Bentonite-Based Low-Cost Ceramic Microfiltration Membranes\nfor Sewage Wastewater Treatment

The study focused on fabricating\nand evaluating bentonite-based\nceramic membranes to treat sewage wastewater. Three distinct membranes,\nM1, M2, and M3, were fabricated by varying the compositions of bentonite,\nstarch, and carboxymethyl cellulose (CMC). The raw materials underwent\ncharacterization using FTIR and XRD. Green membranes, 6.1 cm in diameter\nand 0.4 cm thick, were fabricated via a dry pressing technique and\nsintered at 900 °C. The sintered membranes were evaluated for\nsurface morphology, shrinkage, porosity, chemical stability, water\nflux, and pore size. Among these membranes, M3 emerged as the most\nsuitable for sewage wastewater treatment, possessing 30% porosity,\n0.193 μm pose size, 144.93 L/m<sup>2</sup> h bar permeability,\nand exceptional chemical stability. Cost analysis revealed that the\nraw material cost for the M3 membrane was estimated as $21.65/m<sup>2</sup>, contributing to a total fabrication cost of approximately\n$66/m<sup>2</sup>. The membrane M3 was applied to sewage wastewater\ntreatment and effectively removed 93–97% of chemical oxygen\ndemand (COD) and 94–99% of turbidity under applied pressures\nranging from 0.69 to 1.72 bar. Fouling analysis using Hermia’s\nmodels indicated that cake filtration is dominating, suggesting that\nthe membrane fouling could be managed and reversed.