The Role of Chemistry and Materials Science in_EN

Report
SAND No. 2011-5958P
Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company,
for the United States Department of Energy’s National Nuclear Security Administration
under contract DE-AC04-94AL85000.
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
2
Glass reinforced plastics - corrosion
Pump coatings - friction reduction
Pipe lining – trenchless technology
Source : U.S. Filter
Composite pumps – corrosion resistant
Steel alloys (Duplex SS)- corrosion
resistant
Polymers, resins, additives- treatment
Polymeric membranes- porous: water
purification, nonporous: desalinationpressure driven
3
http://www.gewater.com/products
/equipment/mf_uf_mbr/zeeweed_5
00.jsp
http://www.pall.com/power_34168.asp
http://www.ionics.com/tech
nologies/ro/index.htm#
4
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) 137154
Alyson Sagle and Benny D. Freeman,
5
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.
6
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.
7
•Asymmetric membranes are
formed by phase inversion
and produces anisotropic
material.
Membrane Polymers
•Polysulfone (PSF),
•Polyethersulfone,
•Poly(vinylidene fluoride),
•Polyacrylonitrile,
•Polypropylene.
Source : Pall
Pressurized
in housing
Submerged
in cassette
8
Source: Zeeweed
UF and MF membranes can be
“inside-out” or “outside in”
Mean pore size ~ size rating of filter (.01 -10 micron)
Lumen
Source:
Koch Membranes
Permeate
Feed
Skin
Porous membranes can be
backflushed and cleaned.
9
Primary difficulty with membranes is
fouling
Dead-end membrane operation
feed
permeate
Cross-flow membrane operation
feed
∆P
∆P
permeate
Crossflow operation scours the surface
and reduces stagnation near membrane
surface.
10
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
11
2007 EDS Conference, Halkidiki, Greece
Craig Bartels*, Mashiko Hirose, Hiroki Fujioka
*Hydranautics
12
saline feed
posttreatment
pretreatment
high pressure pump
concentrate disposal
fresh
water
Thin film composite membrane
RO Plant
dense polyamide membrane
porous polymer
mechanical support
•concentration dependent,
• membranes susceptible to fouling,
O
• pre-treatment required,
NH
polyamide
H 2N
• polyamide membranes degraded by Cl2.
O
NH
O
13



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.
Kah Peng Lee, Tom C. Arnot, Davide Mattia
14
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)
4551–4566. Dan Li and
Huanting Wang
15
Membrane cost
per volume
water
Year
Year
Energy required
(kWh/m3)
Salt Passage (%)
Energy consumption and membrane costs have
been reduced by new membrane formulations.
Year
Journal of Membrane Science, 370 (2011) 1-22.
Kah Peng Lee, Tom C. Arnot, Davide Mattia
16
Contact angle (°)
Membrane surface hydrophilicity
enhanced by surface modification
Coating solution (mg/L)
Surface modification leads to
decrease in contact angle;
Less fouling potential,
somewhat reduced water
permeability
Journal of Membrane Science 371 (2001)293-306.
Sanchuan Yu, Zhenhua Lu, Zhihai Chen, Xuesong
Liu, Meihong Liu, Congje Gao
17
Membrane smoothness has
an effect on membrane
fouling
Journal of Membrane Science188 (2001)115-128.
Eric M. Vrijenhoek, Seungkwan Hong, Menachem
Elimelech
Smoother membrane
surface leads to less fouling
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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.
Guo-Dong Kang, Cong-Jie Gao, Wei-Dong Chen, XingMing Jie, Yi-Ming Cao, Quan Yuan
19
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
20
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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