<br>热解碳在介导水和固体介质中从粘土矿物到铬的电子转移中的双重作用,Journal of Hazardous Materials

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热解碳在介导水和固体介质中从粘土矿物到铬的电子转移中的双重作用
Journal of Hazardous Materials ( IF 12.2 ) Pub Date : 2024-04-13 , DOI: 10.1016/j.jhazmat.2024.134290
Biao Li ₁ , Yifeng Zhang ₁

Affiliation

粘土矿物（CM）和热解碳（PC）经常共存于环境中并参与污染物的氧化还原循环。这项研究揭示了 PC 在水性和琼脂固化介质中以 CM 为主的铬转化中的双重作用。研究结果表明，CM 和 PC 吸附的 Cr(VI) 极少，而还原的 CM 和 PC 则表现出显着差异，分别通过反应性结构 Fe(II) 和官能团直接将 Cr(VI) 还原为固体/溶解的 Cr(III)。。此外，发现溶解的 PC 在水和固体介质中介导从还原的 CM 到 Cr(VI) 的电子转移。有趣的是，固体 PC 对还原 CM 还原 Cr(VI) 的影响是浓度依赖性的。在较低浓度下，固体 PC 分散还原的 CM，充当电子介体并促进直接和间接 Cr(VI) 还原，从而产生固体 Cr(III) 而不是溶解的 Cr(III)。相反，在较高浓度下，固体 PC 充当氧化还原缓冲液，存储从还原的 CM 转移到 Cr(VI) 的电子。在这两种情况下，转化的铬主要固定在 CM 的表面而不是 PC 的表面。这些发现为与 CM 和 PC 相关的污染物转化提供了宝贵的见解，加深了我们对其地球化学过程的理解。

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Dual role of pyrogenic carbon in mediating electron transfer from clay minerals to chromium in aqueous and solid media

Clay minerals (CMs) and pyrogenic carbons (PCs) often co-exist in the environment and participate in the redox cycling of pollutants. This study unveiled the dual role of PCs in CM-dominated chromium transformation in both aqueous and agar solidification media. The findings showed that CMs and PCs adsorbed minimal Cr(VI), while reduced CMs and PCs displayed a substantial difference by directly reducing Cr(VI) to solid/dissolved Cr(III) through reactive structural Fe(II) and functional groups, respectively. Moreover, dissolved PCs were found to mediate electron transfer from reduced CMs to Cr(VI) in aqueous and solid media. Interestingly, the effect of solid PCs on Cr(VI) reduction by reduced CMs was concentration-dependent. At lower concentrations, solid PCs dispersed reduced CMs, acting as electron mediators and facilitating both direct and indirect Cr(VI) reduction, resulting in solid Cr(III) rather than dissolved Cr(III). Conversely, at higher concentrations, solid PCs served as redox buffers, storing electrons transferred from reduced CMs to Cr(VI). In either case, the transformed chromium was primarily immobilized on the surface of CMs rather than PCs. These findings offer valuable insights into pollutant transformations associated with CMs and PCs, deepening our understanding of their geochemical processes.

更新日期：2024-04-13

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