Copper doping improves hydroxyapatite sorption for arsenate in simulated groundwaters.
Copper doping improves hydroxyapatite sorption for arsenate in simulated groundwaters.
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DOI：
10.1021/es9015734
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发表时间：
2010-02
影响因子：
11.4
通讯作者：
Guojing Liu;J. Talley;Chongzheng Na;S. Larson;L. Wolfe
中科院分区：
文献类型：
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作者：
Guojing Liu;J. Talley;Chongzheng Na;S. Larson;L. Wolfe
羟基磷灰石（Hydroxyapatite， HAP）被广泛用于固定化水体和土壤中的多种阳离子重金属。与对金属阳离子的强吸附相比，HAP对金属阴离子（如砷）的吸附能力不太显著。由于环境中砷的存在引起了严重的健康问题，因此需要具有成本效益的修复方法，因此提高羟基磷灰石对阴离子砷的吸附对扩大其应用潜力具有重要意义。在这项工作中，我们报告了一种创新的铜掺杂方法来提高合成HAP对模拟地下水中砷酸盐的吸附，砷酸盐是一种主要的水砷物种。采用XRD、FTIR、N(2)吸附和SEM对未掺杂HAP和铜掺杂HAP （CuHAP）进行了表征，并对其作为吸附剂进行了砷酸盐去除试验。实验结果表明，铜的掺杂改变了HAP的形貌，增加了HAP的表面积。在pH值为7.7-8.0的模拟地下水中，CuHAP比未掺杂HAP多吸附1.6-9.1倍的砷酸盐。砷酸盐吸附性的提高可能是由于铜掺杂增加了HAP的表面积。除铜掺杂水平外，随着水pH和钙浓度的增加，砷酸盐对HAP和CuHAP的吸附也会增加。实验结果表明，吸附剂的溶解是影响吸附剂对HAP和CuHAP吸附砷酸盐的重要因素。
Hydroxyapatite (HAP) has been widely used to immobilize many cationic heavy metals in water and soils. Compared with its strong sorption for metal cations, the abilities of HAP to sorb metal anions, such as arsenic, are less significant. Improving HAP sorption for anionic arsenic species is important for expanding its application potential because the presence of arsenic in the environment has raised serious health concerns and there is need for cost-effective remediation methods. In this work, we report an innovative method of copper doping to improve a synthetic HAP sorption for arsenate, which is a primary aqueous arsenic species, in simulated groundwaters. The undoped HAP and copper doped HAP (CuHAP) were characterized with XRD, FTIR, N(2) adsorption, and SEM, and then evaluated as sorbents for arsenate removal tests. The experimental results suggest that copper doping changed the morphology and increased the surface area of HAP. The CuHAP sorbed 1.6-9.1x more arsenate than the undoped HAP did in a simulated groundwater at pH of 7.7-8.0. The improved arsenate sorption is presumably due to the increase in surface area of HAP as a result of copper doping. In addition to the copper doping level, the arsenate sorption to HAP and CuHAP can also be increased with increasing water pH and calcium concentration. The experimental data indicate that sorbent dissolution is an important factor governing arsenate sorption to HAP and CuHAP.