Synthesis of N and S co-doped Citrus maxima (Burm.) Merr-derived porous carbon for removal of pollutants and energy storage

Phenolic compounds are typical organic pollutants that persist in water and remain difficult to remove efficiently. Developing sustainable materials that can achieve both high adsorption and catalytic degradation without additional energy input is still a major challenge. In this study, nitrogen and sulfur co-doped porous carbon (NSPC) was prepared from Citrus maxima (Burm.) Merr. through a simple pyrolysis method. The materials were characterized by XRD, BET, SEM, FE-SEM, EDX, Raman spectroscopy, and XPS. NSPC showed a high adsorption capacity of 51.078 mg/g and a degradation efficiency of 84.44 % for phenol within 60 min through peroxydisulfate activation. The synergistic effect between adsorption and catalytic oxidation was responsible for this efficient performance. In addition, NSPC exhibited good electrochemical properties with specific capacitance of 283.31 F/g and capacitance retention of 86.05 % after 1000 charge–discharge cycles. These results demonstrate that biomass-derived NSPC can act as a metal-free platform with dual functionality for environmental remediation and energy storage, offering a promising direction for future scalable and sustainable technologies.