Waste Science and Technology, Luleå University of Technology, Luleå, Sweden.
Waste Science and Technology, Luleå University of Technology, Luleå, Sweden.
J Environ Manage. 2021 Jul 15;290:112573. doi: 10.1016/j.jenvman.2021.112573. Epub 2021 Apr 16.
Electrochemical degradation using boron-doped diamond (BDD) electrodes has been proven to be a promising technique for the treatment of water contaminated with per- and poly-fluoroalkyl substances (PFAS). Various studies have demonstrated that the extent of PFAS degradation is influenced by the composition of samples and electrochemical conditions. This study evaluated the significance of several factors, such as the current density, initial concentration of PFAS, concentration of electrolyte, treatment time, and their interactions on the degradation of PFAS. A 2 factorial design was applied to determine the effects of the investigated factors on the degradation of perfluorooctanoic acid (PFOA) and generation of fluoride in spiked water. The best-performing conditions were then applied to the degradation of PFAS in wastewater samples. The results revealed that current density and time were the most important factors for PFOA degradation. In contrast, a high initial concentration of electrolyte had no significant impact on the degradation of PFOA, whereas it decreased the generation of F. The experimental design model indicated that the treatment of spiked water under a current density higher than 14 mA cm for 3-4 h could degrade PFOA with an efficiency of up to 100% and generate an F fraction of approximately 40-50%. The observed high PFOA degradation and a low concentration of PFAS degradation products indicated that the mineralization of PFOA was effective. Under the obtained best conditions, the degradation of PFOA in wastewater samples was 44-70%. The degradation efficiency for other PFAS in these samples was 65-80% for perfluorooctane sulfonic acid (PFOS) and 42-52% for 6-2 fluorotelomer sulfonate (6-2 FTSA). The presence of high total organic carbon (TOC) and chloride contents was found to be an important factor affecting the efficiency of PFAS electrochemical degradation in wastewater samples. The current study indicates that the tested method can effectively degrade PFAS in both water and wastewater and suggests that increasing the treatment time is needed to account for the presence of other oxidizable matrices.
电化学降解使用掺硼金刚石 (BDD) 电极已被证明是一种很有前途的技术，可用于处理受全氟和多氟烷基物质 (PFAS) 污染的水。各种研究表明，PFAS 的降解程度受样品组成和电化学条件的影响。本研究评估了电流密度、PFAS 的初始浓度、电解质浓度、处理时间等几个因素的重要性，以及它们对 PFAS 降解的相互作用。采用 2 因素设计来确定所研究因素对全氟辛酸 (PFOA) 降解和氟化物生成的影响。然后将表现最佳的条件应用于废水样品中 PFAS 的降解。结果表明，电流密度和时间是 PFOA 降解的最重要因素。相比之下，电解质的初始高浓度对 PFOA 的降解没有显著影响，但会降低 F 的生成。实验设计模型表明，在电流密度高于 14 mA cm 的条件下处理 3-4 小时，可以将 PFOA 的降解效率提高到 100%，生成的 F 部分约为 40-50%。观察到 PFOA 的高降解率和 PFAS 降解产物浓度较低，表明 PFOA 的矿化是有效的。在获得的最佳条件下，废水中 PFOA 的降解率为 44-70%。这些样品中其他 PFAS 的降解效率为全氟辛烷磺酸 (PFOS) 的 65-80%和 6-2 氟代烷硫磺酸 (6-2 FTSA) 的 42-52%。发现高总有机碳 (TOC) 和氯化物含量是影响废水中 PFAS 电化学降解效率的重要因素。本研究表明，所测试的方法可以有效地降解水和废水中的 PFAS，并表明需要增加处理时间来考虑其他可氧化基质的存在。
