Functional material innovations in ultrafiltration and microfiltration for advanced water treatment: a comprehensive review

Abstract

Due to their energy efficiency, compactness, and versatility, membrane technologies represent a viable alternative for water purification, replacing more expensive methods such as coagulation and adsorption. Membrane processes commonly used in water treatment include reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF), and microfiltration (MF), which play key roles in desalination and wastewater purification. For example, MF is generally used for the retention of dispersed dyes or pigments and as pretreatment for RO, while UF is often applied to groundwater purification or as pretreatment for NF and RO. Membrane performance depends on composition, structure, morphology, and operating parameters, and can be enhanced by incorporating nanomaterials or other specific additives. Membrane materials can be organic or inorganic. Ceramic membranes, in particular, offer advantages under high temperature, high pressure, and aggressive environments, and the use of natural mineral resources has enabled cost-effective production. Conventional polymer membranes, however, face limitations such as fouling, low chemical resistance, and limited mechanical strength, which affect long-term performance and economic viability. Hybrid membranes have been developed to overcome these challenges and improve pollutant removal efficiency. This paper reviews the main raw materials used to synthesize porous MF and UF membranes, highlighting cost-effective options such as zeolites, chitosan, and waste-derived resources, as well as methods for producing high-performance porous membranes. Despite these advances, addressing challenges related to large-scale fabrication, long-term stability, and industrial implementation remains crucial for the widespread adoption of MF and UF membranes in sustainable water treatment.