PhD Fellowship in Adsorption and Transport of CO2 in Nanoporous Solids

Despite the importance of predicting flows through disordered media (ie in oil and gas reservoirs, membranes for fluid separation, drug transport through biomembranes), there are few studies available in the literature that combine multi-scale tools capable of connecting nano and macro scales. It has been shown that nano-flows through disordered media exhibit transport properties that deviate from their continuous analogues. Here we will investigate this in more detail and advance the field substantially by employing advanced techniques of molecular dynamics simulations under non-equilibrium conditions for nanoscale flow in order to provide relevant transport properties (eg permeabilities, diffusion coefficient, solubility, etc.) of CO 2 in nano-confinement. 

Project aims

The long-term objective of the research is to obtain an understanding of the fundamental physics behind the adsorption and transport processes in the micro and nanoscale with the aid of well-guided computational simulations. A coarse-grained molecular simulation approach is expected to allow researchers to cover mixing complexities, system sizes, time scales and length inaccessible with any other experimental or modeling technique, filling a current knowledge gap. The objective of this project is to explore the relationships between porous media properties (pore size distribution, nanopore shape and roughness, connectivity, surface chemical composition, heterogeneity, etc.) in local and macroscopic adsorption and flow properties. These in silico are sufficiently accurate to be used as guidelines for the reverse engineering of membranes and porous media (membranes and / or adsorption beds) for separation and purification of the fluid phase. 

Methodology

It is proposed to perform molecular dynamics simulations of large-scale coarse-grained CO 2(and mixtures) permeating through confined regions of the model. Non-equilibrium techniques similar to those used to study the flow of mixtures through porous media, previously documented in the literature [1,2], will be employed allowing the direct evaluation of adsorption, diffusion and permeability. The geometry and chemical composition of the pore surface will be systematically modified to understand the effects of these variables on the permeability and selectivity of porous networks. We employ coarse granulation models that allow the implementation of very large size systems and the exploitation of large time scales which in turn will provide unique information on the equilibrium and dynamics properties of CO 2 transport in nanoconfinition. " Graining Coarse "(English coarse graining ) is a term that refers to the use of simplified molecular model, where the atomistic description is removed and replaced by a description of molecules in terms of" super atoms ", which typically represent a small number of atoms For example, in a standard CG representation, a CO 2 molecule could be modeled as an isotropic spherical sphere where all the electronic details, intramolecular vibrations, link flex and molecular topology are incorporated into a paired interaction model of points [3]. 

Requirements

This project is only suitable for Brazilian applicants or foreigners with permanent residency in Brazil who are highly motivated to act in research involving computational simulations. Candidates must have a master's degree in Mechanical Engineering, Chemistry, Petroleum, or Chemistry or Physical Education). Programming / scripting skills and experience with simulation software are required, as well as excellent communication skills. 

Minimum score for Brazilian candidates enrolling for the PhD at Imperial College is 7.5 out of 10 and minimum score at IELTS, 6.5. 

Additional information

The selected candidate will receive the full sponsorship of the tuition values ​​for the PhD at Imperial College and a scholarship granted by CNPq. 

References

1. H. Frentrup, et al., "Transport diffusivities of fluids in nanopores by non-equilibrium molecular dynamics simulation", Mol. Simul., 38, 540-553 (2012)
2. H. Frentrup, K. Hart , C. Colina, and E. Muller, "In Silico Determination of Gas Permeabilities by Non-Equilibrium Molecular Dynamics: CO 2 and He through PIM-1," Membranes, 5, 99-119, (2015).
3. C. Avendaño, T. Lafitte, A. Galindo, CS Adjiman, G. Jackson, and EA Müller, "SAFT-γ Force Field for the Simulation of Molecular Fluids. 1. A Single-Site Coarse Grained Model of Carbon Dioxide, J. Phys. Chem. B, 115, 11154-11169, (2011).