Electrocoagulation by solar energy feed for textile wastewater treatment including mechanism and hydrogen production using a novel reactor design with a rotating anode

Abstract

This paper describes the treatment of textile wastewater using a unique design of an electrocoagulation (EC) reactor with a rotating anode. The effects of various operational parameters such as rotational speed of the anode, current density (CD), recirculation flow rate, operational time (RT) and continuous flow regime on the efficiency of pollutant removal in terms of chemical oxygen demand (COD) and colour were examined. The mechanisms of EC treatment and hydrogen production were also evaluated. In addition, the model verification was an attempt to study the passivation and adsorption phenomena. The results indicated that the optimum conditions were achieved at CD = 4 mA cm⁻², RT = 10 minutes and rotational speed = 150 rpm, where the operating cost was 0.072 US$ per m³. The removal efficiencies of COD and colour were 91%, 95% for the batch system and 91.5%, 95.5% for the continuous flow system respectively. Zeta potential values indicate that the chemical interaction happened, and XRD analysis of the sludge produced reveals that the reaction is a chemo-adsorption type, where the final product is environmentally friendly (aliphatic sludge). Hydrogen production was enhanced under the optimal conditions to produce 12.45%, reducing the power consumption by 9.4%. The passivation and adsorption resistance values validate the removal rate of pollutants.