电吸附处理氰化废水过程中外加电压的影响研究

Treatment of Cyanide Wastewater by Electric Adsorption with Applied Voltage

以自制的煤基电极材料为阴阳极,采用电吸附技术处理氰化废水,主要研究了外加电压对电吸附处理氰化提金废水的影响,测定了煤基电极材料的循环伏安曲线,并用扫描电子显微镜(SEM)、能谱分析(EDS)对吸附后的电极片进行分析表征。研究表明,外加电压对电吸附过程的影响显著,外加电压越大,离子的去除率越大。开路状态下仅发生离子的吸附现象,反应5 h后铜离子和总氰的去除率为14.60%,10.50%;当外加电压为0.4 V时,各离子在电场作用下发生定向迁移,富集于电极的双电层上,该过程主要发生离子的定向迁移及电吸附现象,各离子吸附顺序依次为Cu(CN)3-4,Zn(CN)2-4,Cu(CN)2-3,CN-,SCN-,5 h后铜离子和总氰的去除率为19.93%,22.53%;当外加电压2.0 V时,溶液中离子在定向迁移、电吸附与富集沉淀的共同作用下,5 h后铜离子及总氰的去除率可达到88.49%,75.17%,在此过程中阳极附近产生硫氰酸铜等絮状沉淀物。

Adopting self-made coal-based material as electrodes,cyanidation wastewater treatment by electrosorption technology was used. The effect of applied voltage on treatment of cyanidation waste water was mainly studied,cyclic voltammetry curves of self-made coal-based electrode material was tested. Furthermore,the surface morphology and load substances of the electrodes after adsorption were analyzed by scanning electron microscopy（SEM） and energy dispersive spectroscopy（EDS）. The research showed that applied voltage had a significant effect on electrosorption process,and the removal rates of ions increased gradually with the increase of applied voltage. At open circuit voltage,there only existed ion adsorption. After reacting for 5 h,removal rates of copper ions and total cyanide were 14. 60% and 10. 50%,respectively. At applied voltage of 0. 4 V,some ions in solution underwent directional migration to the electric double layer of the electrode under the electric field. The process mainly contained the directional migration and electric adsorption of ions,and the ion adsorption order was Cu（CN）4^3-,Zn（CN）4^2-,Cu（CN）3^2-,CN^-,SCN^-. After adsorption of 5 h,the removal rates of copper ions and total cyanide were 19. 93% and 22. 53%,respectively. With the applied voltage of 2. 0 V,the ions in solution interacted by directional migration,enrichment precipitation and adsorption process,and the adsorption time of 5 h,the removal rates of copper ions and total cyanide reached 88. 49% and 75. 17%,respectively. The precipitates of cupric thiocyanate and other flocculent precipitates generated near the anode in this process.