Chemosphere_Study on the interaction of catalase with pesticides
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生态毒理学报Asian Journal of Ecotoxicology第18卷第5期2023年10月V ol.18,No.5Oct.2023㊀㊀基金项目:国家自然科学基金资助项目(32071617);江苏省自然科学基金资助项目(BK20191455);江苏省 双创博士 项目(JSSCBS20210723)㊀㊀第一作者:陈晨(1998 ),女,硕士研究生,研究方向为风险评价与生态安全,E -mail:****************㊀㊀*通信作者(Corresponding author ),E -mail:***************.cnDOI:10.7524/AJE.1673-5897.20221112001陈晨,宋杰,闫瑾,等.微(纳米)塑料和抗生素的相互作用及对鱼类的联合毒性效应研究进展[J].生态毒理学报,2023,18(5):56-73Chen C,Song J,Yan J,et al.Advances on interaction between micro(nano)plastics and antibiotics along with their joint toxicity to fish [J].Asian Journal of Ecotoxicology,2023,18(5):56-73(in Chinese)微(纳米)塑料和抗生素的相互作用及对鱼类的联合毒性效应研究进展陈晨,宋杰,闫瑾,王慧利,钱秋慧*苏州科技大学环境科学与工程学院,苏州215000收稿日期:2022-11-12㊀㊀录用日期:2023-01-20摘要:中国是微(纳米)塑料和抗生素生产和使用大国,由于过度使用和废水处理设施的限制,大量的抗生素和微(纳米)塑料进入水环境中,对生态环境和人类健康带来潜在威胁㊂微(纳米)塑料可以作为载体通过多种物理和化学作用吸附抗生素并将其转移到生物体内,对水生生物的肠道㊁肝脏㊁神经和生殖系统等造成损伤,并且通过食物链富集和转移,最终威胁到人类的健康㊂本文系统地综述了微(纳米)塑料和抗生素的相互作用以及对鱼类的危害,对微(纳米)塑料和抗生素的联合作用机制的研究方向进行了展望,以期对微(纳米)塑料和抗生素的环境风险研究提供更多理论参考㊂关键词:微(纳米)塑料;抗生素;联合暴露;相互作用;毒性文章编号:1673-5897(2023)5-056-18㊀㊀中图分类号:X171.5㊀㊀文献标识码:AAdvances on Interaction between Micro (nano )plastics and Antibiotics a-long with Their Joint Toxicity to FishChen Chen,Song Jie,Yan Jin,Wang Huili,Qian Qiuhui *School of Environmental Science and Engineering,Suzhou University of Science and Technology,Suzhou 215000,ChinaReceived 12November 2022㊀㊀accepted 20January 2023Abstract :China is one of the major countries manufacturing and using micro(nano)plastics and antibiotics.How -ever,owing to the overuse by human beings and low -efficient removal of micro(nano)plastics and antibiotics by the most wastewater treatment facilities,large quantities of micro(nano)plastics and antibiotics have entered the aquatic environment,posing a huge potential threat to the ecological environment and human health.With adsorbing antibi -otics via a variety of physicochemical interactions and further transferring them into organisms,micro(nano)plastics can damage the intestinal,liver,nervous and reproductive systems of aquatic organisms,which later can be en -riched and migrated through the food chain and finally affect human health.In this review,we summarized the in -teraction between micro(nano)plastics and antibiotics and their joint toxic effects on fish in detail and prospected the future research directions of the mechanism of their joint interactions.This review provides a comprehensive survey and theoretical guidance for the future investigations on evaluation of the environmental risks of micro第5期陈晨等:微(纳米)塑料和抗生素的相互作用及对鱼类的联合毒性效应研究进展57㊀(nano)plastics and antibiotics.Keywords:micro(nano)plastics;antibiotics;joint exposure;interaction;toxicity㊀㊀微(纳米)塑料(micro(nano)plastics,MNPs)和抗生素是地表水体中2种新型环境污染物㊂环境中的微(纳米)塑料主要来源于日化用品(如合成纺织品㊁个人护理产品)㊁运输业(如合成橡胶轮胎的腐蚀)和工业生产(如塑料颗粒),通过河流运输或直接排放到海洋中[1],对水生生物造成影响㊂因COVID-19暴发,抗生素的市场需求暴增[2];同时,废水设施的限制,使得进入市政污水处理厂的部分抗生素随尾水排出,在自然水体中大量累积㊂因此,MNPs和抗生素均在水体中大量存在,其造成的长期效应会在水生生物体内积累,并通过食物链逐渐放大,甚至引起整个水生态系统的慢性毒性效应㊂抗生素与MNPs具有相似的来源和迁移途径,它们在水生环境中不可避免地共存,形成复合污染,因此研究抗生素与MNPs之间的相互作用及其在水生环境中的联合毒性至关重要㊂本文综述了MNPs和抗生素在环境中的污染现状以及两者之间的吸附方式及影响因素,概述了两者联合暴露对鱼类的毒性效应,并对两者的联合作用机制进一步的研究方向进行了展望㊂1㊀抗生素及MNPs的污染现状(Contamination of antibiotics and MNPs)1.1㊀抗生素的污染现状抗生素具有水溶性高和易排出体外的特点,同时由于其大量使用,造成土壤和水体中抗生素的大量积累,已构成生态风险及健康威胁㊂尽管大多数抗生素的半衰期很短,但由于持续排放到环境中,抗生素被认为是一种 假持久性 有机污染物[3]㊂抗生素在医院㊁养殖场等特殊环境中广泛存在[4-7],已有大量文献报道了地表水体中抗生素的浓度,如表1所示㊂尽管抗生素的环境浓度通常处于痕量水平(ng㊃L-1~μg㊃L-1),但低浓度的抗生素仍然可能对水生生物构成风险,同时伴随着抗生素耐药菌株和抗性基因的产生和传播,对水生生态环境和人类健康造成威胁㊂1.2㊀MNPs的污染现状据报道,我国湖水中MNPs的丰度为900~ 34000个㊃m-3[21-25],其中长沙城市湖泊地表水中MNPs的丰度为7050个㊃m-3[24],并且超过89.5%的MNPs尺寸<2mm,最严重的为鄱阳湖,含量达5000 ~34000个㊃m-3[25]㊂美国南卡罗来纳州查尔斯顿港和温亚湾MNPs的检出浓度分别为(6.6ʃ1.3)个㊃m-3和(30.8ʃ12.1)个㊃m-3[26]㊂德国托伦斯湖中MNPs的浓度为0.14个㊃m-3[27]㊂印度红山湖作为向钦奈市北部供水的淡水系统之一,检出MNPs的丰度为5.9个㊃L-1[28]㊂在抗生素检出较多的区域,如污水处理厂㊁垃圾填埋场和蔬菜生产基地等,其周围检测出大量MNPs,丰度为4~72个㊃L-1,并且粒径主要为0~50μm,占检出颗粒的80%[29]㊂Wang等[30]在工业厂房㊁养殖场和鱼塘废水中均检测到了MNPs,其丰度分别为8~23㊁8~40和13~27个㊃L-1,其中89%的MNPs 直径<500mm㊂不同来源的污水或废水之间没有明显差异,表明它们都构成了微塑料污染㊂生活污水处理厂的进水和出水中MNPs丰度分别为18~890个㊃L-1和6~26个㊃L-1,去除效率为35%~98%㊂南京[31]2家污水处理厂进水中的微塑料浓度分别为22.05个㊃L-1和10.30个㊃L-1,虽然其总去除率达到98%和97.67%,但由于日进水量巨大,因此仍有大量微塑料随尾水排放到自然水体中㊂在世界各地,包括偏远的极地地区,几乎都可以检测到微塑料[32-33]㊂因此,在不同营养层级㊁不同栖息地和拥有不同摄食特征的水生生物体内也发现MNPs亦不足为奇[34-35]㊂MNPs和抗生素在环境中广泛分布,尤其在水体中其分布区域重叠度较大,这为它们的相互作用提供了有利条件[36]㊂例如,由于密集的人类活动和抗生素的大量使用,在长江口的地表水中均检测到MNPs和抗生素,它们的最高浓度分别达到10200个㊃m-3和287ng㊃L-1㊂MNPs和抗生素也可能同时存在于北美的苏必利尔湖等沉积物中[37-38]㊂据报道,苏必利尔湖沉积物中的MNPs丰度为0~55个㊃kg-1,同时人们也发现抗生素在苏必利尔湖的沉积物中积累[39-40]㊂此外,在东亚沿海循环水养殖系统和中国渤海海岸线的沉积物中,也同时检测到了MNPs和抗生素及抗性基因的存在[41-42]㊂因此, MNPs可以作为抗生素的载体,驱动抗生素和抗性基因在自然界中的迁移转化[43-44]㊂当被生物体摄入时, MNPs也会改变抗生素在生物体内的蓄积和毒性㊂2㊀MNPs吸附抗生素(Antibiotics adsorbed by MNPs)2.1㊀MNPs吸附抗生素的方式MNPs可以通过多种物理和化学作用吸附抗生58㊀生态毒理学报第18卷素,如范德华力㊁氢键㊁疏水相互作用和离子交换等方式,通过生物富集作用对鱼类产生危害(图1)㊂范秀磊等[45]认为,MNPs吸附抗生素主要经过3个阶段㊂第1阶段,抗生素通过疏水分配作用和范德华力吸附在MNPs表面;第2阶段,抗生素缓慢地从表面扩散到MNPs内部;第3阶段,吸附达到平衡㊂目前已有关于不同类型的微塑料吸附各类抗生素的相关研究,详见表2㊂在MNPs吸附抗生素的过程中,氢键的形成发挥了重要的作用㊂抗生素中一些特定的官能团有助于氢键的生成,例如,聚酰胺(PA)的酰胺基(质子供体基团)和阿莫西林(AMX)㊁四环素(TC)和环丙沙星(CIP)的羰基(质子受体基团)之间可以形成氢键[43,46]㊂傅里叶红外光谱分析显示的3500cm-1和3100cm-1处的峰来源于分子间氢键的相互作用,被认为是CIP㊁左氧氟沙星和聚苯乙烯(PS)㊁聚氯乙烯(PVC)表1 抗生素在地表水体中的检出水平和种类Table1㊀The types and levels of antibiotics detected in surface waters类型Types地点Locations浓度/(ng㊃L-1)Concentration/(ng㊃L-1)抗生素种类Class参考文献References河流River中国渭河西安段Xi an Section of the Weihe River,ChinaND~270.6磺胺类㊁大环内酯类㊁喹诺酮类㊁四环素类Sulfonamides,macrolides,quinolones,tetracyclines[8]中国南四湖入湖河流Nansi Lake s inflowing rivers,ChinaND~694磺胺类㊁大环内酯类㊁喹诺酮类Sulfonamides,macrolides,quinolones[9]中国渤海湾入海河流Seaborne rivers of Bohai Bay,China178.89~229.80磺胺类㊁喹诺酮类㊁四环素类Sulfonamides,quinolones,tetracyclines[10]印度亚穆纳河River Yamuna,IndiaND~19460青霉素类㊁喹诺酮类㊁β-内酰胺类Penicillins,quinolones,β-lacams[11]湖泊Lake中国太湖Taihu Lake,ChinaND~36.472磺胺类㊁喹诺酮类㊁四环素类Sulfonamides,quinolones,tetracyclines[12]中国南四湖Nansi Lake,ChinaND~694磺胺类㊁大环内酯类㊁喹诺酮类㊁四环素类Sulfonamides,macrolides,quinolones,tetracyclines[9]中国东洞庭湖East Dongting Lake,ChinaND~843.49磺胺类㊁大环内酯类㊁喹诺酮类㊁四环素类Sulfonamides,macrolides,quinolones,tetracyclines[13]地表径流Surface runoff中国南京Nanjing,China1.958磺胺类㊁大环内酯类㊁四环素类㊁β-内酰胺类Sulfonamides,macrolides,tetracyclines,β-lactams[14]中国浙江Zhejiang,China508.7磺胺类㊁喹诺酮类㊁四环素类㊁氨霉素Sulfonamides,quinolones,tetracyclines,aminomycins[15]西班牙Spain1300磺胺类㊁大环内酯类㊁喹诺酮类Sulfonamides,macrolides,quinolones[16]水产养殖场Aquafarm中国固城湖蟹塘Crab ponds of Lake Guchenghu,China122~1440磺胺类㊁大环内酯类Sulfonamides,macrolides[17]中国江苏养殖场Aquafarm,Jiangsu,ChinaND~9600磺胺类㊁四环素类Sulfonamides,tetracyclines[18]葡萄牙北部Northern Portugal2.4~10喹诺酮类㊁四环素类Quinolones,tetracyclines[19]污水处理厂Sewage treatmentplant中国杭州Hangzhou,ChinaND~88磺胺类㊁大环内酯类Sulfonamides,macrolides[16]瑞典Sweden410喹诺酮类㊁大环内酯类Quinolones,macrolides[20]海洋Sea中国渤海湾沿海水域Coastal waters of Bohai Bay,China27.85~478.33磺胺类㊁喹诺酮类㊁四环素类Sulfonamides,quinolones,tetracyclines[10]注:ND表示未检出㊂Note:ND means not detected.第5期陈晨等:微(纳米)塑料和抗生素的相互作用及对鱼类的联合毒性效应研究进展59㊀图1 微(纳米)塑料和抗生素联合暴露对鱼类的毒性效应Fig.1㊀The toxicity effects on fish by the joint exposure of micro(nano)plastics and antibiotics之间通过氢键相连接的证据[47-48]㊂Yang 等[49]发现随着pH 值的升高,CIP 上的氢离子减少,并且在PS 上的吸附量降低,因此推测CIP 与PS 通过氢键吸附㊂同时,氢键也被证明是磺胺甲噁唑(SMX)在PA ㊁PS ㊁PVC ㊁聚乙烯(PE)㊁聚丙烯(PP)和聚对苯二甲酸乙二醇酯(PET)上吸附的主要机制[50]㊂大多数MNPs 具有丰富的烷基基团和较强的疏水性,由疏水相互作用主导吸附过程[51]㊂研究表明,疏水作用在一定程度上主导了AMX ㊁TC ㊁CIP ㊁甲氧苄氨嘧啶(TMP)㊁泰乐菌素(TYL)㊁SMX ㊁磺胺甲基嗪和磺胺嘧啶在MNPs 上的吸附,并且具有较高正辛醇-水分配系数(log K ow )的抗生素对MNPs 的亲和力更强[43,52-57]㊂PS 和TC 的结构中均具有苯环,因此二者主要通过疏水相互作用吸附在一起[58]㊂Fu 等[59]还发现老化后的PA ㊁PVC 和PET 可通过疏水相互作用吸附磺胺类抗生素㊂范德华力也是MNPs 吸附抗生素最常见的方式,主要由π-π和静电相互作用组成㊂例如PE 仅通过范德华力吸附CIP ㊁TMP 和磺胺嘧啶(SDZ),并且淡水系统中CIP 通过静电引力增加了在MNPs 表面的吸附能力[43];当pH<6时,PS 和聚丁二酸丁二醇酯(PBS)通过静电相互作用吸附诺氟沙星(NOR)[60];PA ㊁PE ㊁PVC ㊁PS 和PP 主要通过范德华力吸附SDZ [61]㊂在研究对CIP ㊁TMP 和SDZ 吸附机制时,研究者发现PS 能够同时利用非特异性范德华力和π-π相互作用,而PE 仅利用范德华力,从而导致PS 对于CIP ㊁TMP 和SDZ 具有较高的吸附能力[49,62]㊂Chen 等[63]的研究也证明TC 在PE 上的吸附主要是由范德华力和微孔填充机制控制㊂除此之外,土霉素(OTC)对PS 的吸附主要由阳离子交换机制主导[64]㊂PE 通过疏水和静电相互作用吸附CIP [65]㊂一些MNPs 能够同时通过氢键和π-π堆积作用吸附抗生素,形成稳定结合[66]㊂另外,Wu 等[67]提出了几个新的吸附机制㊂PVC 上的氯原子可以作为电子受体,苯环和双酚上的羟基可以作为电子供体,从而在PVC 和双酚之间形成卤素键[68]㊂因此,推测PVC 与含羟基和苯环的抗生素之间能够形成卤素键㊂烷基和芳香环之间的CH/π相互作用也可以驱动PE 和具有苯环的抗生素之间的吸附㊂由此可知,抗生素在MNPs 上的吸附受到多种机制的影响㊂MNPs 和抗生素的特定结构和性质会影响各种驱动力的贡献,导致吸附能力存在很大差异㊂因此,未来的研究可以集中研究吸附过程中各个机制的相对贡献㊂2.2㊀MNPs 吸附抗生素的影响因素抗生素在MNPs 上的吸附-解吸过程共同决定抗生素在MNPs 上的吸附量,从而影响抗生素在环境中的迁移㊁分布和富集㊂这一吸附-解吸过程主要受到抗生素性质㊁MNPs 类型和环境条件(如离子强度㊁pH 