A high-efficiency oil/water emulsion separation sponge based on sodium alginate-loofah composite gels

Nowadays, many reported oil/water (O/W) emulsion filter materials have issues such as susceptibility to fouling, complex processing, high costs, and environmental unfriendliness. Herein, a novel O/W emulsion separation membrane-like sponge (SA/GO-SL) is prepared in this study by utilizing reshaped waste loofah (LF) as skeleton, the in situ formed sodium alginate (SA) gels as binder, and the graphene oxide (GO) added into the gels as functional component. Reshaped LF provides an enough anti-pressure ability and micron-sized pores structure, which guarantees a water flux of 63.8 Lm^-2 h^-1 under the 0.25 bar pressure. SA and GO improve the surface roughness and hydrophilicity of the filter sponge comprehensively, so that the sponge exhibits excellent separation capability towards the emulsified oils, with the retention rate of emulsified oil in water up to 99.3 %. Moreover, the sponge exhibits a non-ignorable retention effect on heavy metal ions such as Pb²⁺ and Cu²⁺ due to the electrostatic adsorption. The excellent separation effect makes this carbohydrate polymer sponge be the potential candidate in water purification field.