Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, 15 Broadway, NSW 2007, Australia; School of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China.
Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, 15 Broadway, NSW 2007, Australia.
Chemosphere. 2020 Jan;239:124722. doi: 10.1016/j.chemosphere.2019.124722. Epub 2019 Sep 2.
Perfluorooctanoic acid (PFOA) has attracted considerable attention worldwide due to its widespread occurrence and environmental impacts. This research focused on the photocatalytic process for the treatment of PFOA in water and wastewater. Gallium oxide (GaO) and peroxymonosulfate (PMS) were mixed directly in PFOA solution, which was irradiated under different light sources. The treatment system showed excellent performance that 100% PFOA was degraded within 90 min and 60 min under 254 nm and 185 nm UV irradiation, respectively. Moreover, the degradation efficacy was unaffected by initial PFOA concentration from 50 ng L to 50 mg L. Acidic solution (pH 3) improved the degradation process. The quantum yield in the PMS/GaO system under UV light (254 nm) was estimated to be 0.009 mol E. Scavengers such as tert-butanol (t-BuOH), disodium ethylenediaminetetraacetate (EDTA-Na) and benzoquinone (BQ) were added into PFOA solution to prove that sulfate radicals (SO), superoxide radical (O) and photogenerated electrons (e) were the main active species with strong redox ability for PFOA degradation in PMS/GaO/UV system. Combined with the intermediates analysis, PFOA was degraded stepwise from long chain compound to shorter chain intermediates. In addition, PFOA in real wastewater exhibited similar degradation efficiency, together with 75-85% TOC removal by GaO/PMS under 254 nm UV irradiation. Therefore, GaO/PMS system was highly effective for PFOA photodegradation under UV irradiation, which has potential to be applied for the perfluoroalkyl substances (PFAS) treatment in water and wastewater.
全氟辛酸 (PFOA) 因其广泛的存在和对环境的影响而引起了全球的关注。本研究主要关注水中和废水中 PFOA 的光催化处理过程。将氧化镓 (GaO) 和过一硫酸盐 (PMS) 直接混合在 PFOA 溶液中，然后在不同的光源下进行照射。该处理系统表现出优异的性能，在 254nm 和 185nmUV 照射下，100%的 PFOA 在 90min 和 60min 内完全降解，而且初始 PFOA 浓度从 50ng/L 到 50mg/L 对降解效果没有影响。酸性溶液 (pH 3) 可改善降解过程。在紫外光 (254nm) 下，PMS/GaO 体系的量子产率估计为 0.009molE。向 PFOA 溶液中加入叔丁醇 (t-BuOH)、乙二胺四乙酸二钠 (EDTA-Na) 和苯醌 (BQ) 等清除剂，证明 SO、O 和光生电子 (e) 是主要的活性物质，具有很强的氧化还原能力，可用于 PMS/GaO/UV 体系中 PFOA 的降解。结合中间产物分析，PFOA 从长链化合物逐步降解为短链中间产物。此外，实际废水中的 PFOA 也表现出相似的降解效率，在 254nmUV 照射下，GaO/PMS 可将 TOC 去除 75-85%。因此，GaO/PMS 体系在紫外光照射下对 PFOA 的光降解非常有效，有望应用于水中和废水中的全氟烷基物质 (PFAS) 处理。