和其他污染物)的影响㊂60㊀生态毒理学报第18卷表2㊀微(纳米)塑料吸附抗生素的主要方式Table2㊀The main modes for the adsorption of antibiotics by micro(nano)plastics抗生素类型Types of antibiotics微(纳米)塑料类型Types of micro(nano)plastics吸附方式Adsorption modes参考文献References磺胺甲噁唑Sulfamethoxazole聚乳酸㊁聚丙烯Polylactic acid,polypropylene疏水相互作用或静电相互作用Hydrophobic interaction or electrostatic interaction[69]磺胺嘧啶Sulfadiazine聚酰胺㊁聚对苯二甲酸乙二醇酯㊁聚乙烯㊁聚氯乙烯㊁聚苯乙烯㊁聚丙烯Polyamide,polyethylene terephthalate,polyethylene,polyvinyl chloride,polystyrene,polypropylene范德华力和微孔填充Van der Waals forces and micropore filling[61]磺胺类抗生素Sulfonamides老化聚酰胺㊁聚氯乙烯Aged polyamide,polyvinyl chloride聚对苯二甲酸乙二醇酯Polyethylene terephthalate疏水相互作用Hydrophobic interaction[59]磺胺嘧啶㊁环丙沙星Sulfadiazine,ciprofloxacin聚乙烯Polyethylene静电相互作用Electrostatic interaction[43]环丙沙星Ciprofloxacin聚乙烯Polyethylene疏水相互作用和静电相互作用Hydrophobic interaction and electrostatic interaction[70]聚苯乙烯㊁聚氯乙烯Polystyrene,polyvinyl chloride疏水相互作用㊁π-π堆叠㊁静电相互作用和氢键Hydrophobic interaction,π-πstacking,electrostatic interaction and hydrogen bonds[71]诺氟沙星Norfloxacin聚苯乙烯㊁聚丁二酸丁二醇酯Polystyrene,polybutanediol succinate静电相互作用Electrostatic interaction[60]恩诺沙星㊁环丙沙星㊁诺氟沙星Enrofloxacin,ciprofloxacin,norfloxacin 聚丙烯㊁聚乙烯㊁聚氯乙烯Polypropylene,polyethylene,polyvinyl chloride疏水相互作用和静电相互作用Hydrophobic interaction and electrostatic interaction[52]土霉素Oxytetracycin聚苯乙烯Polystyrene离子交换Ion exchange[64]四环素Tetracycline聚苯乙烯Polystyrene疏水相互作用Hydrophobic interaction[60]四环素㊁环丙沙星Tetracycline,ciprofloxacin聚乳酸㊁聚氯乙烯Polylactic acid,polyvinyl chloride氢键㊁π-π堆叠和静电相互作用Hydrogen bonds,π-πstacking,and electrostatic interaction[72]四环素㊁金霉素㊁土霉素Tetracycline,aureomycin, oxytetracycin聚乙烯Polyethylene范德华力和微孔填充Van der Waals forces and micropore filling[63]阿奇霉素㊁克拉霉素Azithromycin,clarithromycin聚乳酸㊁聚苯乙烯Polylactic acid,polystyrene疏水相互作用Hydrophobic interaction[73]阿莫西林Amoxicillin聚乙烯㊁聚对苯二甲酸乙二醇酯㊁聚丙烯㊁聚苯乙烯㊁聚氯乙烯Polyethylene,polyethylene terephthalate,polypropylene,polystyrene,polyvinyl chloride静电相互作用Electrostatic interaction[74]阿莫西林㊁四环素㊁环丙沙星Amoxicillin,tetracycline, ciprofloxacin聚酰胺Polyamide氢键Hydrogen bonds[46]第5期陈晨等:微(纳米)塑料和抗生素的相互作用及对鱼类的联合毒性效应研究进展61㊀续表2抗生素类型Types of antibiotics微(纳米)塑料类型Types of micro(nano)plastics吸附方式Adsorption modes参考文献References磺胺嘧啶㊁阿莫西林㊁四环素㊁环丙沙星Sulfadiazine,amoxicillin, tetracycline,ciprofloxacin 聚乙烯㊁聚苯乙烯㊁聚酰胺㊁聚丙烯㊁聚氯乙烯Polyethylene,polystyrene,polyamide,polypropylene,polyvinyl chloride氢键Hydrogen bonds[43]磺胺硫唑㊁磺胺美嗪㊁磺胺甲噁唑㊁环丙沙星㊁恩诺沙星㊁氧氟沙星㊁诺氟沙星㊁四环素Sulfathiazole,sulfametizine, sulfamethoxazole, ciprofloxacin,ennofloxacin, ofloxacin,norfloxacin,tetracycline聚丙烯Polypropylene氢键和疏水相互作用(原始聚丙烯)氢键和静电相互作用(老化聚丙烯)Hydrogen bonds and hydrophobicinteraction(primary polypropylene)Hydrogen bonds and electrostaticinteraction(aging polypropylene)[75]2.2.1㊀抗生素的性质抗生素的疏水性以及与其疏水性相关的特性(log Kow 和电离常数p Ka)在吸附过程中发挥着重要作用[76]㊂郭梦函[77]研究了AMX㊁CIP和TC在MNPs上的吸附能力,发现吸附能力与抗生素的疏水性成正相关的关系㊂大多数MNPs富含烷基且疏水性较强,因此更倾向于吸附疏水性污染物[51]㊂Syranidou和Kalogerakis[78]的研究表明,具有较高log Kow值的抗生素对MNPs的亲和力更强,因为它们具有更强的疏水性㊂抗生素是可电离的化合物,其电离常数也会影响MNPs和抗生素之间的结合机制,尤其涉及到静电相互作用㊂抗生素的p Ka㊁介质的pH值和MNPs 的零电荷pH点(pHpzc)共同影响抗生素和MNPs之间的静电吸附过程[79]㊂根据抗生素的电离常数和结构,在不同的pH条件下抗生素会表现出不同的离子形态(两性离子㊁阳离子和阴离子),例如,在pH= 2和4时CIP主要是以阳离子形式存在[52]㊂Li等[43]研究了CIP在特定的pH条件下的离子形态,发现在pH为6.7~7.1时,CIP以两性离子㊁阴离子和阳离子的形式存在;而在pH为8.0时,CIP的主要存在形式为两性离子和阴离子㊂在这2种情况下,MNPs的pHpzc均小于环境pH值,呈现负电性㊂因此在pH为8.0时,MNPs和CIP之间的静电排斥作用增强,从而降低CIP的吸附水平㊂TC的p Ka2= 7.7,当pH<7.7时,TC主要以两性离子和阳离子形式存在,带负电的MNPs可通过静电作用吸附TC;当pH>7.7时,TC的主要存在形式为阴离子,由于与MNPs静电排斥,此时TC的吸附量大大降低[80]㊂除此之外,抗生素的极性也对MNPs-抗生素的吸附过程有影响,具有多个极性官能团的抗生素可以促进MNPs的吸附㊂例如,喹诺酮类抗生素具有较多的极性官能团如羧基㊁羟基等,易于与环境中的MNPs发生吸附作用;磺胺类抗生素仅有苯氨基和酰胺基,因此MNPs对其的吸附能力较弱[81]㊂2.2.2㊀MNPs的性质MNPs由于其具有比表面积大㊁疏水性强和流动性高的特点,在环境中可以积聚各种毒素和化学污染物,并作为远距离运输污染物的载体㊂MNPs 的性质,如极性㊁比表面积和结晶度等,对污染物的吸附能力有很大影响[82-83]㊂MNPs的官能团和极性在MNPs-抗生素的吸附过程中起主导作用㊂PS㊁PP和PE通常是非极性塑料,而PVC㊁PET和PA是极性的㊂例如,强极性聚合物PA对磺胺甲噁唑和磺胺甲嗪具有比PE更强的吸附能力,这是由于PA中的酰胺基团(质子供体基团)和抗生素结构中存在的羰基(质子受体基团)之间形成了氢键,从而增强了吸附作用[84]㊂同样地, Fu等[85]也发现由于形成了稳定的氢键,PA对SDZ㊁AMX㊁TC㊁CIP㊁TMP的吸附能力超过了PS㊂MNPs的比表面积越大,意味着吸附位点越多,因此可以吸附的污染物的量就越大㊂Li等[43]发现PS㊁PP,尤其是PA的孔隙结构较为发达,使得这3种MNPs对AMX㊁TC和CIP的吸附能力高于PE 和PVC㊂其次,对于特定类型的MNPs,尺寸较小的MNPs通常具有较大的比表面积,从而对TC具有较高的吸附能力㊂然而,MNPs的粒径并不总是与其比表面积成反比㊂PS(50nm)的实测比表面积(63.462㊀生态毒理学报第18卷m2㊃g-1)低于理论值114.3m2㊃g-1,这可能是由于PS 的团聚导致比表面积降低[86]㊂粒径大小仅在一定范围内影响MNPs的吸附能力,最终吸附的效果取决于比表面积㊂MNPs另一个影响吸附过程的特性是结晶度㊂结晶度是聚合物中结晶区域所占的比例,MNPs具有无定形和结晶区域,无定形区域由不规则排列的长链组成,结晶区域则由规则排列成几何晶格的链段构成[87-88]㊂有机污染物对无定形区域的亲和性大于结晶区域,说明MNPs的结晶度越低,其对有机污染物的吸附能力越强㊂Liu等[48]发现低结晶度PVC 对CIP的吸附能力显著高于PS㊂Gong等[89]研究报道在玻璃化转变温度下,聚丁二酸丁二醇酯(PBS)表现为橡胶状聚合物,而聚乳酸(PLA)表现为玻璃状聚合物㊂玻璃状聚合物PLA的分子链密集且交联,阻碍了有机污染物的移动㊂因此,PBS的吸附能力大于PLA㊂然而,关于MNPs的结晶度在抗生素吸附中的作用仍缺乏明确的结论㊂此外,老化作用也能够增加MNPs的吸附能力㊂其原因有多个方面,老化后MNPs颗粒碎裂从而导致比表面积增加,其表面含氧官能团增加也会导致MNPs极性和表面性质发生变化,以及MNPs的表面形成生物膜,可通过降低其疏水性来增强MNPs 的吸附能力[48,90]㊂Yu等[91]在我国东山湾的海鱼养殖场对5种微塑料进行原位老化,并探究其在海洋养殖环境中对抗生素的吸附情况及影响因素㊂通过现场的原位吸附实验,研究发现与PS㊁PP㊁PE㊁PVC 和PET相比,老化PP由于具有更发达的孔隙结构,因而对抗生素具有更高的吸附效率㊂2.2.3㊀环境因素离子强度在MNPs吸附抗生素的过程中发挥着重要的作用,其作用机理是通过影响双层膜的厚度和界面电位来控制吸附剂与吸附质表面之间的静电和非静电相互作用,从而影响两者的结合[92]㊂NaCl 是水环境中最常见的离子,随着NaCl浓度的升高,钠离子取代了MNPs表面酸性官能团中的氢离子,抑制了氢键的形成,使得MNPs对抗生素的吸附量显著下降[93-95]㊂然而一些阳离子,如Cr3+㊁Zn2+,与抗生素在MNPs表面具有金属桥连作用,反而促进了吸附作用[47,96]㊂pH值在一定程度上也决定了静电相互作用,从而影响抗生素在MNPs上的吸附㊂例如,Xue等[97]发现当pH值大于磺胺类抗生素的等电点时,一部分磺胺带负电,此时与带负电的MNPs之间存在静电排斥,导致吸附能力下降㊂Wang等[83]发现在低pH条件下,阴离子形式的全氟辛烷磺酸(PFOS)在PE上的吸附能力高于非离子形态的PFOS,并且PFOS在MNPs上的吸附量随着pH的升高而降低㊂在淡水和海水中,MNPs对抗生素的吸附能力也不尽相同㊂在pH范围为6.7~7.1的淡水中,抗生素的存在形式大多为两性离子和阴离子,但仍存在部分阳离子形式;海水的pH值比淡水更高,抗生素几乎都以两性离子和阴离子的形式存在,与携带负电荷的MNPs具有较高的静电斥力㊂因此与淡水相比,MNPs在海水中吸附抗生素的程度较低㊂Yang 等[49]认为,PS在海水中对CIP的吸附能力远低于在去离子水中的吸附能力,可能是因为海水中存在的许多离子加速了溶液环境中电子的流动㊂当水体中存在其他有机污染物和重金属时,会影响MNPs对抗生素的吸附㊂相较于抗生素,重金属离子通过离子交换更容易吸附到MNPs上[98-100]㊂因此当重金属与抗生素共存时,MNPs的大多数活性吸附位点被重金属离子填充,从而导致其吸附抗生素的能力受到限制㊂同时,重金属和MNPs之间的静电相互作用也会导致重金属被吸附,占据MNPs表面的吸附位置,从而降低MNPs对抗生素的吸附[101]㊂然而,多价金属离子又可以和抗生素的负电荷络合,在抗生素㊁金属离子和MNPs之间形成共价键,从而提高抗生素的吸附量[102]㊂由于表面活性剂会改变污染物的界面特性,因此当水体中存在表面活性剂时会影响MNPs对抗生素的吸附能力㊂例如,十二烷基苯磺酸钠(SDBS)能与PS和PE结合,提高PS和PE的表面电负性并且降低比表面积和孔隙率,使其在保持基本晶体结构的同时表面官能团略有改变,大大提高了PS和PE 对OTC和NOR的饱和吸附率㊂SDBS也会增强MNPs的亲水性,使其更易于吸附溶解在水中的抗生素[97]㊂腐殖质也会影响抗生素在MNPs上的吸附,例如,郭梦函[77]研究了3种抗生素(AMX㊁CIP和TC)在4种MNPs(PVC㊁PS㊁PP和PE)上的吸附情况,发现在不同浓度腐殖酸的条件下,3种抗生素在MNPs上的吸附能力先降低后升高㊂低浓度下3种抗生素在MNPs上的吸附量均呈现下降的趋势,这是因为腐殖质与抗生素竞争MNPs上的吸附位点,导致吸附量降低㊂而高浓度下腐殖质吸附到MNPs 上会形成包裹层,与抗生素发生阳离子π键和π-π给第5期陈晨等:微(纳米)塑料和抗生素的相互作用及对鱼类的联合毒性效应研究进展63㊀体受体作用,从而导致抗生素在MNPs上的吸附量增加㊂此外,当水体中存在蛋白质时,蛋白质会在老化MNPs上形成蛋白质电晕,从而加强对磺胺的吸附能力[59]㊂3㊀MNPs与抗生素联合暴露对鱼类的毒性(The joint toxicity of MNPs and antibiotics to fish)水体环境中大量的MNPs和抗生素会对水生生物产生毒性影响,造成严重的生态风险,并且还可能通过食物链转移和富集,从而威胁人类健康[103-105]㊂大量文献显示MNPs-抗生素的复合污染可能引起生物体分子组织㊁细胞和行为方面的改变,导致生物体的损伤[106],因此MNPs和抗生素联合毒性的研究势在必行㊂鱼类因其容易获得㊁实验室易饲养并且对毒物敏感的特征,常被用于水环境中污染物毒性的研究㊂已有大量文献报道了各类抗生素对斑马鱼的毒性,如表3所示㊂在生物体内,MNPs通过吸附抗生素并干扰代谢来增强抗生素的生物积累,但不能被水生生物摄取的大尺寸MNPs会降低抗生素的生物积累㊂由于抗生素在外部环境和生物体内与MNPs的吸附以及它们对同一生物靶标的作用, MNPs增强/缓解了抗生素对生物体的毒性㊂MNPs 和抗生素对鱼类的联合毒性主要表现在肠道㊁肝脏㊁神经㊁生殖和发育毒性等方面㊂3.1㊀对肠道的影响肠道是鱼类重要的消化和营养获取器官㊂鱼类是较低等的脊椎动物,消化能力弱,肠道干细胞分化成更多功能性细胞(如杯状细胞㊁淋巴细胞和柱状上皮细胞)来吸收营养或分泌消化液以应对外部刺激[129],并且肠道微生物群的干扰可导致宿主的生理功能障碍和某些疾病[130]㊂因此肠道受损会引起鱼类多种疾病的发生,增加健康受损的风险㊂表3㊀抗生素对斑马鱼的毒性Table3㊀The toxicity effects of antibiotics on zebrafish抗生素类型Class 抗生素种类Types暴露方式Exposure对斑马鱼的毒性Toxicity to zebrafish参考文献References四环素类Tetracyclines土霉素Oxytetracycline金霉素Chlorotetracycline四环素Tetracycline急性暴露Acute exposure胚胎孵化延迟,诱导氧化应激Embryo hatching was delayed and oxidative stress was caused[107]慢性暴露Chronic exposure探索行为㊁多动和冻结行为增加Exploration behavior,hyperactivity and freezing behavior were increased导致炎症反应,扰乱肠道菌群Inflammatory response was induced and gut flora were disrupted[108][108-110]慢性暴露Chronic exposure运动距离减少,认知行为下降,攻击行为增加Motor distance was decreased,cognitive behavior wasdecreased,and aggressive behavior was increased[111]急性暴露Acute exposure胚胎孵化延迟,体长变短,卵黄囊肿,游囊发育受阻,引起氧化应激及细胞凋亡Embryo hatching was delayed,body length became shorter,yolk cyst appeared,follicle development was blocked,and oxidative stress and cell apoptosis were induced[112]慢性暴露Chronic exposure肝脏脂质空泡化,肝脏代谢途径失调Liver lipid vacuolation and liver metabolic pathway disorders[113]β-内酰胺类β-lactams阿莫西林Amoxicillin头孢噻肟钠Cefotaxime sodium阿莫西林Amoxicillin头孢他啶Ceftazidime急性暴露Acute exposure慢性暴露Chronic exposure胚胎过早孵化Premature hatching of embryos[107]幼鱼体长变短Larvae became shorter in length[114]社交行为减少,引起氧化应激Social behavior was reduced,and oxidative stress was caused[115]运动距离增加,攻击行为加剧Movement distance was increased and aggressive behavior was intensified[111]。
褪黑素对碱性盐胁迫下猴樟呼吸代谢相关酶活性的影响朱育贤施诗岂子雁吴思诺王秋楠韩浩章*(宿迁学院建筑工程学院,江苏宿迁223800)摘要碱性盐环境影响植物的生长发育,褪黑素能有效缓解盐碱逆境对植物的伤害。
