Modelling across Multiple Scales to Design Biopolymer Membranes for Sustainable Gas Separations: 1-Atomistic Approach
Kseniya Papchenko1, Eleonora Ricci2, Maria Grazia De Angelis1,3
1Institute for Materials and Processes, School of Engineering, University of Edinburgh, Sanderson Building, Robert Stevenson Road, Edinburgh EH9 3FB, UK.
Polymers
|April 13, 2023
Summary
This study evaluated carbon dioxide (CO2) and methane (CH4) capture in biodegradable polyhydroxyalkanoate copolymers. Molecular modeling identified the 100% 3-hydroxyvalerate (HV) homopolymer as a promising material for membrane applications.
Area of Science:
- Polymer Science
- Materials Science
- Chemical Engineering
Background:
- Polyhydroxyalkanoates (PHAs), specifically copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV), are biodegradable materials with potential for gas separation membranes.
- Previous research indicated good CO2 capture potential in PHBV due to favorable solubility-selectivity.
- PHBV offers a sustainable alternative to conventional synthetic polymers used in membrane technology.
Purpose of the Study:
- To assess the CO2 and CH4 sorption and transport properties of PHBV copolymers.
- To screen the performance of PHBV across a range of compositions (0% to 100% 3-hydroxyvalerate (HV)) using molecular modeling.
- To guide the selection of optimal PHBV-based membrane materials for gas separation.
Main Methods:
- Experimental testing of a commercial PHBV material with 8% HV.
- Molecular dynamics (MD) simulations for PHBV copolymers with 0%, 8%, 60%, and 100% HV.
- Validation of MD models against experimental density, solubility parameters, and X-ray diffraction data.
- Widom insertion method for CO2/CH4 solubility-selectivity prediction.
- Mean square displacement analysis for diffusivity-selectivity estimation.
Main Results:
- MD simulations showed good agreement with experimental CO2/CH4 solubility-selectivity.
- Diffusivity-selectivity predictions were somewhat overestimated by MD simulations.
- Simulations indicated that the homopolymer with 100% HV exhibits promising gas transport properties.
- Experimental data on 8% HV material corroborated simulation findings.
Conclusions:
- PHBV copolymers demonstrate potential as biodegradable materials for CO2 and CH4 separation membranes.
- The 100% HV homopolymer is identified as a particularly promising candidate for membrane applications.
- Molecular modeling is a valuable tool for screening and predicting the performance of PHBV-based membranes.
- Further investigation using macroscopic models will compare simulation approaches.
