1
Flocculation
Flocculation
DATE: 2012/04/20::
2
How does flocculation / flotation work? (video)
How does flocculation / flotation work? (video)
DATE: 2011/08/22::
3
Coagulation Flocculation
Coagulation Flocculation
DATE: 2012/12/11::
4
The Flocculation Process
The Flocculation Process
DATE: 2013/11/07::
5
Chemistry: Colloid Formation and Flocculation
Chemistry: Colloid Formation and Flocculation
DATE: 2010/09/20::
6
Wastewater Treatment - Clay Flocculation Demo
Wastewater Treatment - Clay Flocculation Demo
DATE: 2011/09/15::
7
WSO: Coagulation, Flocculation & Sedimentation DVD Preview
WSO: Coagulation, Flocculation & Sedimentation DVD Preview
DATE: 2014/05/30::
8
Homeade algae bio-reactor with NaOH flocculation for oil extraction
Homeade algae bio-reactor with NaOH flocculation for oil extraction
DATE: 2014/06/14::
9
Deflocculated and Flocculated Glazes
Deflocculated and Flocculated Glazes
DATE: 2012/12/19::
10
08 - coagulation and flocculation
08 - coagulation and flocculation
DATE: 2015/03/08::
11
Flocculation Animation 2
Flocculation Animation 2
DATE: 2014/03/20::
12
Lecture 10 Coagulation and Flocculation
Lecture 10 Coagulation and Flocculation
DATE: 2007/12/20::
13
Algae flocculation by Chitosan
Algae flocculation by Chitosan
DATE: 2014/11/24::
14
Flocculation
Flocculation
DATE: 2012/05/07::
15
Enhanced flocculation with hydrodynamic cavitation (ROTOCAV)
Enhanced flocculation with hydrodynamic cavitation (ROTOCAV)
DATE: 2015/04/13::
16
Coagulation and Flocculation
Coagulation and Flocculation
DATE: 2009/12/07::
17
Mechanical flocculation unit at Guaraú Water Treatment Plant
Mechanical flocculation unit at Guaraú Water Treatment Plant
DATE: 2013/08/14::
18
Polyurea Spraying inside Flocculation Tanks
Polyurea Spraying inside Flocculation Tanks
DATE: 2011/06/28::
19
Flocculation
Flocculation
DATE: 2012/02/05::
20
How does flocculant work?
How does flocculant work?
DATE: 2011/11/02::
21
Coagulation and Flocculation - Step 1: Add coagulants
Coagulation and Flocculation - Step 1: Add coagulants
DATE: 2014/08/17::
22
Coagulation, flocculation jar test
Coagulation, flocculation jar test
DATE: 2015/03/26::
23
flocculation
flocculation
DATE: 2008/02/04::
24
flocculation and settling
flocculation and settling
DATE: 2011/10/07::
25
Recycling power wash waste water through flocculation
Recycling power wash waste water through flocculation
DATE: 2014/10/27::
26
Flocculation
Flocculation
DATE: 2014/07/12::
27
Water and Waste Water Engineering Lec 10 Coagulation & Flocculation
Water and Waste Water Engineering Lec 10 Coagulation & Flocculation
DATE: 2015/02/05::
28
Simon Yuan: Success Criteria for Flocculation of High Density Fluid Fine Tailings
Simon Yuan: Success Criteria for Flocculation of High Density Fluid Fine Tailings
DATE: 2014/09/11::
29
Coagulation & Flocculation
Coagulation & Flocculation
DATE: 2014/05/28::
30
AGPR201 07 08 Flocculation
AGPR201 07 08 Flocculation
DATE: 2010/01/09::
31
Portable Flocculation Treatment System
Portable Flocculation Treatment System
DATE: 2011/01/28::
32
1000 floculation
1000 floculation
DATE: 2009/06/19::
33
COAGULATION - FLOCCULATION (WWTP_CAMIX VIETNAM)
COAGULATION - FLOCCULATION (WWTP_CAMIX VIETNAM)
DATE: 2013/10/08::
34
Flocculation method.wmv
Flocculation method.wmv
DATE: 2012/06/19::
35
Orchard Diary 2/7/2014:  Yeast flocculation in the shop at 45F
Orchard Diary 2/7/2014: Yeast flocculation in the shop at 45F
DATE: 2014/02/07::
36
Flocculation Animation
Flocculation Animation
DATE: 2011/11/22::
37
Filtration Flocculation
Filtration Flocculation
DATE: 2011/10/17::
38
Coagulation/ Flocculation: Surface Chemistry 06/06
Coagulation/ Flocculation: Surface Chemistry 06/06
DATE: 2013/11/13::
39
Flocculant for water treatment
Flocculant for water treatment
DATE: 2013/06/09::
40
Coagulation and Flocculation - Step 3: Sedimentation
Coagulation and Flocculation - Step 3: Sedimentation
DATE: 2014/08/17::
41
FKC Flocculation Tank
FKC Flocculation Tank
DATE: 2011/01/28::
42
SWIMMING POOL FLOCCULANT - MYTHS & FACTS
SWIMMING POOL FLOCCULANT - MYTHS & FACTS
DATE: 2014/01/09::
43
Aqua Excel Coagulation Flocculation and Balloons
Aqua Excel Coagulation Flocculation and Balloons
DATE: 2014/12/22::
44
Flocculation in Stop Motion 1
Flocculation in Stop Motion 1
DATE: 2014/03/20::
45
Mutant sas2 wine yeast with high flocculation.
Mutant sas2 wine yeast with high flocculation.
DATE: 2010/09/29::
46
Clay Flocculation of Microcystis in a Test Tube
Clay Flocculation of Microcystis in a Test Tube
DATE: 2010/05/06::
47
Flocculation Mixer - B
Flocculation Mixer - B
DATE: 2013/02/23::
48
Water Purification using a Flocculant
Water Purification using a Flocculant
DATE: 2011/04/10::
49
Flocculation Mixer - C
Flocculation Mixer - C
DATE: 2013/02/23::
50
Flocculation from RST Environmental Solutions Ltd
Flocculation from RST Environmental Solutions Ltd
DATE: 2013/04/14::
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RESULTS [51 .. 101]
From Wikipedia, the free encyclopedia
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"Flocculent" redirects here. For the galaxy type, see Flocculent spiral galaxy.
IUPAC definition

