Impact of pore size controlling on adsorption of volatile organic compounds on MCM-41
孔径调变对MCM-41分子筛吸附VOCs性能的影响

Molecular sieves 8-MCM-41,12-MCM-41,and 16-MCM-41 were synthesized using alkylammonium salts CnTAB of different alkyl chain lengths (n=8,12,16) as templates.Dynamic adsorption of toluene,o-xylene,and mesitylene on these mesoporous molecular sieves was studied.The results show that the mean pore diameter can be adjust to 4.1 nm,3.2 nm,and 2.4 nm by decreasing the alkyl chain length.The amount of toluene and o-xylene adsorbed increased significantly as the mean pore diameter decreased.There was little increase in mesitylene adsoption due to diffusion.The adsorption isotherms showed that the adsorption of VOCs on molecular sieves with a pore diameter of 2.4 nm followed Langmuir monolayer adsorption;when the mean pore diameter was larger than 2.4nm,the adsoption appeared to be multilayer,with capillary condensation observed.