Li Yuan, Zhao Chun, Deng Hui-ping
Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Huan Jing Ke Xue. 2010 Apr;31(4):990-5.
5A and 13X, as two kinds of hydrophilic zeolites with different bore diameters, were chosen as adsorption materials for oxytetracycline (OTC) adsorption and desorption in aqueous. The effects of pH value and temperature on OTC adsorption were investigated respectively, and then the adsorption kinetics as well as thermodynamic were calculated to analyze the corresponding adsorption mechanism. The results showed that two zeolites had satisfactory adsorption capacities on OTC and the adsorption processes were well fitted by the single-layer adsorption model. The saturated adsorption were 667 mg/g and 1429 mg/g on 5A and 13X respectively (298K, pH = 7.0). The adsorption property of OTC on 13X was much better than that of 5A at the same temperature. The adsorption kinetics were well described by the secondary kinetic equations and the OTC desorption rates by 5A and 13X were 91% and 95% individually in the desorption processes. The maximum adsorption capacities of two zeolites were in neutral solutions. And the thermodynamic calculations showed that the adsorption of OTC on two zeolites was spontaneous endothermic reaction with the chemical hydrogen bond as dominant.
5A和13X作为两种孔径不同的亲水性沸石，被选作水溶液中土霉素（OTC）吸附和解吸的吸附材料。分别研究了pH值和温度对OTC吸附的影响，然后计算了吸附动力学和热力学，以分析相应的吸附机理。结果表明，两种沸石对OTC均具有良好的吸附容量，吸附过程符合单层吸附模型。在5A和13X上的饱和吸附量分别为667 mg/g和1429 mg/g（298K，pH = 7.0）。在相同温度下，OTC在13X上的吸附性能远优于5A。二级动力学方程很好地描述了吸附动力学，在解吸过程中，5A和13X对OTC的解吸率分别为91%和95%。两种沸石的最大吸附容量均出现在中性溶液中。热力学计算表明，OTC在两种沸石上的吸附是自发吸热反应，以化学氢键为主导。
