Evaluation of absorption efficiency of Zeolite ZSM-5 in the removal of styrene vapors

Background: Volatile organic compounds (VOCs) are one of the most important and prevalent air pollutants. The vapor produced as a result of the vaporization ‎of these compounds, even at very low concentrations, is harmful to the environment and human health. Thus, the aim of this study was to evaluate the removal of styrene vapor from the air flow using Zeolite ‎(ZSM-5) in a continuous flow reactor. Materials and Methods: This cross-sectional study was conducted at a laboratory scale. Styrene concentrations of 200 and 300 ppm were selected for this study and steam saturation method was used to obtain the desired ‎dynamic concentration. The desired concentration of dynamic styrene vapor was prepared in a fireproof cubic continuous flow reactor (canopy). ZSM-5 was synthesized and ground in a flat steel plate with standard mesh number of 20-40 and was used to remove the styrene vapors. In order to evaluate the removal efficiency, two variables of time and initial concentration of pollutant were investigated. In addition, scanning electron microscopy (SEM), X-ray powder diffraction (XRD), the Brunauer–Emmett–Teller (BET) technique, and energy-dispersive X-ray spectroscopy (EDX) were used to investigate the surface and quality of the obtained adsorbent. Results: The results of SEM and XRD indicated the uniform surface and high purity of the synthesized zeolite. Adsorption breakthrough and saturation for 200 ppm of styrene concentration occurred in the first 35 and 510 minutes of the experiment, and for 300 ppm of styrene concentration, occurred 23 and 385 minutes after the beginning of the test, respectively,. Conclusions: ZSM-5 showed a high level of efficiency in the removal of styrene vapors from polluted air; thus, it can be used to remove this pollutant from large industrial environments.