离子交换改性β分子筛吸附二氯甲烷

Adsorption of dichloromethane by ion exchangedβmolecular sieve

采用过渡金属离子(Ag~+、Ce^(3+)、Cu^(2+)、Co^(2+))对Naβ分子筛进行离子交换改性,利用低温氮气吸附/脱附、X射线衍射、X射线荧光光谱和氨气程序升温脱附等手段对改性前后的β分子筛进行表征,考察了改性β分子筛对二氯甲烷的吸附性能及循环使用性能,并研究了吸附相平衡和吸附热力学。结果表明,各种金属离子交换改性的β分子筛对二氯甲烷的穿透吸附量表现为Agβ>Ceβ>Cuβ>Coβ。AgNO_(3)溶液浓度对改性后Agβ分子筛的吸附性能有显著影响,0.05 mol/L AgNO_(3)溶液改性后的Agβ分子筛吸附性能最好,其饱和吸附量为172.40 mg/g,较Naβ分子筛提高44.3%,其穿透吸附量为128.91 mg/g,较Naβ分子筛提高70.0%。表征结果和吸附相平衡、热力学研究表明,Agβ分子筛的酸性明显增强,增强了其对二氯甲烷的吸附作用力,从而使得饱和吸附量明显增加。

Naβmolecular sieve was modified by ion exchange with transition metal ions(Ag^(+),Ce^(3+),Cu^(2+),Co^(2+)).Theβmolecular sieves before and after modification were characterized by low temperature nitrogen adsorption-desorption,X-ray diffraction,X-ray fluorescence spectroscopy and ammonia temperature-programmed desorption.The adsorption capacities and recycling performances of modifiedβmolecular sieves for dichloromethane were investigated,and the adsorption phase equilibrium and adsorption thermodynamic were studied.The results showed that the breakthrough adsorption capacity of various molecular sieves for dichloromethane followed the order of Agβ>Ceβ>Cuβ>Coβ.The concentration of AgNO_(3)solution had a significant impact on the adsorption capacity of Agβ.Agβmodified by 0.05 mol/L AgNO_(3)solution had the highest adsorption capacity and its saturated adsorption capacity reached 172.40 mg/g,which was 44.3%higher than that of Naβ.The breakthrough adsorption capacity reached 128.91 mg/g,which was 70.0%higher than that of Naβ.The characterization results,adsorption phase equilibrium and thermodynamic studies showed that the acidity of Agβwas significantly enhanced,which enhanced its adsorption affinity for dichloromethane,and thus significantly improved the adsorption capacity.