Chemical Engineering June 2016 - 51

The use of EPFs for filtration offers
the possibility of removing soluble
materials, such as heavy metals, endocrine
disrupters, pesticides, algae
toxins and PCBs from water because
such filters can support sorbent materials.
In the case of nanoAl-coated
EPFs, the filtration mechanism is
believed to be the result of the electrostatic
field inherent in the nanoalumina,
which causes polarization
of those compounds that have high
dipole moments.
Powdered activated carbon (8-µm
average particle size) embodied into
non-woven nanoAl has proven to
be very successful in drinking water
applications.
The media shown in Figure 1, center,
consisting of nanoAl that contains
ultrafine (8-µm) PAC particles, has
also been characterized for its ability
to retain metal and particles. Its
retention of colloidal and suspended
solids, including bacteria and virus,
were found to be equivalent to the
non-PAC filter.
EPF media offers a unique way
to facilitate the use of new nano
sorbents by embodying them into
new structures that could result in
high dynamic adsorption media,
much as was achieved with PAC in
nano-Al. Experimental procedures
used by the authors for development
of novel media involve the
preparation of non-woven handsheets,
12 × 12 in., embodying
the test sorbent. discs (25-mm
dia. × 1-mm thick) are punched
out and mounted in 25-mm-dia.
filter holders (Pall Syringe filter,
vWR part #28144-109), each of
which can hold up to three discs.
The mounted filters can be tested
individually or by stacking them in
series. Significant adsorption and
hydrodynamic data can be derived
on the use of novel sorbents embodied
in thin layer structures.
dE can be coated with AlooH
to produce an electropositive filter
media (known as dEAL). Quantities
of dEAL can be mixed with
test sorbents. This scheme is particularly
advantageous where the
sorbent particles are sub-micron in
size. distributing it over a coarser
dEAL particle bed allows better
access to the fluid stream and less
pressure drop.
Pleating and flowrate
Filtration often involves tradeoffs
between filtration efficiency and
flowrate. Engineers must determine
the optimal performance for both
depending on the requirements of
a particular application. one of the
key factors determining the design
and form of filters is the ability to
achieve increased effective filtration
area that will facilitate scaling
and speeding up of a filtration process
[15]. The primary motivation
for developing pleated membrane
cartridges is the need for increased
filter area to lower applied differential
pressures. Pleating also has
an added benefit in that less plant
space needs to be allocated for filter
installations.
For nonwoven filters, the thickness
of the filter also plays a role in
whether it can be pleated or not. Figure
3 shows flowrate data for several
electropositive depth media including
some of those listed in Table1. n
Edited by Scott Jenkins
References
1. Meltzer, T. H., Modus of Filtration. Adv Biochem Eng.
Biotechnol. vol. 98, pp. 27-71. 2006.
2. Pall, D. B., Kirnbauer, E. A.; and Allen B. T., Particulate
retention by bacteria retentive membrane filters, Colloids
and Surfaces. vol. 1, Issues 3-4, pp. 235-256.
July 1980.
3. Ostreicher, E.A., T. E. Arnold, and R. S. Conway,
Charge Modified Filter Media, Chapter 2, pp. 23-46,
in " Filtration and Purification in the Biopharmaceutical
Industry, " edited by Maik W. Jornitz, Theodore H.
Meltzer, 2nd ed. Informa, New York, 2008.
4. Kaledin, L.A., F. Tepper and T.G. Kaledin, Long-range
attractive forces extending from the alumina's nanolayer
surface in aqueous solutions, Int. J. Smart Nano
Mater. vol. 6 (3), pp. 171-194, 2015.
5. Kaledin, L.A. and F. Tepper, Scavenging cobalt and
other transition metals from radwaste, EPRI International
LLW Conference, June 21-23, 2016, Orlando,
Fla.
6. Brant, J., B. Dorr, and S. Thibeault Economic and
Performance Assessment of Electropositive Filtration
as a Pretreatment Process for Reverse Osmosis.
27th Annual Water Reuse Symposium September
9-12, 2012.