Flocculation (in polymer science): Reversible formation of aggregates in
which the particles are not in physical contact.[1]


Agglomeration (except in polymer science)
Coagulation (except in polymer science)
Flocculation (except in polymer science)
Process of contact and adhesion whereby dispersed molecules or particles
are held together by weak physical interactions ultimately leading to phase
separation by the formation of precipitates of larger than colloidal size.

Note 1: In contrast to aggregation, agglomeration is a reversible process.

Note 2: The definition proposed here is recommended for distinguishing
agglomeration from aggregation.

Note 3: Quotation from ref.[1]

[2]

Flocculation, in the field of chemistry, is a process wherein colloids come out of suspension in the form of floc or flake; either spontaneously or due to the addition of a clarifying agent. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution. In the flocculated system, there is no formation of a cake, since all the flocs are in the suspension.

Term definition[edit]

According to the IUPAC definition, flocculation is "a process of contact and adhesion whereby the particles of a dispersion form larger-size clusters." Flocculation is synonymous with agglomeration and coagulation / coalescence.[3][4]

During flocculation, gentle mixing accelerates the rate of particle collision, and the destabilized particles are further aggregated and enmeshed into larger precipitates. Flocculation is affected by several parameters, including mixing speeds, mixing intensity, and mixing time. The product of the mixing intensity and mixing time is used to describe flocculation process.

Applications[edit]

Surface chemistry[edit]

In colloid chemistry, flocculation refers to the process by which fine particulates are caused to clump together into a floc. The floc may then float to the top of the liquid (creaming), settle to the bottom of the liquid (sedimentation), or be readily filtered from the liquid.

