Ecofriendly isolation and characterization of microcrystalline cellulose from giant reed using various acidic media

This work reports the isolation of cellulose from giant reed through an ecofriendly multistep procedure including alkali treatment and totally chlorine free delignification, followed by acid hydrolysis to prepare microcrystalline cellulose using different acidic solutions (HCl, HNO3, H2SO4, HCl/HNO3 (2:1, v/v), and HCl/H2SO4 (2:1, v/v)). Several characterizations were performed in order to investigate the properties of each sample. FTIR results affirmed that the successive alkali treatment, totally chlorine free bleaching, and acid hydrolysis remove efficiently hemicellulose, lignin, and amorphous regions from the giant reed, and showed that the characteristic peaks of the prepared giant reed microcrystalline celluloses (GRMCC-HCl, GRMCC-HNO3, GRMCC-H2SO4, GRMCC-HCl/HNO3, and GRMCC-HCl/H2SO4) were similar to those of the commercial one. XRD measurements exhibited that microcrystalline cellulose produced from giant reed belong to cellulose I allomorph, with crystallinity index ranging from 73 to 80%. SEM micrographs revealed non-uniform micro sized rod-like shape morphology of GRMCC samples. The thermal analysis results displayed that the thermal decomposition of the obtained GRMCCs shifted to higher temperatures compared to the respective giant reed cellulose. This work opened a new pathway to prepare cellulose and microcrystalline cellulose from an abundant natural source using an ecofriendly process, and it could be expected to have applications in several areas. [GRAPHICS] .