7. Wnek, W. Electrokinetic and chemical aspects of
water filtration. Filter Separation. vol. 11 (3), p. 237.
1979.
8. Yu, W. and H. Xie. A Review on Nanofluids: Preparation,
Stability Mechanisms, and Applications. Journal
of Nanomaterials, vol. 2012, 2012.
9. Lukasik, J., S.R. Farrah, S.E. Truesdail, and D.O.
Shah. Adsorption Mechanisms to Sand and Diatomaceous
Earth Particles Coated with Metallic Hydroxides.
KONA, vol. 45, pp. 87-91, 1997.
ChemiCal engineering www.Chemengonline.Com June 2016
10. Truesdail, S.E., G. B. Westermann-Clark, and D. O.
Shah. Apparatus for streaming potential measurements
on granular filter media, J. Environment. Engineer,
Dec. 1998, pp. 1,226-1,232.
11. Tepper, F. and L. A. Kaledin, Nanosize electropositive
fibrous adsorbent. U.S. patent no. 6,838,005, 2005.
12. Kaledin, L.A., F. Tepper, and T.G. Kaledin, Aluminized
Siliceous Powder and Water Purification Device, Incorporating
U.S. Patent no. 9,309,131, 2016.
13. Meltzer, T.H. and M. W. Jornitz, Concerning Mechanisms
of Particle Removal by Filters Chapter 5, pp.
81-149, in " Filtration and purification in the biopharmaceutical
industry, " edited by Maik W. Jornitz,
Theodore H. Meltzer, 2nd ed. Informa, New York,
2008.
14. Baloda, S.B., Filter Designs, Chapter 3, pp. 47-64,
in " Filtration and purification in the biopharmaceutical
industry, " edited by Maik W. Jornitz, Theodore H.
Meltzer. 2nd ed. Informa, New York, 2008.
15. Graham, D., Characterization of physical adsorption
systems. III. The separate effects of pore size and
surface acidity upon the adsorbent capacities of activated
carbon. J. Phys. Chem., Vol. 59, 1955.
Further reading
Kaledin, L.A., F. Tepper, and T.G. Kaledin, Long-range
attractive forces extending from alumina nanofiber
surface, Int. J. Smart Nano Mater., Vol. 5, pp. 133-
151, 2014.
Purchas, D.B; Sutherland, K. " Handbook of Filter
Media, " Elsevier Science Ltd., New York, p. 18,
2002.
Hua, M., S. Zhang, B. Pan, W. Zhang, L. Lv, Q. Zhang
Heavy metal removal from water/wastewater by
nanosized metal oxides: A review. Journal of Hazardous
Materials, Vol. 211-212, pp. 317-331, 2012.
Authors
Fred Tepper is president of Argonide
Corp. (291 Power Court, Sanford,
FL 32771; Phone: 407-3222500;
Email: Fred@argonide.
com). Tepper has been leading Argonide
since 1997. He formed the
company in 1996 to commercialize
nanotechnology originally developed
in Russia. Prior to starting
that company, Tepper served as
vice president of Mine Safety Appliances Co. (Pittsburgh,
Pa.) as well as general manager of the instrument division.
Tepper has also served as general manager for a
subsidiary of Mine Safety Appliances Co., and has been
involved with the company since 1957. Tepper holds a
B.S. in chemistry from New York University and a master's
degree in metallurgy from the NYU College of Engineering.
He has authored several peer-reviewed scientific
papers and is the co-inventor on 15 U.S. patents.
Leo Kaledin is vice president of
Argonide Corp. (same address and
phone; Email: kaledin@argonide.
com) and head of research and
development. Kaledin joined the
company in 1998, after several
academic research posts, at
Emory University (Atlanta, Ga.), the
Massachussets Institute of Technology
(MIT; Cambridge, Mass.)
and the Institute for Applied Sciences in Moscow, Russia.
He holds a Ph.D. from Moscow State University and
master's and bachelor's degrees from the Moscow Institute
of Physics and Technology. Kaledin has presented
research at several international scientific conferences
and is co-inventor on several patents.
51
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