Recovery of zinc from electroplating wastewater using green emulsion liquid membrane

Abstract

In this research study, removal of zinc ions from the industrial wastewater was investigated using green emulsion liquid membrane technology. The liquid membrane was prepared by using waste cooking oil along with the surfactant, SPAN 80 and the internal phase, sulfuric acid. The extraction percentage of zinc increased with the increase in concentration of surfactant. The response surface methodology (RSM) analysis identified that the optimal variable values for the maximum extraction of zinc were: external pH – 3.8, surfactant concentration 4% (vol.), internal phase concentration – 1.61N, zinc concentration – 742 mg/L, external phase to emulsion volume ratio – 0.94 and carrier concentration – 8.9%. At the optimized conditions experiment was carried out and the maximum extraction was found to be 97.4%. The perturbation plot shows that the extraction of zinc was affected by variables in the following order of effect: zinc concentration > surfactant concentration > carrier concentration > external pH > external phase to emulsion volume ratio > internal phase concentration. HIGHLIGHTS The use of waste cooking oil for the extraction of zinc from industrial wastewater is a novel study.; Optimization of operating variables using RSM for zinc recovery is a first of its kind.; Studies on industrial wastewater for zinc recovery is a novel attempt.;

Keywords

• efficiency
• emulsion
• membrane
• metal
• recovery
• zinc