Park Junyoung, Choe Jong Kwon, Bae Jiyeol, Baek Soyoung
Department of Civil and Environmental Engineering, Seoul National University, Seoul, 08826, South Korea.
Institute of Construction and Environmental Engineering, Seoul National University, Seoul, 08826, South Korea.
Heliyon. 2024 Jul 5;10(14):e34199. doi: 10.1016/j.heliyon.2024.e34199. eCollection 2024 Jul 30.
Perfluoroalkyl substances (PFAS) are emerging contaminants present in various water sources. Their bioaccumulation and potential toxicity necessitate proper treatment to ensure safe water quality. Although iron-based monometallic photocatalysts have been reported to exhibit rapid and efficient PFAS degradation, the impact of bimetallic photocatalysts is unknown. In addition, the mechanistic effects of utilizing a support are poorly understood and solely based on physicochemical properties. This study investigates the efficacy of bimetallic photocatalysts (FeO/MnO) in inducing the photo-Fenton reaction for the degradation of perfluorooctane sulfonate (PFOS) and perfluorononanoic acid (PFNA) under various conditions. The rapid removal of both PFAS was observed within 10 min, with a maximum efficiency exceeding 97 % for PFOS under UV exposure, aided by the photocatalytic activation (photo-Fenton) of the oxidant (HO). Contrary to expectations, the use of the SiO support material did not significantly improve the removal efficiency. The efficacy of PFNA decreased despite SiO providing larger surface areas for FeO/MnO loading. Further analysis revealed that the adsorption of PFAS onto the catalyst surfaces owing to electrostatic interactions contributed to the removal efficiency, where the degradation efficacy was worse than that of the catalyst with SiO. This is because adsorption hindered the effective contact of HO with catalytic reaction sites, thereby impeding the generation of hydroxyl (·OH) radicals. This study indicates the importance of considering chemical properties, including surface charge, in catalyst design to ensure effective degradation, focusing on physicochemical properties, such as surface area might overlook crucial factors.
全氟烷基物质（PFAS）是各类水源中出现的新兴污染物。它们的生物累积性和潜在毒性使得必须进行适当处理以确保水质安全。尽管已有报道称铁基单金属光催化剂能快速高效地降解PFAS，但双金属光催化剂的影响尚不清楚。此外，利用载体的作用机理了解甚少，且仅基于物理化学性质。本研究考察了双金属光催化剂（FeO/MnO）在各种条件下引发光芬顿反应降解全氟辛烷磺酸（PFOS）和全氟壬酸（PFNA）的效果。在10分钟内观察到两种PFAS均能快速去除，在紫外线照射下，PFOS的最高去除效率超过97%，这得益于氧化剂（HO）的光催化活化（光芬顿）。与预期相反，使用SiO载体材料并未显著提高去除效率。尽管SiO为FeO/MnO负载提供了更大的表面积，但PFNA的去除效果却下降了。进一步分析表明，由于静电相互作用，PFAS在催化剂表面的吸附对去除效率有贡献，但其降解效果比含SiO的催化剂差。这是因为吸附阻碍了HO与催化反应位点的有效接触，从而阻碍了羟基（·OH）自由基的产生。本研究表明，在催化剂设计中考虑包括表面电荷在内的化学性质对于确保有效降解很重要，仅关注表面积等物理化学性质可能会忽略关键因素。
