Perfluorooctane sulfonate adsorption on powder activated carbon: Effect of phosphate (P) competition, pH, and temperature
Perfluorooctane sulfonate adsorption on powder activated carbon: Effect of phosphate (P) competition, pH, and temperature
复制标题
全氟辛烷磺酸在粉末活性炭上的吸附：磷酸盐 (P) 竞争、pH 值和温度的影响
DOI：
10.1016/j.chemosphere.2017.05.033
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发表时间：
2017
期刊：
影响因子：
8.8
通讯作者：
Tian Xin
中科院分区：
文献类型：
--
作者：
Qian Jin;Shen Mengmeng;Wang Peifang;Wang Chao;Li Kun;Liu Jingjing;Lu Bianhe;Tian Xin
采用粉末活性炭（PAC）作为吸附剂，对水溶液中的全氟辛烷磺酸（PFOS）进行了吸附研究。通过实验室批量实验研究了磷酸盐竞争、温度和pH对PAC吸附全氟辛烷磺酸的影响。结果表明，在单组分和双组分体系中，较高的温度有利于PFOS的吸附。动力学数据符合准二级动力学模型。从热力学上讲，单组分和双组分体系中全氟辛烷磺酸吸附的吸热焓分别为125.07和21.25 kJ mol−1。在单一和二元体系中，全氟辛烷磺酸吸附的熵值分别为0.479和0.092 kJ mol−1K−1。吉布斯常数是负的。这些结果表明，吸附过程是自发的。全氟辛烷磺酸的吸附等温线符合Langmuir模型。在单一体系中，PFOS的吸附量随pH值的升高而降低。受抑全内反射（FTIR）结果表明，磷竞争增加了PAC的亲水性，增强了PAC与PFOS之间的静电排斥作用，使PFOS的吸附量降低。研究还表明，在较高温度下，全氟辛烷磺酸的吸附增加主要是由于全氟辛烷磺酸分子的扩散速率较高，以及PAC表面开放的活性位点数量较多。
Powdered activated carbon (PAC), as an adsorbent, was applied to remove perfluorooctane sulfonate (PFOS) from aqueous solution. Laboratory batch experiments were performed to investigate the influences of phosphate (P) competition, temperature, and pH for PFOS adsorption onto PAC. The results showed that higher temperature favored PFOS adsorption in single and binary systems. The kinetic data fitted very well to the pseudo second-order kinetic model. Thermodynamically, the endothermic enthalpy of the PFOS adsorption in single and binary systems were 125.07 and 21.25 kJ mol−1, respectively. The entropy of the PFOS adsorption in single and binary systems were 0.479 and 0.092 kJ mol−1K−1, respectively. And the Gibbs constants were negative. These results indicated that the adsorption processes were spontaneous. The adsorption isotherms of PFOS agreed well with the Langmuir model. In the single system, PFOS adsorption decreased with increased pH value. The difference in the amount of PFOS adsorption between the single and binary systems increased at higher pH. Frustrated total internal reflection (FTIR) demonstrated that P competition increased the hydrophilicity of the PAC and the electrostatic repulsion between PFOS and PAC, then the PFOS adsorption amount decreased. It also demonstrated that, at higher temperature, increased PFOS adsorption was mainly due to the higher diffusion rate of PFOS molecules and greater number of active sites opened on the PAC surface.