Thermodynamic aspects of the adsorption of hexametaphosphate on kaolinite.
The adsorption of hexametaphosphate ion, an important deflocculant used in the ceramic industry, from aqueous solutions onto kaolinite has been studied at different temperatures. The adsorption isotherm follows the Langmuir model: the thermodynamic parameters DeltaG(ads)(0), DeltaH(ads)(0), and DeltaS(ads)(0) were calculated and found to be consistent with an interaction model involving the formation of an inner-sphere complex between HMP and aluminol groups. Also, the dependence of the adsorption behavior on the kaolinite volume fraction has been studied and discussed in term of association processes between the clay particles.
Castellini
Elena
E
Department of Chemistry, University of Modena and Reggio Emilia, via Campi 183, I-41100 Modena, Italy. castellini.elena@unimore.it
Lusvardi
Gigliola
G
Malavasi
Gianluca
G
Menabue
Ledi
L
D000327:Adsorption; D007616:Kaolin / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics
D010710:Phosphates; C005035:hexametaphosphate; D007616:Kaolin