Adsorption phenomena are very diverse and complex physicochemical processes that have applications in both gaseous and aqueous systems. Due to their complexity, adsorption models are often simplified down to empirical  expressions to describe equilibria and kinetics. While these simplified models work well under a specific set of conditions, they can often fail to accurately predict adsorption behavior when the conditions of a system change. Designing reliable and fundamental adsorption models often requires the solution to large, non-linear systems of equations or numerical solutions to partial differential equations. Therefore, in order to facilitate a more fundamental approach for studying realistic and complex adsorption behavior, we have been developing a simple and lightweight framework that abstracts away the challenging mathematics of adsorption modeling, thus allowing a user to focus on the physicochemical process itself rather than the numerical methods. This modeling framework contains at its core some state-of-the-art solvers for large linear and non-linear problems, while keeping efficiency in mind by utilizing sparse operators and/or preconditioning when available. Built on top of the core of the framework are a set of more targeted modeling modules for solving specific types of problems, such as adsorption reaction kinetics and/or mass and energy transport phenomena. These second tier software kernels are fully extendable and customizable to the particular type of problem one seeks to solve. As a demonstration of the capabilities of this framework, models for adsorption processes in aqueous and gaseous systems have been developed. For aqueous systems, a model of metal-ion adsorption onto polymer fibers has been developed. This model includes effects of temperature, ionic strength, surface charging, pH, and competing metal ions to give a detailed picture of the adsorption mechanism. In gaseous systems, a multi-species adsorption equilibria model has been developed and coupled with a diffusion kinetics model for mass transfer in bi-porous and homogeneous adsorbent pellets and includes the effects of changing temperature and partial pressures of the various gas species. As more and more modeling challenges are brought forth, our modeling framework continues to grow and develop, thus creating a dynamic structure for modeling adsorption processes of many different types.

Modeling framework for adsorption processes in environmental remediation and monitoring

255th National Meeting (2018)

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