Filtration is a mechanical or physical operation which is used for the separation of solids from fluids (liquids or gases) by interposing a medium through which only the fluid can pass. Oversize solids in the fluid are retained, but the separation is not complete; solids will be contaminated with some fluid and filtrate will contain fine particles (depending on the pore size and filter thickness).

  • Filtration is used to separate particles and fluid in a suspension, where the fluid can be a liquid, a gas or a supercritical fluid. Depending on the application, either one or both of the components may be isolated.
  • Filtration, as a physical operation is very important in chemistry for the separation of materials of different chemical composition. A solvent is chosen which dissolves one component, while not dissolving the other. By dissolving the mixture in the chosen solvent, one component will go into the solution and pass through the filter, while the other will be retained. This is one of the most important techniques used by chemists to purify compounds.
  • Filtration is also important and widely used as one of the unit operations of chemical engineering. It may be simultaneously combined with other unit operations to process the feed stream, as in the biofilter, which is a combined filter and biological digestion device.
  • Filtration differs from sieving, where separation occurs at a single perforated layer (a sieve). In sieving, particles that are too big to pass through the holes of the sieve are retained (see particle size distribution). In filtration, a multilayer lattice retains those particles that are unable to follow the tortuous channels of the filter. Oversize particles may form a cake layer on top of the filter and may also block the filter lattice, preventing the fluid phase from crossing the filter (blinding). Commercially, the term filter is applied to membranes where the separation lattice is so thin that the surface becomes the main zone of particle separation, even though these products might be described as sieves.
  • Filtration differs from adsorption, where it is not the physical size of particles that causes separation but the effects of surface charge. Some adsorption devices containing activated charcoal and ion exchange resin are commercially called filters, although filtration is not their principal function.
  • Filtration differs from removal of magnetic contaminants from fluids with magnets (typically lubrication oil, coolants and fuel oils), because there is no filter medium. Commercial devices called "magnetic filters" are sold, but the name reflects their use, not their mode of operation.

The remainder of this article focuses primarily on liquid filtration.

From Wikipedia under the GNU Free Documentation License
Fri Feb 19 12:57:32 2010

What is the purest/most filtered bottled water?
Q. I know that tap water is typically better than bottled water, but I was just wondering if anyone knew or had a link that would say which is the purest or most filtered brand of bottled water.
Asked by lauren - Sat Dec 15 02:08:28 2007 - - 7 Answers - 0 Comments

A. smart water, i tasted it at the convention once and it was so pure and tasted good. water from other bottles taste too hard, but smart water is smooth and tastes great. its not fishy.
Answered by :) - Sat Dec 15 02:11:58 2007

If they remove your bile, the toxins filtered by the liver will go to the intestines how?
Q. I know people can live without their bile(how - I suppose on a rigid diet, right?), but the liver needs to dump the toxins it filtered from the blood. How will this be done, if the bile is cut out? Is there a special conduct only for this purpose?
Asked by I Will Understand - Mon Aug 18 12:45:02 2008 - - 3 Answers - 0 Comments

A. The bile is not going to be removed. If you have gallstones or malfunctions of your gall bladder, the gall bladder may be removed by surgery. The gall (bile), produced by the liver will then directly flow into the intestines without any storage by a bladder. It may sometimes create problems when you east fatty food since that would require for digestion more bile than what is continuously produced. But your body will adjust.
Answered by Nicolas - Mon Aug 18 12:56:30 2008

What is a Holland Electronics SAW Filtered Modulator?
Q. What is a Holland Electronics SAW Filtered Modulator and what does it do exactly? We were remodeling a closed Circuit City that had left audio/video equipment behind and I'm curious what this unit is and what its purpose is.. Thanks!
Asked by Scott D - Thu Sep 17 00:30:01 2009 - - 1 Answers - 2 Comments

A. Hmms saw modulator the HMMS-* mini-modulator is a commercial grade fixed channel design that integrates with Holland's Mini-Modulator System. The HMMS-* accepts any A/V base-band signal and outputs on CATV channels 2-135 at a minimum 45 dBmV. HRC and IRC offsets available. In other words, it is used to send an AV signal over Cable - for example the output of a DVD player to multiple TVs in the store.
Answered by TV guy - Thu Sep 17 10:17:18 2009

From Yahoo Answer Search: "filtered"
Wed Sep 8 03:06:18 2010

Gen. Stanley McChrystal's loose lips - Los Angeles Times
latimes.com
Gen. Stanley McChrystal's loose lips - Los Angeles Times
Wed, 23 Jun 2010 07:08:13 GMT+00:00
Los Angeles Times Even though some of McChrystal's opinions were filtered through aides, it's clear that the general was out of line. Not only was he terribly foolish to ...
Dems Spar in First Debate - WOKV
wokv.com
Dems Spar in First Debate - WOKV
Tue, 22 Jun 2010 17:03:04 GMT+00:00
wokv he says that money should instead be filtered in to funding research and development of clean energy. Meek adds this will only go so far if off-shore ...
People state what drives them to vote - Fremont Tribune
fremonttribune.com
People state what drives them to vote - Fremont Tribune
Tue, 22 Jun 2010 16:14:22 GMT+00:00
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From Google News Search: "filtered"
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Have You Been Filtered ? Moog Brew Ends July 31st | The Bob Moog ...
moogfoundation.org
Have You Been Filtered ? Moog Brew Ends July 31st | The Bob Moog ...

Michelle Moog-Koussa

Fri, 02 Jul 2010 00:31:24 GM

Moog . Filtered. Ale will be sold only until July 31, after which it will no longer be available. It is distributed nationally and internationally​ in 22-ounce bottles through Asheville's Bruisin' Ales. It's also sold in bottles at ...

Moog Filtered Ale to Add Buzz to BMF Fundraising | The Bob Moog ...
moogfoundation.org
Moog Filtered Ale to Add Buzz to BMF Fundraising | The Bob Moog ...

Michelle Moog-Koussa

Wed, 05 May 2010 14:07:19 GM

Moog . Filtered. Ale will be be distributed nationally and internationally​ in 22-ounce bottles through Asheville's Bruisin' Ales and will be available on tap in various locations throughout Western North Carolina. The beer will be sold ...

New Facebook Activity Stream Plugin Brings Filtered Stream to Any ...
insidefacebook.com
New Facebook Activity Stream Plugin Brings Filtered Stream to Any ...

Susan Su

Wed, 21 Apr 2010 22:32:48 GM

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From Google Blog Search: "filtered"
Wed Sep 8 03:06:18 2010