Catalytic degradation of dyes on N‐doped bioresource char and its radical and nonradical mechanism

Abstract BACKGROUND Biochar has received much attention for disposal of aqueous organic contaminants because of its great potential in adsorption and catalysis. N‐doped rice husk biochar (N‐BC) was synthesized in this work and used to activate potassium peroxymonosulfate (PMS) to remove different types of dyes. The influence of preparation conditions of N‐BC and reactive conditions on removal rate was discussed in detail. Free radical quenching experiment and electron spin resonance were used to analyze the active species and mechanism in the reaction. RESULTS N‐BC with abundant graphitic‐N, which is the main form of N to activate PMS, can be obtained by N‐doping with carbamide at 900 °C. The removal rate for new coccine can reach nearly 100% in 30 min. Furthermore, the removal rate can still be maintained at 77.21% after reusing four times only washing with water, and it can be further promoted to 98.78% after annealing treatment at 900 °C. N‐BC has excellent applicability to different types of dyes. CONCLUSION Consequently, the mechanism is the combination of radical (O 2 •− ) and nonradical ( 1 O 2 ) oxidation. First, the preparation method in this work is relatively simple. Second, the material can adapt to a very wide pH range. Third, the material shows high efficiency at room temperature (the removal rate can reach nearly 100% in 30 min). Fourth, the material shows high efficiency with only a small amount. This study provides a new path of rapid dye water purification using biochar, with simple synthesis, wide pH range adaptability, and high efficiency with only a small amount. © 2023 Society of Chemical Industry (SCI).