Chemical Chemical Security Security Program Program The Role
Chemical Chemical Security Security Program Program The Role of Chemistry and Materials Science in Advanced Water Treatment Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energys National Nuclear Security Administration under contract DE-AC04-94AL85000. The Role of Chemistry and Materials Science in Advanced Water Treatment Materials Science is an Essential Part of Water Treatment Infrastructure
Introduction Water treatment processes Materials science for water infrastructure Membrane technology- polymeric Micro and ultrafiltration (MF and UF) Nanofiltration and reverse osmosis (NF and RO) Recent RO membrane advances 3 Materials Science has a Dramatic Effect on Water Treatment Infrastructure Glass reinforced plastics - corrosion Source : U.S. Filter
5 Membrane Separation Spectrum Dissolved salts Nonporous Suspended solids/ DOM Porous Virus Bacteria Porous: Filtration by size - molecular weight cutoff (MWCO). Nonporous: Solution diffusion separation hydrated ions. Removal: Salinity can be reduced only by RO/NF membrane treatment. The Future of Desalination in Texas:Texas Water Development Board 2,(2004) 137-154 Alyson Sagle and Benny D. Freeman,
6 Basic Water Treatment Removes Particles and Dissolved Organics Coagulant Coagulation Flocculation Sedimentation and or filtration Removal of particles and natural organic matter (NOM), color, disinfection byproducts (DBP), iron, manganese, arsenic, taste, odor.
Granular activated carbon can be used as a filter and adsorber, but regeneration may be different than sand media. 7 Microfiltration (MF) and Ultrafiltration (UF) can be used Instead of Sand Filters Coagulant Microfiltration or Ultrafiltration concentrate Coagulation Flocculation
Membrane filtration normally uses hollow fiber bundles that can be submerged or pressurized. These membranes can be air scoured , backflushed and cleaned and are not usually sensitive to chlorine. 8 Hollow Fiber Units Consist of Tube Bundles (UF-MF) Pressurized in housing Source : Pall Asymmetric membranes are formed by phase inversion and
produces anisotropic material. Membrane Polymers Polysulfone (PSF), Polyethersulfone, Poly(vinylidene fluoride), Polyacrylonitrile, Polypropylene. Submerged in cassette Source: Zeeweed 9 UF and MF Membranes can be Inside-out or Outside in Mean pore size ~ size rating of filter (.01 -10 micron)
Source: Koch Membranes Lumen Permeate Feed Skin Porous membranes can be backflushed and cleaned. 10 Primary Difficulty with Membranes is Fouling Dead-end membrane operation
feed permeate Cross-flow membrane operation feed P P Crossflow operation scours the surface and reduces stagnation near membrane surface. permeate 11 Non-porous Membranes: Nanofiltration, Reverse Osmosis-thin Film Composite (TFC)*
thin, dense polymer coating on porous support (composites) Journal of Membrane Science, 158 (1999) 143-153. Seung-Yeop Kwak, Dae Woo Ihm Surface morphology Thin (100 - 200 nm) polyamide membrane Porous support (polysulfone UF membrane) Woven mechanical support * Discussion will not focus on cellulose acetate asymmetric membranes 12
Spiral Wound Membrane has Multiple Flat Sheet leafs 2007 EDS Conference, Halkidiki, Greece Craig Bartels*, Mashiko Hirose, Hiroki Fujioka *Hydranautics 13 Reverse Osmosis Primarily Uses Polyamide TFC Membranes saline feed me m pretreatment high pressure pump bra
n e posttreatment concentrate disposal fresh water concentration dependent, membranes susceptible to fouling, pre-treatment required, polyamide membranes degraded by RO Plant Thin film composite membrane dense polyamide membrane
porous polymer mechanical support Cl2. O NH polyamide H2N O NH O 14 Reverse Osmosis Membrane Performance Measured by Four Factors
Salt rejection, Water permeability, Fouling (multifaceted), Chlorine tolerance. Salt Rejection Normalized water permeability m3/(m2 bar day) Journal of Membrane Science, 370(2011) 1-22. 15 Kah Peng Lee, Tom C. Arnot, Davide Mattia Active Research Topics in RO Membrane Science and Desalination
Modification of PSF substrate Increase hydrophilicity Control of interfacial polymerization Crosslinking Membrane thickness Increase hydrophilicity Increased chlorine tolerance Surface post treatment Modify surface charge Membrane morphology Surface roughness New thin film nanocomposite studies Polymer with zeolite, Ag, TiO2 Journal of Membrane Science, 370 (2011) 1-22. Kah Peng Lee, Tom C.
Arnot, Davide Mattia J. Mater. Chem., 20 (2010) 45514566. Dan Li and Huanting Wang 16 Materials Science has Provided Major Breakthroughs in Water Treatment Energy consumption and membrane costs have been reduced by new membrane formulations. Journal of Membrane Science, 370 (2011) 1-22. 17 Kah Peng Lee, Tom C. Arnot, Davide Mattia Membrane Surface Hydrophilicity Enhanced by Surface Modification
Surface modification leads to decrease in contact angle; Less fouling potential, somewhat reduced water permeability Contact angle () Coating solution (mg/L) Journal of Membrane Science 371 (2001)293-306. Sanchuan Yu, Zhenhua Lu, Zhihai Chen, Xuesong Liu, Meihong Liu, Congje Gao 18
Membrane Smoothness has an Effect on Membrane Fouling Smoother membrane surface leads to less fouling Journal of Membrane Science188 (2001)115-128. Eric M. Vrijenhoek, Seungkwan Hong, Menachem Elimelech 19 Membrane Degradation by Chlorine Thin film composite membrane dense polyamide membrane porous polymer mechanical support
Membrane degradation proceeds by chlorination of the amide followed by ring chlorination Journal of Membrane Science, 300 (2007) 165-171. GuoDong Kang, Cong-Jie Gao, Wei-Dong Chen, Xing-Ming Jie, Yi-Ming Cao, Quan Yuan 20 Chlorine Tolerant Membranes Being Studied A new polymer formulation holds promise as a chlorine tolerant RO membrane. Angew. Chem. 120 (2008), 6108 6113. Ho Bum Park, Benny D. Freeman, Zhong-Bio
Zhang, Mehmet Sankir, James E. McGrath 21 Conclusion Polymer science and composite fabrication have lead to increased use of membranes and advanced materials in water treatment. Microfiltration and Ultrafiltration membranes have provided compact, efficient means of removing suspended solids and wastewater contaminants. Nanofiltration and RO membranes provide lower energy alternatives for water desalination.
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