重金属络合作用对喹诺酮类抗生素光降解特性的影响

发布时间：2018-11-17 11:54

【摘要】：氟喹诺酮类抗生素(Fluoroquinolone antibiotics, FQs)具有抗菌谱广、体内分布广、组织浓度高、活性强、耐药发生率低等特点,被广泛应用于水产养殖、畜禽养殖及人类处方药中,对人体及动物的疾病治疗产生了积极的效应。然而,FQs并不能被完全吸收,而是作为母体或是代谢产物的形式,通过多种途径进入环境介质中。FQs会对人体产生中枢系统毒性、肝肾毒性、血液系统毒性以及光毒性等,同时可以诱导环境中的细菌产生耐药性,对人体和生态环境产生一定影响。抗生素在表层水环境中也会以各种形式进行降解,尤其以光降解为主,而环境介质中存在的重金属如何影响FQs的降解,对研究抗生素在不同环境因子下的形态及其迁移转化具有重要意义。本文以环丙沙星(Ciprofloxacin, CIP)、氧氟沙星(Ofloxacin, OFL)、诺氟沙星(Norfloxacin,NOR)为研究对象,在紫外光及自然光下,研究了水体中硝酸镉(Cd(NO3)2)、硝酸铅(Pb(NO3)2)、氯化镉(CdCl2)、氯化铅(PbCl2)、对三种FQs的光降解性能的影响。主要研究结论如下：(1)通过摩尔比法研究了重金属Cd或Pb与CIP、OFL及NOR三种抗生素的络合比。实验结果表明Cd、Pb与三种抗生素的络合比在1：2及1：3之间变化。(2) CIP、OFL及NOR在黑暗中几乎不降解,而在紫外光下发生快速光降解,且随着抗生素初始浓度的增大,光降解速率减小,主要是由于单位浓度抗生素接受光子产量的变化所致。Cd(NO3)2和Pb(NO3)2对CIP光降解主要表现为促进作用,且随着摩尔比的增大(即硝酸盐浓度降低),对CIP光降解的促进作用逐渐降低；CdCl2和PbCl2对CIP光降解主要表现为抑制作用,随着摩尔比的增大(即氯化盐浓度降低),对CIP光降解的抑制作用逐渐增强。Cd(NO3)2和Pb(NO3)2对OFL的光降解主要表现为抑制作用；CdCl2和PbCl2对OFL的光降解主要表现为抑制作用。Cd(NO3)2和Pb(NO3)2对NOR的光降解主要表现为促进作用；高、低浓度NOR实验组中,CdCl2对其光降解主要起抑制作用,而在中浓度NOR实验组中,CdCl2对其光降解主要起促进作用,PbCl2对NOR的光降解主要表现为抑制作用。(3)在自然光照下,研究了NOR的光降解,同时也研究了Cd(NO3)2、 Pb(NO3)2、CdCl2和PbCl2对其光降解的影响。研究结果表明Cd(NO3)2和Pb(NO3)2对NOR的光降解既有促进作用,同时也有一定的抑制作用；CdCl2和PbCl2对NOR的光降解主要表现为促进作用。对于硝酸盐和氯化盐,随着摩尔比的增大(即硝酸盐和氯化盐的浓度降低),对NOR光降解的影响变化比较复杂,无法给出明确的变化趋势。
[Abstract]:Fluoroquinolones antibiotic (Fluoroquinolone antibiotics, FQs) has been widely used in aquaculture, livestock and poultry breeding and prescription drugs for its characteristics of wide antibacterial spectrum, wide distribution in vivo, high tissue concentration, strong activity and low incidence of drug resistance. It has a positive effect on the treatment of human and animal diseases. However, FQs can not be completely absorbed, but as a form of mother or metabolite, it can enter into environmental media through many ways. FQs can produce systemic toxicity, liver and kidney toxicity, blood system toxicity and phototoxicity to human body, etc. At the same time, bacteria in the environment can be induced to develop drug resistance, and have a certain impact on the human body and the ecological environment. Antibiotics are also degraded in various forms in the surface water environment, especially photodegradation, and how heavy metals exist in environmental media affect the degradation of FQs. It is of great significance to study the morphology and migration and transformation of antibiotics under different environmental factors. Using ciprofloxacin (Ciprofloxacin, CIP), ofloxacin (Ofloxacin, OFL), norfloxacin (Norfloxacin,NOR) as research object, cadmium nitrate (Cd (NO3) 2 and lead nitrate (Pb (NO3) 2 in water were studied under ultraviolet and natural light. Effects of cadmium chloride (CdCl2) and lead chloride (PbCl2) on photodegradation of three kinds of FQs. The main conclusions are as follows: (1) the complexation ratio of heavy metal Cd or Pb with CIP,OFL and NOR was studied by molar ratio method. The results showed that the complexation ratio of Cd,Pb to three antibiotics varied between 1:2 and 1:3. (2) CIP,OFL and NOR almost did not degrade in darkness, but rapid photodegradation occurred under ultraviolet light. With the increase of the initial concentration of antibiotics, the photodegradation rate decreased, which was mainly due to the change of photonic yield in the unit concentration of antibiotics (. Cd (NO3) 2 and Pb (NO3) 2, which promoted the photodegradation of CIP. And with the increase of molar ratio (i.e. nitrate concentration), the promotion of CIP photodegradation gradually decreased. The photodegradation of CIP was mainly inhibited by CdCl2 and PbCl2, and decreased with the increase of molar ratio. The inhibition of CIP photodegradation was enhanced gradually by. Cd (NO3) 2 and Pb (NO3) 2, which mainly inhibited the photodegradation of OFL. The photodegradation of OFL by CdCl2 and PbCl2 was mainly inhibited by. Cd (NO3) 2 and the photodegradation of NOR by Pb (NO3) 2 was mainly promoted. In the high and low concentration NOR experimental group, CdCl2 mainly inhibited the photodegradation, while in the middle concentration NOR experimental group, CdCl2 mainly promoted the photodegradation, PbCl2 mainly inhibited the NOR photodegradation. (3) in natural light, the photodegradation of NOR was inhibited. The photodegradation of NOR was studied, and the effects of Cd (NO3) 2, Pb (NO3) 2 CD Cl2 and PbCl2 on the photodegradation were also studied. The results showed that Cd (NO3) 2 and Pb (NO3) 2 not only promoted the photodegradation of NOR, but also inhibited the photodegradation of NOR by CdCl2 and PbCl2. For nitrate and salt chloride, with the increase of molar ratio (that is, the concentration of nitrate and chloride), the influence on the photodegradation of NOR is complex, and it is impossible to give a definite change trend.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X50

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