Editing Flocculation (section)

== Term definition ==
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 [[particle aggregation|agglomeration]] and coagulation/[[coalescence (chemistry)|coalescence]].<ref>{{GoldBookRef |title = flocculation|file = F02429}}</ref><ref>{{cite book
|last = Hubbard|first = Arthur T.|title = Encyclopedia of Surface and Colloid Science|publisher = CRC Press|year = 2004|url = https://books.google.com/books?id=vnb2X7Q8_cYC&q=ostwald+ripening+emulsion+polymerization&pg=PA4230|access-date = 2007-11-13|isbn = 978-0-8247-0759-0|page = 4230}}</ref>

Basically, coagulation is a process of addition of coagulant to destabilize a stabilized charged particle. Meanwhile, flocculation is a technique that promotes agglomeration and assists in the settling of particles. The most common used coagulant is [[alum]], Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>·14H<sub>2</sub>O.

The chemical reaction involved:

:Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> · 14 H<sub>2</sub>O → 2 Al(OH)<sub>3</sub>{{abbr|(s)|solid}} + 6 H<sup>+</sup> + 3 {{chem|SO|4|2-}} + 8 H<sub>2</sub>O

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 shear and intensity, time and [[pH]]. The product of the mixing intensity and mixing time is used to describe flocculation processes.

=== Jar test ===
The process by which the dosage and choice of flocculant are selected is called a jar test. The equipment used for jar testing consists of one or more beakers, each equipped with a paddle mixer. After the addition of flocculants, rapid mixing takes place, followed by slow mixing and later the sedimentation process. Samples can then be taken from the aqueous phase in each beaker. <ref>{{cite book |author=<!--Staff writer(s); no by-line.--> |date=2011-06-01 |title=Operational Control of Coagulation and Filtration Processes (M37): AWWA Manual of Practice |url= https://engage.awwa.org/PersonifyEbusiness/Store/Product-Details/productId/6726|publisher= American Water Works Association|isbn=978-1583218013}}</ref>