Study of essential oils adsorption on three phosphate fertilizers

Abstract

In this paper, we report the study of essential oils adsorption on three phosphate fertilizers: monoammonium phosphate (MAP), diammonium phosphate (DAP) and triple superphosphate (TSP), with the aim to prepare a bifunctional product which can be used as a fertilizer and biopesticide. Essential oils were isolated by steam distillation from Eucalyptus salubris and Artemisia herbaalba and analysed by GC-MS and GC-FID. About 12 and 22 constituents were identified and quantified in these oils, respectively. The kinetic adsorption study of essential oils showed that DAP and TSP exhibited high adsorption capacities compared with MAP (DAP (0.143 g/g) and TSP (0.139 g/g) for E. salubris essential oil and (DAP (0.135 g/g) and TSP (0.134 g/g) for A. herba- -alba essential oil). The adsorption isotherms of all identified components in the E. salubris essential oil were determined and the Langmuir and Freundlich models were used to describe the experimental data. Langmuir model fitted well the isotherms of the majority of the essential oil components (1,8-cineole, ?-pinene, ?-pinene, isopinocarveol, ?-eudesmol, ?-phellandrene, pinocarvone, p-cymene and spathulenol) and only terpineol and globulol isotherm data followed the Freundlich model. The selectivity was affected by the abundance of each component in the crude essential oil and the polarity of terpenic components.