不同干燥方式对钠基蒙脱石吸附雌酮的影响研究

The Influence of Different Drying Methods on the Sorption of Estrone onto Na-montmorillonite

为了探明2种干燥方法对钠基蒙脱石吸附的影响及机制,通过冻干和110℃烘干方式分别制备钠基蒙脱石并作为吸附剂,以雌酮(E1)为吸附质,考察2种不同干燥方式下制备的钠基蒙脱石对E1的等温吸附和吸附动力学,并分析pH值对吸附的影响。结果表明,冻干钠基蒙脱石比表面积和孔容积均大于烘干钠基蒙脱石,2种处理方式对钠基蒙脱石官能团影响较小。吸附动力学结果显示,2种蒙脱石对E1均具有较快的吸附速率,冻干钠基蒙脱石45 min达到吸附平衡,烘干钠基蒙脱石20 min达到吸附平衡。其中,冻干钠基蒙脱石符合拟一级动力学方程,烘干钠基蒙脱石符合拟二级动力学方程。吸附等温线结果表明,冻干钠基蒙脱石对E1的吸附亲和力明显高于烘干钠基蒙脱石。pH值对2种钠基蒙脱石吸附E1的影响相似,pH呈强酸性或碱性均不利于钠基蒙脱石对于E1的吸附,pH值为6左右时吸附效果最好。

The sorption mechanism and effects of pH of Na-montmorillonite dried by two different methods on estrone(E1)were investigated in this study.Freeze-dried and 110℃oven-dried methods were used as the two different drying methods for Na-montmorillonite,and they were used for subsequent sorption isotherms and kinetic experiments.Results show that specific surface area and pore volume of freeze-dried Na-montmorillonite were higher than those of 110℃oven-dried one.However,no significant variations of surface functional groups presented for the two Na-montmorillonites.According to the kinetic results,the two Na-montmorillonites both had rapid sorption rates,reaching sorption equilibrium in 45 min for freeze-dried one and in 20 min for 110℃oven-dried one.Besides,the proposed first-order kinetics equation for the freeze-dried Na-montmorillonite and the pseudo-second-order rate equation for 110℃oven-dried Na-montmorillonite were described.Moreover,the sorption isotherms indicate that freeze-dried Na-montmorillonite had significantly higher sorption affinity with E1 compared to oven-dried Na-montmorillonite.The effects of pH on the sorption of E1 by the two kinds of Na-montmorillonite were comparable.High or low pH value was not conducive to sorption of E1 by Na-montmorillonite,and the optimal pH value for adsorption is 6.