石墨烯和零价铁基纳米杂化物(rGO-nZVINH)与氧化剂H2O2可以在受控的水生环境中通过吸附降解去除全氟辛酸(PFOA)和全氟辛烷磺酸(PFOS)。在这项研究中,我们评估了不同的环境和运行参数如何以及在多大程度上,例如初始PFAS浓度,H2O2剂量,pH值,离子强度,和天然有机物(NOM),影响rGO-nZVI对全氟辛烷磺酸和全氟辛烷磺酸的去除。随着初始PFAS浓度的增加(从0.4到50ppm),pH(3至9),离子强度(0至100mM),和NOM(0至10ppm),全氟辛烷磺酸的去除减少了20%,30%,2%,6%,分别,虽然PFOA去除减少了54%,76%,11%,分别为33%。相比之下,全氟辛烷磺酸和全氟辛烷磺酸的去除率分别增加了10%和41%,分别,随着H2O2的增加(从0到1mM)。总的来说,对于PFOA,环境和操作参数变化的影响比PFOS更明显。机械上,·OH自由基的产生和可用性对PFOA去除显示出深远的影响。此外,rGO-nZVINH与去质子化PFAS化合物之间的静电相互作用是去除的另一个关键因素。最重要的是,我们的研究证实,在H2O2的存在下,rGO-nZVI可以通过确定重要的副产物,如乙酸盐,在一定程度上降解PFOS和PFOA,甲酸盐,和氟化物。
Graphene and zero-valent-iron based nanohybrid (rGO-nZVI NH) with
oxidant H2O2 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, H2O2 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 H2O2 (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 H2O2 can degrade both PFOS and PFOA to some extent by identifying the important by-products such as acetate, formate, and fluoride.