Recovery of transition metal complex by reverse flow adsorption

Reverse flow adsorption (RFA) is a technique with a definite potential to prevent the leaching of a homogenous catalyst. In this work, we model an RFA-process for a continuous ideally stirred tank reactor with an adsorption bed upstream and another one downstream from the reactor. The model parameters concerning adsorption equilibrium and kinetics are taken from previous experimental studies on CoCl₂ adsorption on polymer-bound trifenylfosfine. We use this model to study the concentration profiles of CoCl₂ in the adsorption beds during consecutive adsorption-desorption cycles. The model calculations show that the concentration profile eventually reaches a fixed position after a number of adsorption-desorption cycles, even though internal mass transfer was a limiting factor. Hence, the transition metal is kept within the system boundaries, which is an essential requirement for the application of RFA.