Research On The Adsorption-Desorption Performance Of Vocs On ZSM-5Zeolite

With the development of modern industries, the control and treatment of Volatile Organic Compounds (VOCs) has become one of the hottest topics in the field of environmental protection. The adsorption technology is an effective method to dealing with VOCs. Active carbon, as the commonly used adsorbent today, is flammable and explosive. Meanwhile, it is also difficult to regenerate. So it is not adapt to the treatment of complex and changeable industrial waste gas.In our research, we prepared H-ZSM-5molecular sieve through the ion exchange method by using the commercial Na-ZSM-5zeolite as raw material. The influences of different surface cations and Si/Al ratios on the hydrophobicity and toluene adsorption property of ZSM-5zeolite were investigated, it was found that Na-ZSM-5has better hydrophobicity and adsorption performance of toluene, and the high silicon (Si/Al=300) Na-ZSM-5has better hydrophobicity and the selective adsorption ability of toluene. At the same time, we used the Thermal Gravimetric Analysis(TGA) to study the desorption of toluene on ZSM-5zeolite, the result showed that toluene on these ZSM-5zeolites can all be desorbed before400℃, they all have good thermal regeneration performance.In order to study further on the adsorption and desorption performances of different VOCs on the ZSM-5zeolite, we chose four types of VOCs(such as alcohols, esters, hydrocarbons and ketones) to investigate their adsorption and desorption performances on Na-ZSM-5zeolite. The result showed that, Na-ZSM-5zeolite was more suitable to adsorb micromolecule VOCs whose carbon number is less than six such as isopropyl alcohol, acetone and ethyl acetate and so on; but those macromolecule VOCs such as cyclohexane and cyclohexanone have worse adsorption results because of the lack of using the inner surface area as they can’t go into the pore of zeolite. Moreover, we also found that, because their molecular size and polarity both increase with the increasing of carbon number of the VOCs with the same group, their interaction force with zeolite became more and more stronger, and their adsorption amount on zeolite rised as well.In order to know the adsorption property of the actual industrial waste gas on Na-ZSM-5zeolite, we simulated several common industrial waste gases to investigate the use of Na-ZSM-5in dealing with these simulating waste gases. The result showed that, Na-ZSM-5zeolite had good adsorption performance of all these simulating waste gases, it has better selective adsorption property of VOCs in waste gases with micromolecule and strong polarity, but its adsorption property of VOCs with macromolecule and weak polarity is not ideal.