Adsorption kinetic modeling of toxic vapors on activated carbon in the batch reactor

Abstract

The compound ortho-chlorobenzylidene malononitrile (OCM) is the defining component of tear gas commonly referred to as CS gas. In present work, at first, OCM was changed from solid state to aerosol form (vapor) using thermal technique and then the kinetics of adsorption of OCM aerosol on a cylindrical activated carbon was experimentally investigated. For this purpose, an experimental setup was designed and manufactured for measurement of adsorbed-gas equilibrium pressure. The effects of the initial weight of OCM (3–15 mg) and time of adsorption were studied. The kinetic adsorption data were correlated with eight different models in order to select the best model for this system. The kinetic adsorption data were well described by fractal-like pseudo-first order (FL-PFO) with high correlation coefficient (average R2 > 0.9963) and the appropriate physical interpretation of model coefficients. In addition, the t test results confirm the high capability of FL-PFO model for the analysis of the kinetic data. The obtained results showed that the equilibrium adsorption time significantly increased and the adsorption rate coefficient decreased (to a minimum value) with increasing initial weight of OCM. Also, the analysis of adsorption data for this system confirms that there are heterogeneous sites in the adsorbent surface with different adsorption energies.