Effect of Relative Humidity on Adsorption Capacity of Organic Vapors on Activated Carbon and Prediction by Modified D-R Equations

The effects of the presence of water vapor on adsorption of benzene, toluene, acetone and ethyl acetate were studied. Results show that competitive adsorption of water in binary system had depression effect on the adsorption of organic vapors, and the depression effect of humidity on the adsorption capacity of organic vapors increases with an increase in relative humidity and polarity of organic vapors molecules. Based on the Polanyi adsorption potential theory, the modified D-R equation was proposed by introducing a concentration effect coefficient variable A, and structural adjusting constant B, and water adsorption capacity in certain relative humidity W_w. The comparison of prediction value and experiment value indicates that the modified D-R equation is accurate with relative error 5.0%, and can be used to explain and predict the equilibrium adsorption capacity of organic vapor in the presence of water.