Cellulose aerogels in water pollution treatment: Preparation, applications and mechanism

Water pollution remains one of the most pressing global challenges, driving an urgent need for advanced sustainable treatment materials. Derived from cellulose, the most abundant natural polymer on earth, cellulose aerogels (CAs) have become a highly promising candidate due to their unique three-dimensional porous structure, low density, high specific surface area, biodegradability and easy functionalization. Inspiration from the material and structural designs of natural biological systems has also effectively promoted the development and multifunctional applications of high-performance aerogels, positioning cellulose aerogels as a key area of research in the field of water treatment. This review systematically summarizes recent advancements in the design and functionalization strategies of cellulose aerogels specifically tailored for water pollution treatment. Firstly, it provides a comprehensive overview of CAs classification (native, regenerated, derivative, and composite), principal preparation methodologies including sol-gel processes and drying techniques (supercritical, freeze, and ambient pressure drying), and crucial functionalization approaches (such as surface chemical modification, incorporation of functional materials, and biomimetic structural design.). Subsequently, the review elaborates on the diverse applications of functionalized CAs in tackling various water contaminants, including efficient oil-water separation, removal of heavy metal ions, adsorption of organic dyes, treatment of emerging pollutants like microplastics, and solar-driven water desalination. The underlying pollutant removal mechanisms are analyzed in depth, encompassing physical adsorption, size sieving, interfacial wettability control, electrostatic interactions, coordination/ion exchange, photothermal conversion, catalytic degradation, and synergistic effects. This review provides insights for developing advanced cellulose-based aerogels, while highlighting current challenges and future perspectives in water treatment.