Composite polyvinylidene fluoride (PVDF) membrane impregnated with Fe2O3 nanoparticles and multiwalled carbon nanotubes for catalytic degradation of organic contaminants

Abstract

Porous polyvinylidene fluoride (PVDF) polymeric membranes with inclusion of Fe2O3 nanoparticles and multi-walled carbon nanotubes (MWCNTs) were developed for the Fenton-like catalytic degradation of organic contaminants at neutral pH. The PVDF was modified by in situ polymerization with methyl methacrylate to improve its hydrophilicity, and a range of membranes with different Fe2O3 and MWCNTs loadings were casted. The effect of these compositions on membrane morphology, surface functionality and hydrophilicity was investigated by microscopic, spectroscopic and surface characterization techniques. Contact angle measurements showed that MWCNTs did not change the membrane hydrophilicity, while the Fe2O3 was effective in increasing hydrophilicity. The optimum combination of 0.2% MWCNTs and 1% Fe2O3 induced pore formation and improved membrane permeability. The removal efficiency of cyclohexanoic acid (CHA) and humic acids (HAs) were evaluated. Batch studies revealed that 48% of CHA was degraded after 24h of membrane exposure with H2O2. For HAs, removal with H2O2 addition was significantly higher than without at 53.1±4.4% and 28.1±4.1%, respectively. These membranes also showed a significant reduction in membrane fouling. Overall, the permeate flux achieved with H2O2 was four times higher as compared to without H2O2 addition which is ascribed to the catalytic oxidation of organic molecules which accumulated at the membrane surface.