Adsorption behavior of lead on aquatic sediments contaminated with cerium dioxide nanoparticles
Adsorption behavior of lead on aquatic sediments contaminated with cerium dioxide nanoparticles
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纳米二氧化铈污染的水生沉积物中铅的吸附行为
DOI：
10.1016/j.envpol.2016.05.025
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发表时间：
2016
影响因子：
8.9
通讯作者：
Miao Lingzhan
中科院分区：
文献类型：
--
作者：
Wang Chao;Fan Xiulei;Wang Peifang;Hou Jun;Ao Yanhui;Miao Lingzhan
水生沉积物是工程纳米材料（enm），如金属氧化物纳米颗粒（MeO NPs）和碳纳米管（CNTs）的重要汇。由于其显著的特性，enm显示出极大的潜力来干扰其他污染物在水生沉积物中的吸附行为，从而改变这些污染物的生物利用度和毒性。到目前为止，大多数研究都是研究CNTs对沉积物吸附其他污染物的影响。二氧化铈纳米颗粒（CeO2NPs）作为一种重要的MeO纳米颗粒，由于其广泛的使用，也不可避免地排放到水生沉积物中。在本研究中，我们研究了在质量比为5.0%的情况下，添加CeO2NPs的沉积物对Pb2+的吸附行为。结果表明：CeO2NPs污染沉积物后，吸附过程中三个阶段的吸附速率均明显增加；吸附等温线结果表明，Langmuir等温线模型最适合沉积物和受CeO2NPs污染的沉积物等温线数据。添加CeO2NPs后，沉积物对Pb2+的理论最大单层吸附量（Qmax）从4.433 mg/g增加到4.995 mg/g， Langmuir等温线系数（KL）从8.813降低到7.730 L/g。研究了CeO2NPs对沉积物表面电荷和孔隙表面性质的影响，因为这些性质影响了几种化学物质在沉积物中的吸附。结果表明：CeO2NPs污染后，沉积物的pHzpc、SBET、Sext和平均孔径明显减小；因此，CeO2NPs较强的吸附能力以及CeO2NPs引起的沉积物表面电荷和孔隙表面性质的变化是影响Pb2+吸附行为的重要因素。沉积物中埋藏的CeO2NPs可能会增加水生环境中Pb2+的潜在风险。
Aquatic sediments serve as an important sink for engineered nanomaterials (ENMs), such as metal oxide nanoparticles (MeO NPs) and carbon nanotubes (CNTs). Owing to their remarkable properties, ENMs demonstrate significant potential to disturb the adsorption behavior of other contaminants in aquatic sediments, thereby altering the bioavailability and toxicity of these contaminants. Thus far, most studies have investigated the effect of CNTs on the adsorption of other contaminants on sediments. Cerium dioxide nanoparticles (CeO2NPs), as one of the important MeO NPs, are also inevitably discharged into aquatic sediments because of their widespread use. In this study, we investigated the adsorption behavior of Pb2+on sediments spiked with CeO2NPs at a weight ratio of 5.0%. The results showed that the adsorption rates at three stages occurring during adsorption clearly increase for sediments contaminated with CeO2NPs. Moreover, the results obtained from the adsorption isotherms indicated that the Langmuir isotherm model best fits the isotherm data for both sediments and those contaminated with CeO2NPs. After spiking the sediments with CeO2NPs, the theoretical maximum monolayer adsorption capacity (Qmax) for Pb2+increased from 4.433 to 4.995 mg/g and the Langmuir isotherm coefficient (KL) decreased from 8.813 to 7.730 L/g. The effects of CeO2NPs on the surface charge and pore surface properties of sediments were also studied as these properties affect the adsorption of several chemicals in sediments. The results showed that pHzpc, SBET, Sext, and average pore size of sediments clearly decrease for sediments contaminated with CeO2NPs. Hence, the strong adsorption capacity of CeO2NPs and the changes of sediment surface charge and pore surface properties caused by CeO2NPs are important factors affecting the adsorption behavior of Pb2+. The potential risk of Pb2+in aquatic environment may increase with CeO2NPs buried in sediments.