A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Microwave synthesis of delaminated acid saponites using quaternary ammonium salt or polymer as template. Study of pH influence
Abstract Mesoporous saponites were prepared at pH8 and 13 without and with template (surfactant or polymer) at 453K and autogenic pressure using microwaves or conventional oven during the hydrothermal ageing treatment. Acidity was obtained by calcination of the NH4-form. The effect of dilution (H2O/Si molar ratios of 250, 125 and 50) was studied for the samples prepared at pH8 with surfactant. In order to compare the effect of introducing surfactant during or after saponite synthesis, several samples prepared at pH13 were modified after synthesis by refluxing or by stirring at room temperature in a surfactant solution. Preparation of samples at pH13 favoured the ordering in the stacking direction, improved AlT/AlO ratio and led to samples with lower amorphous siliceous material content. The use of microwaves and surfactant for the synthesis at pH13 afforded a saponite with the highest surface area (603m2/g) and the smallest lamellae crystallite size (about 4nm). The properties of the samples synthesized at pH8 with surfactant depended on the dilution. Thus, the degree of delamination, the BET area and the AlT/AlO ratio increased whereas the amorphous siliceous material content decreased at lower slurry dilution. The incorporation of the surfactant by post-synthesis resulted in some degree of delamination especially when using refluxing. However, the degree of delamination was higher for the saponites prepared with the addition of the surfactant during the hydrothermal synthesis.
Graphical abstract Display Omitted
Highlights Synthesis of delaminated saponites using microwave and templates Surfactant is more effective than polymer for saponite delamination. Highest area saponite was synthesized at pH13 with microwaves and surfactant. Low dilution and surfactant enhanced delamination in saponite synthesized at pH8. Post-synthesis modification with surfactant improved saponite delamination.
Microwave synthesis of delaminated acid saponites using quaternary ammonium salt or polymer as template. Study of pH influence
Abstract Mesoporous saponites were prepared at pH8 and 13 without and with template (surfactant or polymer) at 453K and autogenic pressure using microwaves or conventional oven during the hydrothermal ageing treatment. Acidity was obtained by calcination of the NH4-form. The effect of dilution (H2O/Si molar ratios of 250, 125 and 50) was studied for the samples prepared at pH8 with surfactant. In order to compare the effect of introducing surfactant during or after saponite synthesis, several samples prepared at pH13 were modified after synthesis by refluxing or by stirring at room temperature in a surfactant solution. Preparation of samples at pH13 favoured the ordering in the stacking direction, improved AlT/AlO ratio and led to samples with lower amorphous siliceous material content. The use of microwaves and surfactant for the synthesis at pH13 afforded a saponite with the highest surface area (603m2/g) and the smallest lamellae crystallite size (about 4nm). The properties of the samples synthesized at pH8 with surfactant depended on the dilution. Thus, the degree of delamination, the BET area and the AlT/AlO ratio increased whereas the amorphous siliceous material content decreased at lower slurry dilution. The incorporation of the surfactant by post-synthesis resulted in some degree of delamination especially when using refluxing. However, the degree of delamination was higher for the saponites prepared with the addition of the surfactant during the hydrothermal synthesis.
Graphical abstract Display Omitted
Highlights Synthesis of delaminated saponites using microwave and templates Surfactant is more effective than polymer for saponite delamination. Highest area saponite was synthesized at pH13 with microwaves and surfactant. Low dilution and surfactant enhanced delamination in saponite synthesized at pH8. Post-synthesis modification with surfactant improved saponite delamination.
Microwave synthesis of delaminated acid saponites using quaternary ammonium salt or polymer as template. Study of pH influence
Gebretsadik, Fiseha B. (author) / Mance, Deni (author) / Baldus, Marc (author) / Salagre, Pilar (author) / Cesteros, Yolanda (author)
Applied Clay Science ; 114 ; 20-30
2015-05-04
11 pages
Article (Journal)
Electronic Resource
English
Rapid microwave-assisted synthesis of saponites and their use as oxidation catalysts
| Online Contents | 2011
Synthesis of a Polymerizable Quaternary Ammonium Salt Antibacterial
| British Library Online Contents | 2008