Modification of the thermally exfoliated vermiculite by sonication and grafting methods

Abstract EN

In the present study, the thermally exfoliated vermiculite has been sonicated in order to grafting with the butyl-imidazolium.

A suspension of vermiculite-water with 1% of concentration was sonicated at 20 KHz.

This led to the decrease in the size of grains to16 μm after 2 h of treatment.

Increasing of sonication time, presence of H2O2, and the increase of the vermiculite concentration have caused an accentuation of sonication effect, this resulted the decreasing of the size to 10 μm.

Moreover, a 2% fraction of submicron-sized particles was appeared.

The pH of the vermiculite suspensions was increased.

The number of the -OH sites was determined by acid-base titration using Gran method.

The infrared spectra of the raw and sonicated vermiculites in H2O or containing H2O2 were very similar.

In the presence of H2O2, two bands were observed at 1380 and 1460 cm-1.

These are due to the presence of carbonates anions formed during sonication in H2O2.

XRD spectra showed that the sonication did not affect the vermiculite structure.

The grafting was carried out on sonicated samples during 5 h in H2O.

This was realized in two steps.

In the first step, we grafted 3-chloropropyltrimethoxysilane instead of the –OH sites.

In the second step, we conducted a nucleophilic substitution of chlorine with methyl-imidazole.

We proved by infrared spectroscopy and Gran method that grafting was real and XRD that this was not an intercalation