Adsorption of cadmium(II) on humic acid coated titanium dioxide
Adsorption of cadmium(II) on humic acid coated titanium dioxide
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腐植酸包覆二氧化钛对镉(II)的吸附
DOI：
10.1016/j.jcis.2011.10.005
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发表时间：
2012-02-01
影响因子：
9.9
通讯作者：
Hu, Xialin
中科院分区：
文献类型：
--
作者：
Chen, Qiqing;Yin, Daqiang;Hu, Xialin
随着纳米技术的迅速发展，人们对纳米颗粒的环境影响和健康风险越来越关注。许多研究探讨了有毒污染物在纳米粒子上的吸附，然而，重金属和天然有机物（NOM）包覆的金属氧化物纳米粒子之间的相互作用的研究很少。以腐殖酸（HA）为模型NOM，研究了腐殖酸包覆二氧化钛（HA-TiO 2）纳米粒对Cd（II）的吸附行为。溶液参数，如pH值和盐度进行了研究，以开发的机制。结果表明，TiO 2和HA-TiO 2对Cd（II）的吸附等温线均符合Freundlich吸附等温式。q（e）值随pH值的增加而增加，主要是由于静电吸引作用;而q（e）值随盐度的增加先增加后减小，主要是由于络合作用和静电作用。值得注意的是，与TiO 2相比，HA-TiO 2对Cd（II）的吸附总体趋势更高，这意味着HA涂层可能会改变水环境中重金属的生物利用度。从静电相互作用和共价作用两个方面对吸附机理进行了解释，X射线光电子能谱（XPS）结果也证实了吸附机理的可能性。(C)2011 Elsevier Inc. All rights reserved.
The rapid increase in nanotechnology has led to growing concerns on environmental effects and health risks of nanoparticles (NPs). Many studies investigated the adsorption of toxic pollutants on NPs; however, the interaction between heavy metals and natural organic matter (NOM) coated metal oxide NPs was scarcely studied. In this study, using humic acid (HA) as model NOM, the adsorption of Cd(II) on humic acid coated titanium dioxide (HA-TiO2) NPs was investigated. Solution parameters such as pH and salinity were investigated to exploit the mechanisms. Our results demonstrated that the adsorption isotherms of Cd(II) to both TiO2 and HA-TiO2 complied well with Freundlich model. q(e) values increased with pH increase, mainly due to electrostatic attraction, whereas q(e) values increased initially and then decreased at 100 mmol L-1 with salinity increase, mainly due to complexation and electrostatic effects. It is noteworthy that an overall trend of higher Cd(II) adsorption was observed on HA-TiO2 compared to that on TiO2, implying that HA coating might modify bioavailability of heavy metals in aquatic environment. The possible adsorption mechanisms in views of electrostatic interactions and covalent effects were interpreted, and the X-ray photoelectron spectroscopy (XPS) results also verified the possible mechanisms. (C) 2011 Elsevier Inc. All rights reserved.