Natural manganese oxides could induce the intermolecular coupling reactions among small-molecule organics in aqueous environments, which is one of the fundamental processes contributing to natural humification. These processes could be simulated to design novel advanced oxidation technology for water purification. In this study, periodate (PI) was selected as the supplementary electron-acceptor for colloidal manganese oxides (Mn(IV)) to remove phenolic contaminants from water. By introducing polyferric sulfate (PFS) into the Mn(IV)/PI system and exploiting the flocculation potential of Mn(IV), a post-coagulation process was triggered to eliminate soluble manganese after oxidation. Under acidic conditions, periodate exists in the HIO form as an octahedral oxyacid capable of coordinating with Mn(IV) to form bidentate complexes or oligomers (Mn(IV)-PI*) as reactive oxidants. The Mn(IV)-PI* complex could induce cross-coupling process between phenolic contaminants, resulting in the formation of oligomerized products ranging from dimers to hexamers. These oligomerized products participate in the coagulation process and become stored within the nascent floc due to their catenulate nature and strong hydrophobicity. Through coordination between Mn(IV) and HIO, residual periodate is firmly connected with manganese oxides in the floc after coagulation and could be simultaneously separated from the aqueous phase. This study achieves oxidizing oligomerization through a homogeneous process under mild conditions without additional energy input or heterogeneous catalyst preparation. Compared to traditional mineralization-driven oxidation techniques, the proposed novel cascade processes realize transformation, convergence, and separation of phenolic contaminants with high oxidant utilization efficiency for low-carbon purification.

中文翻译：

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均相氧化低聚与混凝相结合的水净化


天然锰氧化物可以在水环境中诱导小分子有机物之间的分子间偶联反应，这是促进自然腐殖化的基本过程之一。可以模拟这些过程来设计用于水净化的新型高级氧化技术。在这项研究中，选择高碘酸盐（PI）作为胶体氧化锰（Mn(IV)）的补充电子受体，以去除水中的酚类污染物。通过将聚合硫酸铁（PFS）引入Mn（IV）/PI体系并利用Mn（IV）的絮凝潜力，触发后混凝过程以消除氧化后的可溶性锰。在酸性条件下，高碘酸盐以 HIO 形式作为八面体含氧酸存在，能够与 Mn(IV) 配位形成二齿络合物或低聚物 (Mn(IV)-PI*) 作为活性氧化剂。 Mn(IV)-PI* 络合物可以诱导酚类污染物之间的交叉偶联过程，从而形成从二聚体到六聚体的低聚产物。这些低聚产物参与混凝过程，并由于其链状性质和强疏水性而储存在新生絮凝物中。通过Mn(IV)与HIO的配位作用，残留的高碘酸盐与混凝后絮体中的锰氧化物牢固结合，同时可以从水相中分离出来。本研究通过温和条件下的均相过程实现了氧化低聚，无需额外的能量输入或非均相催化剂制备。 与传统的矿化驱动氧化技术相比，所提出的新型级联工艺实现了酚类污染物的转化、汇聚和分离，具有高氧化剂利用率，可实现低碳净化。