Predictive Tools for Modelling Adsorption Phenomena

 Predictive Tools for Modelling Adsorption Phenomena

Richard T. Cimino, Rutgers University

1st Year Postdoctoral Fellow

Research Interests:

From cell signaling to the capture and sequestration of CO₂, phenomena that occur on the nanoscale (1-100nm) have a critical impact on our “macroscale” existence.  The technological advances in this broad field are felt today in many aspects of life – from the most mundane (water filters, air purifiers and cat litter!) to the most extraordinary (drug treatments, solar cells and super capacitors). In particular, my research focuses on one of the most ubiquitous classes of nanoscale phenomena – that of adsorption. Adsorption - the process by which one nanoscale object “sticks” to another -  has myriad subfields and applications and though it has been studied theoretically for over a century, our understanding of the fundamentals of the adsorption process are still the subject of scientific inquiry.  Using statistical mechanics and computational modelling, my research seeks to provide the scientific community with a more complete understanding of the fundamentals of this nanoscale phenomenon, while also providing practical and predictive tools that can be used by others to further their adsorption-related research.

Postdoctoral Projects: “Calculation of the Isosteric Heat of Adsorption Using Quenched Solid Density Functional Theory”

Under supervision of Alexander V. Neimark, Distinguished Professor, Department of Chemical and Biochemical Engineering, Rutgers University

PhD Dissertation: “Molecular Modeling of Adsorption of Simple and Complex Fluids on Nanoporous Materials”

Under supervision of Alexander V. Neimark, Distinguished Professor, Department of Chemical and Biochemical Engineering, Rutgers University

Research Experience:

My doctoral research focused on the development of computational and theoretical tools to describe the adsorption of simple and complex fluids in nanoporous materials using a variety of techniques including density functional theory, Monte Carlo simulation, and analytical modelling. Nanoporous materials consisted primarily of tailored, hierarchically structured (containing micro, meso- and macropores) carbons and silicas, which are touted for their high surface area-to-volume ratio. I have created novel hybrid Density Functional Theory kernels to analyze Ar, N₂ and CO₂ sorption isotherms on molecularly rough carbon and silica materials. These kernels have been incorporated into industrial software produced by Quantachrome Instruments and used by scientists across the world for the characterization of porous materials.

In another project, I developed a model of polymer interaction chromatography based on a fundamental thermodynamic approach utilizing Monte Carlo simulations and classical mass transfer dynamics.  This model is capable of describing the three modes of liquid chromatographic elution: SEC, LAC, and liquid chromatography at critical conditions (LCCC) with minimal parameterization.  This model can be used by chromatographic practitioners to predict the order of elution of polymer chains, or to determine the critical conditions of adsorption for chains of similar chemistry.

Teaching Interests:

            In addition to my research experience, I have an extensive teaching history in both Chemical Engineering and Mathematics.  As an undergraduate, I worked as a student mentor for three years within Rutgers’ Mathematics Department, working one-on-one with students during Calculus recitation sessions. I had the unique opportunity for the duration of my senior year to teach a recitation of Precalculus Mathematics, with thirty students per semester.  I worked for the majority of my Chemical Engineering graduate program at Rutgers as a Teaching Assistant, teaching Kinetics and Reactor Design four times at the Graduate level and once at the undergraduate, and teaching Fluid Mechanics two semesters at the Graduate level. In the future, I would like to teach Kinetics, as well as introductory courses in molecular simulation and statistical thermodynamics, aimed at Graduate students.

Future Direction: 

Of interest to me are several problems in adsorption which concern medical/biological applications of adsorption and environmental sustainability.

Adsorption Dynamics and Nanoscale Effects during Hydraulic Fracturing

The exploitation of shale gas reservoirs by hydraulic fracturing in the United States and other countries over the past 15 years has led to a boom in natural gas production, with the US currently deriving roughly 40% of its natural gas from shale. However, speculation on future production estimates is controversial due to uncertainty about shale gas availability and concerns about hydraulic fracturing’s effect on the environment. There is therefore a need to improve our understanding of the hydraulic fracturing process, in order to design safer and more cost-effective drilling operations. I intend to pursue a research program to computationally study the complex interactions of alkane mixtures in the pores of shale materials in an effort to 1.) examine the effect of slickwater (the mixture of water, sand, and chemicals pumped into wells prior to liberating gas) and on adsorption and mixing of alkanes in shale pores under geological conditions and 2.) explore the transport dynamics of alkane/slickwater mixtures in the pores of shale.  I have recently submitted this project as a proposal to the NRC postdoctoral competition.

Critical Adsorption and separation of biological polymers

            As an extension of my work on polymer chromatography, I would like to investigate the application of critical adsorption to the separation of realistic biopolymers – namely proteins, DNA and RNA for drug applications and gene sequencing.  Some specific problems in this field that I would like to contribute are 1.) the translocation of biopolymers for sequencing, 2.) The separation of biopolymers by critical properties, 3.) the adsorption and uptake of drug molecules by tumors.  4.) Application of adsorption to protein folding and solvation. 

Selected Publications:

§ R. Cimino, C. Rasmussen, Y. Brun, A. V. Neimark. Mechanisms of Chain Adsorption on Porous Substrates and Critical Conditions of Polymer Chromatography: Insight from Monte Carlo Simulations (Submitted)

§ R. Cimino, C. Rasmussen, Y. Brun, A. V. Neimark. Critical conditions of polymer adsorption and chromatography on nonporous substrates, Journal of Colloid and Interface Science. 474 p. 25-33 (2016)

§ R. Cimino, C. Rasmussen and A. V. Neimark, Communication: Thermodynamic analysis of critical conditions of polymer adsorption, J. Chem. Phys., 139 (20) p.201101-1-4 (2013)

§ R. Cimino, K. Cychosz, M. Thommes and A. V. Neimark, Experimental and theoretical studies of scanning adsorption–desorption isotherms, Colloids Surf. A: Physicochem. Eng. Aspects, 437 (SI) p.76-89 (2013)

§ K. Cychosz, X. Guo, W. Fan, R. Cimino, G. Gor, M. Tsapatsis, A. V. Neimark, and M. Thommes, Characterization of the Pore Structure of Three-Dimensionally Ordered Mesoporous Carbons Using High Resolution Gas Sorption, Langmuir, 28 (34) p.12647-12654 (2012)        

§ R. Cimino, C. Rasmussen, Y. Brun, A. V. Neimark. Simulation of Polymer Interaction Chromatography: A Review (in preparation for submission)

§ R. Cimino, K. Cychosz, M. Thommes and A. V. Neimark, Characterization of Micro-Mesoporous Carbons by High-Pressure CO₂ Adsorption with Hybrid QSDFT Methods (in preparation for submission)

§ R. Cimino, P. Kowalczyk, A. V. Neimark, “Calculation of the Isosteric Heat of Adsorption Using Quenched Solid Density Functional Theory” (in preparation for submission)