摘要
为了解红壤吸附抗生素的能力以及作用机制,本文采用批量平衡法和超高效液相色谱-三重四极杆串联质谱(UPLC-MS/MS)测试技术,以典型兽用抗生素土霉素(oxytetracycline,OTC)为目标污染物,江西宜春养猪场区所采集的粉砂质红壤为试验对象,研究OTC在红壤中的吸附-解吸特征及影响因素.结果表明,OTC在红壤中的吸附非常快,6 h即可基本达到平衡,准一级动力模型仅能较好地拟合吸附初期1 h的吸附过程,准二级动力模型能非常好地拟合整个吸附过程,解吸过程存在明显的滞后性;Freundlich模型能够更好地拟合试验土壤对OTC的等温吸附过程;OTC在试验土壤上的吸附量与pH呈负相关;共存阳离子中,随着离子强度增加,吸附量均呈逐渐减少的趋势,且阳离子价态越高,离子半径越大,吸附抑制性越强;共存阴离子中,仅HCO3-对吸附存在影响,影响程度与pH相关.该研究证明了土霉素在红壤中残留的可能性非常大,污染持久性强,对土壤环境污染程度高.
Abstract
In this study,the adsorption ability and mechanism of oxytetracycline in red soil were investigated using the batch equilibrium method and ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry(UPLC-MS/MS).Oxytetracycline(OTC),a commonly used veterinary antibiotic,was chosen as the target pollutant.The silty red soil collected from Yichun pig farm in Jiangxi Province was used to study the adsorp-tion-desorption characteristics and influencing factors of OTC in red soil.The results revealed that the adsorption of OTC in the red soil occurred rapidly reaching equilibrium in approximately 6 hours.The pseudo-first-order kinetic model only adequately described the adsorption process within the first hour,while the pseudo-second-order kinetic model provided a much better fit for the entire adsorption process.The desorption process exhibited significant hysteresis.The Freundlich model proved more effective in representing the isothermal adsorption process of OTC in the tested soil.Additionally,the adsorption amount of OTC on the tested soil exhibited a negative correlation with pH.Among coexisting cations,the adsorption capacity decreased gradually with increasing ionic strength,and cations with higher valence state with larger ionic radius showed stronger adsorption inhibition.Among the coexisting anions,only HCO3-was found to affect the adsorption and this effect was pH dependent.This study demonstrates that oxytetracycline residues in red soil can lead to persistent and significant environmental pollution,posing a high degree of soil contamination.
基金项目
国家自然科学基金国际(地区)合作与交流项目(51861145308)
江西省教育厅科学技术研究项目(GJJ2200720)
南昌市水文地质与优质地下水资源开发利用重点实验室开放基金(20231B21)
地下水循环与环境演化教育部重点实验室开放基金(2023-006)
江西省大学生创新创业训练计划(S202410405051)
NETL
NSTL
万方数据