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Surface Acidity of Amorphous Aluminum Hydroxide
Author(s) -
FUKUSHI K.,
TSUKIMURA K.,
YAMADA H.
Publication year - 2006
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2006.tb00232.x
Subject(s) - titration , protonation , amorphous solid , hydroxide , acid–base titration , deprotonation , chemistry , inorganic chemistry , solubility , base (topology) , titration curve , aluminium , nuclear chemistry , organic chemistry , ion , mathematical analysis , mathematics
The surface acidity of synthetic amorphous Al hydroxide was determined by acid/base titration with several complementary methods including solution analyses of the reacted solutions and XRD characterization of the reacted solids. The synthetic specimen was characterized to be the amorphous material showing four broad peaks in XRD pattern. XRD analyses of reacted solids after the titration experiments showed that amorphous Al hydroxide rapidly transformed to crystalline bayerite at the alkaline condition (pH>10). The solution analyses after and during the titration experiments showed that the solubility of amorphous aluminum hydroxide, K sp = a Al1+ / a 3 H+ , was 10 10.3 . The amount of consumption of added acid or base during the titration experiment was attributed to both the protonation/deprotonation of dissolved Al species and surface hydroxyl group. The surface acidity constants, surface hydroxyl density and specific surface area were estimated by FITEQL 4.0.