State Key Joint Laboratory of Environment Simulation and Pollution Control, Key Laboratory for Emerging Organic Contaminants Control, School of Environment, Tsinghua University, Beijing, 100084, China.
State Key Joint Laboratory of Environment Simulation and Pollution Control, Key Laboratory for Emerging Organic Contaminants Control, School of Environment, Tsinghua University, Beijing, 100084, China.
Chemosphere. 2019 Jun;224:187-194. doi: 10.1016/j.chemosphere.2019.02.132. Epub 2019 Feb 22.
Adsorption by powder activated carbon (PAC) is recognized as an efficient method for the removal of perfluorinated compounds (PFCs) in water, while the poor separation of spent PAC makes it difficult for further regeneration, increasing the treatment cost significantly. In this study, an ultrafine magnetic activated carbon (MAC) consisting of FeO and PAC was prepared by ball milling to remove PFCs from water efficiently. Increasing the percentage of FeO and balling milling time decreased its adsorption capacity for perfluoroctane sulfonate (PFOS), whereas increased the magnetic separation property to some degree. The optimized MAC was prepared with a FeO to PAC mass ratio of 1:3 after ball milling for 2 h, and the adsorption equilibriums of all the four PFCs on the optimal MAC were reached within less than 2 h, with the adsorption capacities of 1.63, 0.90, 0.33 and 0.21 mmol/g for PFOS, perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS) and perfluorobutane sulfonate (PFBS), respectively. Increasing the solution pH hindered the adsorption of PFOS significantly when the pH was less than the zero potential point (around 6) of the MAC, due to the decreased electrostatic attraction. The spent MAC could be easily separated with a magnet and regenerated by a small volume of methanol, and the regenerated MAC could be reused for more than 5 time and remain stable adsorption capacity for PFOS after 3 cycles. This study provides useful insights into the removal of PFCs by separable magnetic PAC in wastewater.
粉末活性炭（PAC）吸附被认为是去除水中全氟化合物（PFCs）的有效方法，而用过的 PAC 难以分离，这使得进一步再生变得困难，从而显著增加了处理成本。在这项研究中，通过球磨制备了由 FeO 和 PAC 组成的超细微磁活性炭（MAC），以有效地去除水中的 PFCs。增加 FeO 的百分比和球磨时间会降低其对全氟辛烷磺酸（PFOS）的吸附能力，但在一定程度上会提高磁分离性能。经 2 h 球磨后，FeO 与 PAC 的质量比为 1:3 时制备的优化 MAC，所有四种 PFCs 在最佳 MAC 上的吸附平衡在 2 h 内达到，PFOS、全氟辛酸（PFOA）、全氟己烷磺酸（PFHxS）和全氟丁烷磺酸（PFBS）的吸附容量分别为 1.63、0.90、0.33 和 0.21 mmol/g。当溶液 pH 小于 MAC 的零电位点（约 6）时，会显著抑制 PFOS 的吸附，这是由于静电引力的减小。用过的 MAC 可以很容易地用磁铁分离，并通过少量甲醇再生，再生后的 MAC 可以重复使用 5 次以上，在 3 次循环后对 PFOS 的吸附容量保持稳定。这项研究为在废水处理中使用可分离的磁性 PAC 去除 PFCs 提供了有用的见解。
