Zinc Presence during Mineral Formation Affects the Sorptive Reactivity of Manganese Oxide
Zinc Presence during Mineral Formation Affects the Sorptive Reactivity of Manganese Oxide
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DOI：
10.3390/soilsystems2020019
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发表时间：
2018-04
期刊：
影响因子：
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通讯作者：
Shiliang Zhao;Chenning Li;Pan Liu;Rixiang Huang;E. M. Saad;Yuanzhi Tang
中科院分区：
文献类型：
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作者：
Shiliang Zhao;Chenning Li;Pan Liu;Rixiang Huang;E. M. Saad;Yuanzhi Tang
层状锰氧化物的吸附反应性受其层状结构和层间结构的控制，而层状结构又会受到金属共沉淀等过程的影响。研究了锌共沉淀对常见的层状锰氧化物矿物δ-MnO_2吸附活性的影响。选择阳离子(即Cd)和阴离子(即磷酸盐和砷酸盐)来考察δ-MnO_2吸附反应性的变化。锌共沉淀抑制了δ-MnO_2对Cd的吸收，但增加了δ-MnO_2对Cd和Zn的总吸收，表明有更多的有效空位(例如，更小的颗粒尺寸和更高的空位密度)。锌共沉淀法显著提高了δ-MnO_2对磷和砷的吸附，且这种促进作用比纯δ-MnO_2对锌的吸附更有效。X射线衍射和X射线吸收光谱分析没有检测到表面沉淀物和/或三元络合物的形成。锌共沉淀δ-MnO_2对阴离子的吸附增强可能是由于吸附的锌对表面负电荷的补偿，以及锌共沉淀引入的结构修饰。这一研究结果可以更好地理解自然环境中金属共沉淀锰氧化物与其他物种之间的相互作用。
The sorptive reactivity of layered manganese (Mn) oxides is controlled by their layer and interlayer structure, which can be affected by processes such as metal coprecipitation. This study investigated the effects of Zn coprecipitation on the sorptive reactivity of δ-MnO2, a common layered Mn oxide mineral. Selected cation (i.e., Cd) and anion (i.e., phosphate and arsenate) species were used to probe the changes in δ-MnO2 sorptive reactivity. Cd uptake by δ-MnO2 was suppressed by Zn coprecipitation but total metal uptake (Cd and Zn) was enhanced, indicating more available vacancy sites (e.g., smaller particle size and higher vacancy site density) in Zn-coprecipitated δ-MnO2. Phosphate and arsenate sorption on δ-MnO2 was significantly enhanced by Zn-coprecipitation, and the enhancement was more effective compared to Zn sorption on pure δ-MnO2. X-ray diffraction and X-ray adsorption spectroscopy analysis did not detect the formation of surface precipitations and/or ternary complexes. The enhanced anion sorption on Zn-coprecipitated δ-MnO2 was likely due to the compensation of negative surface charge by sorbed Zn, as well as the structural modifications introduced by Zn coprecipitation. Results from this study can provide a better understanding on the interactions between metal-coprecipitated Mn oxides and other species in natural environments.