Dopamine-induced biomimetic mineralization for in situ developing antifouling hybrid membrane

Abstract

Membrane technology has raised significant interests over the past decade for sustainable water purification. Developing antifouling membranes are always the fundamental strategy to deal with the bottlenecks of ubiquitous membrane fouling. In this work, we provide a novel and facile strategy for developing antifouling hybrid membranes via dopamine-induced biomimetic mineralization of dopamine/TiO2 hybrid nanoparticles (DA/TiO2 HNPs) in situ within polyvinylidene fluoride membrane matrix. During biomimetic mineralization, dopamine, as the cationic inducer, favors the in situ hydrolysis/condensation of the titania precursor to form hybrid nanoparticles within polymer chains. Antifouling hybrid membranes are then obtained via non-solvent induced phase separation. The as-prepared hybrid membranes exhibit homogeneous nanoparticle dispersion, higher surface hydrophilicity, high surface energy, underwater superoleophobicity and higher mechanical strength. The in situ mineralized DA/TiO2 HNPs enhance both the separation performance and antifouling property of hybrid membranes. With the increase of hybrid nanoparticle loading, the water fluxes of the hybrid membranes are increased by three times. Moreover, the antifouling properties of hybrid membranes are effectively improved during the separation of 1 g/L oil-in-water emulsion with flux recovery ratio up to 95%. Especially for the PVDF/DA/TiO2 membrane with highest DA/TiO2 HNPs loading, it can maintains more than 85% flux recovery even challenged with oil-in-water emulsions of 50-fold higher concentration, indicating the reliable and extensive antifouling property of hybrid membranes against oil fouling. This study provides a potential in situ biomimetic mineralization strategy to construct antifouling hybrid membranes, and suggests the promising future of as-prepared antifouling hybrid membranes for water treatment.