Hybrid ceramic membranes for sustainable wastewater treatment: Low-Cost materials, hybrid separation mechanisms, and applications

The rapid expansion of industrial activity in recent decades has led to a substantial increase in wastewater generation. Industries such as petrochemicals, textiles, tanneries, and dairy processing discharge effluents containing oils, fats, biological oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS). To prevent environmental contamination, treating these effluents before discharge is imperative. Membrane technology offers high separation efficiency, low energy consumption, and environmental sustainability, making it a promising route for modern wastewater management. Ceramic membranes provide superior mechanical strength, resistance to fouling, and thermal and chemical stability. However, the high sintering temperatures (typically 1200–1600 °C) and cost of conventional raw materials limit their broad deployment. Recent research demonstrates that low-cost ceramic membranes derived from natural minerals and industrial wastes can achieve oil removal efficiencies of 92–99% while reducing sintering temperatures by 200–400 °C, representing an emerging class of hybrid and composite materials aligned with eco-designed hybrid technologies. This review synthesizes advances in alternative raw materials, hybrid ceramic–composite structures, and cost-efficient fabrication technologies, highlighting how sintering temperature, pore formers, and raw material composition influence pore size (0.2–1.5 μm), porosity (25–50%), and mechanical strength. Applications in treating oily wastewater, textile dyes, heavy metals, dairy effluents, poultry slaughterhouse wastewater, and pulp and paper industry effluents are examined, along with bacterial and viral removal. Overall, low-cost hybrid ceramic membranes are emerging as sustainable materials for wastewater treatment, bridging performance gaps between polymers and traditional ceramics while offering quantifiable improvements in efficiency, cost, and energy consumption, thereby supporting the global transition toward hybrid and environmentally responsible technologies.