Removal of furosemide from water by emulsion liquid membrane: Influence of experimental conditions and real water matrices

This work investigates the removal of furosemide (FSM) from low pH aqueous phase by emulsion liquid membrane (ELM). The influence of various experimental conditions on FSM permeation rate and subsequent emulsion stability, such as surfactant concentration, diluent type, stripping solution concentration, feed solution pH, stripping solution/membrane solution volume ratio, emulsification time and speed, stirring rate, initial FSM concentration, and emulsion/feed solution volume ratio, was evaluated. The ability to extract FSM in different natural complex matrices was examined. The ELM system is formed by Span 80 (5% w/w) as surfactant, hexane as diluent, NaOH (0.01 N) as stripping agent, stripping solution/membrane solution volume ratio of 1/1, treatment volume ratio of 20/200, and mixing rate of 200 rpm. The treatment process demonstrates complete removal of FSM within a remarkably short time span of 20 min. In seawater and natural mineral water, the extraction efficiency is 94.3% and 96.8%, respectively, after 20 min. Additionally, the stripping efficiency of FSM is reported to be excellent (100%), demonstrating the remarkable ability of ELM to remove and recover FSM from water. For these reasons, the ELM technique is a particularly interesting process for treating FSM-contaminated water.