Design and characterization of a cost-effective cermet membrane: implementation in paper mill wastewater treatment

This work aims to produce ceramic-metal composite (cermet) membrane supports based on kaolin and aluminum powders. Flat ceramic membrane supports were prepared from the mixtures of kaolin (K), feldspar (F), sand (S), and two types of aluminum: industrial aluminum waste (Ali) and commercial aluminum (Alc).The samples were obtained by uniaxial pressing with 58.5 MPa in cylindrical moulds and then sintered at 1,350 degrees C for 2 h in order to obtain flat cermet membrane supports of 30 mm in diameter and 6 mm in thickness. Porosity, permeability, and mechanical properties of these supports were studied as functions of the amount of aluminum powder. These characterizations proved that the addition of 4 wt.% aluminum to a 50% kaolin, 25% feldspar, and 25% sand porcelain matrix has a beneficial effect on the membrane support properties. In particular, the presence of aluminum progressively increased water permeability, porosity, and mechanical strength. The cermet membrane support application in the treatment of wastewater from paper mills shows a significant decrease in turbidity, about 97% retention rate of chemical oxygen demand, and an almost total color removal.