Superhydrophilic and Photothermal Fe-TCPP Nanofibrous Membrane for Efficient Oil-in-Water Nanoemulsion Separation

Separation and purification of surfactant-stabilized oil-in-water nanoemulsions is a great environmental challenge. Membrane-based separation strategies are more effective over conventional methods in the treatment of nanoemulsion waste water. In this paper, we construct a superhydrophilic membrane by coating a thin photothermal-responsive iron tetrakis(4-carboxyphenyl)porphyrin (Fe-TCPP) nanofibrous metal organic framework (MOF) selective layer on a macroporous polyethersulfone membrane. The as-prepared membrane exhibits high separation performance of oil-in-water nanoemulsions with permeance of 46.4 L·m-2·h-1·bar-1 and separation efficiency of 99%. It also demonstrates nice anti-oil/ionic-fouling property, good recyclability, and desirable stability. The high separation performance is accredited to the superhydrophilicity, highly charged surface, and nanometer pore sizes of the Fe-TCPP nanofibrous membrane. Due to the unique photothermal property of Fe-TCPP nanofibers, the permeance can be enhanced more than 50% by visible light without deteriorating the rejection. This photo-stimuli MOF-based thin-layer membrane offers great potential for the generation of point-of-use water treatment devices.