Behavior and mechanisms for sorptive removal of perfluorooctane sulfonate by layered double hydroxides
Behavior and mechanisms for sorptive removal of perfluorooctane sulfonate by layered double hydroxides
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层状双氢氧化物吸附去除全氟辛烷磺酸的行为和机制
DOI：
10.1016/j.chemosphere.2017.08.082
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发表时间：
2017
期刊：
影响因子：
8.8
通讯作者：
Liu Jianguo
中科院分区：
文献类型：
--
作者：
Hu Zhihao;Song Xin;Wei Changlong;Liu Jianguo
众所周知，全氟辛烷磺酸具有极强的持久性，对野生动物和人类有毒。在这项研究中，我们评估了从水溶液中使用三种形式的层状双氢氧化物（LDHs），即硝酸盐，碳酸盐和氯化物插层LDHs的吸附去除行为。静态吸附实验表明，吸附过程非常迅速，平衡时间为10-60 min。硝酸根-LDH对PFOS的去除能力最强，在PFOS初始浓度为100 mg/L时，去除率可达99.7%，最大吸附量可达865 mg/g。吸附动力学和平衡数据分别可用准二级动力学模型和Langmuir模型拟合。颗粒内扩散模型表明，外扩散和颗粒内扩散是全氟辛烷磺酸吸附到LDHs的限速过程。初始pH值、背景电解质浓度和共存离子影响LDHs对PFOS的吸附。结果表明，PFOS在水滑石上的吸附过程既有表面吸附作用，也有阴离子交换作用。
Perfluorooctane sulfonate (PFOS) is known to be extremely persistent and is toxic to wildlife and humans. In this study, we evaluated the sorptive removal behavior of PFOS from aqueous solution using three forms of layered double hydroxides (LDHs), namely, nitrate-, carbonate- and chloride-intercalated LDHs. Batch experiments showed that the sorption process was very fast with an equilibrium time of 10–60 min. The nitrate-LDH had the greatest ability to remove PFOS with a removal rate of 99.7% at an initial concentration of 100 mg/L and the maximum uptake capacity reached 865 mg/g. The sorption kinetic and equilibrium data could be fitted well with the pseudo-second-order model and Langmuir model, respectively. The intraparticle diffusion model suggests that both external diffusion and intraparticle diffusion are the rate-limiting processes for PFOS sorption onto the LDHs. The initial pH, background electrolyte concentration and coexisting ions influenced the sorption of PFOS by the LDHs. It was concluded that both surface adsorption and anion exchange were involved in the PFOS sorption onto the LDHs.