第一作者：Long Cheng
通讯作者：吉远辉 教授
通讯单位：东南大学化学化工学院
DOI:10.1016/j.gee.2022.07.006
构建了一种由N掺杂生物炭（NBCs）、MnFe2O4和紫外下亚硫酸盐活化（NBCs/MnFe2O4/sulfite/UV）组成的新型光催化体系，实现了四环素（TC）的高效去除。作为MnFe2O4的载体，以紫花苜蓿为原料合成NBCs，具有较大的比表面积、类石墨结构和分级多孔结构。吸附等温线表明NBCs/MnFe2O4-2:1对TC（347.56 mg g-1）的吸附性能最好。通过协同吸附和光催化，TC的去除率达到84%，明显高于MnFe2O4。电化学阻抗谱（EIS）和光致发光（PL）表征结果表明，NBCs的引入提高了光生电子和空穴对的分离效率，增强了光催化性能。此外，通过HPLC-MS测量与理论计算相结合，系统地分析了催化剂对TC的吸附、降解机理和降解路径。考虑到 NBCs/MnFe2O4 降解性能优异、成本低、易分离和环境友好等优点，该工作有望为生物炭的实际应用提供新的途径。
采用水热反应制备了N掺杂生物炭/MnFe2O4（NBCs/MnFe2O4）复合材料，并与紫外光协同活化亚硫酸盐。具体目标是：1）表征NBCs/MnFe2O4的形貌、比表面积、价带等性质，2）评价TC在紫外光下在NBCs/MnFe2O4/亚硫酸盐体系中的吸附和降解性能，3） 通过研究TC降解的影响因素来评价NBCs/MnFe2O4的实际应用潜力，4）通过密度泛函理论（DFT）计算和实验阐明NBCs/MnFe2O4的吸附、降解机理。
Figure 1. XRD patterns of NBCs, MnFe2O4, NBCs/MnFe2O4-1:1, NBCs/MnFe2O4-1:2, and NBCs/MnFe2O4-2:1.
Figure 2. SEM images of NBCs (a and b), MnFe2O4 (c and d), and NBCs/MnFe2O4-2:1 (e and f).
Figure 3. FTIR spectra of the NBCs, MnFe2O4, NBCs/MnFe2O4-1:1, NBCs/MnFe2O4-1:2, and NBCs/MnFe2O4-2:1. (black line: the curves before adsorption; green line: the curves after sorption of TC).
Figure 4. XPS spectra of pure NBCs and NBCs/MnFe2O4-2:1: (a) survey, (b) C 1s, (c) O 1s, (d) N 1s.
Figure 5. Nitrogen absorption–desorption isotherms and the pore size distribution curves of NBCs and NBCs/MnFe2O4-2:1.
Figure 6. (a): Raman spectra of NBCs and NBCs/MnFe2O4-2:1; (b): Magnetization curves of pure MnFe2O4 and NBCs/MnFe2O4-2:1.
Figure 7. UV–vis DRS spectra of NBCs, MnFe2O4 and NBCs/MnFe2O4-2:1 (a); plots of (αhυ)2 versus hυ for MnFe2O4 and NBCs/MnFe2O4-2:1 (b).
Figure 8. Adsorption kinetics of TC onto NBCs (a), NBCs/MnFe2O4-1:1 (b), NBCs/MnFe2O4-1:2 (c), and NBCs/MnFe2O4-2:1 (d). The full black symbols represent the experimental results. The dashed and dotted curves represent the fitting results of pseudo first-order model and pseudo second-order model, respectively.
Figure 9. Adsorption kinetics (Intra-particle diffusion model) of TC onto NBCs (a), NBCs/MnFe2O4-1:1 (b), NBCs/MnFe2O4-1:2 (c), and NBCs/MnFe2O4-2:1 (d).
Figure 10. Adsorption isotherms of TC onto NBCs (a), NBCs/MnFe2O4-1:1 (b), NBCs/MnFe2O4-1:2 (c), and NBCs/MnFe2O4-2:1 (d), Langmuir model (dashed curves), Freundlich model (dotted curves) and Sips model (solid curves).
Figure 11. Comparisons of photocatalytic activities towards TC degradation by different photocatalysts (a); apparent reaction rate constants for the degradation of TC (b).
Figure 12. The optimized configuration between TC and NBCs.
Figure 13. (a) PL spectra of NBCs, MnFe2O4, and NBCs/MnFe2O4-2:1; (b) EIS Nyquist plots of NBCs, MnFe2O4, NBCs/MnFe2O4-1:1, NBCs/MnFe2O4-1:2 and NBCs/MnFe2O4-2:1.
Figure 14. Photocatalytic degradation pathway of TC by NBCs/MnFe2O4-2:1 under UV light irradiation.
在本研究中，亚硫酸盐作为烟气脱硫的副产物，用于提高 NBCs/MnFe2O4 的光催化活性。首先，采用水热法制备NBCs/MnFe2O4复合材料，MnFe2O4均匀分布在NBCs表面。XRD、BET、Raman、PL等结果表明，NBCs具有较大的比表面积（985.20 m2 g-1）、石墨状结构和发达的孔径，有利于提高光生电子和空穴的分离。在吸附过程中，所有材料均与Sips等温线模型具有较高的一致性，NBCs/MnFe2O4-2:1对TC的最大吸附量为347.56 mg g-1。伪二阶模型适合拟合吸附动力学数据，证明化学吸附是限速步骤。光催化降解结果表明，NBCs/MnFe2O4-2:1对TC的降解效率最高（84%）。此外，还研究了pH值、TC浓度、亚硫酸盐浓度和不同无机盐对TC光催化降解率的影响。自由基捕获实验表明，亚硫酸根在 NBCs/MnFe2O4/Na2SO3/UV 体系的 TC 光催化降解中起重要作用。最后，通过HPLC-MS结合DFT计算分析了降解机理和可能的途径。表明NBCs/MnFe2O4/Na2SO3/UV技术在废水中抗生素处理方面具有广阔的前景。
Long Cheng, Yuanhui Ji, Photocatalytic activation of sulfite by N-doped porous biochar/MnFe2O4 interface-driven catalyst for efficient degradation of tetracycline, Green Energy & Environment, 2022
https://doi.org/10.1016/j.gee.2022.07.006
声明：本公众号仅分享前沿学术成果，无商业用途。如涉及侵权，请立刻联系公众号后台或发送邮件，我们将及时修改或删除！
邮箱：Environ2022@163.com
欢迎大家将《水处理文献速递》加为星标
即时获取前沿学术成果
若有帮助，请点击“在看”分享！
投稿、转载请扫描下方二维码联系小编吧
