Structural tailoring of ceria nanoparticles for fabricating fouling resistant nanocomposite membranes with high flux distillation

Abstract

This study stems from the morphological design of ceria (CeO2) filler into the membrane matrix, which might provide a varied method for building nanocomposite membranes with superior performance. We synthesized nanostructured CeO2 with controlled size and shape using aqueous ceric ammonium carbonate complex (precursor) and decanoic acid under reflux and hydrothermal conditions. Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP)/CeO2 nanocomposite membranes were fabricated through the phase inversion technique for desalination via direct contact membrane distillation (DCMD) using the synthesized CeO2 of various morphologies. The influence of CeO2 morphology on the performance of the membrane was investigated by various morphological and spectral techniques along with transmembrane flux and salt rejection. Among the fabricated membranes, (18% PVDF-co-HFP/1%) CeO2 (synthesized through hydrothermal route with 1:16 ratio of ceric ammonium nitrate to decanoic acid) -M-HT1:16 membrane was adjudged the most suitable with 5.33 L m(-2) h(-1) permeate flux and 99.98% salt rejection for desalination of 8% NaCl solution at 60 degrees C feed temperature. The smooth spherical morphology of CeO2 nanoparticles improved surface roughness, membrane porosity, and hydrophobicity for the M-HT1:16 membrane. A mathematical model was also proposed which describe the vapor flux profile of the DCMD process. The model was validated by experimental data with reasonable accuracy. Exceptional thermal stability, anti-fouling nature, along with feasible scale-up make MHT1:16 nanocomposite membrane a promising candidate for seawater desalination by the DCMD process.