State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Sci Total Environ. 2022 Nov 25;849:157855. doi: 10.1016/j.scitotenv.2022.157855. Epub 2022 Aug 5.
Extracellular organic substances (EOSs) usually control sludge biodegradability. Metal-organic framework-808 (MOF-808), a catalyst with a high ability of catalytic hydrolysis and proton transfer, has great potential to enhance biodegradability of EOSs. In this study, the underlying mechanism of MOF-808 enhancing the biodegradability of EOSs via abiotic catalysis was investigated. Experimental results showed that protein-like and humic acid-like substances were the main organic components in EOSs, and the MOF-808 enhanced the disintegration of protein-like substances rather than humic acid-like substances. Analyses of the changes in the functional group, the secondary structure of protein-like substances, and the electron transfer of catalytically degraded EOS samples revealed that the MOF-808 enhanced the hydrolysis of EOSs protein-like substances, loosened their secondary structure, and improved the electron transfer in EOSs. Further analyses of the MOF-808 before and after the catalysis reaction revealed that the coordination of Zr sites with protein-like substance-specific active sites (such as ZrN) in the MOF-808 substantially contributed to the high-efficiency catalysis. Biochemical methane potential assays confirmed that MOF-808-based abiotic catalysis promoted the generation efficiency of methane from the EOSs. These findings can elucidate the abiotic catalytic effect of MOF-808 on sludge biodegradability during the anaerobic digestion process.
细胞外有机物质 (EOSs) 通常控制着污泥的生物降解性。金属有机骨架-808 (MOF-808) 作为一种具有高催化水解和质子转移能力的催化剂，具有增强 EOSs 生物降解性的巨大潜力。在本研究中，通过非生物催化作用，研究了 MOF-808 增强 EOSs 生物降解性的潜在机制。实验结果表明，蛋白质样物质和腐殖酸样物质是 EOSs 中的主要有机成分，而 MOF-808 增强了蛋白质样物质的解体，而不是腐殖酸样物质。对功能基团、蛋白质样物质的二级结构和催化降解 EOS 样品的电子转移变化的分析表明，MOF-808 增强了 EOSs 蛋白质样物质的水解，使其二级结构松散，并改善了 EOSs 中的电子转移。对催化反应前后的 MOF-808 进一步分析表明，Zr 位点与 MOF-808 中蛋白质样物质特定活性位点（如 ZrN）的配位对高效催化有很大贡献。生物化学甲烷潜能分析证实，基于 MOF-808 的非生物催化促进了从 EOSs 中生成甲烷的效率。这些发现可以阐明 MOF-808 在厌氧消化过程中对污泥生物降解性的非生物催化作用。
