Simultaneous studies of emulsion stability and extraction capacity for the removal of tetracycline from aqueous solution by liquid surfactant membrane

Abstract

In this article, the removal of tetracycline (TC) from aqueous solutions was investigated by liquid surfactant membrane technique using n-heptane as a diluent, span80 as a surfactant, tri-butyl-phosphate as carrier, and HCl acid as the internal phase. The effect of various operating parameters on the emulsion stability by means of breakage and sauter mean diameter and the extraction efficiency were studied such as homogenizer speed, emulsification time, internal to membrane volume ratio, surfactant concentration, internal phase concentration, carrier concentration, external phase pH, mixing speed and external to emulsion volume ratio. Maximum extraction of TC was found to be more than 95% after 15min contact time under the optimum experimental condition that gives a lowest membrane breakage of 1.23% and best sauter mean diameter (d32) of 4.82μm. While 93% of the extracted TC can be stripped by the internal phase. The reusing of membrane phase was also investigated throughout this work, and the results indicated that the extraction efficiency slowly decreased and the stability enhanced with the reusing process up to three times.