Valorization of orange bagasse through one-step physical and chemical combined processes to obtain a cellulose-rich material

BACKGROUND Orange bagasse (OB) is an agroindustrial residue of great economic importance that has been little explored for the extraction of cellulose. The present study aimed to investigate different combinations of chemical (sodium hydroxide, peracetic acid and alkaline peroxide) and physical (autoclaving and ultrasonication) treatments performed in one-step processes for cellulose extraction from OB and to characterize the materials obtained according to their composition, morphology, crystallinity and thermal stability. RESULTS The processing yields ranged from 140 to 820 g kg(-1), with a recovery of 720-1000 g kg(-1) of the original cellulose. Treatments promoted morphological changes in the fiber structure, resulting in materials with higher porosity, indicating partial removal of the noncellulosic fractions. The use of combined chemical treatments (NaOH and peracetic acid) with autoclaving was more efficient for obtaining samples with the highest cellulose contents. CONCLUSION Therefore, AC(SH) (processed by autoclaving with NaOH) was the most effective one-step treatment, resulting in 71.1% cellulose, 0% hemicellulose and 19.0% lignin, with a crystallinity index of 42%. The one-step treatments were able to obtain materials with higher cellulose contents and yields, reducing reaction times and the quantity of chemical reagents employed in the overall processes compared to multistep conventional processes. (c) 2020 Society of Chemical Industry

Automated summary

The study investigated different combinations of chemical and physical treatments for cellulose extraction from orange bagasse. The most effective treatment was found to be the combination of NaOH and peracetic acid with autoclaving, resulting in higher cellulose content and yield in a one-step process compared to traditional multistep processes.