Development and Characterization of Nanocomposite Membranes based on Chitosan, Polystyrene and Montmorillonite for Pervaporation Separation of Phenol and Chlorophenols from Water

Abstract

The novel nanocomposite membranes were successfully prepared by the incorporation of different concentrations (5, 10, and 15 wt%) of montmorillonite (MMT) as a nanoadditive into a blend of chitosan/polystyrene (CS/PS) at a ratio of 3:1 on the basis of solution-casting method and they were subsequently used for the separation of phenol, p-chlorophenol, and 2,4-dichlorophenol from water through pervaporation process. The effects of feed composition, the MMT content, and various feed types were investigated on pervaporation performance. All the membranes were water selective and the permeation rate increased with increasing the MMT content. The presence of MMT, increased the hydrophilicity of CS/PS blend polymer matrix, resulting in the formation of a higher flux to water molecules. The best separation performance was achieved for the CS/PSMMT-15 nanocomposite membrane containing a 15 wt % of MMT with 2,4-dichlorophenol in the feed, i.e., the 2,4-dichlorophenol concentration from 0.1 to 0.4 wt %, the flux values from 10.7 to 14.2 g/m2.h and the separation factor from 1784 to 721. The separation of 2,4-dichlorophenol/water mixture proceeded easier than that of the phenol/water and p-chlorophenol/water mixtures because of the larger molecular size of 2,4-dichlorophenol and the relatively weak coupling phenomenon with the water molecules and hydrophilic membranes.