ADSORPTION BEHAVIOUR OF THIOPHENE ON HZSM-5 STUDIED BY FREQUENCY RESPONSE METHOD

The adsorption of thiophene on HZSM-5 was studied by using frequency response(FR) and intelligent gravimetric analyzer(IGA).An adsorption isotherm was recorded by IGA at 373 K and the FR spectrum of thiophene on HZSM-5 was recorded at the pressure range of(0.2-6.0)×133.3 Pa and the temperature range of 302-623 K.The results were interpreted according to the Yasuda model and Langmuir model,suggesting that the adsorption process was the rate controlling step for the mass transfer process of thiophene on HZSM-5,and two different adsorption processes,high frequency adsorption and low frequency adsorption,occured in the system.At 373 K,for the high frequency adsorption process,the Langmuir model can be applied,implying that a single layer adsorption takes place with an adsorption site number,N(2)s,of 0.922 mmol/g,while for the low frequency adsorption the Langmuir model cannot be applied and the adsorption site number,N(1)s,is 0.588 mmol/g.The high frequency adsorption is the main process for the adsorption of thiophene on HZSM-5.