Cellulosic materials from pea (Pisum Sativum) and broad beans (Vicia Faba) pods agro-industrial residues

Abstract

Agro-industrial activities generate large quantities of lignocellulosic waste; however, their reuse is still rarely practiced. The use of these unexploited residues to develop high added value cellulosic materials is a crucial step towards sustainable development. This work evaluated pea and broad beans pods agro-industrial residue, for the first time, as promising sources of cellulose derivatives. Cellulose microfibers (CMF) and nanocrystals (CNC) were successfully extracted from pea pods (CMFP and CNCP) and broad beans pods (CMFB and CNCB) using chemical treatments (alkaline-extraction, bleaching, and acid hydrolysis). Pure CMFP and CMFB exhibited a diameter of 10.68 ± 1.28 µm and 14.67 ± 2.29 µm, and a crystallinity of 79% and 70%, respectively. While CNCP and CNCB showed a needle shape, a diameter of 5.4 ± 2.3 nm and 6.3 ± 1.8 nm, and a length of 483 ± 74 nm and 529 ± 68 nm, giving rise to an aspect ratio of 89 and 84, respectively. Besides, CNCP and CNCB showed high crystallinity and thermal stability. The extraction of CMF and CNC from pea and broad beans pods has the potential to recover these underused residues and reduce the accumulated waste volume in the environment.