本研究以猴樟幼苗为材料,研究外源褪黑素处理对猴樟幼苗呼吸代谢相关酶活性的影响,以期为褪黑素处理提高植物耐碱性盐胁迫的机理研究提供依据。
结果表明,30~50μmol/L褪黑素处理明显提高碱性盐胁迫下猴樟幼苗中丙酮酸脱氢酶、柠檬酸合成酶、异柠檬酸脱氢酶、琥珀酸脱氢酶和苹果酸脱氢酶的活性,100~150μmol/L褪黑素处理对猴樟幼苗呼吸代谢相关酶活性的促进作用不明显。
适宜浓度褪黑素处理能通过促进呼吸代谢提高猴樟幼苗耐碱性盐胁迫能力。
关键词猴樟;褪黑素;碱性盐胁迫;呼吸代谢;酶活性中图分类号Q945;S792.23文献标识码A文章编号1007-5739(2023)24-0088-04DOI:10.3969/j.issn.1007-5739.2023.24.025开放科学(资源服务)标识码(OSID):Effects of Melatonin on Respiratory Metabolism Related Enzyme Activities ofCinnamomum bodinieri Under Alkaline Salt StressZHU Yuxian SHI Shi QI Ziyan WU Sinuo WANG Qiunan HAN Haozhang*(School of Architecture and Engineering,Suqian University,Suqian Jiangsu223800) Abstract Alkaline salt environment affects plant growth and development,and melatonin can effectively alleviate the damage of saline-alkali stress on plants.This study used Cinnamomum bodinieri seedlings as materials to investigate the effects of exogenous melatonin on respiratory metabolism related enzyme activities of Cinnamomum bodinieri,in order to provide a basis for the research on the mechanism of improving plant resistance to alkaline salt stress by mela-tonin treatment.The results showed that30-50μmol/L melatonin treatment significantly increased the activities of pyru-vate dehydrogenase,citrate synthetase,isocitrate dehydrogenase,succinate dehydrogenase and malate dehydrogenase of Cinnamomum bodinieri under alkaline salt stress.Melatonin treatment with100-150μmol/L didn't significantly promote the activity of respiratory metabolism related enzymes of Cinnamomum bodinieri.The appropriate concentration of mela-tonin can improve the alkaline salt tolerance of Cinnamomum bodinieri seedlings by promoting respiratory metabolism.Keywords Cinnamomum bodinieri;melatonin;alkaline salt stress;respiratory metabolism;enzyme activity土壤盐碱化是影响植物生长发育和限制作物产量的严峻问题,全世界约20%的灌溉农田存在不同程度的盐碱化,已超过地球陆地面积的7%[1]。
纳米氧化铁与氧化剂对多环芳烃污染农田土壤修复和蔬菜健康风险的影响*第一作者:周佳靖,女,1996年生,硕士研究生,主要从事土壤修复研究。
通讯作者。
*山东省自然科学基金资助项目(No.ZR2020MD107、No.ZR2017MC068)。
周佳靖1柳修楚1郭 瑾1陈小宇1柴超1葛 蔚(1青岛农业大学资源与环境学院,山东 青岛266109 &.青岛农业大学生命科学学院,山东 青岛266109%摘要采用纳米氧化铁和氧化剂(过硫酸钠、H .O 2)联合技术修复多环芳烃(PAHs )污染农田土壤,分析纳米氧化铁与氧化剂联合修复对小白菜(Brassica chinensis L.)生长、PAHs 富集的影响,并进行健康风险评估#结果表明:(1)纳米氧化铁(2.0 g/kg )和H .O.C g/kg )联合修复对土壤、小白菜中PAHs 的去除效果最好,土壤中PAHs 去除率可达32.9%,小白菜地下部和地上部PAHs去除率分别为38.8%和38.9% # $)纳米氧化铁和过硫酸钠联合修复对小白菜生长存在抑制作用# $)经纳米氧化铁(2.0 g/kg )单独修复或纳米氧化铁$.0 g/kg )和H 2O 2$ g/kg )联合修复后,小白菜地上部中PAHs 对青少年和女性老年人的潜在致癌风险不再 存在#关键词纳米氧化铁过硫酸钠H .O .多环芳烃修复风险DOI :1015985/ki1001-3865.2021.02.016Effects of nano-Fe 2 O 3 and oxidants on soil remediation and health risk of polycyclic aromatic hydrocarbon in vegetablefrom contaminated farmland ZHOU Jiajing 1 LIU Xiuchu 1 ,GUO Jin 1 , CHEN Xiaoyu 1 , CHAI Chao' , GE Wei 2.(1.College of Resources and Environment Qingdao Agricultural University Qingdao Shandong 266109 ; ..College ofLif#Sci#nc#s "QingdaoAgriculturalUniv#rsity "QingdaoShandong 266109)Abstract : Remediationofpolycyclicaromatichydrocarbons (PAHs )contaminatedfarmlandsoilbynano-ferric oxidecombined withoxidants (sodiumpersulfate "H 2O 2 )wasstudied.Thee f ectsofnano-ferricoxidecombinedwith oxidantonthegrowthandPAHsaccumulationofpakchoi (Bra s icachinensis L .)wereanalyzed andthehealthriskwasassessed.Theresultsshowedthat :(1)thecombinedremediationofnano-ferricoxide (2.0g /kg )and H 2O 2 (2g/kg ) had the best effect on the removal of PAHs in soil and pakchoi. The removal rate of PAHs in soil was 32.9 % , and the reduction rates of PAHs in the underground and aboveground parts of pakchoi were 38. 8 % and 38. 9 % , respecively. (2) The combined remediaEion ofnano-ferric oxideand sodium persulfaEe inhibi edEhe growEh of pakchoi. (3) AfEernano-ferricoxide (2.0g /kg ) aloneornano-ferricoxide (2.0g /kg ) combinedwiEhH 2O 2 (2g /kg )"EherewasnoEhepoEenialcarcinogenicriskofPAHsinEheabovegroundparEsofpakchoiEoEeen-agersandfemaleseniors.Keywords : nano-ferric oxide ; sodium persulfate ; H2O2; polycyclic aromatic hydrocarbons ; remediation ; risk多环芳烃(PAHs )是环境中最普遍的有机污染物 之一,-,具有较高的遗传毒性与致癌性⑵。
'f e知库环境工程学报第15卷第2期2021年2月Vol. 15, No.2 Feb. 2021Eco-Environmental Knowledge Web Chinese Journal of Environmental Engineering^(010) 62941074文章栏目:土壤污染防治001l〇12030/j.cjee.202003018 中图分类号X523 文献标识码A吕言臣,李明,章长松,等.纳米零价铁协同Fe( II)活化过碳酸钠降解含吐温-80水体中的三氯乙烯[J].环境工程学报,2021, 15(2): 688-698.LYU Yanchen, LI Ming, ZHANG Changsong, et al. Degradation o f trichloroethylene in aqueous solution containing surfactant Tween-80 by nanoscale zero-valent iron and Fe( I I) synergistically activating sodium percarbonate[J]. Chinese Journal o f Environmental Engineering, 2021, 15(2): 688-698.纳米零价铁协同Fe(n)活化过碳酸钠降解含吐 温-80水体中的三氯乙烯吕言臣\李明\章长松2,吕树光〃1. 华东理T.大学资源与环境工程学院,国家环境保护化X过程环境风险评价与控制重点实验室,上海2002372.上海亚新建设工程有限公司,上海200436第一作者:吕言臣(1995—),男,硕士研究生。
研究方向:土壤与地下水修复。
E-mail: ******************通信作#:吕树光(1965—),男,博士,教授。
研究方向:土壤与地下水修复。
E-mail: ********************.cn摘要在表面活性剂吐温-80(Tween-80)存在下,采用纳米零价铁(n Z V l)协同Fe( II)共同活化过碳酸钠(SPC)体系去除污染场地水相中的三氯乙烯(TCE),验证了SPC/Fe(丨丨>/nZVI体系降解TCE的有效性,探究了Tween-80浓度、无机阴离子以及溶液初始p H对TCE降解效果的影响,并确定了该体系中活性氧自由基的类型。
第 43 卷第 8 期2023年 8 月Vol.43 No.8Aug.,2023工业水处理Industrial Water Treatment DOI :10.19965/ki.iwt.2022-0855碳化ZIF-67催化过硫酸盐降解水中的甲基橙陈晴空1,2,雷翼妃1,2,陈治君1,2,王欢1,2,范剑平3,李姗泽4,王殿常5(1.重庆交通大学 环境水利工程重庆市工程实验室,重庆 400074;2.重庆交通大学 水利水运工程教育部重点实验室,重庆 400074;3.重庆文理学院 环境材料与修复技术重庆市重点实验室,重庆 402160;4.中国水利水电科学研究院 流域水循环模拟与调控国家重点实验室,北京 100038;5.长江生态环保集团有限公司,湖北武汉 430062)[ 摘要 ] 通过溶剂热法制备了ZIF-67,并碳化生成ZIF-67(C )。
利用红外光谱、BET 比表面积测试、Zeta 电位、X 射线衍射和X 射线光电子能谱等对ZIF-67(C )进行表征。
以甲基橙(MO )降解实验验证了ZIF-67(C )对过一硫酸氢钾(PMS )的催化作用,鉴定了反应中的主要活性物种是硫酸根自由基(SO 4·-),讨论了金属与有机配体物质的量之比、溶剂种类和煅烧温度(T )以及MO 初始浓度、反应初始pH 、ZIF-67(C ))投加量和PMS 投加量对ZIF-67(C )活化PMS 降解MO 的影响。
结果表明:与ZIF-67比,ZIF-67(C )不仅有较好的吸附性能,且对PMS 的催化能力更强。
当制备条件为n (Co 2+)∶n (2-MIM )=1∶8、甲醇为溶剂、T =500 ℃时,ZIF-67(C )表现出最优的PMS 催化性能;当MO 初始质量浓度为10 mg/L ,ZIF-67(C )投加质量浓度为0.2 g/L ,PMS 投加质量浓度为0.2 g/L 时,1 h 内MO 的去除率达93.7%。
中国环境科学 2020,40(2):647~652 China Environmental Science 过一硫酸盐碱催化处理染料废水翟俊1*,柳沛松1,赵聚姣1(重庆大学环境与生态学院,三峡库区生态环境教育部重点实验室,重庆 400045)摘要:利用PMS碱催化法处理亚甲基蓝、酸性橙7(AO7)和罗丹明B(RhB)3种典型染料,优化了脱色条件并分析了机理.在pH=10.8~11.5(亚甲基蓝)或pH=10.0~10.8(酸性橙7或罗丹明B),PMS投加量100mg/L的最优条件下,亚甲基蓝、酸性橙7和罗丹明B的脱色速率常数可分别达到0.097,0.074,0.004min-1,脱色率可分别达到95.1%,93.3%和30.1%.捕获剂实验证实PMS碱催化脱色3种染料时起主要作用的均是单线态氧.基于紫外-可见全波长光谱的结果推测,亚甲基蓝和酸性橙7反应脱色较快可归因于单线态氧对噻嗪生色基团和偶氮键的攻击更有效率.关键词:染料废水;过一硫酸盐(PMS);碱催化中图分类号:X703 文献标识码:A 文章编号:1000-6923(2020)02-0647-06Treatment of dye wastewater by base catalysis of peroxymonosulfate (PMS). ZHAI Jun1*, LIU Pei-song1, ZHAO Ju-jiao1 (1.Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment, College of Environment and Ecology, Chongqing University, Chongqing 400045, China). China Environmental Science, 2020,40(2):647~652Abstract:Three typical dyes, methylene blue, acid orange 7, and rhodamine B were treated by base catalysis of PMS in this study to investigate the optimal degradation conditions and the mechanism. Under the optimal condition (pH=10.8~11.5(methylene blue) or pH=10.0~10.8(acid orange 7 or rhodamine B), PMS dosage=100mg/L), the decolorization rate constants of methylene blue, acid orange 7 and rhodamine B were 0.097, 0.074, and 0.004min-1, respectively, and the decolorization efficiency were 95.1%, 93.3%, and 30.1%, respectively. The scavenging tests indicated that singlet oxygen played a critical role in the treatment by PMS/base for all of the three dyes. Based on the results of UV-Vis spectra analysis, it could be speculated that the faster decolorization rates of methylene blue and acid orange 7 could be due to the more efficient oxidation of the thiazide chromophore group and the azo bond by singlet oxygen.Key words:dye wastewater;peroxymonosulfate (PMS);base catalysis我国是染料生产大国,产量可达全球的65%以上[1],这也导致我国染料废水污染问题尤为严峻.染料种类繁多且具有生物毒性,传统的生物法难以对其进行有效处理.利用强氧化性自由基处理污染物的高级氧化技术在处理染料废水方面受到了广泛的关注,如芬顿法已经被用于处理酸性品红和丽春红等染料,显示出了优异的效果[2-3].但传统芬顿法具有适用pH值范围窄(pH=3~6)且产生大量铁泥的缺点,严重限制了其进一步应用[4].过一硫酸盐(PMS)法作为一种类芬顿技术近年来日益受到重视.PMS可在较宽pH值范围内产生强氧化性的硫酸根自由基(2.5~3.1eV),能够实现对有机染料的快速降解[5].如徐鹏飞等[6]通过紫外活化光催化剂过硫酸盐对废水中的甲基橙染料进行降解,在pH=9条件下反应90min,降解率达到87.6%.刘贝贝[7]利用Co2+催化PMS降解罗丹明B,反应1min,去除率达到100%.Huang等[8]用Co2+催化PMS降解双酚A, TOC的去除率可达40%.然而,现有研究大多依靠外部能量(紫外光)或可能导致二次污染的催化剂进行激活,限制了技术的应用前景.研究表明,PMS在碱性条件下无需催化剂和外部能量就可以发生自身活化过程,实现对污染物的降解[9-10].这种PMS碱催化技术避免了上述现有PMS活化技术的缺点,有广阔的潜在前景.