Adsorption-Desorption of BTX (Benzene, Toluene and O-xylene) on Fe, Fe-Al Pillared Clay

Abstract

The studies are conducted in laboratory to determine the adsorption-desorption behavior of BTX (benzene, toluene and o-xylene) in gas phase on Fe, Fe-Al pillared clays adsorbents. In experimental conditions of constant atmospheric pressure, initial concentrations with an increasing volume (0.5 - 2 ml) injected benzene (2.25), toluene (1.89) and o-xylene (1.66) μmol/L at T (40℃, 60℃ and 80℃), and the adsorption increases with increase of temperature, indicating that the adsorption process would be a chemical adsorption rather than physical one. The results are shown that the BTX adsorption data fitted very well (R2 > 0.999) to the both equations Langmuire and Elovitch for the three samples: bentonite (B), Fe-bentonite () and Fe-Al/bentonite (). At 80℃, the BTX adsorption capacity increased in the following order: . The maximum adsorption capacity () at 80℃ is 175.13, 171.84 and 171.81 μg/g respectively for benzene, toluene and o-xylene for ; the last is a good adsorbent of BTX removal. The benzene diffuses faster than toluene and o-xylene. Thermodynamic parameters, such as ,and are also discussed and the results suggested that the BTX adsorption on all samples used is a spontaneous and endothermic process. Desorption studies show that BTX is very easily desorbed with .