The Effect of the Order of Reagent Addition on the Settling Rate of Aluminium Hydroxide in the Al(III)-Na2CO3 System

Content Provider	Semantic Scholar
Author	Demirata, Birsen Apak, Resa̧t Gümüş, Gülçin Afşar, Hüseyin
Copyright Year	2002
Abstract	The effects of several factors on the settling rate of aluminiumhydroxide were investigated during chemical coagulation using aluminium salts. Experimental variables were pH, aluminium (III) concentration and the order of addition of reagents. Experiments were carried out at pH 5–8 and rapid settling was achieved when aluminium (III) solutions were added to Na2CO3 solutions near neutral pH, close to the minimumsolubility pH of Al(OH)3. For a narrow range of total Al concentration where Al(III) species were supersaturated with respect to the solid phase, Al(III)-added-to-carbonate type mixtures yielded a higher settling rate than mixtures obtainedby the reverse order of reagent addition. The results were interpreted by comparing the rates of formation of polymer andsolid (amorphous Al(OH)3) phases. It was concluded that Al(III) coagulants should be added to water containing natural or artificially incorporated carbonate alkalinity for rapid settling of Al(OH)3 flocs.
Starting Page	265
Ending Page	282
Page Count	18
File Format	PDF HTM / HTML
DOI	10.1023/A:1012970801795
Alternate Webpage(s)	https://page-one.springer.com/pdf/preview/10.1023/A:1012970801795
Alternate Webpage(s)	https://doi.org/10.1023/A%3A1012970801795
Volume Number	133
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article