Biosynthesis of zinc oxide nanoparticles using leaf extract of Calotropis gigantea: characterization and its evaluation on tree seedling growth in nursery stage

Sadhan Kumar Chaudhuri,Lalit Malodia

doi:10.1007/s13204-017-0586-7

Abstract

Green synthesis of zinc oxide nanoparticles was carried out using Calotropis leaf extract with zinc acetate salt in the presence of 2 M NaOH. The combination of 200 mM zinc acetate salt and 15 ml of leaf extract was ideal for the synthesis of less than 20 nm size of highly monodisperse crystalline nanoparticles. Synthesized nanoparticles were characterized through UV–Vis spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), EDX (energy dispersive X-ray), and AFM (atomic force microscopy). Effects of biogenic zinc oxide (ZnO) nanoparticles on growth and development of tree seedlings in nursery stage were studied in open-air trenches. The UV–Vis absorption maxima showed peak near 350 nm, which is characteristic of ZnO nanoparticles. DLS data showed that single peak is at 11 nm (100%) and Polydispersity Index is 0.245. XRD analysis showed that these are highly crystalline ZnO nanoparticles having an average size of 10 nm. FTIR spectra were recorded to identify the biomolecules involved in the synthesis process, which showed absorption bands at 4307, 3390, 2825, 871, 439, and 420 cm−1. SEM images showed that the particles were spherical in nature. The presence of zinc and oxygen was confirmed by EDX and the atomic % of zinc and oxygen were 33.31 and 68.69, respectively. 2D and 3D images of ZnO nanoparticles were obtained by AFM studies, which indicated that these are monodisperse having size ranges between 1.5 and 8.5 nm. Significant enhancement of growth was observed in Neem (Azadirachta indica), Karanj (Pongamia pinnata), and Milkwood-pine (Alstonia scholaris) seedlings in foliar spraying ZnO nanoparticles to nursery stage of tree seedlings. Out of the three treated saplings, Alstonia scholaris showed maximum height development.

Highlights

In the recent years, the use of metal nanoparticles gained greater interest due to their diverse applications in the field of medicine, biology, physics, chemistry, and material sciences (Kumar et al 2014)
Synthesized nanoparticles were characterized through UV–Vis spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), EDX, and AFM
We reported the biosynthesis of stable colloidal zinc oxide nanoparticles using leaf extract of C. gigantea

Summary

Introduction

The use of metal nanoparticles gained greater interest due to their diverse applications in the field of medicine, biology, physics, chemistry, and material sciences (Kumar et al 2014). Nanoparticles can be defined as particles that have at least one dimension less than 100 nm in size (Thakkar et al 2014) Unlike bulk materials, they have unique optical, thermal, electrical, chemical, and physical properties. They have unique optical, thermal, electrical, chemical, and physical properties They find a variety of applications in the areas of medicine, chemistry, environment, energy, agriculture, information and communication, heavy industries, and consumer goods (Panigrahi et al 2004). Nanotechnology has emerged as a state-of-theart and cutting-edge technology with multifarious applications in a wide array of fields. It is a very broad area comprising nanomaterials, nanotools, and nanodevices. Majority of the research has mainly focused on nanoparticles as they can be prepared and manipulated

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