Extraction and Characterisation of Cellulose Nanocrystals Structures from Waste Office Paper

Abstract

The increase of consumption of paper has led to environmental issues due to the landfill and incineration activities. Subsequently, one of the major cellulosic waste materials includes the waste office paper (WOP). This wastage undergoes a value added process, which is by having it converted into cellulose nanocrystals (CNC) that is prepared by an environmentally friendly and cost-effective method. Hence, this study is performed to synthesise CNC from WOP by acid hydrolysis method with the optimum acid concentration chosen based on the selected parameters. Until present time, limited research has been carried out on the preparation of CNC from WOP. Furthermore, the process of preparing CNC from WOP is easier and it is more energy and time efficient due to the minimum amount of lignin, compared to other cellulosic wastes. The alkali pretreatment and acid hydrolysis methods were conducted before further analysis by using X-ray Diffraction (XRD) in order to establish the crystallinity index (CrI) and Fourier-transform infrared (FTIR) spectroscopy, which show the confirmation of non-cellulosic materials that has been removed by alkali treatment with the 5 wt % concentration. In addition, via the Scanning Electron Microscopy (SEM), it was found that the surface morphology of the alkali-treated WOP was smoother than the untreated ones. From the result obtained, the optimum acid concentration is 30 wt %, with 90 minutes of hydrolysis time and 45°C temperature with the highest CrI and crystallite size of 36.35% and 32.92 nm, respectively. The extraction of CNC from WOP provides possible application as reinforcement in the nanocomposite industry. Thus, the use of WOP can be considered as green material, where it aligns with the sustainable design and development.