A fluorine-free customizable membrane using sintered copper for oil/water and surfactant-stabilized water-in-oil emulsion separation

This study investigates a fluorine-free, non-wetting copper membrane for separating oil and water and water-in -oil emulsions. The porous membrane produced by sintering copper powder is rendered superhydrophobic by coating it with N-(2-Aminoethyl)-11-aminoundecyltrimethoxysilane, which resists water while letting oil pass through. This selectivity is demonstrated even with surfactant stabilized water-in-oil emulsions. This study shows how to vary separation flux and efficiency by changing the pore size via a controlled sintering process. For separating oil from water, the study demonstrates the largest separation flux of 24,009 L/(m2h) for dichloro-methane/water and the highest separation efficiency of 99.9% for toluene/water. As for water-in-oil emulsions, the largest separation flux of 2614 L/(m2h) was seen in the Water-in-Hexane emulsion, with the highest sepa-ration efficiency of 99.02% for Water-in-Toluene emulsion. With a decrease in the average pore size of the sintered copper membrane, we show a general increase in separation efficiency with a corresponding decrease in the separation flux. In addition, the membranes tested in this study are shown to resist mechanical abrasion, exhibit chemical durability, and possess the ability to separate surfactant-stabilized emulsions at high separation efficiencies using only gravity.