Rapid preparation of N,P co-doped carbon for advanced oxidative degradation of wastewater

Abstract

Heteroatom-doped porous carbon materials are highly favored as catalysts for activating persulfates in the oxidative degradation of organic pollutants due to their low metal leaching risk and cost-effectiveness. Nonetheless, the complex process of creating heteroatom-doped carbon materials often results in suboptimal doping effects. This study uses N,P-enriched plants (Eichhornia crassipes after being used for nutrient-rich water remediation) as a raw material to prepare N-P co-doped catalysts in a single step. We thoroughly investigated their performance and mechanisms in dye degradation. The findings demonstrated that the adsorbent, with its rich pore structures, surface chemical functional groups, and graphite defect structures, could completely degrade a 100 mg L⁻¹ MB solution within 20 min. Free radical quenching experiments and EPR analysis confirmed the presence of •OH, SO₄^•—, O₂^•— and ¹O₂, verifying their oxidative contributions. Moreover, it was determined that the non-radical pathway (¹O₂ oxidation) primarily drives the oxidative degradation in this system. Additionally, tests using a small-scale fixed-bed reactor and interference resistance highlighted the practical application potential of the adsorbent developed in this study. This study not only offers a dual solution for tackling nutrient enrichment and organic pollution in water bodies but also introduces a straightforward method for preparing N, P co-doped catalysts, significantly benefiting environmental protection.