Final Report: Computer Simulation of Osmosis and Reverse Osmosis in Structured Membranes
Molecular simulation methods were developed as part of this project to increase our fundamental understanding of membrane based separation systems. Our simulations clarified for example that steric (size) effects had a significant impact on the desalination membranes. Previously it was thought the separation was entirely driven by coulombic force (attractive/repulsive forces at the membrane surfaces). Steric effects played an important role, because salt ions in brackish water are never present alone, but are strongly hydrated which effectively increases their size, and makes it impossible to enter a membrane, while the smaller water molecules can enter more readily. Membrane surface effects did play a role in increasing the flux of water, but not in the separation itself. In addition we also developed simulation methods to study ion exchange, gas separations, and pervaporation. The methods developed were used to once again increase our fundamental understanding of these separation processes. For example our studies showed that when the separation factor of gases in membranes can be significantly affected by the presence of another gas, it is generally because the separation mechanism has changed. For example in the case of nitrogen and carbon dioxide, in their pure state the separation factor is determined by diffusion, while in mixtures it is influenced more by adsorption in the membrane (zeolite in our case) Finally we developed a new technique using the NMR chemical shift to determine intermolecular interactions for mixtures. For polar-nonpolar systems such as Xe dissolved in water we were able to significantly improve the accuracy of gas solubilities, which are very sensitive to the cross interaction between water and Xe.
- Research Organization:
- University of Illinois at Chicago
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- FG02-96ER14680
- OSTI ID:
- 1032490
- Report Number(s):
- FINAL REPORT; TRN: US201218%%968
- Country of Publication:
- United States
- Language:
- English
Similar Records
Forward osmosis :a new approach to water purification and desalination.
Ion Exclusion by Sub 2-nm Carbon Nanotube Pores
Related Subjects
42 ENGINEERING
54 ENVIRONMENTAL SCIENCES
ACCURACY
ADSORPTION
CARBON DIOXIDE
CHEMICAL SHIFT
COMPUTERIZED SIMULATION
DESALINATION
DIFFUSION
GASES
ION EXCHANGE
MEMBRANES
MIXTURES
NITROGEN
OSMOSIS
PURE STATES
SEPARATION PROCESSES
SIMULATION
WATER
Molecular Modeling
Reverse Osmosis
Gas Separation
Water Treatment
Pervaporation.