Removal of Silica from Cooling Water by Electrocoagulation: A Comprehensive and Systematic Study Using Response Surface Methodology

Abstract

To effectively recycle and reuse water, the prevention of silica deposits become an urgent requirement in many industries. The laboratory scale electrocoagulation system was investigated to remove silica. And the interactions between all the influencing factors were analyzed not only for silica removal efficiency, but also for energy consumption, electrode consumption and sludge production. The values of adj R² of the models were 0.9315 for silica removal efficiency, 0.9768 for energy consumption, 0.7633 for electrode consumption and 0.9698 for sludge production, respectively, which indicated that all the models were significant. The optimal conditions were 60 mg/L initial silica concentration, 2.50 cm interelectrode distance, 40.47 min reaction time, 7.50 pH value, 3.89 mA/cm² current density and 4 cm submerged height of electrode, under which 85.147 % silica removal efficiency, 1.455 KWh/m³ energy consumption, 0.0389 kg/m³ electrode consumption and 0.242 kg/m³ sludge production were obtained and the desirability was 0.831 for the optimal conditions. By performing the optimum conditions, 83.243 % silica removal efficiency, 1.466 KWh/m³ energy consumption, 0.0400 kg/m³ electrode consumption and 0.245 kg/m³ sludge production were obtained.