Removal of crystal violet by electrocoagulation: Optimization and reaction mechanisms involved

Solutions of crystal violet are treated by electrocoagulation using a batch reactor. All the authors working with aluminum electrodes in the electrocoagulation process have shown that dissolution occurs at the cathode. The most probable reaction is a chemical attack by hydroxyl ions (generated during water reduction) on the aluminum cathode.To avoid these reactions the coulometric efficiency is increased; a stainless steel cathode and an aluminum anode are used in this study.The influence of various process parameters (pH, conductivity, interelectrode distance, current density and initial concentration) on treatment efficiency was investigated to optimize the system. The results indicated that slightly acidic solutions (pH=5.43) containing a dye concentration of 100 mg/L, can be clarified (removal of CV>99%; abatement of 98% of the Chemical Oxygen Demand (COD) in less than 1 hour of electrolysis and can be achieved at relatively low current density (250 A/m super( 2)). Finally, tests complexations with EDTA were performed on the treated solution and sludge formed and the results were used to write different reaction mechanisms involved in the electrocoagulation process.