Preparation and application of catalytic polymeric membranes based on PVDF/cobalt nanoparticles supported on MWCNTs

Abstract

In this study, preparation, characterization and application of catalytic polymeric membranes incorporated with cobalt nanoparticles-decorated multi-walled carbon nanotubes (Co/MWCNTs) have been reported as an efficient catalyst for reduction of 4-nitrophenol to 4-minophenol. A facile and green method was used to synthesize Co/MWCNTs by two reducing agents, including sodium borohydride (NaBH4) and l-ascorbic acid, carried out at room temperature. Fourier transform infrared, differential scanning calorimetry, vibrating sample magnetometer, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy analyses were employed to characterize the structure and morphology of the prepared catalyst. Catalytic polymeric membranes were prepared through the phase inversion method by embedding the Co/MWCNTs with three different concentrations (1%, 2% and 3% wt%) in polyvinylidene fluoride matrix. Furthermore, the composition and morphology of the nanocompsite membranes were characterized by energy-dispersive X-ray spectrograph and SEM analyses. To investigate the catalytic activity of the prepared membranes, they were applied in a flow-through reactor, showing good catalytic activity toward the reduction of 4-nitrophenol with NaBH4 aqueous solution. After each run, the solution was analyzed by ultraviolet–visible spectrophotometer, and the conversion of the reactant was calculated. The best result was observed for the catalytic membrane containing 3% of Co/MWCNTs, exhibiting 100% conversion by applying two runs.