An Overview on the Manufacture and Properties of Clay-Based Porous Ceramics for Water Filtration

This study explores the different techniques used to manufacture porous clay-based ceramics, examining their properties such as porosity, strength, permeability and filtration efficiency. Different techniques are discussed in this review, with additive manufacturing being one of the most innovative techniques for manufacturing porous ceramics. Porous ceramics have their applications in numerous domains. Such ceramic filters have the advantages of retaining heavy materials, suspended particles, bacteria, viruses and, water turbidity. Thus, the choice of the technique and propriety is a crucial step in obtaining a porous ceramic with the best performance. Barry et al. prepared porous phyllosilicate-based ceramics by freeze-tape casting on four samples and obtained porosity values in the range of 67–79% and diametrical compressive strength in the range of 3–7 MPa. Manni et al. prepared porous red ceramics from Moroccan clay and coffee waste (10, 20 and 30 wt.%) via uniaxial pressing and sintering at 1150 °C. They obtained porosities ranging from 30.2 to 63.8% and flexural strength values from 1.8 to 19.5 MPa. Medri et al. prepared ZrB2-based porous bodies with the use of sponges and polyurethane foams as templates via the replica method and obtained high porosity over 80% and compressive strength up to 4.8 MPa. The use of clay and peanut shell mixtures was used in preparing porous silicate ceramics after unidirectional pressing and sintering at 1100 °C. These samples included 25 mass% of peanut shells, and exhibited porosity in the range of 40 to 60% and diametrical compressive strength in the range of 1–6 MPa. Such properties are suitable for domestic use of these types of clay-based ceramic filters. Moreover, the permeability values and removal of some pollutants, like arsenic, have been satisfactory for the first set of samples.