Li Xiang, Jia Yan, Zhou Minghua, Su Xianfa, Sun Jianhui
School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang 453007, China.
School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang 453007, China.
J Hazard Mater. 2020 Oct 5;397:122764. doi: 10.1016/j.jhazmat.2020.122764. Epub 2020 Apr 23.
In this study, the Fe, N co-doped biochar (Fe-N-BC) was prepared by pyrolyzing wheat straw, urea and iron salts and used to activate persulfate (peroxydisulfate, PS) for organic contaminant degradation. Iron oxide doping not only introduced magnetism into the biochar for easy separation, but also influenced its catalytic ability for PS activation. In the Fe-N-BC/PS system, almost all acid orange (AO7) was removed within 90 min with an apparent rate constant (k) of 0.114 min, which was almost 37 times larger than that of pure N-BC (0.003 min). Factors influencing the removal of AO7 were investigated, including PS concentration, catalyst dosage, and initial pH. The Fe-N-BC/PS system had high removal efficiencies for various organic contaminants and showed high resistance to inorganic anions in aquatic environments. The radical quenching studies, electron paramagnetic resonance (EPR) measurements, and electrochemical analyses verified that the mechanism of AO7 degradation in the Fe-N-BC/PS system included both radical and non-radical pathways involving the generation of OH, SO, O, O, and electron transfer. Additionally, persistent free radicals (PFRs) on the catalysts also related to their catalytic efficiencies. These results demonstrated that the Fe-N-BC/PS system had the potential for wastewater treatment applications.
在本研究中，通过对小麦秸秆、尿素和铁盐进行热解制备了铁、氮共掺杂生物炭（Fe-N-BC），并将其用于活化过硫酸盐（过二硫酸盐，PS）以降解有机污染物。掺杂氧化铁不仅使生物炭具有磁性便于分离，还影响其活化PS的催化能力。在Fe-N-BC/PS体系中，90分钟内几乎所有的酸性橙（AO7）都被去除，表观速率常数（k）为0.114 min，几乎是纯N-BC（0.003 min）的37倍。研究了影响AO7去除的因素，包括PS浓度、催化剂用量和初始pH值。Fe-N-BC/PS体系对各种有机污染物具有较高的去除效率，并且在水环境中对无机阴离子具有较高的抗性。自由基淬灭研究、电子顺磁共振（EPR）测量和电化学分析证实，Fe-N-BC/PS体系中AO7的降解机制包括自由基和非自由基途径，涉及·OH、SO、O、O的生成以及电子转移。此外，催化剂上的持久性自由基（PFRs）也与其催化效率有关。这些结果表明，Fe-N-BC/PS体系具有废水处理应用潜力。
