A novel method for the preparation of inorganic and organo-modified montmorillonite essential oil hybrids

Abstract

In this study, a novel method which can be easily applied in industry for the modification of sodium exchanged montmorillonite (NaMt) and commercial organically modified montmorillonite (OrgMt) with essential oils (EO) such as oregano oil, thyme oil and basil oil was presented. The obtained clays-essential oils powders were promising nanostructures for controlled release applications. The presence of EO molecules in the interlayer space was studied with X-ray diffraction (XRD) analysis. Thermogravimetric Analysis (TG) was used to calculate the adsorbed amount of EO into NaMt and OrgMt clay layers and to determine the temperature region where EO release took place. Fourier-Transform Infrared (FTIR) spectroscopy was used to study the adsorption mechanism. The interlayer space of NaMt was found not to be affected by the adsorption of EO molecules while a significant increase of OrgMt interlayer space was recorded. EO amount released from NaMt surface above 220°C and between 100°C to 220°C in OrgMt. A hydrogen bond between OH groups of EO and external surface OH groups of NaMt in the case of NaMt/EO hybrids and a weak interaction between aromatic EO groups and amino chains in interlayer space of OrgMt in the case of OrgMt/EO hybrids were suggested.