Double aluminum recovery and its reuse in wastewater treatment

Abstract

This work evaluates the use of aluminum contained in the aluminum–polyethylene films as anodic electrodes using the electrocoagulation technique to reduce the pollutant contents of industrial wastewater quickly and effectively. Thermal treatment at 500 °C produces pure aluminum (according to TGA and SEM/EDS analysis) which is used to construct aluminum disks (applying 6 tons/cm2 of pressure). Aluminum disks are used as cathodes and anodes in an electrochemical cell. The current density applied in the recovered Al electrodes was 12 mA cm−2, and the maximum COD reduction of wastewater was 77 % at 25 min of treatment. The color and turbidity reductions are 87 and 90 %, respectively. The resulting sludge of wastewater treatment was thermally treated and a second aluminum recovery was reached; since the organic material present in the sludge was removed by the high temperature, the obtained aluminum was pure enough for its reuse. The use of aluminum–polyethylene films as electrodes in the electrocoagulation process contributes to the pollutant removal without the addition of chemical reagents or changing the pH, so it is both effective and environmentally friendly.