但在染料废水处理方面,该技术仍处于初步阶段.由于染料种类繁多,不同类型染料在氧化处理时其反应过程会有所差异,因此了解PMS碱催化对多种染料的处理效果具有重要意义,而相关的研究仍未见报道.本研究选择了噻嗪类阳离子型染料亚甲基蓝、氧杂蒽类阳离子染料罗丹明B(RhB)、偶氮类阴离子型染料酸性橙7(AO7)3种染料的模拟废水作为处理对象,考察了PMS碱催化方法对其的处理效果,收稿日期:2019-06-24基金项目:重庆市社会事业与民生保障科技创新专项重点研发项目(csct2017shms-zdyfX0050)* 责任作者, 教授, zhaijun@648 中国环境科学 40卷优化了脱色条件并分析了pH值、PMS投加量、温度等因素的影响,阐明了反应过程中的自由基机理并对脱色途径进行了分析.研究成果有望提高对于PMS碱催化过程的认识深度并为该技术在染料废水处理方向的潜在应用提供理论参考.1材料与方法1.1 主要试剂与仪器主要试剂:过硫酸氢钾,纯度≥47%,购于上海阿拉丁生化科技股份有限公司;L-组氨酸,纯度≥98.5%,购于成都市科隆化学品有限公司;其他使用的化学品试剂均为分析纯.主要仪器:紫外分光光度计(型号:UV-2550)、pH 计(型号:PHS-3C)、恒温磁力搅拌器(型号:85-2A)、顺磁共振波谱仪ESR/EPR(型号:布鲁克a300).1.2 PMS碱催化处理染料废水实验1.2.1 pH值对PMS碱催化的影响实验在250mL烧杯中进行,反应总体系为100mL,亚甲基蓝浓度为50mg/L.用NaOH溶液调节反应体系pH值到指定值,稳定后加入有效浓度为100mg/L的PMS,反应开始.由于PMS为酸性,在PMS加入后需立即用NaOH溶液将反应体系pH值调回原设定的pH 值,避免对碱催化造成影响.反应过程中控制反应体系温度为25℃,转速为400r/min.在不同时间点取样测量反应体系中亚甲基蓝浓度的变化情况,研究pH值对PMS碱催化的影响,确定反应最佳pH值.为排除pH值对染料显色的影响,实验在不同pH值下分别作了标线.1.2.2 PMS投加量的影响控制反应温度25℃,转速为400r/min,在之前确定的最佳pH值下,投加指定量的PMS,进行上述反应,同时不投加PMS,进行上述反应,作为空白实验,研究PMS投加量对反应的影响,确定最佳PMS投加量.1.2.3温度对PMS碱催化的影响控制转速为400r/min,在确定的最佳pH值与PMS投加量下,调节反应体系到指定温度后进行上述反应,研究温度对PMS碱催化的影响,确定反应活化能.1.2.4对多种染料的处理效果采用与上述实验相同方法,在最佳PMS投加量下,控制反应温度25℃,转速为400r/min,调节反应体系到指定pH值,分别研究PMS碱催化对酸性橙7与罗丹明B的脱色效果,各染料浓度均为50mg/L.同时在最佳pH值下,不投加PMS,进行上述反应,作为空白实验,研究单独pH值对酸性橙7和罗丹明B显色的影响.1.2.5自由基捕获实验在之前得到的最佳反应条件下分别对亚甲基蓝、酸性橙7、罗丹明B进行上述反应.反应前分别向反应体系中加入浓度为0.4mol/L的乙醇、0.4mol/L的叔丁醇、50mmol/L的L-组氨酸作自由基抑制剂,研究PMS碱催化反应中主要起作用的自由基,同时在最佳pH值条件和最佳PMS投加量下,进行电子顺磁共振(EPR)检测.1.2.6脱色途径分析在之前得到的最佳反应条件下分别对亚甲基蓝、酸性橙7、罗丹明B进行上述反应.对反应前后的混合溶液进行紫外分光光度计的全波段扫描,根据反应前后UV-Vis谱图变化,研究各污染物的脱色途径.2结果与讨论2.1pH值对PMS碱催化效果的影响0102030 40 5060 00.20.40.60.81.0C/C时间(min)图1 亚甲基蓝在不同pH值下的脱色效果Fig.1 Decolorization efficiency of methylene blue at differentpH values如图1所示,不同pH值下,亚甲基蓝的脱色均符合一级动力学模型.随着初始pH值从7.0提高11.5,反应的速率逐渐上升,60min反应对亚甲基蓝的脱色率从25.5%提高至96.8%,在pH=10.8时反应速率常数可达0.097min-1.当pH值从10.8增加到11.5时,反应效果提升并不明显,且当pH=13时反应速率反而出现下降.过高pH值导致效率下降2期翟 俊等:过一硫酸盐碱催化处理染料废水 649的原因是高浓度的OH -会导致PMS 自分解为SO 42-和O 2.基于此可以确认最佳脱色的pH 值条件为10.8~11.5,这一结论也与文献处理其他污染物的报道相一致[9-10].2.2 PMS 投加量的影响在pH=10.8,亚甲基蓝初始浓度50mg/L,反应体系温度为25℃的条件下,向反应体系中分别加入浓度为0,50,100,125mg/L 的PMS,结果如图2所示.在不加入PMS,单独的高pH 值环境下,亚甲基蓝脱色率仅为9.9%,仅在加入PMS 后出现明显的脱色现象.在不同PMS 浓度下,亚甲基蓝的脱色均符合一级动力学模型.当PMS 浓度从50mg/L 增大到100mg/L 时,动力学常数从0.043min-1增大到0.097min -1,60min 时亚甲基蓝脱色率可达95.1%.而进一步提高浓度至125mg/L 时,动力学仅有微弱提高(达到0.115min -1).考虑到PMS 利用效率,故确定PMS 最佳投加量为100mg/L.0 10 20 3040 50 60C /C 0时间(min)图2 亚甲基蓝在不同PMS 投加量下的脱色效果 Fig.2 Decolorization efficiency of methylene blue at differentPMS dosages2.3 温度对碱催化的影响在pH=10.8,亚甲基蓝初始浓度50mg/L,PMS 投加浓度为100mg/L 的条件下,将反应体系温度分别调节至25,34,42℃后开始反应,一级反应速率常数分别为0.097,0.119,0.140min -1,反应速率随温度的提升而加快,实验结果如图3所示.进一步根据阿伦乌斯方程计算了反应所需活化能,如下式所示:ln ln aE k A RT=−(1) 式中:R 为通用气体常数(8.314kJ/(mol ·K)).将ln k 和1/T 进行线性拟合,根据斜率可得到碱催化PMS 脱色亚甲基蓝的反应活化能为16.79Kj /mol.102030 40 506000.20.40.60.81.0C /C 0时间(min)图3 亚甲基蓝在不同温度下的脱色效果Fig.3 Decolorization efficiency of methylene blue at differenttemperatures2.4 对多种染料的处理效果在相同的优化条件下分别处理50mg/L 酸性橙7及50mg/L 罗丹明B 模拟废水,结果如图4(a)、4(b)所示.PMS 碱催化反应对酸性橙7和罗丹明B 都有一定的脱色效果,随着pH 值的升高,反应速率先增大后减小,在pH=10.0~10.8时达到最大,这与脱色亚甲基蓝时的情况基本相同.反应60min,酸性橙7的脱色率最高可达到93.3%,反应速率常数为0.074min -1;反应120min,罗丹明B 的脱色率最高可达到30.1%,反应速率常数为0.004min -1.0102030 40 50600.20.40.60.81.0C /C 0时间(min)650中 国 环 境 科 学 40卷0 15 30 45 60 75 90 105120C /C 0时间(min)图4 PMS 碱催化对酸性橙7(a)和罗丹明B(b)的脱色效果 Fig.4Decolorization of acid orange 7 (a) and rhodamine B (b)by base catalysis of PMS研究同时考察了最佳pH 值条件对酸性橙7和罗丹明B 显色的影响,如图5所示.观察到的现象与脱色亚甲基蓝时相似,在单独的高pH 值环境下,染料几乎不出现脱色.仅在同时加入PMS 后出现明显的脱色现象.0 10 20 3040 50 60C /C 0时间(min)图5 高pH 值对酸性橙7和罗丹明B 显色的影响 Fig.5 Effect of high pH value on the coloration of acid orange7 and rhodamine B对比可知,在3种染料的脱色中,PMS 碱催化对亚甲基蓝的脱色速率最快,对罗丹明B 的脱色速率较慢.PMS 的激活是自由基过程,罗丹明B 为氧杂蒽类染料,酸性橙7为偶氮类染料,亚甲基蓝为噻嗪类染料.因此,推断脱色速率差异可能是由于3种染料的化学结构不同影响了它们被自由基氧化的效率. 2.5 自由基捕获实验为确定在PMS 碱催化中起主要作用的自由基种类进行了捕获剂实验,结果如图6(a)所示.102030 40 506000.20.40.60.81.0C /C 0102030 40 506000.20.40.60.81.0C /C 0153045 60 75900.60.81.0C /C 0时间(min)图6 PMS 碱催化脱色亚甲基蓝、酸性橙7和罗丹明B 的自由基捕获实验Fig.6 Free radical trapping experiment during decolorization of methylene blue, acid orange 7 and rhodamine B by basecatalysis of PMS硫酸根自由基和羟基自由基通常被认为是活化PMS 过程中产生的主要自由基.叔丁醇是常用的羟基自由基捕获剂( k OH ·=3.8~7.6×108M -1·s -1)[11-12];乙醇是常用的硫酸根自由基和羟基自由基捕获剂(k SO4·=1.6~7.7×107M -1·s -1,k OH·=1.2~2.8×107M -12期翟 俊等:过一硫酸盐碱催化处理染料废水 651·s -1)[10].然而通过实验发现,乙醇和叔丁醇的存在对亚甲基蓝脱色的影响基本可忽略不计,表明硫酸根自由基与羟基自由基并不在PMS 碱催化体系中起主要作用.L -组氨酸为常用的单线态氧捕获剂[13],实验表明L -组氨酸的存在对PMS 碱催化脱色亚甲基蓝有明显的抑制作用,且L -组氨酸的投加量越大,反应的抑制越明显.当L -组氨酸的浓度为50mmol/L 时,反应60min,亚甲基蓝的脱色率仅为9.4%.对PMS 碱催化脱色酸性橙7和罗丹明B 进行自由基捕获实验所得结果也基本相同,如图6(b),6(c)所示.这些结果表明,在PMS 碱催化处理这3种染料的过程中,主要起作用的是单线态氧.单线态氧能与捕获剂4-氨基-2,2,6,6-四甲基哌啶(TEMP)形成稳定的TEMPO 自由基, TEMP O 具有顺磁性能够被EPR 探测到信号.在最佳pH 值和最佳PMS 投加量下,加入0.6mmol/L 的TEMP,测定EPR 图谱(图7). TEMPO 的1:1:1三重峰信号特征也进一步表明反应体系中存在单线态氧[9].3460 3480 3500 3520 3540 3560强度(a .u .)磁场(G)图7 最佳pH 值和最佳PMS 投加量条件下的EPR 谱图 Fig.7 EPR spectrum at optimal pH value and optimal PMSdosage2.6 脱色途径分析利用UV -Vis 全波长扫描考察了亚甲基蓝、酸性橙7和罗丹明B 在PMS 碱催化脱色过程中的结构变化.亚甲基蓝的结果如图8(a)所示,对应于亚甲基蓝的噻嗪生色基团在665nm 处的吸收峰在反应60min 后明显减弱,对应于芳烃和多环芳烃类的245和292nm 等波长处的吸收峰也有所下降[14],说明在脱色中破坏的是亚甲基蓝的噻嗪生色集团、芳烃与多环芳烃结构.200400 600 8000.51.01.52.02.5吸光度t =0min t =60min(a) 亚甲基蓝200400 600 8000.51.01.52.02.53.0吸光度t =0min t =60min(b) 酸性橙7200400 600 8000.51.01.5吸光度波长(nm)t =0min t =120min(c) 罗丹明B图8 亚甲基蓝、酸性橙7和罗丹明B 脱色前后紫外可见吸收光谱变化Fig.8 Variation of UV -visible absorption spectra before andafter decolorization of methylene blue, acid orange 7 andrhodamine B偶氮染料酸性橙7脱色前后的紫外可见吸收光谱如图8(b)所示,在484nm 处的吸收峰对应酸性橙7的偶氮键,229和311nm 的吸收峰分别对应酸性橙7的苯环和萘环[15].在反应60min 后,484nm 处偶氮的吸收峰几乎消失,229和311nm 处苯环和萘环的吸收峰也均有下降,说明在脱色过程中,偶氮键、萘环和苯环均发生破坏.罗丹明B 的脱色主要通过N -位脱乙基作用和生色基团共轭结构的破坏[16].罗丹明B 脱色前后的紫外吸收光谱如图8(c)所示,罗丹明B 位于的554nm 处的吸收峰对应于共轭结构中的C =N 和C =O 结652 中国环境科学 40卷构,259nm处的吸收峰对应于罗丹明B的苯环结构.在反应120min后554和259nm处的吸收峰都有所降低,但并不显著.基于自由基捕获实验与以上脱色过程分析,推测PMS碱催化对3种染料脱色速率差异可归结于单线态氧氧化不同结构染料的效率有所不同.PMS 碱催化脱色亚甲基蓝和酸性橙7更快,可能原因是单线态氧对噻嗪生色基团和偶氮键的攻击更有效率.这一点也见于其他研究的报道[17],在氮掺杂污泥碳活化PMS和丙酮活化PMS以单线态氧为主的氧化体系中,亚甲基蓝与酸性橙7也均能够被有效降解,说明单线态氧在亚甲基蓝与酸性橙7的降解中起重要作用.而单线态氧对C=O键等共轭结构的攻击效率较低导致了其脱色罗丹明B速度较慢.3结论3.1PMS碱催化可以有效处理多种染料废水,脱色亚甲基蓝时反应适合的pH值范围为10.8~11.5,脱色罗丹明B或酸性橙7时为10.0~10.8.在最优反应条件下亚甲基蓝、酸性橙7、罗丹明B的脱色速率常数分别可达0.097,0.074,0.004min-1,具有良好发展前景. PMS碱催化对不同种类染料脱色速率存在显著差异,亚甲基蓝和酸性橙7脱色较快而罗丹明B脱色较慢.3.2 3种染料的脱色过程中,PMS自催化产生的单线态氧均起主要作用.其中亚甲基蓝和酸性橙7脱色较快可以归因于单线态氧对噻嗪生色基团和偶氮键的攻击更有效率.参考文献:[1] 周宁,宇秉勇,宋红,等.染料工业废水产污情况分析 [J]. 染料与染色, 2018,55(1):54-61.Zhou N, Yu B Y, Song H, et al. Analysis on the pollution of dye Industrial wastewater [J]. Dyestuffs and Coloration, 2018,55(1):54-61.[2] 覃思月.Fenton体系处理染料废水耦合铁的回收与资源化研究 [D].杭州:杭州电子科技大学, 2018.Qin S Y. Study on the dye wastewater treatment by Fenton system and iron recycling and resource utilization [D]. Hangzhou: Hangzhou Dianzi University, 2018.[3] 陈文才. Fenton氧化法处理丽春红2R废水及其动力学研究 [D]. 南京:南京农业大学, 2014.Chen W C. Ponceau 2R wastewater degradation with Fenton oxidation and its kinetic study [D]. Nanjing: Nanjing Agricultural University, 2014. [4] 严梅,张青,谢慧芳,等.纳米Fe3O4负载聚苯胺对染料的协同催化降解 [J]. 中国环境科学, 2017,37(4):1394-1400.Yan M, Zhang Q, Xie H F, et al. Load of PANI on nano-Fe3O4 and synergy catalytic degradation of dyes [J]. China EnvironmentalScience, 2017,37(4):1394-1400.[5] 黄振夫.非均相钴催化剂活化PMS降解染料的研究 [D]. 杭州:浙江理工大学, 2016.Huang Z F. Heterogeneous cobalt catalysts for dye degradation based on PMS activation [D]. Hangzhou: Zhejiang Sci-Tech University, 2016.[6] 徐朋飞,郭怡秦,王光辉,等.紫外活化过硫酸盐对甲基橙脱色处理实验研究 [J]. 环境工程, 2017,35(11):58-61+89.Xu P F, Guo Y Q, Wang G H, et al. Experimental study on UV- activated persulfate for decolorization of methyl orange wastewater [J].Environmental Engineering, 2017,35(11):58-61+ 89.[7] 刘贝贝. Co/PMS体系降解染料废水 [D]. 郑州:河南科技大学, 2018.Liu B B. Degradation of dyeingwaster by Co/PMS system [D].Zhengzhou:Henan University of Science and Technology, 2018.[8] Huang Y F, Huang Y H. Behavioral evidence of the dominant radicalsand intermediates involved in Bisphenol A degradation using an efficient Co2+/PMS oxidation process [J]. Journal of Hazardous Materials, 2009,167(1-3):418-426.[9] Qi C D, Liu X T, Ma J, et al. Activation of peroxymonosulfate by base:I mplications for the degradation of organic pollutants [J].Chemosphere, 2016,151:280-288.[10] Nie M H, Deng Y W, Nie S H, et al. Simultaneous removal ofbisphenol A and phosphate from water by peroxymonosulfate combined with calcium hydroxide [J]. Chemical Engineering Journal.2019,369:35-45.