Utilization of environmentally benign emulsion liquid membrane (ELM) for cadmium extraction from aqueous solution

•ELM developed using environmentally benign diluent was employed for cadmium separation from aqueous solution.•98.9% of cadmium were successfully removed from the external phase, proving the feasibility of the ELM for cadmium separation.•Demulsification process using ultrasonication yields 48.8% breaking efficiency in short time (5 min).

Utilization of Emulsion Liquid Membrane (ELM) for cadmium removal from aqueous solution was explored. Basically, ELM consists of 2 phases; internal and membrane phase that form the primary W/O (water-in-oil) emulsion which to be dispersed in the external phase. In this work, Aliquat 336 and Span 80 were used as carrier and surfactant, respectively whereas corn oil was used as an environmentally benign diluent in the membrane phase. Influence of operating conditions that affect ELM performance; ultrasonic power, emulsification time, treat ratio, stirring speed together with initial cadmium concentration were investigated. It was found that 20 W ultrasonic power, 12 min emulsification time, treat ratio of 1:5 and 300 rpm stirring speed were essential to achieve maximum removal efficiency (98.9%) after 15 min. The current study also exhibits the possibility of demulsification process assisted by ultrasonic probe. 48.8% emulsion breaking efficiency was recorded using ultrasonic power ≥ 33W, subjected to 5 min of irradiation time.