Electrocoagulation/Electroflotation of real textile effluent: Improvement of the process in non-conventional pilot external loop airlift reactor

Abstract

A pilot external-loop airlift reactor (ELAR) of 150 liters was designed and used as a non – conventional reactor to carry out Electrocoagulation/Electroflotation to treat real textile effluents containing disperse and reactive dyes. The designed reactor ensure the recovery of sludge by electroflotation (EF) in which complete flotation of the pollutants is achieved without additional mechanical power in the pilot external-loop airlift reactor (ELAR), using only the overall liquid recirculation induced by H 2 microbubbles generated by water electrolysis without filtration process. Aluminum, iron electrodes and combined aluminum – iron electrodes were tested. The obtained results were interesting as they would help managing the Electrocoagulation/Electroflotation process in pilot external – loop airlift reactor to remove real textile effluent. The treatment of the mixtures of the real textile dyeing industry is better when using a combination of the electrodes of iron and aluminum providing a better treatment efficiency of 80% and a lower specific energy consumption (50 kWh/kg dye). In order to analyze the by-product of the electrocoagulation (EC) and the treated effluent, different techniques were used to elucidate the role of different kind of anodes especially when the combined iron – aluminum were used simultaneously as sacrificial anodes.