Hybrid membranes for wastewater treatment based on polymer-coated barium titanate nanoparticles

In this work we present a series of hybrid membranes with piezocatalytic properties for wastewater treatment. For this, four types of barium titanate nanoparticles (BTO NPs) with different coatings were synthesized. These NPs were embedded in a polystyrene (PS) matrix to fabricate hybrid, porous membranes using the breath figures (BF) technique. In-depth electron microscopy analysis showed that the NPs with an amphiphilic coating composed of PS (hydrophobic, compatibilizing them with the PS matrix) and hydrocaffeic acid (HCA) (hydrophilic, favoring the formation of ordered pores) led to the formation of honeycomb-patterned films where these NPs are selectively placed inside of the pores for a wide range of concentrations, from 5 to 100 wt%. We demonstrated the potential of these membranes in piezocatalysis applications, through proof-of-concept studies of methylene blue (MB) degradation in aqueous solutions.