Nanoclay–magnetic nanoparticle composites for decentralized water purification

Abstract Magnetic purification enables water treatment without membranes by combining selective surface chemistry with field-driven recovery of functional particles. Rather than forcing water through porous barriers that inevitably foul, magnetically responsive nanoparticles are dispersed directly in the aqueous phase, bind dissolved or suspended contaminants, and are collected through externally applied magnetic field gradients. This review presents the physical foundations of magnetophoresis and field-induced aggregation, together with recent developments in nanoclay–nanoparticle composite materials and open-channel magnetic architectures. Emphasis is placed on gradient engineering, regeneration physics, and transport phenomena under flow. Reported performance for the removal of hydrocarbons, dyes, and heavy metals is summarized, and available data on cycling stability and long-term durability are discussed. Life-cycle and sustainability aspects are examined, highlighting the advantages of regenerative operation and low chemical consumption. Overall, nanoclay–magnetic nanoparticle composites’ purification emerges as a physically grounded and practically scalable approach for local, near faucet water treatment.