On the solution of diffusion controlled adsorption kinetics by means of orthogonal collocation

The problem of diffusion controlled adsorption kinetics is solved by orthogonal collocation for the Henry and the Langmuir isotherms. The dependence of the surface concentration of a surfactant on time is described by explicit formulae for the whole range of time. The results are compared with those obtained by power series expansions and finite difference methods and have a high accuracy for any time value. The method of orthogonal collocation has been shown to be very effective. It is suitable for applications to similar problems.