Share
VIDEOS 1 TO 50
Flocculation
Flocculation
Published: 2012/04/20
Channel: MITK12Videos
The Flocculation Process
The Flocculation Process
Published: 2013/11/07
Channel: Danniel Rolfe
How does flocculation / flotation work? (video)
How does flocculation / flotation work? (video)
Published: 2011/08/22
Channel: NijhuisWater
Coagulation Flocculation
Coagulation Flocculation
Published: 2012/12/12
Channel: whatup1ratchet
Flocculation
Flocculation
Published: 2017/07/04
Channel: American Water College
How does flocculant work?
How does flocculant work?
Published: 2011/11/02
Channel: CDE Global
How to quickly make a green cloudy pool CRYSTAL CLEAR blue again by using a flocculant... FLOC!
How to quickly make a green cloudy pool CRYSTAL CLEAR blue again by using a flocculant... FLOC!
Published: 2016/08/17
Channel: TAnya13
WSO Water Treatment Grade 1: Coagulation & Flocculation, Ch. 8
WSO Water Treatment Grade 1: Coagulation & Flocculation, Ch. 8
Published: 2016/06/13
Channel: AmericanWaterWorks
Difference between deflocculated and flocculated suspension
Difference between deflocculated and flocculated suspension
Published: 2015/11/17
Channel: Professor Tushar
Portable Flocculation Treatment System
Portable Flocculation Treatment System
Published: 2011/01/28
Channel: WSB & Associates, Inc.
Visualizing Soil Properties: Dispersion and Flocculation
Visualizing Soil Properties: Dispersion and Flocculation
Published: 2016/05/18
Channel: nmsuaces
WSO: Coagulation, Flocculation & Sedimentation DVD Preview
WSO: Coagulation, Flocculation & Sedimentation DVD Preview
Published: 2014/05/30
Channel: AmericanWaterWorks
What do you mean by controlled flocculation
What do you mean by controlled flocculation
Published: 2015/08/18
Channel: Professor Tushar
Algae flocculation by Chitosan
Algae flocculation by Chitosan
Published: 2014/11/24
Channel: prabuddha gupta
Antigen - Antibody Reactions || Immunology || flocculation, Precipitation, Compliment fixation...
Antigen - Antibody Reactions || Immunology || flocculation, Precipitation, Compliment fixation...
Published: 2017/02/19
Channel: MedicoFem
Coagulation, flocculation jar test
Coagulation, flocculation jar test
Published: 2015/03/26
Channel: Kemcore
08 - coagulation and flocculation
08 - coagulation and flocculation
Published: 2015/03/08
Channel: Water treatment knowledge transfer channel
Aqua Excel Coagulation Flocculation and Balloons
Aqua Excel Coagulation Flocculation and Balloons
Published: 2014/12/22
Channel: Aqua Excel
Flocculation Meaning
Flocculation Meaning
Published: 2015/04/18
Channel: SDictionary
Precipitation and Flocculation CE 586
Precipitation and Flocculation CE 586
Published: 2015/09/01
Channel: G.U.N.T. Gerätebau GmbH
Lecture 10 Coagulation and Flocculation
Lecture 10 Coagulation and Flocculation
Published: 2007/12/20
Channel: nptelhrd
Wastewater Treatment - Clay Flocculation Demo
Wastewater Treatment - Clay Flocculation Demo
Published: 2011/09/15
Channel: Joan Butler
Depletion Flocculation
Depletion Flocculation
Published: 2016/02/09
Channel: Hagen@Cal Poly
Flocculation Animation 2
Flocculation Animation 2
Published: 2014/03/20
Channel: Ibrahim Bayram
FKC Flocculation Tank
FKC Flocculation Tank
Published: 2011/01/28
Channel: Wesley Bond
Precipitation and Flocculation
Precipitation and Flocculation
Published: 2017/03/29
Channel: Civil Engineering RWTH Aachen University
Coagulation and Flocculation
Coagulation and Flocculation
Published: 2009/12/07
Channel: Magewede
Coagulation & Flocculation
Coagulation & Flocculation
Published: 2016/08/25
Channel: BEEA BD
Deflocculated and Flocculated Glazes
Deflocculated and Flocculated Glazes
Published: 2012/12/19
Channel: John Britt
Controlled Flocculation - Viscosity Enhancers
Controlled Flocculation - Viscosity Enhancers
Published: 2016/06/09
Channel: Leigham
Flocculation Test
Flocculation Test
Published: 2009/09/25
Channel: Carlos Ramos
Soil flocculation with TERRACALCO
Soil flocculation with TERRACALCO
Published: 2016/06/21
Channel: daniel toma
SNF Flocculation
SNF Flocculation
Published: 2012/07/04
Channel: Xavier POITAU
1000 floculation
1000 floculation
Published: 2009/06/19
Channel: Colin Hammacott
Flocculation Basin Design Example
Flocculation Basin Design Example
Published: 2017/09/14
Channel: David Ladner
Coagulation and Flocculation - Step 2: Flocculation
Coagulation and Flocculation - Step 2: Flocculation
Published: 2014/08/18
Channel: Rouz Busy
Coagulant Flocculant
Coagulant Flocculant
Published: 2013/05/17
Channel: ritewaysEnviro
flocculation and settling
flocculation and settling
Published: 2011/10/07
Channel: stanypensaert
Effect of Adding Flocculant to Slurry
Effect of Adding Flocculant to Slurry
Published: 2008/11/19
Channel: tonsperhourinc
CVE 351 - Class 13 (Coagulation and Flocculation) 11 Oct 2015
CVE 351 - Class 13 (Coagulation and Flocculation) 11 Oct 2015
Published: 2015/10/11
Channel: Isaac Wait
Flocculation test
Flocculation test
Published: 2011/01/30
Channel: berrys66
Lecture 11 Coagulation and Flocculation (Contd)
Lecture 11 Coagulation and Flocculation (Contd)
Published: 2007/12/20
Channel: nptelhrd
Flocculation in Downstream Processing
Flocculation in Downstream Processing
Published: 2013/03/27
Channel: MettlerToledoAC
Pottery Video - How to Flocculate a Ceramic Glaze for Better Coverage - LINDA ARBUCKLE
Pottery Video - How to Flocculate a Ceramic Glaze for Better Coverage - LINDA ARBUCKLE
Published: 2016/10/07
Channel: Ceramic Arts Daily
Yeast Flocculation in Breweries - Morgantown Brewing Company
Yeast Flocculation in Breweries - Morgantown Brewing Company
Published: 2016/04/24
Channel: Matt W
Seleno-X  Separation from Water -Patent - bio fuel flocculation 1 liter perfect filtration
Seleno-X Separation from Water -Patent - bio fuel flocculation 1 liter perfect filtration
Published: 2013/11/11
Channel: רזי רונן
Fenton System Flocculation Tank
Fenton System Flocculation Tank
Published: 2013/03/20
Channel: Bundit Fugsook
Coagulation and Flocculation - Step 1: Add coagulants
Coagulation and Flocculation - Step 1: Add coagulants
Published: 2014/08/18
Channel: Rouz Busy
Advantages and Disadvantages of Coagulation and Flocculation
Advantages and Disadvantages of Coagulation and Flocculation
Published: 2016/11/26
Channel: Leong Khai Kit
flocculation
flocculation
Published: 2017/01/28
Channel: cool fan required
NEXT
GO TO RESULTS [51 .. 100]

WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
Jump to: navigation, search
IUPAC definition
Flocculation (in polymer science): When a sol is colloidally unstable (I.e., the rate of aggregation is not negligible) then the formation of aggregates is called flocculation or coagulation.[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.

Coagulation and flocculation are important processes in water treatment with coagulation to destabilize particles through chemical reaction between coagulant and colloids, and flocculation to transport the destabilized particles that will cause collisions with floc.

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]

Basically, coagulation is a process of addition of coagulant to destabilize a stabilized charged particle. Meanwhile, flocculation is a mixing technique that promotes agglomeration and assists in the settling of particles. The most common used coagulant is alum, Al2(SO4)3•14H2O.

The chemical reaction involved:

Al2(SO4)3•14H2O → 2Al(OH)3(s) + 6H+ + 3SO42- + 8H2O

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 processes.

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. Flocculation behavior of soil colloids is closely related to freshwater quality. High dispersibility of soil colloids not only directly causes turbidity of the surrounding water but it also induces eutrophication due to the adsorption of nutritional substances in rivers and lakes.

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 ageing of the emulsion (droplet coalescence and the ultimate separation of the phases). 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]

Flocculation is used in biotechnology applications in conjunction with microfiltration to improve the efficiency of biological feeds. The addition of synthetic flocculants to the bioreactor can increase the average particle size making microfiltration more efficient. When flocculants are not added, cakes form and accumulate causing low cell viability. Positively charged flocculants work better than negatively charged ones since the cells are generally negatively charged.[7]

Cheese industry[edit]

Flocculation is widely employed to measure the progress of curd formation in the initial stages of cheese making to determine how long the curds must set.[8][9] The reaction involving the rennet micelles are modeled by Smoluchowski kinetics.[8] During the renneting of milk the micelles can approach one another and flocculate, a process that involves hydrolysis of molecules and macropeptides.[10]

Flocculation is also used during cheese wastewater treatment. Three different coagulants are mainly used:[11]

