Application Of Emulsion Liquid Membrane And Double-emulsion Liquid Membrane In Removing Organic Pollutants In Water

Thanks to its large mass transfer area, good selectivity, high mass transfer rateand low operational cost, emulsion liquid membrane has found its application in manyindustries, such as pharmaceutical, petrochemical engineering, wastewater treatment,metallurgy and food industry. This study investigated the extraction of BPA fromwater solutions using emulsion liquid membrane through response surfacemethodology. Based on the research on emulsion liquid membrane, we furtherexplored the stability of the double-emulsion liquid membrane and then investigatedthe process of using this double-emulsion liquid membrane to simultaneously extractphenol and aniline from water solutions.In emulsion liquid membrane studies, the stability of the emulsion exerts a greatinfluence on the whole extraction results, so at the beginning of this study, weinvestigated the operational conditions to achieve stable emulsion. Hydrochloridesolution and sodium hydroxide solution were used as the internal stripping phase, andthe concentration of internal stripping phase, emulsification speed and emulsificationtime were investigated to examine the effect on membrane stability.Based on the membrane stability conditions, we studied the extraction process ofBPA from water solutions by emulsion liquid membrane and optimized theoperational conditions through respond surface methodology, in the end, the optimumconditions were obtained. Under the optimum conditions, the extraction efficiency ofBPA can be as high as97.52%. The membrane phase was reused for the extractionafter demulsification, and the results showed that the extraction efficiency of BPAwas still very high using the recycled membrane.In order to further broaden the application of emulsion liquid membrane, we wenton to explore the stability of double-emulsion liquid membrane, and then use theobtained double-emulsion liquid membrane to extract both phenol and aniline fromwater solutions. Experimental conditions such as the adding order of acid emulsionand base emulsion, extraction time, emulsification speed, emulsification time and thepH of the external phase were investigated. The influence of salt on the extraction results was also examined. Under experimental conditions, the respective optimumextraction efficiencies of phenol and aniline can be90%and85%at the same time.Through the experiments, it is concluded that the double-emulsion liquid membranecan simultaneously extract two different types of pollutants from water solutions.