河流沉积物对镉和铊的竞争吸附-解吸特性

发布时间：2018-04-30 21:03

本文选题：环境工程学 + 沉积物　；参考：《安全与环境学报》2016年06期

【摘要】：探讨了不同粒径的表层沉积物对镉(Cd~(2+))和铊(Tl~+)的单一、竞争吸附-解吸特性,并通过对吸附前后沉积物颗粒进行红外光谱和X-光电子能谱分析,探讨了其吸附机理。结果表明,重金属吸附量均随溶液初始质量浓度增加而增大,且随沉积物粒径增大而减小;吸附率随初始质量浓度增加而减小。沉积物对Cd~(2+)的吸附量高于Tl~+,且Cd~(2+)和Tl~+的吸附等温线均符合Langmuir和Freundlich吸附模型。重金属解吸量随吸附量增加而呈指数增加趋势。当重金属Cd~(2+)和Tl~+共存时,各吸附量均有不同程度的下降,而解吸率略高于单一环境。红外光谱分析表明,沉积物中羟基与羧基均参与了Cd~(2+)和Tl~+的吸附;X-射线光电子能谱分析表明,沉积物吸附Cd~(2+)和Tl~+后,金属价态不发生改变。
[Abstract]:The single and competitive adsorption-desorption properties of CD _ (2 +) and Tl ~ for surface sediments with different particle sizes were discussed. The adsorption mechanism was discussed by means of infrared spectra and X-ray photoelectron spectroscopy (XPS) analysis of sediment particles before and after adsorption. The results show that the adsorption capacity of heavy metals increases with the increase of the initial mass concentration of the solution and decreases with the increase of the sediment particle size, and the adsorption rate decreases with the increase of the initial mass concentration. The adsorption isotherms of Cd~(2) and TL ~ for sediment were higher than those for Tl ~, and the adsorption isotherms of Cd~(2) and TL ~ were in accordance with the Langmuir and Freundlich adsorption models. The desorption amount of heavy metals increased exponentially with the increase of adsorption amount. When the heavy metal (Cd~(2) and Tl ~ (+) co-existed, the adsorption capacity decreased to some extent, and the desorption rate was slightly higher than that in the single environment. Ir spectra showed that both hydroxyl and carboxyl groups in sediments were involved in Cd~(2) and Tl ~ adsorption. X- ray photoelectron spectroscopy (XPS) analysis showed that the valence states of metals did not change after the sediments adsorbed Cd~(2) and Tl ~.
【作者单位】：南华大学土木工程学院;环境保护部华南环境科学研究所;兰州交通大学环境与市政工程学院;
【基金】：国家环境保护公益性行业科研专项(201309051) 广西环保专项
【分类号】：X522

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