Potential theory of adsorption of nonelectrolytes from dilute aqueous solutions. Benzene adsorption

The equilibrium relationship is derived from the potential theory of adsorption, the concept of micropore volume filling, and assumptions that solute adsorption results in a solvent displacement from micropores and in a formation of an interface between an adsorbed phase in micropores and a solution in an extramicropore space. Water desorption from micropores is characterized by the affinity coefficient which is estimated from immersion heats. The energy of the interface formation is calculated from a model of active carbon structure. An isotherm equation shows the relationship between adsorption of the organic component in micropores, on the one hand, and parameters of active carbons (Limiting adsorption volume, micropore volume, characteristic energy, immersion heats, interface area), parameters of solution components (solute and solvent affinity coefficients, interfacial tension, saturated concentration, molar volumes), and conditions of operation (temperature, equilibrium concentration), on the other hand. The correlation between adsorption from aqueous solutions and both the carbon crystallite sizes and the oxygen complexes on the carbon surface is predicted. The main results are discussed in terms of the Weibull distribution function,and the generalized equation is proposed. The theory has been successfully applied to published data for adsorption of benzene ii-om aqueous solutions on active carbons. It is pointed out that there is an urgent need for more independent studies, and a number of suggestions for future work are given.