Isolation and characterization of nanocellulose from jackfruit peel: A comparative analysis of organic and inorganic acid hydrolysis on structural, thermal, and rheological properties

Abstract

Jackfruit peel (JP) is a lignocellulosic biomass rich in cellulosic components with promising upcycling potential. This work involves the comparative study of the extraction of nanocellulose (NC) from JP by using different inorganic (sulphuric (SA), hydrochloric (HA), and phosphoric acid (PA)) and organic (formic (FA), oxalic (OA), and citric acid (CA)) acids at 6M concentration for 3 h at 80 °C. Yield, particle size, zeta potential, crystallinity, morphology (FESEM and TEM), rheological, and thermal properties (TGA) were determined to investigate the influence of organic and inorganic acid hydrolysis on obtained nanocellulose. Inorganic acid hydrolysis produced nanocellulose with particle size ranging from 100 to 160 nm, whereas organic acid hydrolyzed nanocellulose had a particle size ranging from 170 to 230 nm. Organic acid hydrolyzed NCs had higher crystallinity than inorganic acid hydrolyzed NCs (NC/CA > NC/OA > NC/FA > NC/PA > NC/HA > NC/SA). The functional properties of NCs varied with size and crystallinity of NCs. FTIR spectra showed that the native functional groups of cellulose remained intact in the obtained nanocellulose. TGA exhibited good thermal stability of NCs, and cellulose as compared to raw JP. Rheological characteristics revealed the shear thinning behaviour and the gel-forming ability of nanocellulose suspension. The characterization of nanocellulose provided detailed insights into how different acids influence its structural and functional properties, highlighting their implications for diverse applications. This study emphasizes transformation of lignocellulosic biomass into nanocellulose as a sustainable strategy to reduce environmental waste and promote circular economy practices.