Photothermal promotion of peroxydisulfate activated catalytic degradation of phenol by Fe-Cu/P-rGA composites: Insights from experiments and theoretical calculations

In this study, we constructed a system for the photothermal promotion of peroxydisulfate (PDS) activation for phenol degradation, synthesized Fe-Cu/P-rGA catalytic materials and used P doped graphene aerogel (rGA) to enhance the adsorption performance of PDS and pollutants. The synergistic effects of pollutant adsorption, PDS activation, and catalytic oxidation improved the degradation performance of organic pollutants. The Fe-Cu/P-rGA composites showed 97 % degradation activity for phenol (50 ppm) after 10 min of reaction in the synergistic system, which was two times higher than the treatment efficiency of Fe-Cu/rGA under PDS. In addition, the removal efficiencies of COD and TOC for coking wastewater were 82 % and 68 %, respectively. The DFT results showed that P doped graphene favored the adsorption of phenol and PDS. Meanwhile, the photothermal effect caused by of light and the generated hot electrons can also promote PDS activation, synergistically contributing to the generation efficiency of oxidatively active species. Quenching experiments and EPR results showed that hydroxyl radicals (OH), sulfate radicals (SO₄⁻), and single-linear oxygens (¹O₂) were all active species during the degradation process. The synergistic effect of the rGA system on pollutant adsorption along with PDS activation and catalytic oxidation provides a new approach for efficient pollutant degradation.