Minggu, 25 September 2011

Membrane Technology of Water

Membrane is a selective barrier between two phases. Membrane
have different thickness, some thicker and some are thin and
There are homogeneous and there is also heterogeneous. Viewed from the membrane material
composed of natural materials and synthetic materials. Natural ingredients are ingredients derived
of nature such as pulp and cotton, whereas the synthetic material made from chemicals,
eg polymers.
Membrane serves to separate materials by size and shape
molecules, holding the components of the feed which has a larger size than
membrane pores and skip components that have a larger
small. Solution containing components that are retained are called concentrates and
solution that flows is called permeate. Filtration using a membrane other than
serves as a means of separation also serves as a means of concentration and
purification of a solution that is passed on the membrane.
With membrane separation techniques are generally based on particle size
and molecular weight with a different thrust press, the electric field and different
concentration. Membrane separation process with the use of thrust
diff press generally grouped into four types including mikromembran,
ultramembran, nanomembran and reverse osmosis.
Membrane technology has several advantages compared with the process
Another, among others:
• Separation can be carried out continuously
• Energy consumption is generally relatively low
• The membrane can be easily combined with other separation processes
(Hybrid processing)
• Separation can be carried out in conditions that are easily created
• Easy to scale up
• No need for additional materials
• Membrane materials vary so easily adapted to use.
Shortage of membrane technology include: flux and selectivity because at
membrane processes generally occur phenomenon is inversely proportional to the flux
selectivity. The higher flux and often result in decreased selectivity
otherwise. While it is desirable in membrane-based process
is to enhance the flux and selectivity.
1. Microfiltration
Microfiltration is the separation of micron or submicron sized particles.
The shape prevalent form of the cartridge, good for removing particles from water
measuring 0.04 to 100 microns. Provided that the content of total dissolved pdatan
not exceed 100 ppm. Filtration cartridge is an absolute filtration. This means that the particles
solids will be captured, sometimes cylindrical cartridge that can be cleaned.
Cartridges are placed in a specific container (housing). Materials cartridge
wide: cotton, wool, rayon, cellulose, fiberglass, poly propylene, acrylic, nylon, asbestos,
cellulose esters, fluorinated hydrocarbon polymers.
The types of cartridges are grouped:
(1) Cartridge leletan
(2) Cartridge knitting-appendage-straggling
(3) Cartridge sheets - porous (a special filter paper, nirpintal media, membranes,
2. Reverse osmosis (RO)
RO membranes are made of various materials such as cellulose acetate (CA),
polyamide (PA), aromatic polyamide, polieteramida, polieteramina, polieterurea,
polifelilene oxide, polifenilen bibenzimidazol, etc.. Thin film composite membrane
made of various polymer materials for polymer coating plus substrate
functional on it.
Membrane change due memampat and fouling (stoppers).
Flux-compression or declined was similar to the crawl of plastic / metal when
exposed to compression load voltage. The greater the pressure and temperature, usually not
reversible and the membrane more compressible. Normally, the membrane working at a temperature of 21 -
35 degrees centigrade. Membrane fouling was caused by substances in the raw water
eg crust, deposition of colloidal, metal oxide, organic and silica.
Based on economic studies have demonstrated reverse osmosis
following advantages;
1. To feed the total dissolved solids below 400 ppm, reverse osmosis
is an inexpensive treatment.
2. To feed the total dissolved solids in the ATS 400 ppm, with penuruanan
total dissolved solids of 10% initially, reverse osmosis is very profitable
compared with deionized
3. For bait regardless of the concentration of total dissolved solids, accompanied
organic content of more than 15 g / liter, reverse osmosis is very good
for praperlakuan deionization.
4. Reverse osmosis little to do with chemicals, making it more
3. Ultrafiltration
Membrane ultrafiltration is a separation process techniques (use)
membrane to remove solutes BM (molecular weight) high,
various colloids, microbes until the suspended solids from water solution. Membrane
semipermeable used to separate macromolecules from solution. The size and
form of soluble molecules is an important factor.
In the technology of water purification, ultrafiltration membranes with molecular weight
membrane (MWC) 1000-20000 uncommon for removal of pyrogens, while heavy
membrane molecules (MWC) 80000-100000 to use colloidal removal.
Sometimes pyrogens (BM 10 000-20.0000) can be removed by the membrane 80 000
because of the dynamic membrane.
Ultrafiltration system pressure is usually low, 10-100 psi (70-700 kPa), then
can use ordinary centrifugal pumps. Ultrafiltration membranes in relation
with the purification of water used to remove colloids (the cause of fouling)
and elimination of microbes, pyrogens and particles with hygienic module.
Ultrafiltration membranes are made by printing a polymer cellulose acetate (CA)
as a thin sheet. The maximum flux when the membrane anisotropic, there is a thin skin
meetings and porous bearers. Membrane of cellulose acetate (CA) has the properties
but unfortunately a good separation can be damaged by bacteria and chemicals,
pH susceptible. There is also a membrane of polysulfone polymer, acrylic, and polycarbonate,
PVC, polyamide, piliviniliden fluoride, copolymers AN-VC, poliasetal, polyacrylic,
polyelectrolyte complexes, PVA cross tie. Membrane can also be made of ceramic,
aluminum oxide, zirconium oxide, etc..
4. Nanofiltration
Nanofiltration process reduction of hardness, eliminating bacteria and viruses,
color removal because of organic substances without producing harmful chemical substances
such as hydrocarbons terklorinisasi. Nanofiltration is suitable for water total dissolved solids
low, softened and removed organic.
Reduction properties typical of the types of ions: ions dwivalen more rapidly eliminated
than ekavalen, appropriate when the membrane was processed, the formulation tub maker,
temperature, annealing time, and others. The formulation is basically similar to reverse osmosis but
operational mechanism similar to ultrafiltration. So it's a combination of nanofiltration
osmosisi back and ultrafiltration.

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