| Summary: | In this paper, using rice straw as a raw material and urea as a nitrogen precursor, a composite catalyst (a nitrogen-doped rice straw biochar at the pyrolysis temperature of 800 °C, recorded as NRSBC800) was synthesized by one-step pyrolysis. NRSBC800 was then characterized using XPS, BET, TEM and other technologies, and its catalytic performance as an activator for permonosulfate (PMS) to degrade acid orange 7 (AO7) was studied. The results show that the introduction of N-doping significantly improved the catalytic performance of NRSBC800. The NRSBC800/PMS oxidation system could fully degrade AO7 within 30 min, with the reaction rate constant (2.1 × 10 <sup>−1</sup> min<sup>−1</sup>) being 38 times that of RSBC800 (5.5 × 10<sup>−3</sup> min<sup>−1</sup>). Moreover, NRSBC800 not only had better catalytic performance than traditional metal oxides (Co<sub>3</sub>O<sub>4</sub> and Fe<sub>3</sub>O<sub>4</sub>) and carbon nanomaterial (CNT) but also received less impact from environmental water factors (such as anions and humic acids) during the catalytic degradation process. In addition, a quenching test and electron paramagnetic resonance (EPR) research both indicated that AO7 degradation relied mainly on non-free radical oxidation (primarily singlet oxygen (<sup>1</sup>O<sub>2</sub>)). A recycling experiment further demonstrated NRSBC800’s high stability after recycling three times.
|
|---|
