Synthesis and Characterization of Zinc Oxide Nanoparticles (ZnO) and Its Applications for Use in Agriculture

Abstract

Biologically synthesized zinc oxide nanoparticles (ZnO-NPs) have gained significant attention as sustainable alternatives to conventional zinc fertilizers in modern agriculture. This review aims to examine the synthesis routes, characterization methods, and agricultural applications of biogenic ZnO-NPs, with emphasis on their potential to enhance crop productivity and environmental sustainability. A systematic literature review methodology was adopted, using the Scopus database to collect peer-reviewed publications from 2004 to 2025. Relevant studies were selected through keyword searches related to biosynthesis, nanofertilizers, sustainable agriculture, and nanoparticle characterization, resulting in approximately fifty key articles for analysis. Findings indicate that biogenic synthesis using plants, microorganisms, and biological wastes provides environmentally friendly, cost-effective, and scalable approaches for producing ZnO-NPs with desirable physicochemical properties. Characterization techniques such as ultraviolet–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirm nanoparticle formation, size, morphology, crystallinity, and stability. The reviewed studies demonstrate that ZnO-NPs improve zinc availability, nutrient-use efficiency, plant growth, yield, stress tolerance, and antimicrobial protection in crops such as rice, wheat, and maize. However, concerns regarding potential toxicity, regulatory frameworks, large-scale production, and farmer adoption remain significant challenges. In conclusion, biogenic ZnO-NPs represent a promising tool for precision agriculture and sustainable food production by reducing nutrient losses and enhancing crop performance. It is recommended that future research focus on long-term environmental safety assessments, cost-effective manufacturing, standardized regulatory guidelines, and field-scale validation to facilitate widespread adoption of ZnO-NP-based nanofertilizers.