Synthesis of highly intercalated urea-clay nanocomposite via domestic montmorillonite as eco-friendly slow-release fertilizer

ABSTRACT

The present study describes the preparation and characterization of montmorillonite-urea nanocomposites (Mt-Ur) using aqueous suspension technique at various stirring times and different ratio of montmorillonite to urea (Mt/Ur) via an impure and domestic montmorillonite (Mt), without the application of any chemical reagents and high-energy-demand process (environmentally friendly). The intercalation of urea into Mt interlayer was clearly demonstrated by a significant expansion of d₀₀₁ spacing (interlayer space of Mt) from 1.23 to 1.71 nm which has not yet been reported by aqueous suspension technique. Analyses performed by Fourier transform-infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) also confirmed the effectiveness of this simple process to intercalate the urea into clay lamella. The release pattern demonstrated that the nanocomposite had a slow-release behaviour for urea dissolution. The results also suggested that the Mt type applied in the current study, in a 1:20 Mt/Ur ratio and stirred for 1 h, possessed desirable ecological and economic efficiency in the production of slow-release urea fertilizer due to the application of the impure and domestic clay which is of very low-cost and eco-friendly. Nevertheless, urea was fully intercalated into the interlayer of clay by a simple technique and with a good slow-release behaviour.

KEYWORDS:

• Intercalation
• montmorillonite
• nanocomposite
• urea

Acknowledgements

Special thanks go to Professor Torsten Mueller for his valuable supervision in the 6-month scholarship at Hohenheim University. The corresponding author (Hossein Sabahi), also thanks International Foundation of Science, Sweden, for approving a related project. These two important opportunities, allowed the corresponding author to present this project and other undergoing novel ideas in field of mimicking nature.

Disclosure statement

No potential conflict of interest was reported by the authors.