ABSTRACT

Perfluorooctanoic acid (PFOA) is an organic compound that is persistent and very toxic to living organisms and the environment. In this study, two kinds of Mg-Al-layered double hydroxides (namely LDH-1 and 2) were synthesized using hydrothermal and dry grinding methods and used to adsorb PFOA from aqueous solution. The kinetic study revealed that a pseudo-2nd order model was the best method for describing the kinetics of sorption, which could emphasize the chemical interaction between PFOAs and LDHs. Among the models tested, the Freundlich model was the best fit for the sorption isotherms. The removal rates of PFOA adsorption by LDH-1 and LDH-2 were 90% and 98.9%, respectively, in the lowest time compared with similar past studies using different adsorbents. The currently synthesized LDHs showed the least equilibrium time, without thermal treatment and the need for activation. The research bears prospects for removing PFOA from aqueous media, thereby demonstrating the potential of employing synthesized LDHs in a fixed-bed filter for the environmental remediation of PFOA-contaminated wastewater bodies.

摘要

全氟辛酸 (PFOA) 是一种有机化合物，具有持久性，对生物体和环境具有剧毒。本研究采用水热法和干磨法合成了两种 Mg-Al 层状双氢氧化物（即 LDH-1 和 2），用于吸附水溶液中的 PFOA。动力学研究表明，伪二阶模型是描述吸附动力学的最佳方法，可以强调 PFOA 和 LDHs 之间的化学相互作用。在测试的模型中，Freundlich 模型最适合吸附等温线。与过去使用不同吸附剂的类似研究相比，LDH-1 和 LDH-2 对 PFOA 的吸附去除率分别为 90% 和 98.9%。目前合成的LDHs显示出最少的平衡时间，无需热处理且无需活化。该研究具有从水介质中去除 PFOA 的前景，从而证明了在固定床过滤器中使用合成的 LDH 对 PFOA 污染的废水体进行环境修复的潜力。