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Updated: Aug 18, 2026

Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
Adsorption and thermochemical data of divalent cations onto silica gel surface modified with humic acid at
Alexandre G S Prado1, Bárbara S Miranda, Luiz F Zara
1Instituto de Química, Universidade de Brasília, C.P. 4478, 70919-970 Brasília, D.F., Brazil. agsprado@unb.br
Abstract:
Humic acid immobilized onto silica gel surface was studied by the calorimetric titration of divalent cations in aqueous solution. The adsorption isotherms were obtained by the batchwise method and were fitted to a modified Langmuir equation. The maximum number of moles per gram of the material gave: 10.42+/-0.75, 13.16+/-0.58, 7.87+/-0.58 for copper, nickel and zinc, respectively. Gibbs free energies were negative for all systems and the adsorption interactions calorimetrically followed presented endothermic enthalpic values: 6.24+/-0.47, 6.75+/-0.74, 6.97+/-0.58 kJ mol-1 for the same sequence of divalent cations. All liquid/solid interface adsorptions were entropically driven.
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