Physical chemistry[edit]

For emulsions, flocculation describes clustering of individual dispersed droplets together, whereby the individual droplets do not lose their identity.[5] Flocculation is thus the initial step leading to further aging of the emulsion (droplet coalescence and the ultimate separation of the phases).(1993) Flocculation is used in mineral dressing[6]

Civil engineering/earth sciences[edit]

In civil engineering, and in the earth sciences, flocculation is a condition in which clays, polymers or other small charged particles become attached and form a fragile structure, a floc. In dispersed clay slurries, flocculation occurs after mechanical agitation ceases and the dispersed clay platelets spontaneously form flocs because of attractions between negative face charges and positive edge charges.

Biology[edit]

In biology, flocculation refers to the asexual aggregation of microorganisms.

Cheese production[edit]

Flocculation is widely employed to measure the progress of curd formation while in the initial stages of making many cheeses to determine how long the curds must set.[7][8] The reaction involving the rennet micelles are modeled by Smoluchowski Kinetics.[7]

Brewing[edit]

Flocculation refers to the rate at which yeast settles to the bottom of the fermentation vessel. Yeast strains with higher flocculation will settle out of the beer faster once fermentation is complete.

Water treatment[edit]

Flocculation and sedimentation are widely employed in the purification of drinking water as well as sewage treatment, storm-water treatment and treatment of other industrial wastewater streams.

Deflocculation[edit]

A deflocculant is a chemical additive to prevent a colloid from coming out of suspension or to thin suspensions or slurries. It is used to reduce viscosity or prevent flocculation and is sometimes incorrectly called a "dispersant." Most deflocculants are low-molecular-weight anionic polymers that neutralize positive charges on suspended particles, in particular clays and aryl-alkyl derivative of sulfonic acid. Examples include polyphosphates, lignosulfonates, quebracho tannins, and various water-soluble synthetic polymers.

Deflocculation is also used to describe the undesired colloidification effect in an activated sludge basin if the sludge is subjected to high-speed mixing. In general, deflocculation can be prevented or reduced by applying gentle mixing (e.g., by using submersible propeller mixers that utilize large/wide propeller blades and operate at low rotational speed).

See also[edit]

References[edit]

  1. ^ a b "Terminology of polymers and polymerization processes in dispersed systems (IUPAC Recommendations 2011)" (PDF). Pure and Applied Chemistry 83 (12): 2229–2259. 2011. doi:10.1351/PAC-REC-10-06-03. 
  2. ^ Richard G. Jones, Edward S. Wilks, W. Val Metanomski, Jaroslav Kahovec, Michael Hess, Robert Stepto, Tatsuki Kitayama, ed. (2009). Compendium of Polymer Terminology and Nomenclature (IUPAC Recommendations 2008) "The Purple Book" (2nd ed.). RSC Publishing. ISBN 978-0-85404-491-7. 
  3. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version:  (2006–) "flocculation".
  4. ^ Hubbard, Arthur T. (2004). Encyclopedia of Surface and Colloid Science. CRC Press. p. 4230. ISBN 0-8247-0759-1. Retrieved 2007-11-13. 
  5. ^ Adamson A.W. and Gast A.P. (1997) "Physical Chemistry of Surfaces", John Wiley and Sons.
  6. ^ Investigation of laws of selective flocculation of coals with synthetic latexes / P. V. Sergeev, V. S. Biletskyy // ICCS’97. 7-12 September, 1997, Essen, Germany. V. 1. P. 503-506.
  7. ^ a b Fox, Patrick F. (1999). Cheese Volume 1: Chemistry, Physics, and Microbiology (2nd ed.). Gaithersburg, Maryland: Aspen Publishers. pp. 144–150. ISBN 978-0-8342-1378-4. 
  8. ^ Journal of Scientific and Industrial Research 57: 680–681. 1998.  Missing or empty |title= (help)

Further reading[edit]

  • John Gregory (2006), Particles in water: properties and processes, Taylor & Francis, ISBN 1-58716-085-4
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