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Affordable hydrophobic hollow fibre membranes were prepared using kaolin and alumina based ceramic powders via a combined phase inversion and sintering technique, followed by a grafting with fluoroalkylsilane (FAS). The crux of the matter in this paper is to study the changes in the properties of the hollow fibre membranes (gas permeation, mechanical strength, pore size, porosity, tortuosity, morphology, and contact angle) by the addition of alumina (Al 2 O 3 ) to the pure kaolin with mono or multiparticle sizes. By varying the overall loading and particle size of alumina addition, different morphologies of the membranes were obtained due to the differences in the path lengths during phase inversion process for each solvent and nonsolvent exchange. The successful grafting with FAS was evidenced by the increase in contact angle from nearly equal to zero degree before grafting to 140° after grafting. Kaolin-alumina-4, one of the hollow fibres fabricated in this work, achieved a mean pore size of 0.25 µm with the bending strength of 96.4 MPa and high nitrogen permeance of 2.3×10 5 mol·m 2 ·Pa 1 ·s 1 , which makes the hollow fibre most suitable for the membrane contactor application.

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Ceramic membrane has the ability to surpass the utilisation of polymeric membrane in the application that requiring high temperature and pressure condition, as well as harsh chemical environment. Due to the high cost of ceramic membrane, various attempts have been made to use low cost ceramic materials as alternatives to well-known expensive metal oxides. In this work, local Malaysian kaolin has been chosen as ceramic material since it is inexpensive and easily available in Malaysia for the preparation of low cost hollow fibre ceramic membrane. The aim of this work is to study the effect of sintering temperature on the morphology, properties, and performance of kaolin hollow fibre membrane by sintering the prepared precursor at different target temperatures ranging from 1300°C to 1500 °C. The experimental results demonstrated that the kaolin membrane sintered at 1400 °C has influenced the formation of sufficient dense sponge-like structure of skin layer, resulting in good water flux of 74 L/h.m2.

The effects of calcite (CaCO 3 ) as sintering aid on the preparation of local aluminum silicate microfiltration membranes were characterized in terms of morphology, thermal shrinkage behavior, porosity, permeation performance, and pure water permeate flux for the membrane. Material selection is based on availability and formability. In order to create a suspension, an organic solvent (N-methyl-2-pyrrolidone) and a polymer binder were added to a mixture of aluminum silicate and calcium carbonate. The coagulant bath consisted of water, and the suspension was extruded into a hollow fiber using a spinneret. The membrane precursor is subjected to high temperatures up to 1250 °C and this process called the sintering process gets strong hollow fiber with high mechanical stability. The addition of the CaCO 3 ) to the dispersion altered the structure of the resulting sintered membranes. The obtained finding demonstrates that carbon calcium addition to aluminum silicate has an affirmative on overall porosity in contrast to those made from purely natural aluminum silicate, as a result the aluminum silicate calcite ceramic microfiltration membrane, which had a high porosity of above 50%, shows the highest permeability of 35.8 ml m -2 •s -1 and above 97% oil rejection when operating at 0.15 MPa trans-membrane pressure in oil-in-water separation experiments. The results show that low-cost aluminum silicate-calcite component of ceramic membranes and the manufactured ceramic microfiltration membrane can handle emulsified oily wastewater.