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Surface Complexation Modeling of K+, NO3−, SO42−, Ca2+, F−, Co2+, and Cr3+ Ion Adsorption on Silica Gel

✍ Scribed by Márta Berka; István Bányai


Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
148 KB
Volume
233
Category
Article
ISSN
0021-9797

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✦ Synopsis


Surface complex formation of K + , NO - 3 , SO 2- 4 , Ca 2+ , F -, Co 2+ , and Cr 3+ ions was determined on the surface of silica gel. Experimental data obtained by acid-base titration of suspensions were interpreted in terms of the triple-layer model. The value of the deprotonation constant of surface OH could be determined precisely but the protonation constant was rather uncertain. The logarithms of ion pair formation constants for K + , NO - 3 , Ca 2+ , and SO 2- 4 adsorbed in the β-plane are log K ipM,X ∼ 0, therefore these species can be considered inert ions in the investigated pH range. F -, Co 2+ , and Cr 3+ ions were found to be strongly sorbed in the o-plane. In order to provide a good fit and to obtain parameters independent of their initial values, all possible equilibrium must be accounted for in the models.