Fixed bed and batch adsorption of benzene and toluene from aromatic hydrocarbons on 5A molecular sieve zeolite

Adsorption of benzene and toluene from aromatic mixtures extracted from reformate of catalytic naphtha reforming process was investigated. The adsorption kinetics of both adsorbates on 5A molecular sieve zeolite with a surface area of 600 m(2)/g were analyzed using batch and fixed bed systems. The effect of feed flow rate (1.0-2.7 ml/min), bed height (16.5-34 cm), and benzene initial concentration (0.064-0.180 g/ml) on the behavior of breakthrough curves was explained. The results showed that the enhancement of feed flow rate and benzene initial concentration created steeper curves with early breakthrough points, while larger bed height caused a delay in appearance of adsorbates in effluent stream. The displacement of weakly adsorbed benzene by strong toluene was observed. It was deduced that the kinetic data were well described by pseudo-second order model with high correlation coefficient. The adsorption rate constants for benzene and toluene were 0.494 and 0.413 g/g.min, respectively. (C) 2016 Elsevier B.V. All rights reserved.