Characteristics of Adsorption Interactions of Cadmium(II) onto Humin from Peat Soil in Freshwater and Seawater Media
Characteristics of Adsorption Interactions of Cadmium(II) onto Humin from Peat Soil in Freshwater and Seawater Media
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DOI：
10.1007/s00128-014-1205-x
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发表时间：
2014-03-01
影响因子：
2.7
通讯作者：
Zhang, Jing
中科院分区：
文献类型：
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作者：
Andreas, Roy;Zhang, Jing
本研究探讨了镉在pH 2-12的新鲜和海水介质中的溶解度，有和没有胡敏素，以确定镉的物种组成。采用Langmuir-Hinshelwood动力学模型，研究了胡敏素吸附Cd（II）的动力学参数。我们采用Langmuir和Freundlich模型推导热力学参数。Cd（II）在胡敏素上的吸附主要由Cd（H2O）（6）（2+）和CdCl+、CdCl 2氯络合物引起。结果表明，Cd以Cd（II）和Cd（H2O）（6）（+2）的形式溶于水，部分可溶性Cd以Cd（OH）（2）的形式沉淀。在淡水中Cd（II）的速率常数（k）为0.5 × 10 ~（-3）（min ~（-1）），发生在单一相中，而在海水中快相和慢相的k值分别为31.88 × 10 ~（-3）和6.2 × 10 ~（-3）（min ~（-1））。吸附曲线符合Langmuir模型，而非Freundlich模型。
The present study examined Cd solubility in pH 2-12 fresh and seawater media with and without humin to determine Cd species composition. The study, based on the Langmuir-Hinshelwood kinetics model, was conducted to determine the kinetic parameters of Cd(II) adsorption onto humin. We employed the Langmuir and Freundlich models to derive thermodynamic parameters. Aquo (Cd(H2O) (6) (2+) ) and chloro- (CdCl+ and CdCl2) complexes were responsible for Cd(II) adsorption onto humin. Results showed Cd as Cd(II) and Cd(H2O) (6) (+2) was water soluble at 2 < pH < 7; with a portion of the soluble Cd precipitating as Cd(OH)(2). The Cd(II) rate constant (k) in freshwater was 0.5 x 10(-3) (min(-1)), occurring in a single phase, while in seawater fast and slow phase values for k were 31.88 x 10(-3) and 6.2 x 10(-3) (min(-1)), respectively. The adsorption curves showed a better fit with the Langmuir than the Freundlich model.