Y型与ZSM-5型分子筛吸附VOCs性能的对比

Comparison of VOCs adsorption performance between Y and ZSM-5 zeolite

从疏水性较好的分子筛中筛选出2类吸附性能优良的分子筛,通过实验考察其对VOCs的吸附量、脱附量、吸附穿透曲线、脱附活化能等,评价其对VOCs的吸附脱附性能;评估了所选分子筛经多次吸附再生后的性能稳定性,建立了一套分子筛工业应用性能指标体系。结果表明:Y型分子筛性能优于ZSM-5型分子筛;同种分子筛比表面积及孔径越大,单位质量能吸附的VOCs量越多;在甲苯/乙酸丁酯的竞争吸附体系中,Y型分子筛及ZSM-5型对甲苯的吸附量较单组分情况下分别下降了50.1%、40.1%,而对乙酸丁酯的吸附量分别增加了189%、102%;甲苯在Y型分子筛上的脱附活化能为76.7 kJ·mol^(−1),在ZSM-5分子筛上的脱附活化能为64.7 kJ·mol^(−1);Y型分子筛和ZSM-5型分子筛均具有较好的循环使用性,吸附性能稳定;Yoon-Nelson模型能较好地拟合分子筛吸附穿透曲线,拟合系数在0.97以上。

Two kinds of zeolites with good absorbability and excellent hydrophobicity were selected as absorbents.The experiments were conducted to study their adsorption capacity,desorption capacity,adsorption breakout curve,desorption activation energy,etc..The adsorption and desorption properties for volatile organic compounds(VOCs)and the stability after reuse were evaluated,then a set of zeolites industrial application evaluation index system was established.The results indicate that the Y zeolites were superior to ZSM-5 zeolites in adsorption performance.The larger the specific surface area and pore size of zeolite were,the more VOCs could be adsorbed.In the competitive adsorption system of toluene/butyl acetate,the adsorption capacity of toluene decreased by 50.1%and 40.1%,respectively,and the adsorption capacity of butyl acetate increased by 189%and 102%,respectively,comparing with that of single component adsorption system.The activation energy of toluene desorption on Y zeolite and ZSM-5 were 76.7 kJ·mol^(-1) and 64.7 kJ·mol^(-1),respectively.Both Y zeolites and ZSM-5 zeolites had a good recycling performance.Yoon-Nelson model could fit the adsorption penetration curve well,and the fitting coefficient was above 0.97.