Brewing[edit]

In the brewing industry flocculation has a different meaning. It is a very important process in fermentation during the production of beer where cells form macroscopic flocs. These flocs cause the yeast to sediment or rise to the top of a fermentation at the end of the fermentation. Subsequently, the yeast can be collected (cropped) from the top (ale fermentation) or the bottom (lager fermentation) of the fermenter in order to be reused for the next fermentation. While it appears similar to sedimentation in colloidal dispersions, the mechanisms are different.[12]

Water treatment process[edit]

Flocculation and sedimentation are widely employed in the purification of drinking water as well as in sewage treatment, storm-water treatment and treatment of industrial wastewater streams. Typical treatment processes consist of grates, coagulation, flocculation, sedimentation, granular filtration and disinfection.[13]

Jar test[edit]

The purpose of this test is to select types of coagulant (alum) and also to estimate the optimal dose needed in removing the charged particles that occurred in raw water. Jar test is an experiment to understand the processes of coagulation, flocculation and sedimentation (AWWA, 2011).

Jar test apparatus consists of six batch beakers, and equipped with a paddle mixer for each beaker. In a standard practice, jar test involving of rapid mixing, then follow by slow mixing and later with sedimentation process.

Deflocculation[edit]

Deflocculation is the exact opposite of flocculation, also sometimes known as peptisation. Usually in higher pH ranges in addition to low ionic strength of solutions and domination of monovalent metal cations the colloidal particles can be dispersed.[14] The additive that prevents the colloids from forming flocs is called a deflocculant. According to the Encyclopedic Dictionary of Polymers deflocculation is "a state or condition of a dispersion of a solid in a liquid in which each solid particle remains independent and unassociated with adjacent particles. A deflocculated suspension shows zero or very low yield value".[14]

Deflocculation can be a problem in wastewater treatment plants as it commonly causes sludge settling problems and deterioration of the effluent quality.

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, eds. (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. pp. 503–506.
  7. ^ Han, Binbing; Akeprathumchai, S.; Wickramasinghe, S. R.; Qian, X. (2003-07-01). "Flocculation of biological cells: Experiment vs. theory". AIChE Journal. 49 (7): 1687–1701. ISSN 1547-5905. doi:10.1002/aic.690490709. 
  8. ^ 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. 
  9. ^ Journal of Scientific and Industrial Research. 57: 680–681. 1998.  Missing or empty |title= (help)
  10. ^ Fox, Patrick F. (2004). Cheese - Chemistry, Physics and Microbiology (3rd Edition). Elsevier. p. 72. ISBN 978-0-12-263653-0. 
  11. ^ Rivas, Javier; Prazeres, Ana R.; Carvalho, Fatima; Beltrán, Fernando (2010-07-14). "Treatment of Cheese Whey Wastewater: Combined Coagulation−Flocculation and Aerobic Biodegradation". Journal of Agricultural and Food Chemistry. 58 (13): 7871–7877. ISSN 0021-8561. PMID 20557068. doi:10.1021/jf100602j. 
  12. ^ Jin, Y-L.; Speers, R.A.. (1999). "Flocculation in Saccharomyces cerevisiae Food Res. Int.". 31.: 421–440. 
  13. ^ Beverly, Richard P (2014-04-17). "Water Treatment Process Monitoring and Evaluation". Knovel. American Water Works Association (AWWA). Retrieved October 14, 2015. 
  14. ^ a b Gooch, Dr Jan W., ed. (2007-01-01). Deflocculation. Springer New York. pp. 265–265. ISBN 978-0-387-31021-3. doi:10.1007/978-0-387-30160-0_3313. 

Further reading[edit]

  • John Gregory (2006), Particles in water: properties and processes, Taylor & Francis, ISBN 1-58716-085-4
  • John C. Crittenden, R. Rhodes Trussell, David W. Hand, Kerry J. Howe, George Tchobanoglous (2012), MWH's water treatment: principles and design, third edition, John Wiley & Sons, ISBN 978-0-470-40539-0

Disclaimer

None of the audio/visual content is hosted on this site. All media is embedded from other sites such as GoogleVideo, Wikipedia, YouTube etc. Therefore, this site has no control over the copyright issues of the streaming media.

All issues concerning copyright violations should be aimed at the sites hosting the material. This site does not host any of the streaming media and the owner has not uploaded any of the material to the video hosting servers. Anyone can find the same content on Google Video or YouTube by themselves.

The owner of this site cannot know which documentaries are in public domain, which has been uploaded to e.g. YouTube by the owner and which has been uploaded without permission. The copyright owner must contact the source if he wants his material off the Internet completely.

Powered by YouTube
Wikipedia content is licensed under the GFDL and (CC) license