Exploring reductive degradation of fluorinated pharmaceuticals using Al2O3-supported Pt-group metallic catalysts: Catalytic reactivity, reaction pathways, and toxicity assessment

WATER RESEARCH

卷:185

Article

Park, Jaehyeong^1,2  An, Seonyoung^1,2  Jho, Eun Hea³  Bae, Sungjun⁴  Choi, Yongju^1,2  Choe, Jong Kwon^1,2 

[1] Seoul Natl Univ, Dept Civil & Environm Engn, 35-402,1 Gwanak Ro, Seoul 08826, South Korea

[2] Seoul Natl Univ, Inst Construct & Environm Engn, 35-402,1 Gwanak Ro, Seoul 08826, South Korea

[3] Hankuk Univ Foreign Studies, Dept Environm Sci, 81 Oedae Ro, Yongin 17035, Gyeonggi Do, South Korea

[4] Konkuk Univ, Dept Civil & Environm Engn, 120 Neungdong Ro, Seoul 05029, South Korea

关键词: Fluorinated pharmaceuticals;    Emerging contaminants;    Catalytic degradation;    Reductive treatment;    Defluorination;    Water treatment;   

DOI  :  10.1016/j.watres.2020.116242

来源: Elsevier

【 摘 要 】

Recently, an increasing number of pharmaceutical compounds has become fluorinated. Owing to their pharmacological efficacy, the use of these fluorinated pharmaceuticals continues to grow, and they constitute 20% of the drugs on the current market. However, only a few studies have investigated the fate and transformation of these emerging contaminants in natural and engineered aquatic environments. In the present study, the H-2-based reductive transformation of three fluorinated pharmaceutical compounds (levofloxacin, sitagliptin, and fluoxetine) were investigated using alumina-supported monometallic and bimetallic catalysts of the Pt-group noble metals (i.e., Ru, Rh, Pd, and Pt) under ambient temperature and pressure conditions. Degradation of all three compounds was observed with catalytic reactivity ranging from 4.0 x 10(-3) to 2.14 x 10(2) L/(min.g(cat)), in which fluoxetine generally showed the highest reactivity, followed by sitagliptin and levofloxacin. The fluorination yields and transformation products were characterized for each fluorinated compound and three different degradation mechanisms were elucidated: 1) hydrodefluorination of C-F bond to C-H bond, 2) hydrogenation of aromatic ring, and 3) reductive cleavage of C-O bond from phenyl ether. Toxicity assessment using Aliivibrio fischeri showed there were no significant changes in toxicity over levofloxacin and sitagliptin degradation, suggesting the formation of no highly toxic by-products during catalytic reduction. For fluoxetine, an increased toxicity was observed during its degradation while ECOSAR-predicted toxicity values of all identified intermediates were lower than that of fluoxetine, suggesting the formation of unidentified secondary by-products that contribute to the overall toxicity. The study showed that catalytic reduction is a promising remediation process for treating and defluorinating the fluorinated pharmaceutical compounds. (C) 2020 The Author(s). Published by Elsevier Ltd.

【 授权许可】

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