In this paper, a new modeling approach is proposed for adsorption kinetics investigation performed in batch reactors with a fluid–solid system. In particular, the mass balances have been developed by taking into account for both the external and internal mass transfer diffusion limitations, solving the dynamic partial differential equations (PDEs) system along the radius of the sorbent particles, considering both the fluid and solid phases that constitute the sorbent particle. From a numerical point of view, the solution of this type of problem is very challenging because it involves the simultaneous solution of many PDEs, ODEs and AEs