Removal of a textile dye using photovoltaic electrocoagulation

The main objective of this study was to investigate the operation of a continuous photovoltaic electrocoagulation process (PVEC) comprising an electrocoagulation (EC) part provided with aluminum electrodes and a settling zone, for the removal of a textile dye: the overall EC cell had a volume of 8.5 L. The effect of the operating parameters has been followed, e.g. inlet pH and dye concentration, residence time, current density, solar irradiance and energy consumption. The results showed that when the inlet concentration was increased from 50 to 1400 mg L-1 and for the following operating conditions: current density ranging from 100 to 400 A m(-2), inlet flow rate at 15 L h(-1), electrode gap of 1 cm, inlet pH near 7, the removal rates of the color and turbidity were decreased from 96% to 87% and from 96% to 93%, respectively. Use of the photovoltaic cell in the place of the electric supply allowed to reach more than 99% of elimination of turbidity and 95% of the color when the initial concentration of the dye was 1400 mg L-1. The specific electrical energy consumption was found at 16 kWh per kilogram of removed dye for EC using direct current, and at comparable levels upon use of photovoltaic cells. The consumption of the electrodes is at comparable levels for the two sources of energy, respectively at 0.45 and 0.6 kg Al per kg of removed dye).