[11] Neta P, Huie R E, Ross A B, Rate constants for reactions of inorganicradicals in aqueous solution [J]. Journal of Physical and Chemical, Reference Data, 1988,17(3):1027-1284.[12] Wang X, Dong W, Brigante M, et al. Hydroxyl and sulfate radicalsactivated by Fe(I I I)-EDDS/UV: comparison of their degradation efficiencies and influence of critical parameters [J]. Applied Catalysis B: Environmental, 2019,245:271-278.[13] Dai D J, Yang Z Y, Yao Y Y, et al. Highly efficient removal of organiccontaminants based on peroxymonosulfate activation by iron phthalocyanine: mechanism and the bicarbonate ion enhancement effect [J]. Catal. Sci. Technol., 2017,7:934–942.[14] 颜桂炀.ZnS/AIPO-5复合材料光催化降解亚甲基蓝 [C]//中国化学会分子筛专业委员会.第14次全国分子筛学术年会论文集——微孔介孔材料科学及在新能源与节能、减排中的应用.中国化学会分子筛专业委员会:中国化学会, 2008:5.Yan G Y. Photocatalytic degradation of methylene blue over ZnS/AIPO-5composite [C]//CZA 2008: 14th annual symposium on energy and emission related MMM science. Chinese Zeolite Association: Chinese Chemical Society, 2008:5.[15] 程金苹.三维电极法处理酸性橙7(AO7)模拟染料废水的研究 [D].上海:华东师范大学, 2017.Cheng J P. Treatment of acid orange 7 (AO7) simulated dye wastewater by three-dimensional electrode method [D]. Shanghai: East China Normal University, 2017.[16] 田东凡,王玉如,宋薇,等.UV/PMS降解水中罗丹明B的动力学及反应机理 [J]. 环境科学学报, 2018,38(5):1868-1876.Tian D F, Wang Y R, Song W, et al. Degradation of rhodamine B in aqueous solution by UV/PMS system: kinetics and reaction mechanism [J]. Acta Scientiae Circumstantiae, 2018,38(5):1868-1876.[17] Hu W R, Xie Y, Lu S, et al. One-step synthesis of nitrogen-dopedsludge carbon as a bifunctional material for the adsorption and catalytic oxidation of organic pollutants [J]. Science of The Total Environment, 2019,680:51-60.作者简介:翟俊(1977-),男,江苏溧阳人,教授,博士,从事废水处理理论与技术研究.发表论文100余篇.。
化工进展Chemical Industry and Engineering Progress2022年第41卷第8期过渡金属单原子催化剂活化H 2O 2/PMS/PDS 降解有机污染物的研究进展段毅,邹烨,周书葵,杨柳(南华大学土木工程学院,湖南衡阳421001)摘要:单原子催化剂(SACs )是一种将金属以原子态负载于载体上的新型材料,具有原子利用率高、催化活性强和易回收等优点,使其在催化降解有机污染物方面备受关注。
本文介绍了SACs 的催化影响因素,总结了SACs 催化降解有机污染物在环境领域中的应用。
此外,着重综述了不同过渡金属(Fe 、Co 、Mn 、Cu 等)单原子催化剂在基于双氧水或过硫酸盐的高级氧化技术中的催化机理,单原子金属(M )一般与N 键合形成活性位点M —N x ,活化氧化剂生成自由基或单线态氧,高效降解有机污染物。
最后,提出未来SACs 在催化降解有机污染物的研究方向是合成金属负载量高、稳定性高、pH 适用范围更广的SACs ,以及根据SACs 的结构-性能关系和催化机理,对目标污染物设计特定催化剂。
关键词:单原子催化剂;高级氧化;降解;有机污染物;机理中图分类号:TH3文献标志码:A文章编号:1000-6613(2022)08-4147-12Progress in the degradation of organic pollutants by H 2O 2/PMS/PDSactivated by transition metal single-atom catalystsDUAN Yi ,ZOU Ye ,ZHOU Shukui ,YANG Liu(School of Civil Engineering,University of South China,Hengyang 421001,Hunan,China)Abstract:Single-atom catalysts (SACs)are a new type of material that can load metal on the carrier in atomic state.They have the advantages of high atom utilization,strong catalytic activity and easy recovery,so they have attracted much attention in the catalytic degradation of organic pollution.In this work,the influencing factors of SACs were introduced,and the applications of SACs in environmental field for catalytic degradation of organic pollutants are summarized.In addition,the catalytic mechanisms of SACs of different transition metals (Fe,Co,Mn,Cu,etc .)in advanced oxidation technology based on hydrogen peroxide or persulfate are reviewed.Single-atom metal (M)generally bonds with N to form the active site M —N x ,which activates the oxidant to generate radicals or singlet oxygen,and effectively degrades organic pollutants.Finally,the research directions of SACs on the catalytic degradation of organic pollutants are the preparation of SACs of high metal loading,high stability and wide range of pH,and the design of specific catalysts for different target pollutants according to the structure-performance relationship and catalytic mechanisms of SACs.Keywords:single-atom catalysts;advanced oxidation process;degradation;organic pollutant;mechanism综述与专论DOI :10.16085/j.issn.1000-6613.2021-2140收稿日期:2021-10-18;修改稿日期:2022-01-14。
2015年9月 CIESC Journal ·3319·September 2015第66卷 第9期 化 工 学 报 V ol.66 No.9湿式催化过氧化氢氧化技术综述罗磊1,代成义1,张安峰1,宋春山2,郭新闻1(1大连理工大学化工学院,辽宁 大连 116024;2宾夕法尼亚州立大学,美国 宾夕法尼亚州 16802) 摘要:湿式催化过氧化氢氧化技术(CWPO )是一种高效处理难降解有毒有害废水的技术,具有反应条件温和、经济环保、无须外能辅助等优点,在印染、农药、医药等领域具有很好的应用前景和极大的推广价值。
综述了湿式催化过氧化氢氧化技术的反应机理、催化剂选择及催化剂活性和稳定性问题解决的途径。
关键词:Fenton 反应;Fe ;催化氧化;活性;稳定性 DOI :10.11949/j.issn.0438-1157.20150927中图分类号:X 70 文献标志码:A 文章编号:0438—1157(2015)09—3319—05Review on catalytic wet peroxide oxidation processLUO Lei 1,DAI Chengyi 1,ZHANG Anfeng 1,SONG Chunshan 2,GUO Xinwen 1(1School of Chemical Engineering , Dalian University of Technology , Dalian 116024, Liaoning , China ;2Pennsylvania StateUniversity , Pennsylvania 16802, United States )Abstract :Catalytic wet peroxide oxidation (CWPO), as a highly effective treatment of toxic and harmful wastewater technology, is of great prospects and great promotional value in the field of printing and dyeing, pesticides, pharmaceuticals, etc. The basic concepts of this technology, reaction mechanism and catalyst performance, and the way to solve the catalyst activity and stability problems were reviewed. Key words :Fenton reaction ;iron ;catalytic oxidation ;activity ;stability引 言水是人类及一切生物赖以生存的基础,是生产、生活不可替代的宝贵资源。
Study on the interaction of catalase with pesticides by flow injection chemiluminescence and moleculardockingXijuan Tan a ,aKey Laboratory of Synthetic University,229North Taibai Road,bUniversity,a r t i c l e i n f o Article history:Received 4December 2013Accepted 22February 2014Handling Editor:S.Jobling Keywords:Catalase PesticidesInteraction mechanismFlow injection chemiluminescence Molecular dockinga b s t r a c tThe interaction mechanisms of catalase (CAT)with pesticides (including organophosphates:disulfoton,isofenphos-methyl,malathion,isocarbophos,dimethoate,dipterex,methamidophos and acephate;car-bamates:carbaryl and methomyl;pyrethroids:fenvalerate and deltamethrin)were first investigated by flow injection (FI)chemiluminescence (CL)analysis and molecular docking.By homemade FI–CL model of lg[(I 0ÀI )/I ]=lg K +n lg[D ],it was found that the binding processes of pesticides to CAT were spontaneous with the apparent binding constants K of 103–105L mol À1and the numbers of binding sites about 1.0.The binding abilities of pesticides to CAT followed the order:fenvalerate >deltamethrin >disulfoton >isofenphos-methyl >carbaryl >malathion >isocarbophos >dimethoate >dipterex >acephate >methomyl >methamidophos,which was generally similar to the orderof determination sensitivity of pesticides.The thermodynamic parameters revealed that CAT bound with hydrophobic pesticides by hydrophobic interaction force,and with hydrophilic pesticides by hydrogen bond and van der Waals force.The pesticides to CAT molecular docking study showed that pesticides could enter into the cavity locating among the four subdomains of CAT,giving the specific amino acidresidues and hydrogen bonds involved in CAT–pesticides interaction.It was also found that the lg K values of pesticides to CAT increased regularly with increasing lg P ,M r ,MR and MV ,suggesting that the hydrophobicity and steric property of pesticide played essential roles in its binding to CAT.Ó2014Elsevier Ltd.All rights reserved./10.1016/j.chemosphere.2014.02.0750045-6535/Ó2014Elsevier Ltd.All rights reserved.