摘要
为研究表面活性剂对抗生素光解的影响,采用模拟日光(氙灯,λ>290nm)光解实验考察了土霉素在CTAB、SDS、SDBS和Tween804种表面活性剂溶液中的光解。在模拟日光下,土霉素在pH=7.5的纯水和4种表面活性剂溶液中的光解遵循一级反应动力学,4种表面活性剂均促进了土霉素的光解,其中CTAB的促进作用最明显。CTAB的作用受pH值和浓度影响,pH=5.5时抑制土霉素的光解;pH=7.5和pH=9.0时促进土霉素的光解,促进作用与CTAB浓度呈正相关。CTAB可以降低土霉素的pKa,增大其阴离子形态比例,这可能是CTAB促进土霉素光解的重要原因。在自然光照下,纯水和地表水中CTAB的存在分别使土霉素的光解加快了1.62和4.96倍。
Effects of surfactants on photodegradation of oxytetracycline（OTC） in aqueous solution was investigated with Xe lamp（〉290 nm）as simulated sunlight. The photodegradation of OTC at pH=7.5 followed pseudo-first-order kinetics and can be promoted by CTAB, SDS, SDBS and Tween80, in which CTAB exerted the most significant enhancement. The effects of CTAB on the photodegradation of OTC demonstrated pH and concentration-dependent. Photolysis of OTC was inhibited at pH=5.5, whereas it was promoted at pH=7.5 and pH=9.0 by CTAB. A positive correlation between the photolysis rate constants of OTC and the CTAB concentration was observed at pH=7.5. CTAB can decrease the pKa of OTC and thus increase the proportion of anion forms of OTC, which is proposed as an important reason for the promotion effect of CTAB on the photolysis of OTC. In addition, photolysis rate constants of OTC coexisted with CTAB in pure water and surface water were 1.62 and 4.96 times higher than those of OTC alone respectively under natural sunlight.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2013年第7期1451-1455,共5页
Journal of Agro-Environment Science
基金
国家自然科学基金资助项目(21137001
21077016
21277018)
关键词
土霉素
表面活性剂
PKA
光解
oxytetracycline
surfactants
pKa
photodegradation
