Investigation on liquid emulsion membrane (LEM) prepared with hydrodynamic cavitation process for cobalt (II) extraction from wastewater

In the present work, the preparation of liquid emulsion membrane (LEM) considering Aliquat 336 as a carrier was accomplished first time with the use of hydrodynamic cavitation (orifice based) process. The other components/ingredients used for the preparation of LEM were kerosene (diluent), span 80 (emulsifier) and NaOH which was used as a stripping agent in the internal phase. The extraction process of cobalt (II) from wastewater was investigated using the LEM prepared with the orifice plates having diameter equal to 1 mm and 5 mm. Further, the influence of various elected parameters like processing time, orifice diameter, carrier concentration and external feed phase to emulsion membrane phase ratio (i.e. treat ratio) on extraction efficiency of cobalt (II) from the feed phase have been examined and reported. The obtained results confirmed the possibility of 100% extraction of cobalt (II) using hydrodynamically prepared LEM from the aqueous feed phase which contains 100 ppm cobalt (II). The % extraction efficiency of cobalt increases with the carrier concentration and also with LEM prepared in hydrodynamic cavitation for various cavitation time up to certain limit. Further, the concentration of span 80 has been established to be adequate for the stability of the LEM throughout the cobalt (II) extraction process. In the present work, the effectiveness of hydrodynamic cavitation based process for the preparation of stable LEM with an application in the separation of cobalt (II) from the aqueous feed phase has been established.