Prediction for the Adsorption of Low-Concentration Toluene by Activated Carbon

Abstract

Activated carbon filters are widely used to remove gaseous pollutants in order to guarantee a healthy living environment. The standard method for evaluating the adsorption performance of filters is conducted at ~100 ppm. Although this accelerates the test and avoids the high requirements of the test device, it is still far from the contaminant concentration in the indoor environment, and adsorbents in practical application may show different capabilities. Therefore, this study compared several methods for predicting the adsorption performance of activated carbon and recommended a procedure based on the Wheeler–Jonas model to estimate the breakthrough curve at low concentrations using experimental data at high concentrations. The results showed that the Langmuir model and Wood–Lodewyckx correlation were the most suitable for obtaining the equilibrium adsorption capacity and mass transfer coefficient, which are critical parameters in the Wheeler–Jonas model. The predicted service life was derived from the breakthrough curve. A modification method based on a relationship with inlet gas concentration was proposed to reduce the prediction deviation of the service life. After modification, the maximum deviation was within two hours and the relative deviation was no more than 7%.

Experimental and Modeled Results Describing the Low-Concentration Acetone Adsorption onto Coconut Shell Activated Carbon

“…As for the activated carbon with a convex breakthrough curve, the model could not be matched. The breakthrough curves in some experiments were asymmetrical S-shaped, but the variation of breakthrough rate was close to In the early study of [43], the curve described by the Wheeler-Jonas equation was symmetric about the time point at 50% breakthrough and was a standard S-shape. It was presumed that the Wheeler-Jonas equation was suitable for cases when the breakthrough curve was an S-shape or close to an S-shape.…”

“…It was also found that the relative error between the modified and the measured service life was in the range of 0.1% to 4.7%, which further improved the accuracy of the predicted service life. In the early study of [43], the curve described by the Wheeler-Jonas equation was symmetric about the time point at 50% breakthrough and was a standard S-shape. It was presumed that the Wheeler-Jonas equation was suitable for cases when the breakthrough curve was an S-shape or close to an S-shape.…”