Removal of cadmium from simulated wastewaters by electrodeposition on stainless steeel tubes bundle electrode

Electrochemical processes can provide valuable contributions to the protection of the environment through implementation of effluent treatment and production-integrated processes for the minimization of waste and toxic compounds. The performance of a novel pilot scale, fixed bed flow-through cell, consisting of stainless steel tubes bundle cathode, in the removal of cadmium was investigated in the batch re-circulation mode; utilizing the potential results obtained from rotating disc electrode experiments in batch mode. The studied electrochemical reaction was the cathodic reduction of Cd2+ using 0.5 M sodium sulphate as supporting electrolyte. The analyzed parameters were different electrolyte pH, different initial Cd2+ concentrations, and different Reynolds numbers. The tubes bundle consisted of 920 tubes of 0.6 cm outer diameters. The overall empirical mass transfer correlation was found to be: Sh = 0.51 Re-0.859 Sc-1/3 for 5 < Re < 20 and Sc = 649. Experimental results, analysis and correlations showed good performance of the cell and proved its adequacy in the removal of Cd2+ from simulated effluents.