Cadmium adsorption on aluminum oxide in the presence of polyacrylic acid.
Cadmium adsorption on aluminum oxide in the presence of polyacrylic acid.
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DOI：
10.1021/es9913479
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发表时间：
2001-01
影响因子：
11.4
通讯作者：
R. M. Floroiu;A. Davis;A. Torrents
中科院分区：
文献类型：
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作者：
R. M. Floroiu;A. Davis;A. Torrents
已知在许多自然和工程系统中，金属从水溶液吸附到氧化物和其他表面上会影响痕量金属的迁移。因此，重要的是要了解溶解的金属投入是否容易结合到颗粒上，或者是否会在溶液中强烈络合并与水相一起运输。聚（丙烯酸）（PAA），代表天然有机物的模型化合物，对镉（II）吸附到γ-氧化铝的效果，确定使用批吸附实验在pH值范围从4到10。最初，评价了各个组分之间的相互作用。镉在氧化铝上的吸附呈典型的S形吸附曲线。PAA在γ-Al 2 O3上的吸附随着pH值的升高而降低。PAA对Cd 2+的亲和力随着pH值的升高而强烈增加。在三元体系中，PAA的存在导致pH 6以下的Cd（II）吸附增强，这显然是由于三元表面复合物的形成。在pH 6以上，镉吸附到γ-Al 2 O3上的减少，观察到由于可溶性Cd-PAA络合物的浓度增加。总体而言，结果表明，天然有机物的存在可能会对镉在环境中的分布和流动性产生重大影响。由于PAA聚合物的复杂性，简单的表面络合建模不足以描述三元体系中的行为。
Adsorption of metals from aqueous solution onto oxide and other surfaces is known to affect trace metal transport in many natural and engineered systems. It is therefore important to understand whether dissolved metal inputs will be easily bound to particles or will be strongly complexed in solution and transported with the water phase. The effect of poly(acrylic acid) (PAA), representing a model compound for natural organic matter, on the adsorption of Cd(II) onto gamma-Al2O3 was determined using batch adsorption experiments over a pH range from 4 to 10. Initially, interactions among the individual components were evaluated. Cadmium adsorption onto alumina showed a typical S-shaped metal adsorption curve. PAA adsorption onto gamma-Al2O3 decreased with increase in pH. The affinity of PAA for Cd2+ increased strongly with pH. In ternary systems, the presence of PAA resulted in an enhancement of Cd(II) adsorption below pH 6, apparently due to ternary surface complex formation. Above pH 6, a decrease in cadmium adsorption onto gamma-Al2O3 was observed resulting from an increase in the concentration of soluble Cd-PAA complexes. Overall, results indicate that the presence of natural organic matter could have a significant impact on the distribution and mobility of cadmium in the environment. Simple surface complexation modeling was insufficient to describe behavior in the ternary systems due to the complexity of the PAA polymer.