Key Laboratory for Solid Waste Management and Environment Safety (MOE), School of Environment, Tsinghua University, Beijing 100084, China.
Key Laboratory for Solid Waste Management and Environment Safety (MOE), School of Environment, Tsinghua University, Beijing 100084, China.
J Environ Sci (China). 2019 Mar;77:167-173. doi: 10.1016/j.jes.2018.07.002. Epub 2018 Jul 17.
Humification plays a critical role in the environmental fate of organic wastes, and MnO holds great promise for enhancing this reaction. However, the effects of MnO on the enhancement of the humification reaction remain ambiguous. To better reveal the mechanism by which MnO enhances the reaction and investigate the fate of the humification products, abiotic humification experiments were performed using increasing concentrations of dissolved organic matter (DOM) to a fixed amount of MnO. DOM was represented by model humic precursors consisting of catechol, glucose and glycine. The results indicate that the reduction of MnO played a dominant role in the formation of fulvic-like acids (FLAs), and the subsequent reduction products, MnOOH and Mn(II), acted as catalysts in the formation of humic-like acids (HLAs). Moreover, CO release occurred during the formation of FLAs, and a strong linear correlation between CO release and the formation of FLAs was observed (p < 0.01), where 0.73-1.87 mg of CO was released per mg dissolved organic carbon (DOC) FLAs. Furthermore, the concentration of MnO had a pronounced influence on the product behavior, where a lower MnO concentration decreased the quantity of FLAs produced.
腐殖化作用在有机废物的环境归宿中起着至关重要的作用，MnO 对增强这一反应具有很大的潜力。然而，MnO 对促进腐殖化反应的增强效果仍然存在争议。为了更好地揭示 MnO 增强反应的机制，并研究腐殖化产物的归宿，采用增加浓度的溶解有机物（DOM）固定量的 MnO 进行了非生物腐殖化实验。DOM 由儿茶酚、葡萄糖和甘氨酸组成的模型腐殖质前体表示。结果表明，MnO 的还原在富里酸类物质（FLAs）的形成中起着主导作用，随后的还原产物 MnOOH 和 Mn（II）在腐殖酸类物质（HLAs）的形成中起到了催化剂的作用。此外，在 FLAs 的形成过程中释放出 CO，并且观察到 CO 释放与 FLAs 的形成之间存在很强的线性相关性（p < 0.01），其中每毫克溶解有机碳（DOC）FLAs 释放 0.73-1.87 mg 的 CO。此外，MnO 的浓度对产物行为有显著影响，较低的 MnO 浓度会减少生成的 FLAs 的数量。
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