Effects of operational parameters on cadmium removal from aqueous solutions by electrochemical coagulation

Abstract

The aim of present study is to investigate the feasibility of cadmium removal from water using electrocoagulation. Electrocoagulation (EC) is an electrochemical wastewater treatment technology with increased popularity and considerable technical improvements. In the study, effects of operating parameters such as initial solution pH, initial concentration (C-0), reaction time (t), stirring speed, and conductivity (kappa) on cadmium removal from synthetic wastewater-containing cadmium in the batch electrocoagulation process were investigated. It was found from experimental results that initial solution pH is important parameter affecting cadmium removal. pH of initial solution was in the range of 3 to 6 in the experiments. The largest cadmium removal efficiency was obtained with pH 6. pH 6, obtained from initial solution whose pH was 6, reached an agreement with activity to pH diagrams for Al+3 species in equilibrium with Al(OH)(3). Although specific energy consumption increased with decreasing cadmium concentration, whose conductivity was low, cadmium removal efficiency was higher at 25 mg L-1 than 1,000 mg L-1. Stirring speed, below and above 150 rpm, reduces cadmium removal efficiency. The results showed that electrocoagulation method had high effectiveness in removing cadmium from aqueous solutions.