Studies on Removal of Dyes fromWastewater using Electrocoagulation Process

Abstract

Electrocoagulation (EC) is one of the most effective techniques to remove color, COD and organic compounds from wastewater. In this thesis, electrocoagulation technique has been used for the removal of color and COD from dye solutions containing Direct Black 22 and Acid Red 97 in batch and continuous process. For both the process effect of operational parameters such as current density, initial pH of the solution, time of electrolysis and electrode materials were studied to attempt maximum reduction of COD and color with different electrodes such as iron, stainless steel, graphite and aluminum electrode with D.C. current. For batch process, parameters maintained were current density up to 50 to 100 A=m2, electrolysis time was 5, 10 and 15 min and the range of pH between 2.0 to 11.0, conductivity 4 to 12 ms/cm, concentration of dye solution 100 mg/L. In case of continuous process, parameters maintained were current density 100 A=m2, electrolysis time was 5, 10 and 15 min and the range of pH between 5.0. Results shows that for batch process, color removal efficiency obtained was 68-99.67% and COD removal efficiency was 59-75%. The maximum efficiency of color and COD removal was observed in case of stainless steel electrode whereas the minimum efficiency was observed in case of graphite electrode. One more attempt has also been made using APC (Alternating Pulse Current) instead of D.C. was made. In this case, with APC negligible degradation was observed with all four electrodes.