⇑Corresponding author.Tel.:+8602988303798;fax:+8602988302604.E-mail addresses:songzhenghua@ ,zhsong123@ (Z.Song).1.IntroductionThe massive usage of pesticides in agriculture leads to the widely spread of pesticides into the environment ranging from soil to foodstuff,resulting in continued wildlife and human exposure (Köck-Schulmeyer et al.,2012;Rutsaert et al.,2013;Abrantes et al.,2010).Organophosphate(OP),carbamates(CM)and pyre-throid(PY)are primarily utilized pesticides to protect crops or gar-dens from insects(Gupta and Milatovic,2012;Schleier and Peterson,2011).OP and CM,which are commonly known as anti-cholinesterase agents,are being phased out of use gradually due to biomagnification or high non-target toxicity,and PY as neurotoxic agents have been widely used nowadays.Because the long-term pesticide exposure might pose the potential risks of health effects on no-targets mainly via the interactions of proteins with pesti-cides,it is of great importance to investigate the interaction behav-ior between protein and pesticide at molecular level.The protein–small molecule interaction has become a hot spot in thefields of biology(Azami-Movahed et al.,2013;Agostino et al., 2013),medicine(Khan et al.,2012;Yoshimura et al.,2013;Tan and Song,2014),environment(Xie et al.,2010;Akiyoshi et al.,2012)and chemistry(Dobretsov et al.,2013;Saha et al.,2013;Wang et al., 2013)in recent decades.Catalase(CAT,MW$240kDa)presents in the perixisomes of nearly all aerobic cells and serves to protect tissues against damage from hydrogen peroxide by catalyzing its decomposi-tion into molecular oxygen and water without the production of free radicals(Schroeder et al.,1982).It is also one of thefirst enzymes pro-posed to be an effective marker of oxidative stress(Livingstone et al., 1993).CAT exists as a dumbbell-shaped tetramer of four identical sub-units,each subunit formed by a single polypeptide chain with a heme as a prosthetic group(Reid et al.,1981).The interaction of CAT with small molecule has been studied in vitro by approaches including spec-trometry(Zhao et al.,2007;Li et al.,2008;Zhang and Jin,2008),calo-rimetry(Zhao et al.,2007)and equilibrium dialysis(Ruso et al., 2001),etc.Yet,no report on the interactions of CAT with pesticides using chemiluminescence(CL)method combined withflow injection analysis(FIA)has been described.In this current work,it wasfirst found that pesticides(including disulfoton,isofenphos-methyl,mala-thion,isocarbophos,dimethoate,dipterex,methamidophos,acephate, carbaryl,methomyl,fenvalerate and deltamethrin,Scheme S1)obvi-ously quenched the CL intensity from luminol–CAT system and the CL intensity decrements were proportional to the logarithm of pesticides’concentrations within ranges from0.3to30nmol LÀ1.The binding parameters of CAT with pesticides were obtained using the FI–CL model of protein–small molecule interaction,lg[(I0ÀI)/I]= lg K+nlg[D](Wang and Song,2010),giving the binding ability of pesti-cides to CAT,and the major interaction force was speculated by the thermodynamic parameters of CAT–pesticides association process.It is well known that molecular docking(MD)is a method to predict and understand molecular recognition,find the predomi-nant binding mode and binding affinity between the protein and ligand(Brink and Exner,2009;Lie et al.,2011),and give a three-dimensional structural explanation of the protein–ligand interac-tion(Gumede et al.,2012;Hou et al.,2013).In this paper,by MD the specific binding sites of pesticides on CAT and the binding mode were obtained,which was a beneficial complementary explanation to the CL results for understanding the interaction mechanism of CAT with pesticides.2.Material and methods2.1.ReagentsAll reagents were of analytical pure grade,and the deionized water used in this work was passed through a Milli-Q system (Millipore,Bedford,MA,USA,18.2M X cm).Luminol(Fluka, Biochemika,Switzerland)and CAT from bovine liver(C40, Sigma–Aldrich,St.Louis,MO,USA)were used as received without further purification.Pesticides(OP:disulfoton,isofenphos-methyl, malathion,isocarbophos,dimethoate,dipterex,acephate and methamidophos;CM:carbaryl and methomyl;PY:fenvalerate and deltamethrin)with a concentration of5mg mLÀ1(ethanol as solvent)were supplied by Material Evidence Identifying Center of Xi’an Public Security Bureau,China.Luminol stock solution of2.5Â10À2mol LÀ1was prepared by dissolving0.44g luminol in100mL of0.1mol LÀ1NaOH solution in a brown calibratedflask.The stock solution of 5.0Â10À6 mol LÀ1CAT was prepared by dissolving30.0mg lyophilized pow-der in25.00mL deionized water.All stock solutions of pesticides with the concentration of 1.0Â10À4mol LÀ1were prepared in deionized water.Working standard solutions of pesticides were prepared daily from the above stock solutions by appropriate dilution as required.All of the stock solutions were stored at4°C.2.2.ApparatusThe FI mode was shown in Fig.S1.The FI–CL apparatus(Xi’an Remex Analysis Instrument Co.Ltd.,Xi’an,China)consisted of the sampling system(IFFM-E),the photomultiplier tube(PMT),and the PC with an IFFM-E client system(Remax,Xi’an,China).Poly Tetra Fluoro Ethylene(PTFE)tubing(1.0mm i.d.)was used to carry and deliver the solutions.A six-way valve with a loop of100l L was used for quantitatively injecting luminol into carrier stream. The CL detector contained aflow cell made by coiling15cm of colorless glass tube(1.0mm i.d.)into a spiral disk shape with a diameter of2.0cm and placed close to the PMT,and it is important to ensure that the sample compartment and PMT were light tight. The CL signal produced inflow cell was detected by the PMT with-out wavelength discrimination,with output recorded by computer. The temperature of the solutions was controlled in a water bath (T±0.1°C).The F-4500fluorophotometer(Hitachi,Kyoto,Japan)was applied tofluorescence measurements of CAT with pesticides (Supplementary Material).2.3.General proceduresEach solution was placed in a water bath to control the temper-ature.Before the running step was started,the wholeflow system was washed using deionized water until a stable baseline was recorded.With aflow rate of 2.0mL minÀ1on eachflow line, 100l L luminol was quantitatively injected into the carrier stream by the six-way valve and then merged with the mixed solution of CAT and pesticide.The whole mixture was thereafter delivered into theflow cell in an alkaline medium to produce CL emission.The CL signal was detected by the PMT with the negative voltage of700V. The concentration of pesticide was quantified by the decrement of CL intensity.2.4.The optimization of CL experimental conditionsThe effect of luminol concentration on the CL intensity was tested over the ranges of5.0Â10À7to5.0Â10À4mol LÀ1,it was found that the CL signal increased steadily with increasing luminol concentration until2.5Â10À5mol LÀ1,and tended to be stable thereafter.Therefore,2.5Â10À5mol LÀ1luminol was chosen as the optimum concentration.Due to the alkaline medium-dependent nature of the luminol CL reaction,NaOH was introduced into the luminol solution to enhance the sensitivity of the system.A series of NaOH solutions over the ranges of 5.0Â10À3 to0.2mol LÀ1was examined,and the concentration ofX.Tan et al./Chemosphere108(2014)26–32272.5Â10À2mol LÀ1NaOH was used in subsequent experiments. The effect offlow rate and the length of mixing tubes on the CL intensity of this FI–CL system were also tested.Theflow rate of 2.0mL minÀ1on eachflow line was chosen as optima,and the optimum lengths of mixing tubes were10.0and15.0cm for M1 and M2,respectively.2.5.MD studyThe MD investigation was carried out by using AutoDock4.2suit of programs().The structures of pesti-cides with minimum energy were generated by ChemBioOffice 2008.The crystal structure of CAT was taken from the RCSB Protein Data Bank with the entry code of1TGU(/pdb/ explore/explore.do?structureId=1TGU).The numbers of grid points were set to70ÅÂ70ÅÂ70Å,with the grid box spacing of0.375Å. The grid center was set as(21.954Å,27.411Å,42.149Å)(Teng et al.,2011;Qin and Liu,2013).Semi-flexible docking simulations were performed using the Lamarckian Genetic Algorithm(LGA)to search for the optimum binding sites of pesticides to CAT.The population size was150and the maximum number of energy evaluations was250,000.The conformations with the lowest binding free energy were used for further analysis by Pymol1.6.0.0.3.Results and discussion3.1.The relative CL intensity–time profile of luminolCATpesticide systemThe relationship of the relative CL intensity of luminol–CAT–pesticide system vs.time in the FI mode is tested at aflow rate of2.0mL minÀ1with results given in Fig.1(luminol:2.5Â10À5 mol LÀ1;CAT:5.0Â10À9mol LÀ1;carbaryl,isocarbophos and del-tamethrin:5.0Â10À10mol LÀ1).It can be seen that the maximum CL intensity(I max)for luminol–O2system(curve5,solid)is119at the time(T max)of4.8s;while in the presence of CAT(curve1),the I max is200with the T max of3.8s.It can also be seen that the I max for luminol–CAT system with pesticides(curves2–4)decreases from200to168,160and131for carbaryl,isocarbophos and