The Treatment Of Electroplating Wastewater By Aerated Fe/C Internal Electrolysis-Modified Tea Dregs

Internal electrolysis is based on the principle of electrochemical oxidation reduction, and it is used to treat wastewater by enrichment, oagulation, adsorption and filtration. Quantitative studies on tealeaves’s catching metal irons in solution were begun in1986by Japanese scholars such as Kimura. A new kind of environmental engineering adsorption material made of tea dregs can absorb heavy metal irons in wastewater.In this paper, aerated Fe/C internal electrolysis-modified tea dregs is used to treat wastewater containing chromium and cyanide separately. And the optimal parameters are confirmed through experiments. The effect of aerated internal electrolysis-modified tea dregs is better than that of aerated internal electrolysis or modified tea dregs alone.The optimal parameters of treatment of wastewater containing chromium are as follows:internal electrolysis process:Fe(V):C(V) is1:1, pH is1, continuous aeration, reaction time is120min; modified tea dregs process:pH is7.5,0.4g dregs, reaction time is120min, the concentration of Cr6+in final effluent is0.409mg/L which is lower than the maximum allowable emission concentration in GB8978-1996.The optimal parameters of treatment of wastewater containing cyanide are as follows:internal electrolysis process:Fe(V):C(V) is1:1, pH is4, continuous aeration, reaction time is3h; modified tea dregs process:pH is8,1g dregs, reaction time is3h, the concentration of cyanide in final effluent is28.975mg/L which can not reach the discharge standards and needs to be treated further.Simultaneously, the kinetics of internal electrolysis and absorption by modified tea dregs studied. The results show that removing of Cr6+is in accord with the1.6stage reaction and that of cyanide is in accord with the2.8stage reaction and the adsorption of modified tea dregs for Cr6+and cyanide fit the pseudo-second-order model very well.