Cyclic Adsorption–Regeneration of Polar and Nonpolar Volatile Organic Compounds on Honeycomb Zeolite Adsorbents

The adsorption performance of two honeycomb zeolites and beaded activated carbon (BAC) for volatile organic compounds (VOCs) was evaluated under industrially relevant conditions by using 2-propanol and 1,2,4-trimethylbenzene (1,2,4-TMB) as adsorbates. Equilibrium and cyclic adsorption capacity, removal efficiency, and heel build-up were assessed. Surface properties and thermal stability of fresh and used adsorbents were characterized by nitrogen adsorption and thermogravimetric analysis (TGA), while TGA–FTIR was used to examine the desorption behavior and activation energy. Fresh BAC exhibited a higher initial adsorption capacity; however, it showed a significantly higher heel build-up rate. After five adsorption–regeneration cycles, BAC and honeycomb zeolites exhibited comparable adsorption capacity and removal efficiency. TGA results indicated stronger binding and pore entrapment of 1,2,4-TMB on BAC, with nondesorbed species removed at higher temperatures (∼270 °C) compared to zeolites (145 °C). These results demonstrate that honeycomb zeolites are an effective alternative to activated carbon for VOC control under realistic industrial conditions.