能驱动的RED有机废水氧化降解工作机理,通过搭建一个由40对膜电池单元所构成的实验室规模的RED有机废水氧化降解反应器及相应的实验系统,对偶氮染料——酸性橙Ⅱ模拟废水进行氧化降解机理研究.通过3次重复性实验研究发现:在通过正交试验确定的最佳降解条件下,浓度为150 mg·L^(-1)各500 mL的酸性橙Ⅱ模拟废水分别流经RED反应器阴、阳两极,阴、阳极12 min酸性橙Ⅱ平均降解率分别可达90.14%和97.87%,20 min酸性橙Ⅱ平均降解率分别达到97.56%和99.81%.初步研究结果表明,溶液浓差能驱动的RED反应器对难生化降解有机物有较好的降解效果,为后续相关理论和实验研究提供了参考依据.

For the purpose of organic wastewater oxidation degradation powered by low-grade heat, the redox reaction at reverse electrodialysis（RED） electrodes was applied to degrade organic wastewater. In a RED reactor, the HClO will be generated by the oxidation reaction in the anode compartment, and the direct electrochemical oxidation reaction will be produced on the anode surface. Both of these have an oxidation degradation effect on the organic wastewater. The H2O2 will be generated by electro-Fenton reaction in the cathode compartment, which also has an oxidation degradation effect on the organic wastewater. In order to verify the mechanism of oxidation degradation, a lab-scale RED reactor with 40 membrane cell units and experimental system were built. The research on the mechanism of oxidation degradation for a kind of azo dyes, acid orange 7, had done by experiment. The research results by three repeated experiments showed that: under the optimum degradation conditions determined by orthogonal tests, average degradation rates for acid orange 7 simulated wastewater could reach 90.14% and 97.87% in 12 minutes, and 97.56% and 99.81% in 20 minutes, respectively, when the simulated wastewater with an acid orange 7 concentration of 150 mg·L-1 and a volume of 500 mL flows through cathode or anode compartment in RED reactor, respectively. The preliminary investigation results indicated that the RED reactor powered by concentration gradient energy of solutions has a good oxidation degradation effect on organic pollutants resistant to biological processes. The research results could provide a reference for subsequent relevant theoretical and experimental studies.