Isolation and characterization of cellulose nanocrystals from amla (Phyllanthus emblica) pomace.

The present study proposes valorization of amla (Phyllanthus emblica) pomace for the isolation of cellulose nanocrystals (CNCs) to provide a sustainable and low-cost precursor material for the production of nano-based biomaterials. The raw fibers were subjected to bleaching and alkali treatments to obtain cellulose, followed by acid hydrolysis for the isolation of CNC. The resultant nanocrystals were characterized for structural changes using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and transmission electron microscope (TEM). FTIR results showed progressive removal of noncellulosic components such as hemicellulose and lignin. This rendered CNCs with a 45% yield, negative zeta potential value of − 32.33 mV showing greater colloidal stability, and a higher crystallinity index of 45% as determined by XRD. Thermogravimetric analysis revealed that isolated CNCs have higher thermal stability (> 200 °C). TEM images showed that the CNCs exhibit rod-like structures in nano-dimensions with a higher aspect ratio of 10.83. This study will not only aid in the sustainable conversion of food industry waste into a value-added product but also promote the circular economy. This may further help to reduce global emissions and address the key challenges of climatic change. [ABSTRACT FROM AUTHOR]