College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China.
College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China.
Chemosphere. 2020 Sep;255:126975. doi: 10.1016/j.chemosphere.2020.126975. Epub 2020 May 4.
Swine manure biochar (SBC) pyrolyzed at 300 °C, 600 °C and 900 °C were utilized to degrade sulfamethazine (SMT) in heterogeneous Fenton-like systems which achieved excellent degradation efficiency (over 85% in 30 min). Experiments results demonstrated that SBC possessed the poor SMT adsorption capacity but high catalytic performance. Electron Paramagnetic Resonance (EPR) and X-ray photoelectron spectroscopy (XPS) analysis revealed that there were oxygen-centered environmentally persistent free radicals (EPFRs) and carbon-centered EPFRs with an adjacent oxygen atom in SBC. The oxygen-centered EPFRs played a major role in the catalytic process which tended to convert to carbon-centered EPFRs after the reaction. Besides, the electron transfer pathways were the most likely catalytic mechanism of SBC and the contribution of OH was dominant through Electron capture experiments and Linear sweep voltammetry (LSV) measurements. The acidic or alkaline condition can promote the catalytic ability of SBC. The presence of dissolved salts (NaCl) inhibited the catalytic process but the inhibition was slightly weakened at high concentration of NaCl, which showed the high tolerance of Cl in Fenton/Fenton-like systems. Moreover, real wastewater application suggested that SBC600/HO system possessed excellent catalytic efficiency and good adaptability. This research provides a novel swine manure reuse process with high practicability and presents a more explicit perspective about the reaction mechanisms of EPFRs in biochar.
猪粪生物炭（SBC）在 300°C、600°C 和 900°C 下热解，用于在非均相类芬顿体系中降解磺胺甲恶唑（SMT），取得了优异的降解效率（30 分钟内超过 85%）。实验结果表明，SBC 具有较差的 SMT 吸附能力，但具有较高的催化性能。电子顺磁共振（EPR）和 X 射线光电子能谱（XPS）分析表明，SBC 中存在含氧环境稳定自由基（EPFRs）和含碳 EPFRs，且其与相邻氧原子相连。含氧 EPFRs 在催化过程中起主要作用，反应后倾向于转化为含碳 EPFRs。此外，电子转移途径是 SBC 最可能的催化机制，通过电子俘获实验和线性扫描伏安法（LSV）测量表明，OH 的贡献占主导地位。酸性或碱性条件可以促进 SBC 的催化能力。溶解盐（NaCl）的存在抑制了催化过程，但在高浓度 NaCl 存在下，抑制作用略有减弱，表明 Cl 在芬顿/Fenton 体系中具有较高的耐受性。此外，实际废水应用表明，SBC600/HO 体系具有优异的催化效率和良好的适应性。该研究提供了一种具有高实用性的新型猪粪再利用工艺，并对生物炭中 EPFRs 的反应机制提供了更明确的视角。
