Perspectives on Adsorption. What else? A personal view

Abstract

In this Perspectives paper I reviewed my work on the adsorption area starting with section 1- Looking back…and the reading of the old book of C.L. Mantell in 1969 and my doctoral work in Nancy where I learned fixed-bed processes and mechanistic models. Then I mention the creation of my research group at the U. Porto and the organization of four NATO Advanced Study Institute bringing top researchers in the area as well as the origin of the International Adsorption Society and the Fundamentals of Adsorption conferences. In Section 2, I focus on lessons learned mentioning what is important to understand batch isothermal adsorption (adsorption equilibrium isotherm, operating line, LDF kinetic model) and fixed-bed processes, namely the concept of compressive and dispersive concentration waves resulting from De Vault equation (1943). Going from batch to continuous processes is illustrated with the case of Simulated Moving Bed (SMB) technology. In Section 3 I suggest a roadmap for the development of adsorption processes and sorption-enhanced reaction processes (SERP) combining experiments and process simulation, with reference to the importance of IAST theory in predicting multicomponent adsorption equilibrium, shaping and 3D printing of materials and the contribution of molecular simulation both for the screening of adsorbents and prediction of adsorption isotherms and transport properties. Finally in section 4, I discuss some challenges and opportunities related with difficult separations and the relevant choice of materials and processes together. I believe that in this time of transition from fossil energy to renewables many existing technologies will find a place in future biorefineries. Some references are made to CCUS and Power to Gas processes as an example of SERP. Finally, I address the importance in the future of hybrid modeling involving not only mechanistic aspects but incorporating data-driven modeling with tools from AI and machine learning and application of adsorption in different field as perfume engineering.