Use of polymer as template in microwave synthesis of saponite. Study of several factors of influence

Microwave synthesis of delaminated acid saponites using quaternary ammonium salt or polymer as template. Study of pH influence

“…In contrast, the low stacking order of SM8(125)AS ( Fig. 1) was very similar to those of the samples prepared without template or with polymer at pH 8 (SM8(125), SM8(125)P) (Gebretsadik et al, 2014).…”

“…2B) whereas the samples prepared without template, SM8(125), or with polymer, SM8(125)P did not show amorphous siliceous material, in a detectable level, in their FT-IR spectra (Gebretsadik et al, 2014). Other effect observed was that the presence of surfactant and polymer had a positive effect on the order of the O-Si-O band in the saponite structure.…”

“…All samples of pH 13 were prepared at slurry dilution (H 2 O/Si molar ratio) of 125. Ammonium saponites (5 samples), with the same theoretical formula as pH 13 samples, were prepared from a slurry of initial pH = 8 with and without template by modifying the protocol previously reported by our research group (Gebretsadik et al, 2014). In 50 mL of a 3 wt.% ammonia solution, for the samples prepared with template, this was added at 20 wt.% loading with respect to the mass of the other solid reagents.…”

“…Samples prepared at pH = 13 with template (SM13P and SM13AS) and without template (SM13) and at pH = 8 with surfactant SM8(125)AS were compared with each other. Samples prepared previously by our group (Gebretsadik et al, 2014) at pH 8 with polymer (SM8(125)P) and without template (SM8(125)) were also compared. Finally, one reference sample was also synthesized at pH 13 at the same conditions than those employed for preparing SM13, but using conventional heating, instead of microwaves, during the ageing treatment and longer time (72 h).…”

“…Moreover, the use of different technologies and manipulation of the synthesis conditions allowed some degree of control over the pore structure of materials (Costenaro et al, 2012). Saponites with large pores were prepared by microwaves from gels of high slurry dilution (H 2 O/Si molar ratio 250) (Vicente et al, 2010;Gebretsadik et al, 2014). The use of microwaves in preparation also afforded samples with higher delamination and reduced reaction time with subsequent energy saving (Bergadà et al, 2007).…”