| 一硫代砷酸盐在介质上的吸附特征及机制 |
| 摘要点击 1294 全文点击 545 投稿时间：2019-05-30 修订日期：2019-08-19 |
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| 中文关键词 一硫代砷酸盐(MTA) 土壤沉积物 针铁矿 吸附动力学 等温吸附 作用机制 |
| 英文关键词 monothioarsenate (MTA) soil sediments goethite adsorption kinetics adsorption isotherm reaction mechanism |
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| 中文摘要 |
| 在实验室条件下合成纯度>99%的MTA，开展不同pH和固液比条件下MTA在细砂、土壤沉积物和针铁矿这3种介质上的吸附实验，分析其吸附特征和作用机制.结果发现：① MTA质量浓度分别在0.14~23.59、0.19~41.27和0.27~32.02 mg·L-1范围时，其在细砂、土壤沉积物和针铁矿的最大平衡吸附量（Qm）分别为21.54、277.98和2607.42 mg·kg-1.值得注意的是，当MTA在3种介质上达到吸附平衡后，溶液中部分MTA开始转化形成亚砷酸盐和砷酸盐.②随着pH的增加（4~10），MTA在细砂上的平衡吸附量（Qe）逐渐减少，在土壤沉积物和针铁矿上的Qe先减少后增加；随着固液比的增加，MTA在3种介质上的Qe均呈现出逐渐减小趋势.③ XRD、SEM和BET测试结果揭示出3种介质吸附MTA的主要控制因素不同，分别是细砂的低孔容特征、土壤沉积物的高结晶程度以及针铁矿上大量的羟基官能团（-OH）. |
| 英文摘要 |
| Batch experiments were conducted to investigate the adsorption characteristics and mechanism of monothioarsenate (MTA) (>99%) on sand, soil sediment, and goethite under different pH and solid-liquid ratio conditions. Results showed the following. ① When MTA ranged from 0.14 to 23.59, 0.19 to 41.27, and 0.27 to 32.02 mg·L-1 in solutions, its maximum equilibrium adsorption capacity (Qm) in sand, soil sediment, and goethite was 21.54, 277.98, and 2607.42 mg·kg-1, respectively. After its adsorption reached equilibrium, a small amount of the MTA in the solutions transformed into arsenite and arsenate. ② As pH increased from 4 to 10, the equilibrium adsorption capacity (Qe) of MTA on sand decreased gradually, whereas Qe first decreased and then increased for soil sediment and goethite. As the solid-liquid ratio increased, the Qe of MTA in the three media gradually decreased. ③ X-ray powder diffraction (XRD), scanning electron microscope (SEM), and BET results further showed that the major factors controlling MTA adsorption on the three media included the low pore volume of sand, the high degree of crystallization of the soil sediment, and the large number of hydroxyl functional groups (-OH) on goethite. |
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