deltamethrin,respectively,with the same T max of3.8s.It is found that the I max for luminol–O2system with pesticides has no obvious changes.By taking deltamethrin as a representative example,the I max for luminol–deltamethrin system(curve6,dash)only changes from119to115by3.4%with the T max of4.8s.3.2.The possible CL mechanism of luminol–CAT–pesticide systemAs Fig.1shows,it is clear that the I max for luminol–O2system in the presence of CAT increases from119to200by a factor of1.68, and the corresponding T max shortens from4.8to3.8s,indicating that the electron transfer rate of excited3-aminophthalate could be accelerated by CAT.According to literature report(Chen et al., 2012),it is speculated that luminol could bind to the heme group of CAT with the electron transfer rate of luminol’s excited oxidation product accelerated by the Fe(III)in the active center of CAT,pro-ducing the CL intensity enhancement.It is also clear that the I max for luminol–O2system shows no obvious differences in the pres-ence and absence of pesticides,suggesting that the interactions be-tween luminol and pesticides could be ignored.Thus,the CL intensity quenching effect of pesticides on luminol–CAT system might be caused by the interactions of CAT with pesticides.The possible CL mechanism of luminol–CAT–pesticide system can be explained as follows:the acceleration of electron transfer rate of 3-aminophthalate by CAT leads to the complexation enhancement of CL(CEC),giving the enhanced CL intensity from luminol–O2sys-tem;while the CAT–pesticides interactions cause the complexation enhancement of quenching(CEQ),showing the quenched CL inten-sity from luminol–CAT system.3.3.The analytical performance for the determination of pesticidesUnder the optimal experimental conditions,a series of stan-dard solutions of CAT was tested by luminol–O2system,and a ser-ies of standard solutions of pesticides was determined by luminol–CAT system.It is found that the relative CL intensity from luminol–O2system increases with increasing CAT concentration, and the CL intensity increment is proportional to CAT concentra-tions ranging from0.3to30nmol LÀ1,with the linear equation of D I=13.9C CAT+10.7(R=0.9966).In the presence of pesticide,the CL intensity decrement is proportional to the logarithm of pesti-cide concentration within ranges of0.01–3.0nmol LÀ1,following the general equation of D I=A lg C+B(R>0.99,herein,the slope A represents the determination sensitivity of pesticides by luminol–CAT system).The linear equations,linear ranges and limit of detection(LOD,3r)were listed in Table1,showing that the determination sensitivity A of pesticides on luminol–CAT system ranks in order of fenvalerate>deltamethrin>disulfoton> isofenphos-methyl>malathion>isocarbophos>carbaryl>dimeth-oate>dipterex>methomyl>acephate>methamidophos.3.4.The interaction parameters and binding modes of CAT with pesticidesBy FI–CL model of lg[(I0ÀI)/I]=lg K+n lg[D](I and I0refer to the CL intensity of luminol–CAT system with and without pesticides, respectively,and[D]refers to the pesticide concentration),the binding parameters of CAT with pesticides are listed in Table2 and Table S1,with plots of lg[(I0ÀI)/I]vs.lg[D]for disulfoton,car-baryl and deltamethrin as examples shown in Fig.S2.It can be seen that the apparent binding constants K of CAT with OP and CM are at103–104L molÀ1level,and with PY are at105L molÀ1level,sug-gesting that the binding affinities of PY to CAT are higher than OP and CM to CAT.The numbers of binding sites n(0.82–0.97, approximately equal to1.0)reveal that there is one dependant class of binding sites in CAT for pesticides.The binding abilities of pesticides to CAT follow the order:fenvalerate>deltamethrin>28X.Tan et al./Chemosphere108(2014)26–32disulfoton >isofenphos-methyl >carbaryl >malathion >isocarbo-phos >dimethoate >dipterex >acephate >methomyl >methami-dophos,which is generally similar to the order of A values,indicating that pesticide with a higher determination sensitivity may achieve a stronger binding ability to CAT.The enthalpy change (D H ),entropy change (D S )and binding free energy change (D G )of CAT with pesticides are obtained using the Van’t Hoff equation of ln K =–D H /RT +D S /R (Lakowicz,2006).The thermodynamic parameters of pesticides binding to CAT are listed in Table 3and Table S2,with plots of ln K vs .1/T of CAT with methamidophos,acephate,isocarbophos,carbaryl and deltameth-rin as examples are shown in Fig.S3.It is shown that for the strongpolar methamidophos and acephate,the signs for D G ,D H and D S are negative,suggesting that the binding process is spontaneous and exothermic,with hydrogen bond and van der Waals force as the main driving force according to Ross theory (Ross and Subra-manian,1981).For hydrophobic pesticides,the signs for D G and D H are negative and positive,respectively,indicating that the binding process is spontaneous and endothermic.The positive D H and D S reveals that the hydrophobic interaction force plays a major role in hydrophobic pesticides binding to CAT.Using the intrinsic fluorescence of CAT with k Em /k Ex of 280nm/340nm,fluorescence quenching (FQ)method (Lakowicz,2006;Manna and Chakravorti,2013;Roy et al.,2013)is also employed to study the interactions of CAT (5.0l mol L À1)with pesticides (from 1.0to 70l mol L À1).Results show that the K and n (Table 2and Table S1),and D H ,D S and D G (Table 3and Table S2)are extre-mely close to those from FI–CL analysis.Apparently,the proposed FI–CL analysis shows higher sensitivity at least two orders of mag-nitudes than the FQ method.3.5.CAT–pesticides binding investigation by MDAs we know,CAT consists of four identical subunits each with a heme situating in the active site which is accessible from the CAT surface through a main channel about 25–55Åin length (Gouet et al.,1995;Bravo et al.,1999;Putnam et al.,2000;Diaz et al.,2004),and the main channel leads the ligand to the active site (Gouet et al.,1995).The MD results of pesticides to CAT are given in Tables 2and 3and Tables S3and S4.It is found that all pesticides bind to the CAT cavity which locates among the four subdomains of CAT,with disulfoton,carbaryl and deltamethrin to CAT as exam-ples shown in Fig.2.For the hydrophobic pesticides to CAT,it is found that the bind-ing cavity are mainly formed by hydrophobic residues ILE68,PRO69,PRO367,LEU365and PRO390(Table S3),suggesting that hydrophobic interaction is the dominant stable force for hydropho-bic pesticides to CAT.It is also found that the numbers of hydro-phobic residues involved in the interactions for hydrophobic OP to CAT are 13,12,10,9,8and 6for disulfoton,isofenphos-methyl,malathion,isocarbophos,dimethoate and dipterex,respectively (Table S3),following the same monotonic decreasing order of bind-ing constants K.Similarly,the numbers of hydrophobic residues in-volved in CM and PY to CAT show the same trends as OP to CAT.Hydrogen bond (H-bond)is another binding force in the interac-tions of CAT with hydrophobic pesticides except deltamethrin (Table S4),with residues ARG65,ARG362and HIS363in different chains contributing to the H-bonds.For the hydrophilic acephate and methamidophos to CAT,dock-ing results show H-bonds mainly contribute to the stabilities of CAT–acephate/methamidophos complexes.It is clear that the numbers of H-bonds are 3and 2for acephate and methamidophos to CAT,according well with the sequence of binding constants K from FI–CL analysis.The binding constants K (Table 2)and binding free energies D G (Table 3)for CAT Àpesticides interactions well agree with the results obtained by the proposed FI–CL analysis,following the same order of fenvalerate >deltamethrin >disulfoton >isofenphos-methyl >carbaryl >malathion >isocarbophos >dimethoate >dipterex >ace-phate >methomyl >methamidophos.3.6.The relationship of structure–binding ability of pesticide to CAT It is interesting observed that the structural differences of pes-ticides show significant influence on their binding abilities to CAT.For hydrophobic OP pesticides,the dipterex with double bond be-tween O and P has the lowest binding ability to CAT with the K of 7.99Â103L mol À1,and the disulfoton with double bond between