摘要:磺胺类抗生素在现代社会中被广泛使用,不仅能用于人类的临床治疗,在农业、养殖业等领域也很常用。它可以预防和治疗疾病,还有利于动植物的生长。但是由于人类的滥用,用于动物的磺胺类抗生素约有50%~90%以母体或代谢物的形式排出体外,导致越来越多的磺胺类抗生素进入到自然环境中,尤其是自然水体中。进入自然环境后的磺胺类抗生素不仅使生物的耐药性增强,对生态环境也产生一定的威胁。目前许多国家的水体、土壤、河流湖泊沉积物等介质中都检测到了磺胺类抗生素,因此对磺胺类抗生素的处理研究具有重要意义。
本研究采用十六烷基三甲基溴化铵(HDTMA)对埃洛石表面进行改性,分别对比了改性前后埃洛石对水中磺胺类抗生素磺胺甲恶唑和磺胺甲氧嘧啶的吸附效果。考察了HDTMA溶液浓度和改性时间等因素对改性埃洛石吸附效果的影响,确定了最佳改性条件。研究了溶液pH、改性埃洛石用量和吸附时间等因素对HDTMA改性埃洛石吸附磺胺类抗生素效果的影响,确定了最优的吸附条件。在优化的吸附条件下,对吸附热力学和动力学规律进行了数学模拟,探讨了吸附机理。
结果表明,天然埃洛石对磺胺类抗生素吸附效果不佳,去除率只有10%左右。采用HDTMA对埃洛石进行改性后,吸附效果大幅提高。当使用浓度为10%的HDTMA溶液对HNTs改性12h后,改性后得到的HDTMA-HNTs性能较好,对磺胺类抗生素的吸附效率最高可达95%以上。改性埃洛石对抗生素的最优吸附条件为:pH,8.0~9.0;吸附剂用量2.0~3.0g/L,吸附时间60min。在该条件下,HDTMA-HNTs对水中磺胺类抗生素的吸附量在2.6~4.2mg/g,去除率最高可达82%。HDTMA改性埃洛石对磺胺类抗生素的吸附较易且反应自发进行,吸附属于放热反应。吸附过程均符合Freundlich和Langmuir两种等温模型和准一级动力学模型。改性埃洛石对水中磺胺类抗生素的吸附是单分子层吸附且以化学吸附为主。
关键词:埃洛石;吸附;磺胺甲恶唑;磺胺甲氧嘧啶
Abstract:Sulfonamides are widely used in modern society, not only for the clinical treatment of humans but also common, in agriculture, aquaculture and other fields are also common. It can prevent and treat diseases, and conducive to the growth of animals and plants. But for the abuse of humans, for animals, about 50% to 90% of the sulfa antibiotics are excretd in the form of maternal or metabolite, resulting in more and more sulfonamides entering into the natural environment, especially natural water. After entering the natural environment of sulfonamides antibiotics, the biological resistance are enhanced, the ecological environment also have a certain threat. At present, sulfa antibiotics have been detected in water, soil, river lake sediments and so on in many countries, so it is very important to study the treatment of sulfonamides.
In this paper, the surfactant, cetyltrimethyltrimethylphenanthroline was selected to modify the sulfonamides and sulfamethoxazole, adsorption effect was studied before and after the modification. The effects of HDTMA solution concentration and modification time on the adsorption effect of modified alanite were investigated, and the optimum modification conditions were determined. The effects of pH, modified amount of elier and the time of adsorption on the adsorption of sulfonamides were studied. The optimum adsorption conditions were determined. Under the optimized adsorption conditions, the thermodynamics and kinetics of adsorption were simulated and the adsorption mechanism was discussed.
The results showed that natural sulfa antibiotics halloysite ineffective adsorption, removal of only about 10%. With HDTMA of halloysite was modified adsorption greatly improved. When the HDTMA solution with 10% concentration was modified for 12 h, the HDTMA-HNTs obtained after modification had better performance, and the adsorption efficiency of sulfonamides was above 95%. The optimal adsorption conditions of modified alanite were: pH,