The Study Of Electroplating Wastewater Treatment By Electroflocculation-activated Carbon Adsorption

Electroplating wastewater is a kind wastewater with the characteristics of complexity of components which difficult to control. It contains heavy metal ions and fluoride, cyanide which are large toxicity ,and traditional chemical precipitation and adsorption is very hard to treat it. So how to treat with the electroplating wastewater has become a difficult problem on the environmental-protection field home and abroad now. Purpose of this study is to find a utility synthetically treatment technology to purify electroplating wastewater economically, and conform to the situation in our country, thereby reduce the environmental pollution by the electroplating wastewater.Compared and analyzed the present domestic and foreign research of electroplating wastewater treatment, the paper is finally decided to applies the electroflocculation sedimentation and activated carbon adsorption to treat with the electroplating wastewater. Firstly, the most COD of the wastewater is removed by electroflocculation, and large heavy metal ions mixed with the floc caused by the electric reaction, with the form of sedimentation are removed. Then, using activated carbon adsorption as a secondary treatment , adsorbs the remainder heavy metal ions and organic compounds, which can improve the quality of the effluent up to the national emission standards.In this paper, a study based on the heavy metal wastewater from the laboratory was carried out, which is treated by using electric coagulation-activated carbon adsorption.The experiments were conducted to investigate the treatment efficiencies and the influence factors, based on which the optimal operating parameters were subsequently determined. The main context for the study are stated as follows:(1)While electroplating wastewater is disposed by the activated carbon adsorption ,choosing Cu²⁺, Pb²⁺, Zn²⁺, Cr⁶⁺ four kinds ions as a representative ,the paper studies how the effect of treatment is influenced by the quantity of activated carbon, the solution initial pH, temperature, adsorption time, metal ion competitive adsorption and so on. At the same time, the activated carbon adsorption were studied.(2) While electroplating wastewater is disposed by electroflocculation, choosing Cu²⁺, F^-, Zn²⁺, Cr⁶⁺ four kinds ions as a representative , the paper studies how the effect of the current density, solution initial pH, coagulation time, sedimentation time, temperature, electrode spacing, electrode connection, NaCl dosage, sedimentation time, initial concentration and so on. Meanwhile the mechanism of electroflocculation has been studied.(3) The wastewater on washing parts from the Harbin Electroplate Factory was treated by using electric coagulation-activated carbon adsorption .The effluent quality was determined to see whether it can satisfy the emission standards.