Jp. Boisvert et C. Jolicoeur, Influences of sulfate and/or silicate present in partially prehydrolyzed Al(III) flocculants on Al(III) speciation in diluted solutions, COLL SURF A, 155(2-3), 1999, pp. 161-170
Citations number
40
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
Influences of prehydrolysis in partially neutralized Al(III) flocculants co
ntaining of sulfate and/or silicate on Al(III) speciation are investigated.
To this end, many flocculants were synthesized. They were prehydrolyzed wi
th sodium aluminate in the presence of silicate and/or sulfate with increas
ing Si/Al and/or SO4/Al molar ratio and diluted to 0.1-0.01 M Al. Alkalimet
ric titration and Al-27 NMR spectroscopy were used to monitor the Al specia
tion. The results suggest that prehydrolysis with sodium aluminate reduces
Al-13 concentration in comparison with the standard hydrolysis method. The
silicate specifically inhibits Al-13 formation and promotes formation of un
identified soluble species. The sulfate indirectly inhibits Al-13 by promot
ing the formation of solid Al (oxi)hydroxide. In regard to the results pres
ented here, it appears that Al-13 formation is unlikely for conditions of u
se of standard flocculants. (C) 1999 Elsevier Science B.V. All rights reser
ved.