Zeolitic imidazolate framework-8 (ZIF-8) was used as an adsorbent for the removal of toluene in its gas phase at different relative humidity (RH). High-purity ZIF-8 with an average particle size of 0.64 µm synthesized from an aqueous solution at room temperature, and then characterized by X-ray diffraction (XRD), fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) techniques. Dynamic adsorption (continuous mode) experiments of toluene on ZIF-8 were studied using breakthrough curves. The effects of thermal pretreatment (activation) under dry air and N₂ atmospheres on the adsorbent performances was studied. ZIF-8 activated at 300 °C for 3 h under dry air showed the highest adsorption capacity of 562.17 mg∙g⁻¹. Furthermore, it was observed that the adsorption of toluene on ZIF-8 was significantly decreased at 80% RH. The experimental data of dynamic adsorption well fitted into the Thomas and Yan mathematical models.

The zeolitic imidazolate framework-67 (ZIF-67) has been explored for the dynamic adsorption of toluene vapor. We synthesized ZIF-67 through a straightforward room-temperature process and characterized it using XRD, FT-IR, DLS, and SEM techniques. The synthesized ZIF-67 possessed a Brunauer–Emmett–Teller (BET) surface area of 1578.7 m²/g and 0.76 μm particle size. Thermal activation under various conditions revealed that ZIF-67, activated in dry air at 250 °C, demonstrated optimal adsorption efficacy. Its adsorption capacity, time of breakthrough, and time of equilibration were 414.5 mg/g, 420 min, and 795 min, respectively. We investigated the impact of diverse operational parameters on adsorption through breakthrough curve analysis. An increase in the toluene concentration from 100 to 1000 ppm enhanced the adsorption capacity from 171 to 414 mg/g, while breakthrough time decreased from 1260 min to 462 min, respectively.