Photothermal-enhanced bisphenol A degradation in iron doped alginate biochar bead activated peroxymonosulfate Fenton-like system with amplified singlet oxygen contribution.

Herein, iron-doped biochar microspheres ((AB + Fe)-C) were prepared from alginate biomass precursor, which was as a Fenton-like catalyst for peroxymonosulfate (PMS) activation to degrade bisphenol A (BPA) in water with the assistance of photothermal effect. The results indicated that under simulated sunlight irradiation, (AB + Fe)-C/PMS system exhibited remarkable enhanced BPA degradation efficiency, in which the pseudo-first-order rate constant was 2.4-fold higher in photothermal-assisted system (0.17 min-1) than photothermal-absent system (0.072 min-1). Further investigation revealed that photothermal energy could significantly elevate the local temperature of catalyst surface and accelerate Fe2+/Fe3+ redox cycling, reducing the PMS activation energy as a result. Besides, further mechanistic studies confirmed that non-radical mechanisms predominantly contributed BPA degradation in the reaction system, and photothermal effect prominently amplified the contribution proportion of single oxygen (1O2). (AB + Fe)-C/PMS/photo system therefore exhibited high performance in a wide pH tolerance and various water matrices, as well as notable oxidation selectivity towards electron-rich pollutants (R2 = 0.87 for HOMO-ln k correlation, k for observed rate constant, min-1), demonstrating broad application prospects. This study offers a robust strategy for advancing practical organic pollutant degradation in water by upgrading the performance of biochar based Fenton-like catalyst with photothermal technology.