Modeling of Aqueous BTEX Adsorption in Column and Multistage Adsorbers

Theoretical and experimental investigations have been conducted on the adsorption characteristics of benzene, toluene, ethylbenzene, and xylene (BTEX) by macroreticular resins. A theoretical model is proposed for describing the BTEX breakthrough curves of the adsorption column. The column adsorption model contains two model parameters, (tau)and K, that are conveniently estimated using the observed breakthrough data. The model was tested for benzene adsorption with a flow rate between 12 and 30 mL/min, inlet concentration between 200 and 500 mg/L, and temperature between 30 and 60°C. Excellent fit of the model to the measured data was obtained. The proposed model hence offers a convenient means for accurate predictions of the adsorption capacity and breakthrough point of a column BTEX adsorption process. Also developed are the mass balance equations representing countercurrent multistage adsorption process. The countercurrent multistage adsorption process has been shown to save a significant amount of adsorption resin in achieving the same BTEX removal as the single-stage process. Experimental tests for a two-stage example verify that up to 60% of the Ambersorb resin can be saved over a single-stage process.