Abstract:

Sunflower straw-based carbon material (BC) was prepared from agricultural waste sunflower straw by slow pyrolysis. BC was characterized by specific surface area analyzer (BET), scanning electron microscope (SEM), X-ray diffractometer (XRD), and X-ray photoelectron spectroscopy (XPS), and its performance in activating persulfate (PMS) to degrade aniline (AN) in soil was investigated. The effects of pH, BC dosage, PMS concentration, organic matter and co-existing anions on AN degradation were investigated, and the reuse performance of BC was examined. The results showed that BC could efficiently activate PMS to degrade AN in soil, and the degradation rate of AN by BC/PMS system reached 100% in 30 min under the conditions of BC=0.1g/L, PMS=0.5mmol/L, AN=10mg/kg and pH=7. The results of free radical quenching experiments and electron paramagnetic resonance (EPR) tests indicated that the BC/PMS system was a non-radical reaction and ¹O₂ is the active species of the system. Mechanistic analysis elucidates that C\stackrel{}{̿}O was the active site on BC, which interacted with PMS to produce the active species ¹O₂. Cyclic stability experiments demonstrated the reusability of BC.

Key words: sunflower, carbon material, persulfate, aniline, non-free radicals

摘要：

以农业废弃物向日葵秸秆为原料，采用慢速热解法制备了向日葵秸秆基炭材料（BC），通过比表面积分析仪（BET）、扫描电镜（SEM）、X射线衍射仪（XRD）和X射线光电子能谱仪（XPS）等手段对BC进行表征，并研究其活化过一硫酸盐（PMS）降解土壤中苯胺（AN）的性能，探究了pH、BC投加量、PMS浓度、有机质和共存阴离子对AN降解的影响，并考察了BC的重复利用性能。结果表明，BC可高效活化PMS降解土壤中AN，在BC=0.1g/L、PMS=0.5mmol/L、AN=10mg/kg和pH=7的条件下，30min内BC/PMS体系对AN的降解率可达100%。自由基猝灭实验与电子顺磁共振（EPR）测试结果表明，BC/PMS体系为非自由基反应，¹O₂为该体系的活性物种。机制分析阐明C\stackrel{}{̿}O为BC上的活性点位，其与PMS相互作用产生活性物种¹O₂。循环稳定性实验表明BC具有重复使用性。

关键词: 向日葵, 炭材料, 过一硫酸盐, 苯胺, 非自由基