Computational Study on the Al3+ Substitution and Porous Agent Effect on Geopolymer Foams Formation

Document Type : Research Article


1 Department of Inorganic Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon

2 Laboratory of Theoretical Chemistry (LCT) and Namur Institute of Structured Matter (NISM), University of Namur, Namur, Belgium

3 Laboratory of Materials, Local Materials Promotion Authority, MINRESI/MIPROMALO, Yaoundé, , Cameroon

4 Department of Chemistry, High Teacher Training College, University of Yaoundé I, Yaoundé, Cameroon

5 Institut de Recherche sur les Céramiques, Université de Limoges, Limoges, France

6 Department of Applied Chemistry, Faculty of Science, University of Ebolowa, Ebolowa, Cameroon

7 Physical and Theoretical Chemistry Unit, Laboratory of Applied Physical and Analytical Chemistry, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon



This work explores the replacement of Al3+ by Fe2+ or Fe3+ and the effect of porous agent on geopolymers foam formation, using DFT at the level of theory B3LYP/6-31G+(d, p). The obtained results show values of HOMO-LUMO gaps that are respectively 130.46 ; 93.3 and 14.38 Kcal.mol-1 for [Al(OH)4]-, [Fe(OH)4]- and [Fe(OH)4]2- monomers and; 63.79, 5.65, 155.55 and 36.13 Kcal.mol-1 for oligomers[(OH)2Al–(O–Si(OH)3)2]- , [(OH)2Fe–(O–Si(OH)3)2]- , [Al–(O–Si(OH)3)4]- and Fe–(O–Si(OH)3)4]2-. Calculations using thermodynamics parameter reveals the most favorable porous agent amongst the three (silica fume, aluminum powder and oxygenated water) tested. The results reveal that aluminum powder seems to be the best candidate with the lowest change in G (-190.61 Kcal.mol-1) and S (-82.94 cal/mol.K).


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