摘要
氟芳烃类化合物因其独特的理化性质,被广泛应用于含氟医药、农药、液晶材料制备等领域.然而,在其生产和使用过程中会造成水污染,目前在全球多个地区的环境水体中均检测出氟芳烃类化合物的残留.因此,对废水中典型的氟芳烃类化合物如氟苯酚、氟苯甲酸以及氟喹诺酮类分子的有效降解备受关注.氟芳烃类化合物的生物毒性及环境持久性来源于分子结构中氟原子的强电负性、C-F键的高解离能以及芳环结构的强稳定性,而常规的降解方法存在应用条件苛刻、有毒含氟中间体残留以及有机碳矿化不完全等问题.因此,针对氟芳烃分子的结构特点,设计一种可以同时促进脱氟和有机碳矿化的降解策略对降低氟芳烃废水的环境危害至关重要.本文报道了一种基于光电催化的脱氟-氧化过程,通过紫外光实现氟芳烃分子的自活化,并与·OH自由基的原位产生过程进行耦合.利用紫外光光解脱氟的高选择性和·OH自由基的强氧化性,实现4-氟苯酚在温和条件下完全脱氟以及矿化.研究结果表明,苯环结构的4-氟苯酚分子可以吸收λ<320 nm的紫外光,且受到光激发后,其自发光解过程可实现C-F键断裂,该过程具有较高的选择性,但是形成的脱氟中间体无法通过紫外光解进一步降解.通过构建光电催化体系,TiO2纳米柱光阳极可原位产生·OH自由基(λ>320 nm),从而实现脱氟中间体的完全矿化.利用全光谱氙灯光照下的光电催化体系可以耦合紫外光解和·OH自由基氧化过程,对于20 ppm浓度的4-氟苯酚溶液,其表观降解速率可达14.4 gh^(-1)m^(-2),并实现4-氟苯酚完全脱氟及有机碳矿化.此外,该体系在不同溶液pH值(0-2)、外加偏压(0.5-1.5 VRHE)以及照射光源(氙灯、汞灯和LED灯)条件下均具有良好的降解效果和稳定性,并可拓展至其他常见的氟芳烃类化合物如诺氟沙星等含氟医药分子的降解.进一步构建了�
Fluoroarene(FA)derivatives are persistent,toxic,and bioaccumulative pollutants,which pose severe risks to ecosystems and human health.Efficient cleavage of C–F bonds and complete mineralization of defluorinated intermediates are the keys for the deep treatment of FAs due to the high dissociation energy of C–F bonds and the high stability of aromatic rings.Herein,we report a synchronous defluorination-oxidation process using a photoelectrocatalytic device with a TiO_(2)photoanode,in which FAs are selectively cleavage of C–F bonds by photolysis and subsequently efficient oxidized by on-site generated·OH radical.Complete defluorination and mineralization(both over 99.9%)of 4-fluorophenol are achieved under irradiation at 1.0 VRHE in 120 min,the apparent reaction rate constant is 14.4 g h~(-1)m~(-2).This synchronous defluorination-oxidation process provides an efficient and practical technique for the mineralization of FAs in wastewater under mild conditions.
作者
池海波
王旺银
马江平
段睿智
丁春梅
宋睿
李灿
Haibo Chi;Wangyin Wang;Jiangping Ma;Ruizhi Duan;Chunmei Ding;Rui Song;Can Li(School of Chemistry and Materials Science,University of Science and Technology of China,Hefei 230026,Anhui,China;State Key Laboratory of Catalysis,Dalian National Laboratory for Clean Energy,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,Liaoning,China;Key Laboratory of advanced catalysis,Gansu Province,State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering,Lanzhou University,Lanzhou 730000,Gansu,China)
基金
国家自然科学基金(22088102,22372162)
辽宁省兴辽英才计划(XLYC2007002)
中国科学院青年创新促进会(2022178).
关键词
废水处理
氟芳烃
光电催化降解
脱氟
总有机碳移除
Wastewater treatment
Fluoroarene
Photoelectrocatalytic degradation
Defluorination
Total organic carbon removal
