摘要
诺氟沙星(Norfloxacin,NOR)是一种含有C—F键的难降解抗生素,具有强持久性和较高毒性,传统的处理方法难以有效去除NOR.基于过硫酸盐的高级氧化技术具有较高的选择性、适应性、去除效率等优点,已被广泛研究用于有机污染物的去除.本研究以螺旋藻为原材料热解得到的生物炭(Biochar,BC)为基底,选取具有高还原能力的纳米零价铁(Nano zero-valent iron,nZVI)作为其可能的活性中心,将nZVI负载至BC表面制备了生物炭负载纳米零价铁(nZVI-BC),以综合发挥碳载体与铁活性中心的作用高效催化过硫酸盐降解有机污染,并通过研究nZVI-BC的结构特征和对NOR的去除效率,探究其对过一硫酸盐(Peroxymonosulfate,PMS)的活化效能及机理.结果表明,nZVI-BC活化PMS降解NOR具有优异的催化性能,其降解效率随着材料碳铁负载质量比(C/Fe)的减少而升高,在最佳反应条件下,当C/Fe=1:1时,120 min内nZVI-BC/PMS对NOR的去除率可达到98.8%.降解过程符合拟一级动力学,nZVI-BC/PMS体系在2 min内的降解速率可达(0.69±0.09)min-1,分别是nZVI和BC800催化PMS体系的2.55倍和6.27倍,且弱酸条件(pH=4.00)及温度升高(T=45℃)更利于nZVI-BC催化PMS降解NOR.nZVI-BC/PMS降解NOR是以·OH、·SO_(4)^(-)和参与的自由基途径及以^(1)O_(2)主导作用的非自由基途径的协同效果,贡献作用为^(1)O_(2)>·SO_(4)^(-)>·OH>·O_(2)^(-),其中,^(1)O_(2)在整个反应路径中起至关重要的作用,贡献率达38.46%.据降解产物分析,得知NOR在nZVI-BC/PMS体系中的降解主要是通过脱氟和哌嗪环的开环裂解,最终转化为短链酸、CO_(2)和H_(2)O.本研究为实现NOR在水体中的高效去除提供了一种实际可用、高效环保的方法,同时为阻控新型污染物和抗生素耐药污染提供了新策略.
Norfloxacin(NOR)is a refractory C—F bonded antibiotic with strong persistence and high toxicity,and is usually difficult to be effectively removed by traditional treatments.With the advantage of high selectivity,adaptability,and removal efficiency,persulfate-based advanced oxidation technology has been widely studied for organic pollutant removal.In this study,biochar(BC)obtained by pyrolysis of spirulina was used as the substrate,and nano zero-valent iron(nZVI)with high reducing ability was selected as its possible active center.By distributing nZVI onto BC,we prepared biochar-supported nano zero-valent iron(nZVI-BC),which was expected to combine the role of carbon carrier and iron active center to efficiently catalyze the degradation of organic pollution by persulfate.Moreover,the activation efficiency and mechanism for peroxymonosulfate(PMS)were explored by investigating the structural characteristics of nZVI-BC and the removal efficiency of NOR.Our results showed that nZVI-BC had excellent catalytic performance in activating PMS to degrade NOR,and its degradation rates of NOR were increased with the decrease of C/F.At C/Fe=1∶1,the NOR removal ratio reached 98.8%in 120 min,following a pseudo-first-order kinetics.The degradation rates of NOR in nZVI-BC/PMS system reached(0.69±0.09)min-1 within 2 min,which were 2.55 times and 6.27 times of nZVI/PMS and BC800/PMS,respectively.Weak acidic conditions(pH=4.00)and elevated temperature(T=45℃)were more favorable for the nZVI-BC-catalyzed PMS degradation of NOR.The degradation of NOR in the nZVI-BC/PMS system was a synergistic effect of free radical pathway involving·OH,·SO_(4)^(-)and·O_(2)^(-)and a non-free radical pathway dominated by ^(1)O_(2),in which ^(1)O_(2) played a crucial role in the whole reaction pathway,contributing 38.46%of NOR degradation.According to the analysis of degradation products,the degradation of NOR in the advanced oxidation system was mainly composed by defluorination and ring-open cleavage of piperazine rings,and eventually into sho
作者
刘婧妍
李宁
朱栩楷
陈再明
周芷若
汪美贞
黄丹
LIU Jingyan;LI Ning;ZHU Xukai;CHEN Zaiming;ZHOU Zhiruo;WANG Meizhen;HUANG Dan(School of Environmental Science and Engineering,Zhejiang Gongshang University,Hangzhou 310018)
出处
《环境科学学报》
CAS
CSCD
北大核心
2023年第10期47-61,共15页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.U21A20292,42107035)。
