Cd(II) Sorption on Montmorillonite-Humic acid-Bacteria Composites.
Cd(II) Sorption on Montmorillonite-Humic acid-Bacteria Composites.
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蒙脱石-腐植酸-细菌复合材料对 Cd(II) 的吸附
DOI：
10.1038/srep19499
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发表时间：
2016-01-21
影响因子：
4.6
通讯作者：
Huang Q
中科院分区：
文献类型：
--
作者：
Du H;Chen W;Cai P;Rong X;Dai K;Peacock CL;Huang Q
土壤成分（例如，粘土、细菌和腐殖物质）已知在自然系统中产生矿物-有机复合物。采用间歇吸附等温线、等温滴定量热法（ITC）和Cd K边EXAFS谱研究了Cd在蒙脱石-腐殖酸-细菌复合材料上的吸附特性。添加剂吸附和非添加剂Cd（II）的吸附行为观察到的二元蒙特-细菌和三元蒙特-HA-细菌复合材料，分别。具体而言，在三元复合材料中，HA和细菌的共存抑制Cd吸附，这表明腐殖酸和细菌细胞之间的“阻断效应”。吸附在Mont-bacteria和Mont-HA-bacteria复合物上的Cd的EXAFS谱具有较大的正熵（68.1 ~ 114.4J/mol/K）和线性组合拟合，表明Cd主要通过形成内球络合物与细菌表面官能团结合。我们所有的研究结果共同支持的断言，有一定程度的网站掩蔽在三元粘土矿物腐殖酸细菌复合材料。因此，在三元复合物中，Cd优先与较高亲和力的组分结合-即，细菌
Soil components (e.g., clays, bacteria and humic substances) are known to produce mineral-organic composites in natural systems. Herein, batch sorption isotherms, isothermal titration calorimetry (ITC) and Cd K-edge EXAFS spectroscopy were applied to investigate the binding characteristics of Cd on montmorillonite(Mont)-humic acid(HA)-bacteria composites. Additive sorption and non-additive Cd(II) sorption behaviour is observed for the binary Mont-bacteria and ternary Mont-HA-bacteria composite, respectively. Specifically, in the ternary composite, the coexistence of HA and bacteria inhibits Cd adsorption, suggesting a “blocking effect” between humic acid and bacterial cells. Large positive entropies (68.1 ~ 114.4 J/mol/K) and linear combination fitting of the EXAFS spectra for Cd adsorbed onto Mont-bacteria and Mont-HA-bacteria composites, demonstrate that Cd is mostly bound to bacterial surface functional groups by forming inner-sphere complexes. All our results together support the assertion that there is a degree of site masking in the ternary clay mineral-humic acid-bacteria composite. Because of this, in the ternary composite, Cd preferentially binds to the higher affinity components-i.e., the bacteria.