Comparative study on material properties of wood-ash alkali and commercial alkali treated Sterculia fiber
Abstract
Pulp, paper, and related industries consume large amount of commercial alkali to process raw fiber and/or recycle waste. A low-cost alternative to commercial alkali would be useful to reduce production and recycling costs and global alkali use. In this research, we extracted alkali from wood ash and, as a proof of concept, used the alkali to process lignocellulose fiber obtained from Sterculia villosa (locally known as Murgilo or Mudilo), a traditionally important fibrous plant. Material properties of wood-ash alkali (WAA) treated fiber were compared with 5% sodium hydroxide treated fiber. The net weight loss on WAA and sodium hydroxide treatment was found to be 29.1 ± 2.6 and 41 ± 3.3%, respectively. In both methods, the weight loss resulted from the removal of hemicellulose and lignin consistent with reduction of fiber width and weakening of lignin and hemicellulose characteristic bands in FTIR spectra. Interestingly, both methods resulted in fiber having very similar mechanical strength. Cellulose crystallinity, fiber-surface morphology, and thermal stability of cellulose fiber obtained from two methods were systematically compared. These findings suggested that WAA treatment method could be a low-cost method for processing lignocellulose biomass. Graphical abstract: [Figure not available: see fulltext.].