Insights on applications of low-cost ceramic membranes in wastewater treatment: A mini-review

In recent decades, rapid industrialization resulting in the generation of a massive amount of wastewater. Petrochemical, textile, tannery, and dairy industries, etc., generate wastewater consisting of high concentrations of oils, fats, chemical oxygen demand (COD), biological oxygen demand (BOD), and total suspended solids (TSS). Therefore, treating industrial effluents before disposing them into water bodies is mandatory to avoid water contamination. Membrane technology is promising over other technologies in wastewater treatment due to its environmentally friendly nature, operability with less energy requirement, and high separation efficiency. Specifically, ceramic membranes are associated with numerous advantages, including excellent thermal and chemical stability, mechanical strength, fouling resistance, and durability. These properties made ceramic membranes more suitable over polymeric membranes, especially for water treatment applications. However, expensive raw materials and the requirement of high sintering temperatures made ceramic membranes uneconomical. Therefore, several researchers focused on producing ceramic membranes from alternative or low-cost raw materials to reduce the cost of membranes. This review is aimed to present current signs of progress in inexpensive raw materials to prepare ceramic membranes. The influence of various parameters, including sintering temperature, the composition of raw materials, and type of fabrication technique on membrane properties such as pore size, porosity, and flexural strength, are discussed in detail. Furthermore, wastewater treatment applications of low-cost ceramic membranes, including oily wastewater treatment, dairy wastewater treatment, heavy metal ion removal, textile effluent treatment, poultry slaughterhouse effluent treatment, paper and pulp industry wastewater treatment, and separation of bacteria and viruses from contaminated water are presented. Finally, future scope and challenges for further improving low-cost ceramic membranes are also emphasized in this review.