Treatment of cyanide wastewater dynamic cycle test by three-dimensional electrode system and the reaction process analysis

ABSTRACT

Dynamic three-dimensional electrode system treatment of cyanide wastewater used coal-based electrodes as cathode and anode, activated carbon as particle electrodes, the effects of applied voltage, reaction time and flow rate on ion removal rate were studied. SEM-EDS and XPS were used to study the morphology of coal-based electrode and the composition and existing state of the load substances, and the reaction mechanism were analysed and discussed. The results show that the removal rates of CN_T, Cu, Zn, CN⁻, SCN⁻ in cyanide wastewater were 97.03%, 95.79%, 99.82%, 99.42% and 94.19%, respectively, when the applied voltage of 4 V, the electrode distance of 10 mm, the flow rate of 30 ml/min, the reaction time of 2.5 h and the dosage of activated carbon particles of 2 g. The applied voltage is the key factor affecting ion removal. When the voltage was 2 V, the ion removal is mainly due to the synergistic effect of chemisorption and electrosorption. The CN⁻, SCN⁻, and metal cyanide complex anions in wastewater migrate to the anode of coal-based anode and particle electrode rapidly under the combined action of electric field and magnetic stirring. On the surface of porous coal-based electrode, the removal of CN⁻, SCN⁻ was mainly attributed to the oxidation of oxygen evolution from the anode reaction, while the removal of Cu, Zn and other metal ions was mainly by the electrodeposition process on the cathode surface.

GRAPHICAL ABSTRACT

KEYWORDS:

• Three-dimensional electrochemical process
• coal-based material
• cyanide wastewater
• dynamic cycle test

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This project was financially supported by the National Natural Science Foundation of China [No. 51774227], the Natural Science Basic Research Plan in Shaanxi Province of China [No. 2018JZ5001], and Major Basic Research Project of Shaanxi Natural Science Basic Research Program [2017ZDJC-33].