Extraction of Cellulose Nanofibers from Agricultural Waste as Future Nanomaterials

Natural materials are experiencing a renaissance of sorts, as people around the world seek safe, environmentally friendly and renewable alternatives to plastics and other oil-based products. The use of eco-friendly and bio-based materials is a green concept in material science research. Nanocellulose is the most promising sustainable solution for several future challenges in modern society [1]. Toxic nanofillers would effectively be replaced with nanocellulose and this extend their application in biomedical area. Cellulose nanofiber (CNF), which can be derived from plant, is one of the most abundant green resources on Earth. Several plant parts are used to extract cellulose nanofibers. Herein, we have adopted an eco-friendly method to extract cellulose nanofibers by making use of wealth from waste concept. In the current research, cellulose nanofibers were successfully extracted from onion skin and garlic straw, which are popular agricultural waste from food processing industry via. a simple and economic method. There are five steps involved in the extraction process (Fig.1). The alkali treated fibers are bleached with 10% NaOH and 15% hydrogen peroxide (H2O2). Later on acid hydrolysis stage, the bleached fibers were treated with oxalic acid in an autoclave. Finally, the obtained fibers are homogenized in a homogenizer until the fibers are uniformly and further making it into nanoscale dimension. The extracted cellulose nanofibers are characterized using Scanning Electron Microscopy (SEM), Dynamic light scattering (DLS) and 13C NMR spectroscopy techniques. The prepared nanofibers are of high purity, nanoscale dimension and high aspect ratio, which would have potential application in a variety of fields including filter material, high gas barrier packaging material, electronic devices, foods, medicine, cosmetics, photonic materials and health care [2]. Due to the renewable and sustainable nature of cellulose nanofibers, it creates low environmental impact in its production and disposal.