Investigation into the suitability of layered silicates as adsorption media for essential oils using FTIR and GC–MS

• We assess the use of layered silicates as adsorption media for essential oils.
• Using gas chromatography the effect of adsorption on oil molecules was observed.
• Natural montmorillonites modified the essential oil molecular makeup.
• Synthetic layered silicates are shown to be good adsorbents for essential oils.

This study assessed the suitability of layered silicate substrates as adsorption media for an essential oil (EO) blend with antimicrobial properties. It is anticipated that adsorption of the EO blend within the layered silicate will lead to controlled release of the blend. Three montmorillonites (Mt), a natural/synthetic hybrid Mt and two synthetic layered silicates were selected as potential adsorption materials. Gas chromatography (GC) was used to follow static adsorption of the EOs from heptane. The GC adsorption studies enabled the effect of adsorption on the individual molecular components of the oils to be determined, as well as providing a value for the overall level of adsorption of the EO. The Mts were found to degrade some of the important molecules in the EO and were therefore deemed to be unsuitable. The synthetic layered silicates provided the highest levels of adsorption, achieving up to 170 mg·g− 1 without the degradation effects shown by the natural Mts.

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