A novel hydrophilic polymer-ceramic composite membrane 1: Acrylic acid grafting membrane

A novel hydrophilic ceramic/polymeric pervaporation membrane was prepared by free-radical graft polymerization of acrylic acid (AA) onto the ceramic membrane which was pre-coated with a SiO2 active layer by in situ hydrolysis-deposit method. The influence of reaction conditions on the SiO2 layer was studied. The surface property and the morphology of the membrane were analyzed by means of SEM, FT-IR and TGA. Only the AA-chain grafting on the support coated with an active silica layer can lead to high performance membranes for solvent dehydration. The grafted chains imparted a high selectivity to the membrane, but their confinement in rigid ceramic pores led to a singular decrease in the permeation flux when the temperature increases. The membrane performances for the separation of ethanol/water mixtures by pervaporation for different monomer concentrations in the grafting solution were measured. The membrane grafted in 6 wt.% of AA had good separation performances: for the dehydration of 95 wt.% ethanol at 30 °C, the permeation flux was 540 g m−2 h−1 and the water content in permeate was higher than 98.7 wt.%.