Tuning hydrophobicity of HY zeolite by suppressing dealumination process for toluene adsorption in humid conditions

Abstract

HY zeolites are widely used as adsorbent for volatile organic compounds removal due to their acceptable stability and high specific surface area. However, low adsorption capacity of toluene over HY zeolites at humid conditions limits their industrial application. In present work, the hydrophobicity of HY zeolite modified by CeO2 was enhanced successfully via a two-step process of high-temperature hydrothermal treatment and then acid treatment. It can be found that CeO2 introduction can significantly increase the adsorption capacity of toluene over HY zeolites. Typically, HY with 2 wt% CeO2 (2CeO2/HY-del) presented a remarkable adsorption amount of toluene (166.3 mg/gcat) and a satisfied regeneration performance at humid environment, which was higher than those of most reported modified Y zeolites (about 148.5 mg/gcat). The suppression of dealumination and maintaining of specific surface area during the harsh two-step treatment could be mainly responsible for the appropriate toluene adsorption capacity over the HY zeolites. Additionally, dynamic adsorption analysis revealed that the adsorption process belonged to the first-order adsorption kinetics, indicating that the adsorption process was mainly defined as a physical process. This work would guide the development of high toluene adsorption capacity at humid conditions.