铁、锰和铝氧化物吸附硒的行为研究

发布时间：2019-01-27 10:00

【摘要】：表生环境中,吸附是硒进入固相沉积环境的重要途径之一。为了厘清硒氧阴离子团吸附行为及其影响因素,本文选择赤铁矿、二氧化锰和氧化铝作为吸附剂,采用批次实验的方法,研究了溶液pH、硒浓度以及反应时间等对硒的吸附影响。结果表明:为了达到较理想的吸附效果,溶液的pH应控制在4~6之间,在室温、pH为5时,赤铁矿、二氧化锰和氧化铝对亚硒酸盐的饱和吸附量分别约为1.62×10-3、0.33×10-3和1.07×10-3,对硒酸盐的饱和吸附量分别约为1.0×10-3、0、0.55×10-3;其吸附规律均符合Langmuir等温吸附方程,且理论最大吸附量与实验得出的最大吸附量基本一致。运用准一级动力学、准二级动力学、Elvoich方程和颗粒内扩散模型4种动力学模型对实验数据进行拟合,发现硒吸附过程运用准二级动力学方程表示时相关性最好,表明了硒氧阴离子团在铁、锰、铝氧化物表面的吸附过程较为复杂,可能涉及表面物理吸附和颗粒扩散等过程。
[Abstract]:In supergene environment, adsorption is one of the important ways for selenium to enter solid deposition environment. In order to clarify the adsorption behavior of selenium and oxygen anion group and its influencing factors, hematite, manganese dioxide and alumina were selected as adsorbents. Batch experiments were used to study the solution pH,. The effect of selenium concentration and reaction time on the adsorption of selenium was studied. The results show that in order to achieve the ideal adsorption effect, the pH of the solution should be controlled in the range of 4 ~ 6, and at room temperature and pH = 5, hematite can be obtained. The saturated adsorption capacity of manganese dioxide and alumina for selenite is about 1.62 脳 10-3 (0.33 脳 10-3) and 1.07 脳 10-3, respectively. The saturated adsorption capacity for selenite is about 1.0 脳 10-3 (0.55 脳 10-3), respectively. The adsorption rules are in accordance with the Langmuir isothermal adsorption equation, and the theoretical maximum adsorption capacity is basically consistent with the experimental maximum adsorption capacity. The experimental data were fitted with four kinetic models: quasi-first-order kinetics, quasi-second-order kinetics, Elvoich equation and intra-particle diffusion model. It was found that the correlation of selenium adsorption process expressed by quasi-second-order kinetic equation was the best. It is shown that the adsorption process of seleno anions on the surface of iron, manganese and aluminum oxides is complex, which may involve physical adsorption and particle diffusion on the surface.
【作者单位】：中国科学院地球化学研究所环境地球化学国家重点实验室;中国科学院大学;中国地质大学(北京)地质过程与矿产资源国家重点实验室;
【基金】：国家自然科学基金资助项目(编号:41273029) 国家重点基础研究发展计划课题(编号:2014CB238903)
【分类号】：O647.3;P579

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