Utilizing peracetic acid as an eco-friendly bleaching agent: investigating whiteness levels of cellulose microfibers from corn husk waste

Abstract

Currently, the disposal of agro-industrial waste has generated an urgent need to find eco-friendly methods to convert these wastes into value-added products like cellulose, without the use of chlorine for bleaching purposes. Based on this assumption, a comparative study was conducted using corn husk as raw material to evaluate the performance of a chlorine-free whitener such as peracetic acid, after scouring processes for further comparison with conventional bleaching agents such as sodium chlorite and hydrogen peroxide. Successful cellulose isolation using peracetic acid was demonstrated through ATR-IR, attributed to the presence of a characteristic band at 885 cm−1 and the absence of the band at 1224 cm−1 associated with lignin residues. Additionally, XRD analysis identified peaks of cellulose at 2θ = 15.9°, associated with the overlap of the (1-10) and (110) planes, and at 2θ = 22.5°. Thermal analysis demonstrated the stability and purity of the obtained cellulose, identifying water chemisorption at 125 °C and decomposition at 358.5 °C, free from lignin groups. SEM analysis revealed a fibrillated network morphology with a rough surface in cellulose-based materials extracted from corn husk. Moreover, the cellulose obtained by peracetic acid bleaching (PAAC) exhibited the least fluorescence intensity, and the values obtained by reflectance were ΔE = 1.37, WI = 96.7, and YI = 3.46. Finally, PAAC demonstrates its potential as a source for obtaining cellulose nanocrystals (CNC), achieving a particle size of approximately 214.6 nm, and exhibiting a rod-like structure identified by AFM.