Synthesis of novel composite membranes by in-situ intercalative emulsion polymerization for separation of aromatic-aliphatic mixtures by pervaporation

Sodium montmorillonite (NaMMT) clay was coated with copolymer of acrylonitrile and acrylic acid of different comonomer ratios by in situ intercalative emulsion polymerization in water. Both untreated clay and polymer coated clay was incorporated in polyvinyl alcohol (PVA) followed by its crosslinking with maleic acid to form several composite membranes. These membranes were characterized by XRD, FTIR, DTA-TGA, SEM, EDAX, TEM and DMA and the effect of these uncoated and polymer coated clays on sorption and pervaporation of benzene-cyclohexane mixtures through these composite membranes were studied. The polymer coated clay filled membranes showed much higher flux and separation factor for benzene than the unfilled or uncoated clay filled membranes. The results showed that the preferential sorption of aromatic benzene by the polar membranes contributed to high separation factor for benzene in pervaporation. The solvent coupling in sorption and pervaporation were studied. The feed molar ratios of acrylonitrile and acrylic acid, clay: copolymer wt. ratio and wt. % of clay in PVA were optimized with a central composite design (CCD) of response surface methodology (RSM). The polymer coated clay prepared with the copolymer containing 5:1 M ratio of acrylonitrile and acrylic acid and the clay: copolymer wt. ratio of 1:1 was incorporated in PVA and the filled PVA membrane containing 8 wt% of this coated clay showed the optimum flux (g/m(2)h) of 65.38, 85.34 and 168.56 and the optimum separation factor(-) of 187.96, 172.72 and 137.16 for a feed of 0.5, 8 and 50 wt % benzene, respectively which was concentrated to 50.2, 93.0 and 99.2 wt% benzene, respectively after pervaporation.