A comprehensive study on electroplating effluent: Characterization, correlation analysis and electrocoagulation treatment in presence of adsorbent

A wide variety of industries make use of metal finishing processes. Some of the principal industries that use metal finishing processes are the motor car industry, aircraft industry, kitchen, domestic ware industry etc. Electroplating effluents will generally be acid, usually with up to 200 or 300 mg/L of suspended solids, copper nickel and zinc in varying amounts, perhaps up to 300 to 600 mg/L, occasionally with chromium or cadmium or lead and frequently with cyanide present. The cyanide content will sometimes reach several hundreds of mg/L. Processes like blacking give rise to much solid matter in suspension and small concentrations of metals in solution. The wide variety of the processes used in metal finishing leads to effluents that may not be very complex in chemical composition from a single process but which are extremely complicated chemically when they are all present in a sewerage system. In the present study, characterization, correlation analysis and treatment by Electrocoagulation (EC) process were carried out for the electroplating industrial effluent collected from industry located at Thirumangalam near Madurai, Tamilnadu, India. Most of the water quality parameters (WQPs) of printing effluent were found to be higher than the limit prescribed by Bureau of Indian Standards (BIS) for the discharge of industrial effluent. EC technique is employed for the treatment of electroplating effluent with and without adsorbents using iron and aluminium electrodes. The decrease in values of Total Dissolved Solids (TDS) was higher in the case of EC with and without Graphene (GR) and Multi Walled Carbon Nanotubes (MWCNTs) than Commercial Activated Carbon (CAC). The decrease in concentration of both anions and cations are relatively higher in EC with and without GR and MWCNTs than CAC. It was observed that the percentage removal of cations is relatively lower than the other WQPs. The result of present investigation on electroplating industrial effluent revealed that generally the EC process with adsorbent is an effective tool for the treatment of industrial effluent.