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Thrust 2 - Desalination "Advanced Membrane Materials for Water Treatment"

Thrust 2 - Desalination "Advanced Membrane Materials for Water Treatment". Harry Ridgway, Res. Director Orange County Water District Fountain Valley, California & Robert L. Riley, President Separation Systems Technology San Diego, California. Advanced Materials for Water Purification.

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Thrust 2 - Desalination "Advanced Membrane Materials for Water Treatment"

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  1. Thrust 2 - Desalination "Advanced Membrane Materials for Water Treatment" Harry Ridgway, Res. Director Orange County Water District Fountain Valley, California & Robert L. Riley, President Separation Systems Technology San Diego, California Advanced Materials for Water Purification

  2. Background... • Modern water treatment is rapidly becoming dependent on membranes. • Bio-organic fouling is the major problem with the current generation of membrane separations (Example = biofouling). • Opportunities exist for innovation in the design of improved membrane materials for water purification.

  3. Asymmetric Cellulose Acetate General Properties... • random, helical, non-X-linked • dense, smooth, neutral surface • low flux/high salt rejection • poor organics rejection • chlorine tolerant • low fouling tendency • can be biodegraded Popular Membrane Materials...

  4. Polyamide Thin-Film Composites (TFCs) General Properties... • random, X-linked • rough, charged surface • high flux/salt rejection • good organics rejection • chlorine sensitive • high fouling tendency • not biodegradable Popular Membrane Materials...

  5. Cross-Flow Feed Water Flux Semipermeable Membrane (~0.2 micrometers) Porous Interior (~0.5 mm thick) Permeate Asymmetric CA Membrane

  6. Thin-Film Composite (TFC) Membranes... (Polyamide Layer)

  7. How are modern TFC membrane materials made?

  8. Organic Phase (Heptane, etc.) + Acid Chloride COCl Cross-Link or Extension COCl COCl Cross-Link or Extension Diffusion NH2 NH2 COCl O NH2 Random Structure Cross-Link or Extension N C + HCl H COCl + Di-Functional Amine Aqueous Phase Reaction

  9. Ultrastructure of TFC Membranes... PA Layer PA Layer PS Support PS Support

  10. AFM Image of PA Surface AFM Image of PA Surface

  11. -Flux loss -Solute passage 1. Bio-organic Fouling Molecular Adsorption Flux & Organics Rejection De-lamination PA 1 2 3 PS Swelling Chlorine Attack The Issues... 2. Physico-Chemical Integrity

  12. The Challenge... ...is to design a new generation of advanced membrane materials having... 1. Low-fouling surfaces 2. Greater physico-chemical integrity 3. Improved flux and solute rejections

  13. The Approach... • Bacteria and organics respond to a host of membrane surface properties. • A multi-variate approach is needed to identify which properties of membranes contribute to bio-organics adsorption.

  14. Multivariate Models MLR Analysis PC Analysis Cluster Analysis ANN Analysis Membrane Properties (independent variables) Bacterial Adhesion (dependent variable) Correlation of Membrane Surface Properties with Bacterial Attachment

  15. A B C D E F G H I Material Matrices... Hydrophobicity & Pore Aspect Ratio Flux Thickness Charge Hydrophobic Roughness Flux & Pore Diameter

  16. SPEES-PES... SO3H CH3 O O O + = = = O O O C S S O O S = = = n 1 5 O O CH3 O sulfonated polyether-ethersulfone/polyethersulfone (SPEES/PES) (sulfonation number = SPEES/PES = 1/5) polysulfone (PS) Polymer B Polymer A Charged Neutral Membranes Knoell et al., 1999, Journal of Membrane Science

  17. Membrane Topology Membrane Hydrophobicity Membrane Charge Bacterium A (Mycobacterium) Bacterium B (Flavobacterium) Bacteria Respond to Multiple Signals... Knoell et al., 1999

  18. Research Directions... • Anti-fouling surfaces • -neutral, hydrophilic, smooth • Oxidation-resistant surfaces • -new materials (e.g., CPTC) • Enhanced flux & solute rejection • -increased cross-linking; catalytic membranes

  19. Surface Modifications... -smooth, hydrophilic, neutral, mobile, renewable -More X-linking -Tri-amines, etc. -Stereochemistry -Other polymers? Anti-fouling Surfaces Chemical Resistance Catalytic Surfaces Structural Integrity Incorporation of catalyts in membranes -Charged PS layer -Fully aromatic -Glut. X-link MPD Directions... Directions... Directions... Directions...

  20. -OH -OH CH2 Covalent Amide-OH CH2 3-amino-1-propanol CH2 CH2 CH2 CH2 N .. HCl H N H .. O = H Un-Reacted Acid Chloride C Cl O = C PA Membrane To Increase the Hydrophilicity of TFC Surfaces...

  21. X X X X X To Improve Chlorine Resistance...

  22. Catalyst(s) (Pd, PEIs, etc.) CH3 N-N = O CH3 PA Layer Porous PS Polyester Support Pure water Catalytic Membrane Materials...

  23. + Magnetic Particles PA Layer Porous PS Polyester Support Mobile Membrane Surfaces... Kishore Rajagopalan [kishore@wmrc.uiuc.edu]

  24. Isolation & Purification Re-Assembly Flexibacter polymorphus a marine gliding bacterium (Ridgway et al. 1977. J. Bacteriol.) Pore-Like Structure Self-Assembling Renewable Surfaces... • Transport? • Stability?

  25. Self-assembled crystalline protein-lipid arrays • Hierarchical self-assembly: 2 states of organization • Self-organization of long actin protein rods into 2D crystalline sheets • Spontaneous folding of sheets into nested tubules • Potential applications • Molecular ‘fly-paper’ for bacteria • Spontaneous entrapment of bacteria in tubules • Gerard C. L. Wong et al., Science 288, 2035-2039 (2000)

  26. UIUC Stanford Catalysis Clark-Atlanta ACFs, Macrocycle Gates, Hyperbranched PEIs, etc. Catalytic Membranes TFCs Biofilms & Oxidation Studies Surface-Active Materials for Disinfection SST Surface-Modified TFC Membranes Applications R&D & Evaluations Surfaces, Biofilms, Mol. Modeling & Evals. Pilot-Scale Studies & Demonstrations Waste Management Biofilms OCWD Industry Affiliates Synergies & Collaborations... Novel Materials & Processes for Water Purification

  27. Less pretreatment, cleaning, downtime $ Lower Costs of Desalination More robust LF membranes Improved flux, rejection, efficiency, lifetime Expected Benefits of Research... New knowledge of materials/interactions

  28. End of Thrust #2... "Desalination" Next Presentation... Thrust #3..."Membrane Fouling and Mitigation"

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