Ali Md Arafat, Thapa Utsav, Antle Jonathan, Tanim Ehsan Ul Hoque, Aguilar John Michael, Bradley Ian M, Aga Diana S, Aich Nirupam
Department of Civil, Structural and Environmental Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, United States.
Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260, United States.
J Hazard Mater. 2024 May 5;469:133912. doi: 10.1016/j.jhazmat.2024.133912. Epub 2024 Feb 28.
Graphene and zero-valent-iron based nanohybrid (rGO-nZVI NH) with oxidant HO can remove perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) through adsorption-degradation in a controlled aquatic environment. In this study, we evaluated how and to what extent different environmental and operational parameters, such as initial PFAS concentration, HO dose, pH, ionic strength, and natural organic matter (NOM), influenced the removal of PFOS and PFOA by rGO-nZVI. With the increase in initial PFAS concentration (from 0.4 to 50 ppm), pH (3 to 9), ionic strength (0 to 100 mM), and NOM (0 to 10 ppm), PFOS removal reduced by 20%, 30%, 2%, and 6%, respectively, while PFOA removal reduced by 54%, 76%, 11%, and 33% respectively. In contrast, PFOS and PFOA removal increased by 10% and 41%, respectively, with the increase in HO (from 0 to 1 mM). Overall, the effect of changes in environmental and operational parameters was more pronounced for PFOA than PFOS. Mechanistically, •OH radical generation and availability showed a profound effect on PFOA removal. Also, the electrostatic interaction between rGO-nZVI NH and deprotonated PFAS compounds was another key factor for removal. Most importantly, our study confirms that rGO-nZVI in the presence of HO can degrade both PFOS and PFOA to some extent by identifying the important by-products such as acetate, formate, and fluoride.
石墨烯与基于零价铁的纳米复合材料（rGO-nZVI NH）以及氧化剂羟基自由基（HO）可在可控水环境中通过吸附降解去除全氟辛酸（PFOA）和全氟辛烷磺酸（PFOS）。在本研究中，我们评估了不同环境和操作参数，如初始全氟烷基磺酸浓度、羟基自由基剂量、pH值、离子强度和天然有机物（NOM），如何以及在何种程度上影响rGO-nZVI对PFOS和PFOA的去除效果。随着初始全氟烷基磺酸浓度（从0.4增至50 ppm）、pH值（3至9）、离子强度（0至100 mM）和NOM（0至10 ppm）的增加，PFOS去除率分别降低了20%、30%、2%和6%，而PFOA去除率分别降低了54%、76%、11%和33%。相反，随着羟基自由基（从0增至1 mM）的增加，PFOS和PFOA的去除率分别提高了10%和41%。总体而言，环境和操作参数变化对PFOA的影响比对PFOS更为显著。从机制上讲，羟基自由基的产生和可用性对PFOA的去除有深远影响。此外，rGO-nZVI NH与去质子化的全氟烷基磺酸化合物之间的静电相互作用是另一个去除的关键因素。最重要的是，我们的研究通过鉴定乙酸盐、甲酸盐和氟化物等重要副产物，证实了在羟基自由基存在下，rGO-nZVI可在一定程度上降解PFOS和PFOA。
