Grafting of fluoroalkylsilanes on microfiltration Tunisian clay membrane

Ceramic membranes can be described by an asymmetric porous material formed by a macroporous support with successive thin layers deposited on it. Paste from Tunisian silty marls referred M11, is extruded to elaborate a porous tubular configuration used as supports. The support heated at 1190 °C, shows an average pore diameter and porosity of about 9.20 μm and 49%, respectively. The elaboration of the microfiltration layer based on Tunisian clay referred JM18, is performed by slip-casting method. The heating treatment at 900 °C leads to an average pore size of 0.18 μm. The obtained membrane was surface modified to change their hydrophilic character into hydrophobic one by the grafting of the triethoxy-1H,1H,2H,2H-perfluorodecylsilane C8F17(CH2)2Si(OC2H5)3. The resulting products were investigated using Fourier transform infrared spectroscopy FTIR and thermogravimetric analysis TGA. The new surfaces were examined by water contact-angle measurements, Scanning Electron Microscopy (SEM) and the water fluxes through the grafted membranes were also measured. Results of the grafting of microfiltration membrane with fluoroalkylsilane will be given and discussed. The new hydrophobic membrane seems to be promising in the field of membrane distillation. High salt rejection rates higher than 99% were obtained for modified MF ceramic clay membrane.