不同环境条件下Fe~(3+)对金霉素降解机制的影响

金霉素(chlortetracycline,CTC)是一种广泛应用于人类和动植物疾病防治的广谱抗生素,作为一类难降解有机物存在于水环境中.通过对Fe3+与CTC的络合反应机制以及不同条件(Fe3+与CTC的摩尔比、温度、pH)下CTC降解规律的研究,探讨了Fe3+的存在对CTC降解规律的影响.结果表明:1 molCTC分子最多络合2 molFe3+,且Fe3+与CTC的结合部位在CTC分子的A环;Fe3+的浓度会对CTC降解产生影响,当Fe3+与CTC的摩尔比为1∶1时,CTC的降解速率最大;CTC的降解速率随着温度和pH的升高而增大;投入与CTC等浓度的Fe3+时,10和20℃条件下CTC的降解速率分别提高了271%和322%(30℃时,Fe3+的效果不是很显著),pH=3、5和7时CTC的降解速率分别提高400%、141%和179%.由于Fe3+大量存在于金霉素制药废水中,通过研究不同环境条件下Fe3+对金霉素降解机制的影响规律,可为实际工程环境条件的确定及制药废水中CTC降解模型的建立提供科学依据.

Effect of Fe3+ on the Degradation Mechanism of Chlortetracycline Under Different Environmental Conditions

Chlortetracycline is a kind of broad-spectrum antibiotics which is used for treating human diseases and animal diseases,and as a kind of persistent organic pollutants(POPs) remained in the aquatic environment.The degradation of CTC with the influence of Fe3+ was discussed via complexation reaction mechanism and under different conditions(ratio of n(Fe3+) to n(CTC),temperature and pH).Results show that the CTC-Fe3+ complex is likely formed with the A-ring and that a single unit of CTC can complex with a maximum of two units of Fe3+.The degradation rates are different with different concentrations of Fe3+.When the ratio of n(Fe3+) to n(CTC) reaches 1∶1,the degradation rate attains the maximum value.In the presence of Fe(Ⅲ) with the same concentration to CTC,the degradation rate of CTC is significantly enhanced 271% and 322% at 10 ℃ and 20 ℃,respectively(however,the effect of Fe3+ was not significant at 30 ℃),and by 400%,141% and 179% at pH 3,5 and 7,respectively.Because of the abundant appearance of Fe3+,the results can provide a scientific basis for the determination of actual engineering environment condition and the modeling of CTC's degradation in pharmaceutical wastewater treatment.