Magnetic resonance imaging monitoring of 4-chlorophenol removal by an efficient Horseradish Peroxidase-modified hyper-cross-linked resin catalyst

This study presents a catalyst, HCL-NH2@GA-HRP, utilizing a high-surface-Area hyper-cross-linked resin (HCL) modified to be hydrophilic for Horseradish Peroxidase (HRP) binding. The HCL resin, synthesized from divinyl benzene and vinyl benzyl chloride, was nitrated and reduced to create amino-functionalized resins (HCLR-NH2), with HRP covalently immobilized via glutaraldehyde (GA). FT-IR and TG-DTG analyses confirmed successful enzyme anchoring. The catalyst completely removed 4-chlorophenol (4-CP) from water within 30minutes, demonstrating a specific degradation efficiency of 100% under optimized conditions. Furthermore, the immobilized HRP retained 90% removal efficiency after six reuse cycles, highlighting excellent reusability. Immobilization significantly enhances enzyme stability across a wide pH range (4.0-9.0) and temperatures up to 70°C. UV-visible spectrophotometry and real-Time MRI confirmed effective 4-CP removal and provided insights into diffusion and chemical transformations within the system, underscoring its potential for industrial-scale wastewater treatment. © 2025 Elsevier Ltd.