A simplified driving force model for activated carbon adsorption

The use of two simplified driving force expressions are investigated for describing the intraparticle rate behaviour during adsorption onto activated carbon. A previously developed numerical solution to the surface diffusion model is used to compare the linear and quadratic driving force approximation when non‐linear isotherms and time variant boundary conditions are present. The results show that while the linear driving force equation is a poor approximation of the exact solution, the quadratic driving force is a good approximation, and its use in a kinetic model of activated carbon adsorption gives as good a description of adsorption behaviour as is given by the more detailed surface diffusion model. The driving force model has the advantage of being easier to solve, and the numerical solution requires significantly less computational effort.