C/Mn比对有机小分子在Mn-氧化物上吸附和氧化降解的影响,Environmental Science & Technology

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C/Mn比对有机小分子在Mn-氧化物上吸附和氧化降解的影响
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2022-12-19 , DOI: 10.1021/acs.est.2c03633
Hui Li _{1,

2} , Benjamin Reinhart ₃ , Spencer Moller ₄ , Elizabeth Herndon ₂

Affiliation

锰 (Mn) 氧化物具有高表面积和氧化还原电位，可促进有机碳 (OC) 的吸附和/或氧化，但它们在调节土壤碳储存方面的作用相对未被探索。具有不同结构的小型 OC 化合物与 Mn(III/IV)-氧化物反应，以研究 OC/Mn 摩尔比对 Mn-OC 相互作用机制的影响。测量溶解和固相 OC 和 Mn 以量化 OC 吸附和/或与 Mn-氧化物的氧化还原反应。使用 X 射线衍射和 X 射线吸收光谱评估矿物转化。较高的 OC/Mn 比率导致较高的吸附和/或氧化还原转化；然而，对于某些 OC，相互作用机制在低或高 OC/Mn 比率下有所不同。柠檬酸盐、丙酮酸盐、抗坏血酸盐和儿茶酚诱导氧化锰溶解。固相中 Mn 的平均氧化态在与柠檬酸盐反应期间没有变化，表明配体促进了矿物溶解，但在与其他化合物反应期间显着降低，表明还原溶解机制。邻苯二甲酸盐主要吸附在锰氧化物上，没有可检测到的氧化还原产物形成。Mn-OC 相互作用主要通过 OC 氧化成无机 C 而导致 C 损失，但邻苯二甲酸盐除外，它主要固定在固相中。总之，这些结果为土壤中有机-矿物界面发生的反应提供了详细的基本见解。邻苯二甲酸盐主要吸附在锰氧化物上，没有可检测到的氧化还原产物形成。Mn-OC 相互作用主要通过 OC 氧化成无机 C 而导致 C 损失，但邻苯二甲酸盐除外，它主要固定在固相中。总之，这些结果为土壤中有机-矿物界面发生的反应提供了详细的基本见解。邻苯二甲酸盐主要吸附在锰氧化物上，没有可检测到的氧化还原产物形成。Mn-OC 相互作用主要通过 OC 氧化成无机 C 而导致 C 损失，但邻苯二甲酸盐除外，它主要固定在固相中。总之，这些结果为土壤中有机-矿物界面发生的反应提供了详细的基本见解。

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Effects of C/Mn Ratios on the Sorption and Oxidative Degradation of Small Organic Molecules on Mn-Oxides

Manganese (Mn) oxides have a high surface area and redox potential that facilitate sorption and/or oxidation of organic carbon (OC), but their role in regulating soil C storage is relatively unexplored. Small OC compounds with distinct structures were reacted with Mn(III/IV)-oxides to investigate the effects of OC/Mn molar ratios on Mn–OC interaction mechanisms. Dissolved and solid-phase OC and Mn were measured to quantify the OC sorption to and/or the redox reaction with Mn-oxides. Mineral transformation was evaluated using X-ray diffraction and X-ray absorption spectroscopy. Higher OC/Mn ratios resulted in higher sorption and/or redox transformation; however, interaction mechanisms differed at low or high OC/Mn ratios for some OC. Citrate, pyruvate, ascorbate, and catechol induced Mn-oxide dissolution. The average oxidation state of Mn in the solid phase did not change during the reaction with citrate, suggesting ligand-promoted mineral dissolution, but decreased significantly during reactions with the other compounds, suggesting reductive dissolution mechanisms. Phthalate primarily sorbed on Mn-oxides with no detectable formation of redox products. Mn–OC interactions led primarily to C loss through OC oxidation into inorganic C, except phthalate, which was predominantly immobilized in the solid phase. Together, these results provided detailed fundamental insights into reactions happening at organo–mineral interfaces in soils.

更新日期：2022-12-19

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