Coexistence of humic acid enhances the reductive removal of diatrizoate via depassivating zero-valent iron under aerobic conditions
Coexistence of humic acid enhances the reductive removal of diatrizoate via depassivating zero-valent iron under aerobic conditions
复制标题
腐殖酸共存增强了好氧条件下零价铁去钝化泛影酸盐的还原去除
DOI：
10.1039/d0ta04276e
复制
发表时间：
2020
影响因子：
11.9
通讯作者：
Yang Mu
中科院分区：
文献类型：
--
作者：
Chuan-Shu He;Rong-Rong Ding;Guan-Nan Zhou;Di He;Peng Fan;Xiao-Hong Guan;Yang Mu
表面钝化是零价铁（ZVI）成功应用于水净化的最具挑战性的方面之一，特别是当不可避免地存在氧气时。这项研究发现，在好氧条件下，0至40.0 mg-C/L的HA共存明显提高了ZVI还原污染物泛影葡胺（DTA）的准一级动力学速率常数，从0.0454 h−1提高到0.1365 h−1。首次揭示了HA的共存可以通过ZVI表面去钝化而不是之前提出的有氧条件下的电子穿梭机制加速有机污染物的还原去除。有趣的是，DTA去除和Fe 0消耗被发现经历两个阶段，在HA的存在下，与初始轻微的增强归因于Fe（III）-HA复合物的形成部分抑制铁沉淀，随后由显着的促进所产生的HA相关的氧化铁从Fe 0表面脱离。这些发现不仅为在有氧条件下以最小的额外成本和复杂性提高ZVI反应性提供了一个很好的策略，而且有助于理解ZVI在实际应用中的行为。
Surface passivation is one of the most challenging aspects in the successful application of zero-valent iron (ZVI) for water decontamination, especially when oxygen is inevitably present. This study found that the coexistence of HA ranging from 0 to 40.0 mg-C/L appreciably improved the pseudo-first-order kinetic rate constant of pollutant diatrizoate (DTA) reduction by ZVI from 0.0454 to 0.1365 h−1 under aerobic conditions. For the first time, it revealed that the coexistence of HA could accelerate the reductive removal of organic contaminants via ZVI surface depassivation rather than the previously proposed electron-shuttle mechanism under aerobic conditions. Interestingly, both DTA removal and Fe0 consumption were found to undergo two stages in the presence of HA, with an initial slight enhancement attributed to the Fe(III)–HA complex formation partially suppressing iron precipitation, followed by a remarkable promotion arising from the HA-associated iron oxide detachment from the Fe0 surface. These findings not only provide a good strategy to enhance ZVI reactivity with minimal extra cost and complexity under aerobic conditions, but also help understand the ZVI behavior in practical applications.