Grantee Research Project Results
Improving the Quality, Availability and Sustainability of Drinking Water Supplies Through Antifouling and Antiscaling Desalination MembranesEPA Grant Number: FP917500
Title: Improving the Quality, Availability and Sustainability of Drinking Water Supplies Through Antifouling and Antiscaling Desalination Membranes
Investigators: Shaffer, Devin L
Institution: Yale University
EPA Project Officer: Jones, Brandon
Project Period: August 29, 2012 through August 28, 2015
Project Amount: $126,000
RFA: STAR Graduate Fellowships (2012)
Research Category: Academic Fellowships , Fellowship - Environmental Engineering
The objective of this research is to advance membrane desalination technology by reducing the fouling and scaling propensity of thin-film composite desalination membranes through surface modification. Modifying the membrane surface layer to increase the hydrophilicity and decrease the roughness will impart biofouling and scaling resistance by reducing both the attachment of bacteria and the surface crystallization of inorganic precipitates.Approach:
Coating and grafting techniques will be employed to attach poly(vinyl alcohol) and poly(ethylene glycol) polymers to the surface of thin-film composite desalination membranes. These polymers render the membrane surface layer smoother and more hydrophilic. The fouling and scaling resistance of the grafting and coating techniques using different polymers and membranes will be assessed through bench-scale experiments. Biofouling and scaling feed water conditions will be simulated, such as those that might exist for seawater desalination or desalination of brines from brackish water treatment plants. The effects of surface modification on the transport and structural properties of the membranes will be characterized using a laboratory-scale membrane filtration unit.Expected Results:
Surface modification with the selected polymers is expected to reduce the fouling and scaling propensity of desalination membranes by strongly binding water at the membrane surface. Foulants will interact with this bound water layer and not with the membrane surface itself. Reductions in the irreversible attachment of bacteria, an important step in biofilm formation, and the surface crystallization of inorganic precipitates are expected. Some tradeoffs between improved fouling and scaling resistance of the modified membranes and reduced membrane water permeability and salt rejection are anticipated. This work will contribute to an understanding of how the surface modification techniques and conditions affect membrane transport properties.
Potential to Further Environmental/Human
Fouling and scaling resistant membranes will improve the sustainability and reduce the costs of desalination by improving membrane performance, reducing cleaning frequency and intensity, and extending membrane life. Lowering these barriers to implementing membrane desalination technology can help alleviate water quality and water supply problems for communities in diverse geographic areas. Implementing desalination also reduces stress on existing freshwater supplies so that they may be preserved for ecosystem benefits.
desalination, membrane fouling, surface modification