Edge-nitrogenated biochar for efficient peroxydisulfate activation: An electron transfer mechanism
Edge-nitrogenated biochar for efficient peroxydisulfate activation: An electron transfer mechanism
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用于有效过二硫酸盐活化的边缘氮化生物炭：电子转移机制
DOI：
10.1016/j.watres.2019.05.059
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发表时间：
2019
期刊：
影响因子：
12.8
通讯作者：
Ren Nanqi
中科院分区：
文献类型：
--
作者：
Wang Huazhe;Guo Wanqian;Liu Banghai;Wu Qinglian;Luo Haichao;Zhao Qi;Si Qishi;Sseguya Fred;Ren Nanqi
以玉米芯和尿素为原料，采用不同比例热解制备了氮掺杂生物炭（NBCs），该生物炭对过二硫酸盐（PDS）的活化表现出良好的上级催化性能，并对磺胺嘧啶（SDZ）的降解进行了研究。通过动力学拟合和密度泛函理论（DFT）计算，首次揭示了边缘氮化在生物炭（BC）结构中的关键作用。边缘氮配置（吡啶N和吡咯N，而不是石墨N）的掺入产生的PDS激活的反应位点。通过化学淬灭实验、电子自旋共振（ESR）检测、氧化剂消耗监测和电化学分析等手段，对NBC活化PDS的机理进行了深入的研究。与文献报道的单线态氧（1 O2）主导的非自由基反应机理不同，在NBC/PDS体系中，电子传递途径主要是表面活性复合物的作用.由于电子传递机制的作用，NBC/PDS体系不仅具有较宽的pH适应范围，适合于真实的应用，而且对水环境中的无机阴离子具有较强的抵抗能力。我们相信该研究将加深对碳驱动过硫酸盐活化机理的理解，并为BC介导过硫酸盐活化在实际应用中提供强有力的技术支持。
N-doped biochars (NBCs) were prepared by pyrolyzing corncob biomass and urea in different proportion which manifested superior catalytic performance of peroxydisulfate (PDS) activation for sulfadiazine (SDZ) degradation. Through both dynamic fitting and density functional theory (DFT) calculations, the critical role of edge nitrogenation in biochar (BC) structure was revealed for the first time. The incorporation of edge nitrogen configurations (pyridinic N and pyrrolic N rather than graphitic N) generated reactive sites for the PDS activation. Additionally, a thorough investigation was conducted to explicate the PDS activation mechanism by NBC through chemical quenching experiments, electron spin resonance (ESR) detection, oxidant consumption monitoring and electrochemical analysis. Different from the well-reported singlet oxygen (1O2) dominated nonradical mechanism, an electron transfer pathway involving surface-bound reactive complexes was proved to play a major role in the NBC/PDS system. Benefit from the electron transfer mechanism, the NBC/PDS system not only has wide pH adaptation for real application, but also shows high resistance to the inorganic anions in aquatic environment. We believe this study will deepen the understanding of the carbon-driven persulfate activation mechanism and provide strong technical support for the BC-mediated persulfate activation in practical applications.