Characterization of formulated copper chitosan nanoparticles for the controlled release studies of dicamba dimethylamine herbicide

Abstract

In this study, a dicamba herbicide was encapsulated onto copper nanoparticles (CuNPs) via a green chemical reduction method in order to improve its herbicidal activity, with the intention of reducing its negative impacts on the environment. The synthesised Dicamba-copper chitosan nanoparticles (Dic-CuCtsNPs) was characterised using UV-visible spectroscopy, scanning electron microscopy (SEM), Fourier transform- infrared (FT-IR), powder x-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermo gravimetric analysis/differential thermal analysis (TGA/DTA) and energy-dispersive x-ray spectroscopy (EDX). The maximum absorption peak of the Dic-CuCtsNPs was observed at 556 nm. The encapsulation efficiency of the Dic-CuCtsNPs formulation was 86 %. The average crystalline size of the nanoparticles, from its PXRD pattern, estimated using the Debye- Scherrer’s equation was 45.94 nm. The SEM image obtained indicated particle size distribution of 16 – 64 nm. The DSC curve showed that the formulation exists in the crystalline state while the TGA data indicated that the formulation was thermally stable up to 425.75^oC. Aqueous release study of Dic- CuCtsNPs was carried out using three different pH media and two agricultural soils. The leaching profile of the formulated nano-herbicide through the University of Agriculture (UAM) and college of advance and professional studies (CAPS) soil layer index showed a high value for the UAM soil being 43.84 % higher than in the CAPS soil value of 26.92 %. Thus, an eco-friendly herbicide delivery system was formulated using CuCtsNPs, for the successful release of Dicamba in aqueous medium and agricultural soils.

Keywords: Controlled release, Dicamba, Encapsulation, Green synthesis, Herbicide, Soil