Microfiltration ceramic membranes from local Cameroonian clay applicable to water treatment

The present paper reports the elaboration of porous ceramic membranes from natural and local Cameroonian clay (Wak village). This material has been chosen due to its natural abundance, its non-toxicity and low cost and its valuable properties. In a first stage, we developed and characterized low cost mineral membranes for microfiltration application to produce clear water from high turbidity water. Our second objective is to deposit ultrafiltration and nanofiltration layers on the macroporous clay membranes to achieve high quality and potentially drinkable water. Flat porous ceramic membranes were then prepared by axial-pressing of a plastic paste composed of natural clay and sawdust, largely abundant materials in Cameroon recovered from local industries. After drying at room temperature for 24 h, the obtained green membranes were submitted to a thermal treatment at 1100 °C to ensure consolidation and pores formation. After this treatment, the membranes showed an average porosity of 42% and an average withdrawal of 35%. In addition, clay membranes presented a better chemical resistance in acidic medium than in basic medium. The elaborated membranes were used to clarify aqueous suspensions of clay powder at concentrations of 2 g/L and 1 g/L. Dead-end filtrations of these aqueous suspensions containing suspended matter lead to the removal of feed turbidity up to 97%.