Urchin-like FeOOH nanowire arrays on hierarchical Laponite@diatomite scaffolds enable synergistic radical/non-radical peroxymonosulfate activation via confined microreactor

A novel multidimensional mineral composite catalyst, FeOOH@Laponite@Diatomite (FeOOH@La@D), was synthesized by loading FeOOH onto Laponite@diatomite (La@D). The sea-urchin-like structure of FeOOH@La@D provides a large specific surface area and numerous active sites. It has a good adsorption performance for methylene blue (MB) and congo red (CR), with adsorption capacities of 630.3 mg/g and 257.1 mg/g, respectively. The synergistic effect of FeOOH and Laponite enhanced peroxymonosulfate (PMS) activation performance, achieving 99 % methyl orange (MO) removal within 20 min. Quenching experiments and EPR spectra indicate that SO 4 ●- and 1 O 2 are the dominant active species. Electrochemical and XPS results support electron transfer and Fe 2+ /Fe 3+ cycling. Combining response surface methodology with random forest models, pH value and dosage are identified as key factors. This work provides candidate materials and a theoretical basis for designing environmentally friendly non-homogeneous catalysts for wastewater treatment.