Fabrication of catalytic membrane contactors based on polyoxometalates and polyvinylidene fluoride intended for degrading phenol in wastewater under mild conditions

A novel catalytic membrane contactor (CMC) has been designed and constructed by incorporating polyoxometalates (POMs) onto polymeric polyvinylidene fluoride (PVDF) micro-porous hollow fiber membranes which were fabricated by a dry-jet wet spinning process. A simple chemical deposition method was utilized to anchor the Keggin-type polyoxometalate H5[PV2Mo10O40] (PV2Mo10) on the outer surface of the PVDF hollow fiber, which was confirmed by the measurements of field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and Fourier transform infrared spectroscopy (FTIR). The degradation of phenol in synthetic wastewater was carried out using air as green oxidant under room conditions using the CMC. A gas-catalyst-liquid interface was successfully built up to enhance the catalytic efficiency. It was observed that the pressure of the gas flow played an important role and a low pressure is preferable. The long-term stability of the CMC was also preliminarily studied. This novel and facile CMC with PV2Mo10 as catalyst potentially provides a feasible pathway for wastewater treatment under mild conditions.