Millimeter-Sized Nanocomposites for Advanced Water Treatment: Preparation, Synergistic Effects and Applications

Nanomaterial features a high surface area-to-volume ratio and strong surface effects, offering excellent performance in water treatment and broad application prospects. Incorporating nanoparticles into millimeter-scalehosts to prepare millimeter-sized nanocomposite materials can couple the high reactivity of nanoparticles with the easy operability of millimeter-scale hosts. This is an important technical approach to overcome the engineering application bottlenecks of nanomaterials, such as their tendency to agglomerate, low stability, potential environmental risks, and difficult separation. This review summarizes the preparation methods, structural characteristics, and adsorptive and catalytic oxidative removal of pollutants from aqueous systems by millimeter -sized nanocomposites. It elaborates on the confinement effects from the perspectives of confined growth of nanoparticles, confined adsorption properties, and confined catalytic oxidation properties, as well as the synergistic purification effect between the hosts and nanoparticles. Finally, the scientific issues and practical challenges that urgently need to be addressed in the development of millimeter-sized nanocomposites are discussed. We believe this review will provide theoretical guidance and technical references for promoting the practical applications of nanomaterials.