STable 3Thermodynamic parameters of CAT–pesticides by FI–CL/FQ/MD.aPesticidesD H (kJ mol À1)D S (J mol À1K À1)D G (kJ mol À1)FI–CL/FQ FI–CL/FQ FI–CL/FQ/MD disulfoton14.47/14.46141.68/141.60–27.49/–27.52/–27.47isofenphos-methyl 14.35/14.31139.18/139.10–27.24/–27.29/–27.28malathion 12.14/12.35128.71/128.63–25.86/–25.95/–25.83isocarbophos 45.17/45.07235.83/234.45–25.13/–25.27/–24.95dimethoate 10.38/10.50110.17/110.25–22.50/–22.54/–22.52dipterex 10.01/10.18108.09/109.83–22.26/–22.30/–22.27acephate–28.35/–29.68–22.50/–26.85–21.68/–21.63/–21.52methamidophos –25.99/–26.00–17.46/–17.05–20.95/–20.92/–20.86carbaryl 36.40/35.31210.52/186.99–26.08/–26.15/–25.50methomyl 6.86/7.0695.62/94.20–21.02/–21.01/–21.27fenvalerate 25.59/25.07199.96/198.13–34.00/–34.02/–34.12deltamethrin14.61/14.98159.04/160.05–32.68/–32.78/–33.33aThe shown D G values were results at 298K.Table 1Linear equation with of pesticide’s concentration range by luminol–CAT CL system.aPesticidesLinear equations D I =A lg C +BRanges c(nmol L À1)LODs(nmol L À1)R b disulfotonD I =34.1lg C +371.40.03–3.00.010.9975isofenphos-methyl D I =29.9lg C +324.80.03–3.00.010.9992malathion D I =20.0lg C +213.30.03–3.00.010.9968isocarbophos D I =17.1lg C +189.90.01–1.00.0030.9983dimethoate D I =15.2lg C +187.30.03–3.00.010.9961dipterex D I =13.2lg C +140.40.01–3.00.0030.9979acephateD I =11.5lg C +132.40.03–3.00.010.9980methamidophos D I =11.1lg C +124.10.03–3.00.010.9970carbaryl D I =15.6lg C +170.50.01–3.00.0030.9957methomyl D I =11.6lg C +141.30.01–3.00.0030.9955fenvalerate D I =37.3lg C +406.80.03–1.00.010.9971deltamethrinD I =36.2lg C +404.70.03–1.00.010.9967a Each result is the average of five separate determinations.bR :correlation coefficient.Table 2Binding parameters of CAT–pesticides by FI–CL/FQ/MD.aPesticidesK (L mol À1)nFI–CL/FQ/MDFI–CL/FQ disulfoton6.58Â104/6.66Â104/6.54Â1040.92/0.95isofenphos-methyl 5.95Â104/6.07Â104/6.05Â1040.92/0.94malathion 3.41Â104/3.53Â104/3.38Â1040.91/0.92isocarbophos 2.54Â104/2.69Â104/2.35Â1040.90/0.91dimethoate 8.81Â103/8.92Â103/8.77Â1030.88/0.90dipterex7.99Â103/8.11Â103/8.01Â1030.87/0.89acephate6.31Â103/6.18Â103/5.90Â1030.84/0.83methamidophos 4.71Â103/4.65Â103/4.53Â1030.82/0.81carbaryl 3.73Â104/3.84Â104/3.53Â1040.91/0.93methomyl 4.84Â103/4.81Â103/5.33Â1030.82/0.82fenvalerate 9.11Â105/9.19Â105/9.35Â1050.97/0.98deltamethrin5.35Â105/5.56Â105/6.80Â1050.95/0.96aThe binding parameters were results at 298K.X.Tan et al./Chemosphere 108(2014)26–3229and P give the highest K of 6.58Â104L mol À1to paring with the K of disulfoton to CAT,the two ester side chains at S con-necting to the P through single bond in malathion decreases the K by 48.2%,and the additional amino bond in dimethoate decreases the K by 86.6%;while the substitution of N for O which connects to the P via single bond and the additional phenyl group in isofen-phos-methyl decrease the K by 9.6%,and the isocarbophos without the two –CH 3moieties at N atom further decreases the K by 61.4%.For hydrophilic OP pesticides,it is found that the introduced acyl group in acephate causes an additional H-bond between acephate O 8and A/HIS363H of CAT with length of 1.9Å,leading to the K 1.34-fold that of methamidophos.For CM pesticides,the hydro-phobic naphthalene increases the K 7.7times to that of methomyl.For PY pesticeds,the phenyl group in fenvalerate increases the K 1.7times to that of deltamethrin.abcdeltamethrinCBcarbarylA disulfotonCAT binding to pesticides.For (a)–(c),the residues of CAT are represented using line model and the pesticides using stick A–D of CAT).The pesticides in each figure are (a):disulfoton,(b):carbaryl,(c):deltamethrin,respectively.(For interpretation the reader is referred to the web version of this article.)Table 4Physicochemical parameters of the studied pesticides.aPesticideslg P M r .(g mol À1)MR (cm 3)MV (cm 3mol À1)disulfoton4.06274.4072.73233.27isofenphos-methyl 3.84331.3787.26281.81malathion 2.38330.3677.51259.65isocarbophos 2.09289.2973.34226.77dimethoate 1.37229.2654.46175.72dipterex0.48257.4446.95163.52methamidophos À0.78141.1331.45109.71acephate À0.85183.1740.82144.98carbaryl 2.34201.2259.03169.99methomyl 0.60162.2141.19137.97fenvalerate 6.55419.90116.44346.76deltamethrin6.42505.20116.01316.74aThe predicted data are from ChemSpider generated using the ACD/Labs’ACD/PhysChem Suite.30X.Tan et al./Chemosphere 108(2014)26–323.7.The correlations between lgK and the physicochemical parameters of pesticidesThe correlations of lg K values vs.the physicochemical parame-ters of pesticides,including the octanol/water partition coefficient (lg P),relative molecular mass(M r),molar refractivity(MR)and mo-lar volume(MV)with values listed in Table4,are analyzed.As shown in Fig.3,it is clear that the lg K values increase regularly with increasing lg P,M r,MR and MV giving linear relationships with R>0.90,which suggests the hydrophobic,steric properties and molecular size of pesticides have great impacts on the binding abil-ities of pesticides to CAT.It is also clear that the slopes of lg K vs.lg P is far higher than lg K vs.M r,MR and MV,demonstrating the hydro-phobicity of pesticides is the very essential factor affecting their binding abilities to CAT,which offers a valuable insight into the toxic mechanisms of pesticides in vivo.4.ConclusionsThe interaction of CAT with OP,CM and PY was studied by FI–CL analysis in combination with MD for thefirst time.The binding constants K of103–105L molÀ1and the numbers of binding sites about1.0were obtained,and the specific binding sites of pesticides on CAT were given by MD.According to the correlations between lg K and physicochemical parameters,it was suggested that the binding abilities of pesticides to CAT was closely related to their hydrophobic and steric properties,which offered the possibility for speculating pesticides’action regularity in vivo.AcknowledgmentsThis work was supported by the National Nature Science Foun-dation of China,China(No.21275118),the Open Fund from Key Laboratory of Synthetic and Natural Functional Molecule Chemis-try of Ministry of Education,China,and the Northwest University (NWU)Graduate Innovation and Creativity Funds(No.10YZZ29), China.Appendix A.Supplementary materialSupplementary data associated with this article can be found,in the online version,at /10.1016/j.chemosphere. 2014.02.075.ReferencesAbrantes,N.,Pereira,R.,Gonçalves,F.,2010.Occurrence of pesticides in water, sediments,andfish tissues in a lake surrounded by agricultural lands: concerning risks to humans and ecological receptors.Water Air Soil Poll.212, 77–88.Agostino,M.,Mancera,R.L.,Ramsland,P.A.,Yuriev,E.,2013.AutoMap:a tool for analyzing protein–ligand recognition using multiple ligand binding modes.J.Mol.Graph.Model.40,80–90.Akiyoshi,S.,Sai,G.,Yamauchi,K.,2012.Species-dependent effects of the phenolic herbicide ioxynil with potential thyroid hormone disrupting activity: modulation of its cellular uptake and activity by interaction with serum thyroid hormone-binding proteins.J.Environ.Sci.24,949–955.Azami-Movahed,M.,Shariatizi,S.,Sabbaghian,M.,Ghasemi,A.,Ebrahim-Habibi,A., Nemat-Gorgani,M.,2013.Heme binding site in apomyoglobin may be effectively targeted with small molecules to control aggregation.Int.J.Biochem.Cell B45,299–307.Bravo,J.,Mate,M.J.,Schneider,T.,Switala,J.,Wilson,K.,Loewen,P.C.,Fita,I.,1999.Structure of catalase HPII from Escherichia coli at1.9Åresolution.Proteins34, 155–166.Brink,T.T.,Exner,T.E.,2009.Influence of protonation,tautomeric,and stereoisomeric states on protein–ligand docking results.J.Chem.Inf.Model.49,1535–1546.Chen, D.H.,Wang,Z.M.,Zhang,Y.,Xiong,X.Y.,Song,Z.H.,2012.Study on the interaction behavior of catalase with cephalosporins by chemiluminescence withflow injection analysis.Anal.Methods2012(4),1485–1487.Diaz,A.,Horjales,E.,Rudino-Pinera,E.,Arreola,R.,Hansberg,W.,2004.Unusual Cys–Tyr covalent bond in a large catalase.J.Mol.Biol.342,971–985. Dobretsov,G.,Polyak,B.,Smolina,N.,Babushkina,T.,Syrejshchikova,T.,Klimova,T., Sverbil,V.,Peregudov, A.,Gryzunov,Y.,Sarkisov,O.,2013.Interaction of a fluorescent probe,CAPIDAN,with human serum albumin.J.Photochem.Photobiol.,A251,134–140.X.Tan et al./Chemosphere108(2014)26–3231。