Editing Sodium silicate (section)

=== Water treatment ===

Sodium silicate is used as an alum coagulant and an iron [[flocculant]] in [[wastewater treatment]] plants. Sodium silicate binds to [[colloid]]al molecules, creating larger [[Flocculation|aggregates]] that sink to the bottom of the water column. The microscopic negatively charged particles suspended in water interact with sodium silicate. Their [[electrical double layer]] collapses due to the increase of [[ionic strength]] caused by the addition of sodium silicate (doubly negatively charged anion accompanied by two sodium cations) and they subsequently aggregate. This process is called [[coagulation]].<ref name=Ullmann/>