Nanoconfinement catalysis: revolutionizing homogeneous Fenton-like processes for water purification

The homogeneous Fenton-like reaction is a mainstream advanced oxidation process for refractory organic pollutant removal in water treatment, however, its real-world deployment is substantially constrained by three intrinsic drawbacks: an exceedingly narrow pH operation range (2.8–3.2), considerable production of iron sludge, and inefficient oxidant utilization. Different from existing reviews that focus on heterogeneous nanoconfinement catalysis with extensive material introduction, this review is the first to systematically summarize the state-of-the-art progress of nanoconfinement of homogeneous Fenton active sites for boosting Fenton-like water purification, with a core focus on its anti-interference performance in real water matrices and full-life-cycle economic feasibility. We elaborate the synergistic regulation of mass transfer, electronic, steric, and microenvironment effects of nanoconfinement, and reveal how these effects fundamentally overcome the above bottlenecks of homogeneous Fenton systems. A thorough assessment is provided regarding practical implementation, cutting-edge characterization and theoretical simulation approaches, environmental hazards, and techno-economic viability of the system. Finally, the critical scientific challenges and future research directions in this field are proposed to provide theoretical guidance for next-generation efficient water treatment technology.