摘要
不可逆吸附是指在一定条件下,经长时间抽空或吹扫脱附仍脱不出去的那部分吸附质,它们在催化反应中起着十分重要的作用.在沸石分子筛中,由于存在特殊的孔道结构,而使不可逆吸附的作用更大;且可设想,不可逆吸附对其中的扩散将有很大的影响.
The effect of irreversible adsorption of cyclohexane, ethylbenzene, ortho-xylene and n-octane on diffusion in ZSM-5 molecular sieve was investigated by gravimetric method. For the above system, the ratios of diffusivities between two cases of with and without irreversible adsorption are:
cyclohexane: 3.6(348K),
ethylbenzene: 4.8(398K), 1.6(423K),
ortho-xylene: 2.6(423K),
n-octane: 12.3(398K).
It shows that the diffusivity is increased by irreversible adsorption. This effect can be explained by the covering of the strong adsorptive sites with irreversible adsorbates, which decreases diffusional resistance and increases diffusivity.
出处
《化工学报》
EI
CAS
CSCD
北大核心
1991年第6期765-769,共5页
CIESC Journal
基金
国家自然科学基金
