From aquatic biota to autogenous N-doping biochar—using a highly efficient nonradical dominant process for sulfamethoxazole degradation

Biochar has been considered as a promising environmental-friendly catalyst to activate peroxydisulfate (PDS) for contaminant degradation. In this study, a series of autogenous N-rich biochar derived from Spirulina were prepared by K2CO3 impregnation (NPSBs). The pyrolysis temperature and the rational design of morphology by K2CO3 had a significant influence on the performance of NPSBs to activate PDS. The NPSB-700 was capable of degrading 97.59% sulfamethoxazole (SMX) within 40 min because of the high surface area, high defect degree, and good electrical conductivity. The accelerated electron transfer and the generation of 1O2 were elucidated to be the dominant pathways for SMX degradation. It has been proven that this is a process of reducing toxicity. Furthermore, NPSB-700 also showed excellent degradation performance to various pollutants. This study provides a facile modification strategy of Spirulina-based catalysts and deepens the comprehension of persulfate activation via nonradical oxidation.