 |
The
NanoCeram HyFlo™
housing is for applications requiring ultra-pure filtration, but with high flow
rates. |
|
“HyFlo™
Model #HBB-240 |
__small.jpg)
Click image to enlarge |
|
NanoCeram HyFlo™
Data Sheet |
|
|
NanoCeram® media consists of nano alumina (boehmite) fibers 2 nanometers in diameter (Figure 1) that are distributed onto a microglass fiber scaffolding and formed into a non-woven media. Boehmite (AlOOH) is an ingredient in over the counter analgesic medicines.
|
Fig.1- TEM Micrograph
of Alumina Nanofibers
|
The nano alumina is attached to the microglass rather than forming agglomerates that would clog the structure. Cellulose and polymeric fibers are added to strengthen the media and increase its flexibility so that it can be pleated. The resulting media has a maximum pore size of seven microns (as measured by bubble pressure), with an average of two µm. |
|
Argonide
has developed and patented a new filter
media, NanoCeram®,
whose active component is an alumina
(AlOOH) fiber two nanometers in
diameter. The nano alumina fiber is
highly electropositive, and will
attract and retain particles, no matter
how small. The nano fibers are
dispersed throughout a microglass fiber
matrix resulting in a media with 2
micron average pore size and with water
flux typically of that pore size.
However, the media functions as if it
were a 0.03 micron pore size filter.
A single layer 0.8 mm thick retains
greater than 99% of 0.03 µm
monodisperse latex spheres or 0.025 µm
size MS2 virus, justifying an Absolute
rating of 0.03 µm. It can be
pleated to produce a high surface area
cartridge (“Superfilter”) with a high
filtration efficiency, and with a dirt
holding capacity tens or twenty times
greater than microglass, meltblown or
membrane filters.
|
|
|
|
Characteristics of NanoCeram media -
The predominant mode of
filter liquids is mechanical processes such as sieving,
interception, impaction and diffusion. Wound
string depth filters are typically rated down to about 1
micron, with filtration efficiencies ranging up to only
about 95%. Pleated microglass or polymeric filter
media and microporous and ultraporous membrane are
better suited for filtering particles smaller than about
1 micron. Absolute 0.2 µm membrane filters are
capable of retaining all types of bacteria with very
high retention (>99.9999%) but they are transparent to
much smaller particles such as most virus.
Electrokinetic adsorption is used for
filtering particles from both air (“electrets”) and
water. Most colloidal particles in water are
negatively charged as a result of differences in
electrical potential between the water and the particle
phases. This charge is due to an unequal distribution of
ions over the particle surface and the surrounding
solution. Asbestos fiber filters (which are
electropositive) had been used for more than a century
until it was found to be a health hazard. So far there
has been little success in finding an asbestos
substitute. Membranes have been modified to
provide some electropositive functionality but their
flow resistance is very high and because they are
surface filters, they are prone to clogging.
|
|
|
|
|
|
Table 1
below,
shows zeta potential values for NanoCeram® media with a
thickness between 1.5 and 2 microns, comparing MS2 virus (~25 nm
size) adsorption as a function of nano alumina content. The
media becomes highly electropositive when the nano alumina content
exceeds about 15 weight percent, and is then capable of adsorbing >
99.9999% of virus as well as larger particles. |
|
Nano-Ceram®
content,
wt-%
|
True
zeta
potential
(z
true)
,
mV |
Surface
conductance
ls
,
nS
|
MS2
%
removal |
|
0 |
-35 |
0.92 |
8 |
|
5 |
-12 |
0.06 |
29 |
|
10 |
7 |
0.10 |
94 |
|
15 |
23 |
0.55 |
>99.9999 |
|
25 |
32 |
0.67 |
>99.9999 |
|
40 |
29 |
0.42 |
>99.9999 |
|
50 |
23 |
0.3 |
>99.9999 |
|
Table 1
- Zeta
potential and
Specific
Surface
Conductance
of NanoCeram®
filters |
|
|
Retention of Micron and Sub-micron Particles |
| | |
