Purdue University, Department of Agronomy, Ecological Science and Engineering, West Lafayette, IN 47907-2054, USA.
Purdue University, Department of Agronomy, Ecological Science and Engineering, West Lafayette, IN 47907-2054, USA.
J Hazard Mater. 2018 Jan 15;342:20-28. doi: 10.1016/j.jhazmat.2017.08.001. Epub 2017 Aug 6.
PFOS removal at 6 and 21days (d) when reacted with palladium coated zero valent iron nanoparticles (Pd/nFe NPs) was quantified as a function of pH (3.6, 5.5, and 8.7) and temperature (22, 45 and 70°C). PFOS concentrations were measured in aqueous phases and NP extracts. The greatest PFOS removal occurred at 6 d with the lowest pH and highest temperature; however, recovered PFOS increased at 21 d. Furthermore, neither F nor SO (from SO cleavage) generation was observed indicating the absence of PFOS transformation. X-ray diffraction analysis of PFOS-reacted NPs at 45°C revealed generation of FeO(OH) on the NPs at 21 d, which was concomitant with subsequent increases in PFOS recovery. Under anaerobic conditions, strongly adsorbing Fe(OH) is formed which can then transform to less sorptive FeO(OH) via Fe catalyzed transformation. In the process of exploring causes for apparent PFOS removal with Pd/nFe NPs, PFOS as well as other perfluoroalkyl acids (PFAAs) were found to form aqueous-phase complexes with Fe(II/III) which can reduce their quantifiable levels. PFOS-Fe complexation was greater with Fe(III) and increased with Fe concentration and decreasing pH. Complexation was also greater for longer chain perfluoroalkyl acids and complexation of PFNA was greater than for PFOS.
在钯涂覆零价铁纳米粒子 (Pd/nFe NPs) 存在下，研究了 PFOS 在 6 和 21 天 (d) 时的去除情况，其去除率与 pH 值 (3.6、5.5 和 8.7) 和温度 (22、45 和 70°C) 有关。在水相和 NP 提取物中测量了 PFOS 的浓度。在最低 pH 值和最高温度下，6 天时 PFOS 的去除率最大；然而，在 21 天时回收的 PFOS 增加。此外，既没有观察到 F 也没有观察到 SO（来自 SO 裂解）的生成，这表明没有发生 PFOS 的转化。在 45°C 下对反应后的 NPs 进行 X 射线衍射分析表明，在 21 天时在 NPs 上生成了 FeO(OH)，这与随后 PFOS 回收率的增加相一致。在厌氧条件下，形成了强吸附的 Fe(OH)，然后通过 Fe 催化转化转化为吸附性较弱的 FeO(OH)。在探索 Pd/nFe NPs 去除 PFOS 的原因的过程中，发现 PFOS 以及其他全氟烷基酸 (PFAAs) 与 Fe(II/III) 形成了水相络合物，这可以降低其可定量的水平。PFOS-Fe 络合作用随 Fe(III) 的增加而增强，随 Fe 浓度和 pH 值的降低而增强。长链全氟烷基酸的络合作用更强，PFNA 的络合作用大于 PFOS。
