Experimental study on treatment of cyanide wastewater using three-dimensional coal-based adsorption material as electrode

At present,the rapid development of mineral industry,metal industry,electronic equipment manufacturing and other industries has led to a sharp increase in the output of industrial wastewater.A variety of toxic ions( such as chromium,cadmium,arsenic,etc.) and precious metals such as zinc,nickel and gold in wastewater,especially CN_T,SCN-,CN-produced in the process of gold extraction by cyanidation,are harmful and so the harmless management must be carried out. In order to solve the pollution problem of a large number of harmful ions in cyanide wastewater and improve the treatment efficiency of cyanide wastewater,the wastewater treatment method of threedimensional coal-based electrode was explored.The self-made three-dimensional coal-based electrodes were mainly composed of anion,anode and activated carbon particles.The variation of Zn~(2+),CN_Tin cyanide wastewater was observed with voltage and treatment time as variables.The results show that the removal rates of Zn~(2+)and CN_Tions are in agreement with the Lagergren first-order kinetic model.With the long-term and continuous use of coal-based electrodes,the experimental results show that the removal rates of CN_T,Cu~(2+),Zn~(2+),CN-and SCN-are 93.74%,97.28%,95.22%,95.13% and 97.05% respectively.With the increase of coal-based electrodes recycling times,the removal rate of harmful ions in each wastewater decreases slightly.After six cycles,the removal rates of CN_T,Cu~(2+),Zn~(2+),CN-and SCN-are 92. 17%,94.65%,92.67%,90.14%,97.02%.When the voltage is increased,the removal rate of harmful ions does not change with the adsorption saturation of the electrode plate itself,and the coal-based electrode can be reused.Coal-based three-dimensional electrode equipment can be used for industrial waste liquid removal with simplicity,low consumption and high efficiency,which is worth of promotion.