ONE-SIDED SINGLE-PELLET TECHNIQUE FOR ADSORPTION AND INTRAPARTICLE DIFFUSION

The one-sided single-pellet dynamic technique introduced in this artic le is shown to be a very effective and simple method for the analysis of adsorption and diffusion in porous solids. Moment expressions are p resented for reversible and irreversible adsorption processes. Since t he adsorption equilibrium constant is the only unknown parameter in th e first moment expression, this parameter can be evaluated from a sing le set of pulse-response experiments. This technique to evaluate the a dsorption equilibrium constant is illustrated using ethylbromide as tr acer. It is also shown that for a very strongly adsorbing tracer, such as 1,2-dichloroethane in soil, modified moment expressions derived wi th a semiinfinite boundary condition are necessary unless a criterion developed in this work is satisfied.