Ultrasmall Cu3(PO4)2 Nanoparticles Reinforced Hydrogel Membrane for Super-antifouling Oil/ Water Emulsion Separation

Membrane fouling is a persistent and crippling challenge for oily wastewater treatment due to the high susceptibility of membranes to contamination. A feasible strategy is to design a robust and stable hydration layer on the membrane surface to prevent contaminates. A hydrogel illustrates a distinct category of materials with outstanding antifouling performance but is limited by its weak mechanical property. In this research, we report a reinforced hydrogel on a membrane by in situ growing ultrasmall hydrophilic Cu3(PO4)2 nanoparticles in a copper alginate (CuAlg) layer via metal-ion-coordination-mediated mineralization. The embeddedness of hydrophilic Cu3(PO4)2 nanoparticle with a size of 3-5 nm endows the CuAlg/Cu3(PO4)2 composite hydrogel with enhanced mechanical property as well as reinforced hydrate ability. The as-prepared CuAlg/Cu3(PO4)2 modified membrane exhibits a superior oil-repulsive property and achieves a nearly zero flux decline for separating surfactant stabilized oil-in-water emulsions with a high permeate flux up to similar to 1330 L m-2 h-1 bar-1. Notably, it is capable of keeping similar permeate flux for both pure water and oil-in-water emulsions during filtration, which is superior to the currently reported membranes, indicating its super-antifouling properties.

Automated summary

In this research, a reinforced hydrogel on a membrane was developed by growing ultrasmall hydrophilic Cu3(PO4)2 nanoparticles in a copper alginate (CuAlg) layer. The resulting modified membrane exhibited excellent oil-repulsive properties and maintained high permeate flux during the filtration of both pure water and oil-in-water emulsions, indicating its super-antifouling properties.