Membranes céramiques à base d’argiles kaolinitiques, bentonitiques et de calcaire : élaboration, caractérisation et purification des eaux

Abstract

The membrane supports were made from kaolinitic and bentonite clay and limestone harvested respectively in the locality of Mayouom (West, Cameroon), Sabga (North-West, Cameroon) and Figuil (North, Cameroon). Nineteen formulations were made with 10% bentonite and limestone, the rate of which varies between 0-20% (natural and at 700-800°C). These obtained mixtures were shaped into parallelepipedal and cylindrical specimens which were subjected to a heat treatment of 1150° C., at a heating rate of 2° C/min with two hours (2h) of soaking time. To characterize the ceramic membranes obtained, the following analyzes were performed: Color, mercury intrusion porosimetry (MIP), flexural strength, permeability, linear shrinkage, water absorption, density, mass loss, chemical stability and bacterial retention capacity. The results obtained show that after firing, the specimens have retained their initial shape but have a new color (pinkish white) which depends on the composition of the mixture. The addition of limestone in the manufacture of membranes increases the size of the pores, the porosity and therefore the permeability but to the detriment of the performance of bacterial retention. Among the various compositions studied, the membrane containing 7% natural limestone showed the best performance, with 100% of bacterial retention and a maximum water permeability of 566 L.h .m . bar . The membrane containing 5% of limestone pre-sintered at 700°C presents a good performance with 100% of bacterial retention and a maximum permeability of 566 L.h .m .bar while the membrane containing 3% limestone pre-sintered at 800°C has better performance with 100% of bacterial retention and a permeability of 523 L.h .m .bar . These novel low-cost microfiltration membranes are expected to have potential applications in water treatment and domestic applications. The membrane containing 83% kaolin, 10% bentonite and 7% natural limestone is therefore the most optimal membrane.