Wang Xinhua, Zhang Peng, Wang Cuiping, Jia Hanzhong, Shang Xiaofu, Tang Jingchun, Sun Hongwen
MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, Tianjin 300350, China.
MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, Tianjin 300350, China.
J Hazard Mater. 2022 Feb 15;424(Pt A):127225. doi: 10.1016/j.jhazmat.2021.127225. Epub 2021 Sep 15.
Biochar has been widely used in advanced oxidation processes (AOPs) for the decomposition of organic contaminants. However, the role of intrinsic metals in hyperaccumulator biomass in the physico-chemical properties and performance of peroxodisulfate (PDS) activation by biochar is still unclear. This work employed hyperaccumulator biomass containing Fe, Mn and Zn, respectively. Result showed that as the pyrolysis temperature of the biochar increased, Fe was gradually reduced to iron oxide and Fe, and Zn was reduced and volatilized; however, Mn remained in biochar in the form of MnS and CaMnO with high valence states. These thermochemical behaviors of intrinsic metals also facilitated graphitized structure growth and pore development (for Zn) and persistent free radicals (PFRs) generation (for Mn and Zn) in biochar, and these processes were crucial for imidacloprid degradation in biochar/PDS systems. Moreover, Fe/Zn@PB9/PDS showed better imidacloprid degradation performance, while Mn species in Mn@PB were catalytically inert. In addition, the radical pathway depending on·SO and·OH was the dominant pathway for imidacloprid degradation in the Fe@PB9/PDS systems, while the·O-mediated O pathway and O-based nonradical pathway contributed more in the Zn@PB9/PDS systems. These results reveal the role of intrinsic metals in biochar-based catalysts and provide a reference for the preparation of green and efficient hyperaccumulator-derived biochar catalysts for AOPs.
生物炭已广泛应用于高级氧化过程（AOPs）中以分解有机污染物。然而，超富集植物生物质中固有金属在生物炭物理化学性质及过二硫酸盐（PDS）活化性能中的作用仍不明确。本研究分别采用了含Fe、Mn和Zn的超富集植物生物质。结果表明，随着生物炭热解温度升高，Fe逐渐还原为氧化铁和单质Fe，Zn发生还原和挥发；而Mn以高价态的MnS和CaMnO形式保留在生物炭中。这些固有金属的热化学行为还促进了生物炭中石墨化结构的生长和孔隙发育（对于Zn）以及持久性自由基（PFRs）的产生（对于Mn和Zn），且这些过程对生物炭/PDS体系中吡虫啉的降解至关重要。此外，Fe/Zn@PB9/PDS表现出更好的吡虫啉降解性能，而Mn@PB中的Mn物种具有催化惰性。另外，在Fe@PB9/PDS体系中，依赖于·SO和·OH的自由基途径是吡虫啉降解的主要途径，而在Zn@PB9/PDS体系中，·O介导的O途径和基于O的非自由基途径贡献更大。这些结果揭示了固有金属在生物炭基催化剂中的作用，并为制备用于AOPs的绿色高效超富集植物衍生生物炭催化剂提供了参考。
