In situ ultraviolet-light-induced TiO2 nanohybrid superhydrophilic membrane for pervaporation dehydration

The membrane surface property is one of the most important factors that influence the solution-diffusion-controlled pervaporation process. In the present study, a superhydrophilic nanohybrid membrane was successfully prepared by in situ ultraviolet irradiation of titanium dioxide (TiO2) nanoparticles imbedded in polyelectrolyte complexes. The TiO2 precursor solution was dynamically filtered through a layer-by-layer-assembled poly(ethyleneimine)/poly(acrylic acid) multilayer under a specific pressure. Subsequently, ultraviolet radiation was used to improve the hydrophilicity of the nanohybrid membranes via photoinduction of the superhydrophilic property of the TiO2 nanoparticles. When the membranes were irradiated, the surface contact angle decreased from 62° to 3°, which is characteristic of a superhydrophilic membrane surface. The pervaporation performance of the membrane for separating alcohol/water mixtures was investigated. The water content could be enriched from 5 wt% (in the feed) to 99.89 wt% (in the permeate) and the permeate flux was 865 g/(m2 h) in the pervaporation of the ethanol/water mixture. These results indicated that the superhydrophilic surface was beneficial for improving the pervaporation dehydration performance.