Abstract:

Glucocorticoids (GCs), as a kind of environmental endocrine disruptors, have attracted increasing attention in the field of environment. Due to the lack of technology to effectively control GC pollution in water, this research built a paralleling plasma jet/activated carbon fiber (PPJ/ACF) system to effectively degrade fluocinolone acetonide (FA). At PPJ discharge power of 49.7W and ACF dosage of 3g/L, the removal efficiency of FA reached 96% at 60min with energy yield of 96mg/kWh and energy consumption of 0.36kWh/L. The combination of PPJ and ACF showed significant synergistic effects. During PPJ treatment, the added ACF provided catalytic sites and adsorption sites for GCs. In the meantime, PPJ released ACF adsorption sites in situ. In PPJ/ACF system, hydroxyl radicals (·OH) were identified as the functional reactive species for FA degradation by radical scavengers. Transformation intermediates with lower lipophilicity and toxicity were identified by ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometer (UHPLC-QTOF), indicating possible degradation pathways of FA including defluorination, keto acid decarboxylation, demethylation, intramolecular cyclization, cleavage and esterolysis. Overall, this study provides an effective and practical way to control GC pollution by PPJ/ACF treatment.

Key words: glucocorticoids, paralleling plasma jet, activated carbon fiber, synergistic effects, degradation mechanisms

摘要：

糖皮质激素（glucocorticoids，GCs）作为一类环境内分泌干扰物，引起了环境领域越来越多的关注。由于缺乏有效控制水中GCs污染的技术，本研究搭建了并联等离子体射流耦合活性碳纤维系统（paralleling plasma jet/activated carbon fiber，PPJ/ACF）以有效降解水中的糖皮质激素氟轻松（fluocinolone acetonide，FA）。当PPJ/ACF系统的放电功率为49.7W、ACF投加量为3g/L时，处理60min后，FA的去除率可达96 %，能量利用率为96mg/kWh，能耗量为0.36kWh/L。PPJ与ACF联用有显著的协同效应，ACF可提供催化位点及吸附GCs位点，PPJ可原位释放ACF吸附位点。通过添加自由基抑制剂，发现羟基自由基（·OH）是降解FA的主要作用自由基。通过超高效液相色谱飞行时间质谱联用仪（ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometer，UHPLC-QTOF）检测分析了FA可能的中间产物，根据中间产物分析FA的降解途径主要包括脱氟、酮酸脱羧、脱甲基、分子内环化、裂解和酯水解，表明FA毒性降低。因此，PPJ/ACF系统可有效控制GCs污染。

关键词: 糖皮质激素, 等离子体射流, 活性碳纤维, 氟轻松, 降解机理