Extraction and characterization of cellulose nanocrystals from filter paper by sulfuric acid hydrolysis method

Abstract

Cellulose nanocrystals (CNCs) are nanomaterials derived from cellulose, which is the main component of plant cell walls. Nanocrystals are obtained through a process of mechanical or chemical treatment that breaks down cellulose fibres into smaller dimensions at the nanoscale. This study aims to investigate the hydrolysis of filter paper into cellulose nanocrystals (CNCs) using 60% (w/w) sulfuric acid (H2SO4) and identify the characteristics of the extracted CNCs. Filter papers are made from 100% premium pre-treated and high-quality cellulose fibres. The pulverized filter paper mixed the 60% (w/w) sulfuric acid in MLR 1:20 with strong agitation, and the mixture was heated at 50°C for 120 minutes. The mixture was diluted with cold distilled water in a 1:10 ratio to stop hydrolysis. The resulting mixture was centrifuged at 8000 rpm for 15 minutes to separate the CNCs. The precipitate was washed with distilled water using a dialysis membrane until the pH reached neutral. The properties of extracted CNCs have been discovered by Transmission Electron Microscopy (TEM) analysis, Fourier Transform Infrared (FTIR) analysis and X-ray Diffraction (XRD) analysis. The results of TEM analysis showed the needle-shaped morphology of CNCs and sizes ranging from 15–30 nm in diameter to 100–300 nm in length. The FTIR results revealed the functional groups present in the extracted CNCs. The XRD diffraction results showed the crystalline structure of the extracted CNCs. The results indicate that filter paper can be used as a source of cellulose for CNC extraction.