2种孔径沸石分子筛对水中土霉素的去除研究

选择2种不同孔径的亲水性沸石分子筛5A和13X作为吸附材料,对水中的土霉素(OTC)进行吸附和脱附实验,重点考察pH、温度对吸附的影响,进行吸附动力学和热力学的计算,分析亲水性沸石分子筛的吸附机制.结果表明,2种分子筛对OTC均有较大的吸附量,吸附过程可用单层吸附模型拟合,在温度为298K、pH=7.0条件下5A和13X的饱和吸附量分别为667mg/g和1429mg/g;同一温度下13X的吸附量明显大于5A;二级动力学方程能较好地描述2种分子筛对OTC的吸附动力学,在解吸时,5A和13X分别得到91%和95%的OTC脱附率;溶液pH值对吸附影响较大,中性条件下分子筛对OTC的吸附量达到最大;热力学计算显示2种分子筛对OTC的吸附均属于自发的吸热反应,综合表观为化学氢键力占主导作用.

Oxytetracycline Removal in Aqueous by Two Kinds of Zeolites with Different Bore Diameter

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