Nanocomposite Gas Separation Membranes

Industrial energy consumption accounts for approximately 33% of all energy consumption in the United States, and a large proportion of this energy consumption is due to thermal processing. Gas separation, in particular, is often achieved using cryogenic distillation, an extremely energy-intensive process. One specific gas separation challenge is the removal of carbon dioxide from power plant flue gas emissions so as to reduce the impact of power plants on the environment. Traditional methods of CO2 removal require large amounts of energy, which in turn result in the production of more CO2 as more fossil fuels are burned to provide that energy. Membrane separations, on the other hand, are able to separate gases with significantly less energy input than thermal separation methods, leading to a potential to reduce energy consumption for any industrial gas separation process and to aid in the capture of CO2 from power plant emissions.

To efficiently and effectively separate gas mixtures, membranes must exhibit both high gas permeability (fast transport) and high selectivity for one gas over the other. Unfortunately, these properties tend to be diametrically opposed: membranes made of rubbery polymers have high permeabilities but low selectivities, while membranes made of glassy polymers have high selectivities but low permeabilities.  It has long been accepted that the addition of micron-sized inert impermeable particles to a polymer film decreases the permeability while leaving the selectivity unchanged.  However, research has shown that adding nanoparticles to a special class of glassy polymers results in an increase in permeability, while retaining or possibly even improving the selectivity. 

  • Our Work: We are examining the crossover between permeability enhancement and reduction with changes in particle size and polymer type.  Understanding these effects will allow for the design of tunable membranes for gas separations that allow traditional, energy-intensive separation methods to be replaced by more efficient membrane separation processes.
  • Experimental: We have developed techniques for casting polymer membranes from poly(dimethyl siloxane) (PDMS), poly(4-methyl 2-pentyne) (PMP), polycarbonate (PC), and poly (ether imide) (PEI).  We have prepared PDMS/silica and PMP/silica composite films and are working on a novel one-pot synthesis method to synthesize silica nanoparticles, surface treat these particles to make them compatible with the polymer, and cast the . Finally, we run gas permeation experiments on pure and composite films.
  • Modeling: In order to examine what is happening at the nanoscale within the polymers and polymer nanocomposites, we are carrying out molecular modeling using an open-source software called GROMACS.  We have developed a method to model free volume and gas transport in PMP membranes, and have also worked on modeling the silica nanoparticles. We are examining the change in free volume upon particle addition and the polymer-particle interface as well as the diffusivity of gases in the pure polymer and the composite. 
  • Characterization: We use Scanning Electron Microscopy (SEM) to obtain images of our composite films, DLS (dynamic light scattering) to determine the size of nanoparticles synthesized in our lab, and contact angle measurements to determine the hydrophobicity of surface-treated particles.  We also send samples to other labs for free volume determination via Positron Annihilation Lifetime Spectroscopy and Transmission Electron Microscopy (TEM) imaging. 

 

ESSAY PROMPT:

1.     A statement of your interest in research in general and in the project in particular.  Please include:

  • Why you are interested in this project,
  • Which parts of the project most interest you,
  • Information on your relevant background or desire to learn specified skills, and 
  • How many units you would be able to sign up for (typically between one and three) in Spring 2021 and Fall 2021 and briefly explain how adding these additional units per semester year would fit into your academic plan.  Note that each unit requires three hours of research work per week plus meetings.

2.   The names of two HMC professors (or outside research or internship advisors) who could provide references on your work style. Professors from project or lab classes might be especially good choices.

Name of research group, project, or lab
The Lape Lab: Nanocomposite Membrane Team
Logistics Information:
Project categories
Chemical Engineering
Materials Science
Student ranks applicable
First-year
Sophomore
Junior
Student qualifications

This project involves both modeling and experimental work, and you are welcome to decide which combination of these aspects you would like to pursue (assuming we will be able to be on campus in Summer 2021); please note this in your statement.  If you would like to do experimental work, you should feel comfortable in a chemical lab (for film preparation and nanoparticle work) and/or tinkering with equipment (for permeation experiments); if you would like to focus on modeling, you should have a desire to learn polymer physical chemistry and an aptitude for independent learning of theory and software (GROMACS).

 

Please note that this position begins in Sp 2021 (for academic credit) and continues through Summer 2021 (for pay) and Fall 2021 (for academic credit).

Time commitment
Spring - Part Time
Summer - Full Time
Compensation
Academic Credit
Paid Research
Number of openings
2
Techniques learned

Molecular modeling, nanoparticle synthesis, surface treatment, membrane casting, gas permeation experiments, Scanning Electron Microscopy (SEM), DLS (dynamic light scattering), contact angle measurements

Contact Information:
Mentor name
Nancy Lape
Mentor email
lape@hmc.edu
Mentor position
Faculty
Name of project director or principal investigator
Nancy Lape
Email address of project director or principal investigator
lape@hmc.edu
2 sp. | 0 appl.
Hours per week
Spring - Part Time (+1)
Spring - Part TimeSummer - Full Time
Project categories
Materials Science (+1)
Chemical EngineeringMaterials Science