极性VOCs组分在硅胶上的吸脱附性质研究

Adsorption and desorption properties of polar VOCs on silica gel

以丙酮和乙酸乙酯为例,运用吸附处理工艺进行极性挥发性有机物(VOCs)组分在硅胶上的吸脱附研究。通过氮气吸脱附等温线测试发现,所用3种硅胶中1~#硅胶具有最大的比表面积(766 m^2/g),明显优于2~#硅胶(513 m^2/g)和3~#硅胶(380 m^2/g)。1~#硅胶同时具有微孔和介孔结构,而2~#和3~#硅胶只具有介孔结构。通过丙酮和乙酸乙酯在3种硅胶上的吸脱附对比实验发现,在相同操作条件下,1~#硅胶保持出口气体达标时间是2~#和3~#硅胶的2~5倍,1~#硅胶最大的饱和吸附量是2~#和3~#硅胶的1.5倍左右。对应的脱附过程,1~#硅胶的脱附气体浓度提浓2.5倍以上,而2~#和3~#硅胶未检测到明显的气体提浓。选择1~#硅胶进行丙酮和乙酸乙酯的吸附处理是可行且合适的。

The adsorption and desorption of polar volatile organic compounds(VOCs)on silica gel are carried out by vacuum swing adsorption with acetone and ethyl acetate as examples.The nitrogen absorption and desorption isotherm test shows that 1#silica gel has the largest specific surface area(766 m2·g-1)among the three kinds of silica gel(1#,2#and 3#),which is larger than 2#silica gel(513 m2·g-1)and 3#silica gel(380 m2·g-1).Both 2#silica gel and 3#silica gel have mesoporous structure only,1#silica gel has micropore and mesoporous structures both.Through the adsorption and desorption experiments of acetone and ethyl acetate on the three kinds of silica gel,it is found that under the same operating conditions,the time of keeping export gas up to the standard for 1#silica gel is 2-5 times that for 2#silica gel and 3#silica gel,and the maximum saturated adsorption capacity of 1#silica gel is about 1.5 times as much as 2#silica gel and 3#silica gel.For the desorption process,the desorption gas concentration from 1#silica gel increases more than2.5 times compared with the initial concentration of the adsorption process,while the desorption gas of 2#silica gel and3#silica gel is not concentrated obviously.It is feasible and suitable for selecting 1#silica gel to adsorb and remove acetone and ethyl acetate.