Green synthesis, characterization, and biochemical properties of waste walnut (Juglans regia L.) inner shell-based silver nanoparticles

Abstract

Sustainability is important for future ecology and the increase of waste in recent years negatively affects sustainability. The management of waste and using them in the technology field could be a solution for sustainability. Nanotechnology is a developing technology to improve the physical, chemical, and biological properties of matter with the size of 1-100 nm. Nanoparticles could be synthesized by different methods such as physical, biological, and chemical methods. The green synthesis (biological synthesis) method is the most preferred method according to chemical and physical methods because it is eco-friendly, energy-saving, cheaper, less waste-producing, easy to scale, sustainable, and biologically compatible. Walnut is a versatile fruit with its leaves, dry and green fruit, timber, inner/outer shell, and outer peel. Its inner shell and outer peel are not used as food and they are waste. In this study, a waste walnut inner shell was used to synthesize silver nanoparticles (WS-AgNPs). WS-AgNPs were synthesized by green technique, characterized, and biochemical properties were determined. WS-AgNPs were given a maximum absorbance at 460nm with 46-51nm size and they inhibited urease enzyme by 82.16 ± 1.30 % percentage. It was clear that herbal-based wastes could be used in nanotechnology and they have the potential to be used in medicine.