Isolation and Characterization of Microcrystalline Cellulose from Bamboo Pulp Through Extremely Low Acid Hydrolysis

Microcrystalline cellulose (MCC) has a wide range of applications in food, chemical, pharmaceutical industries, etc. In this study, the one-step preparation of MCC from bleached Kraft bamboo pulp (BKBP) by extremely low acid (ELA; acid concentration ≤0.1 wt %) was demonstrated. The experimental data indicate that the crystallinity, degree of polymerization (DP), and yield of MCC were strongly affected by the time and temperature of hydrolysis, as well as the concentration of hydrochloric acid (HCl). Rod-like MCC was obtained with a yield of 76.4% (based on the mass of original BKBP) and exhibited high crystallinity and narrow particle diameter distribution (78.7%, 30–70 μm) under optimal conditions (acid concentration of 0.08 wt%, 165 °C, 40 min). The Fourier transform-infrared spectroscopy (FTIR) and X-ray diffraction (XRD) measurements showed that the resulted MCC maintained cellulose I structure. Thermal analysis demonstrated that the as-prepared MCC exhibited good thermal stability. The ELA hydrolysis process may provide a green alternative for the manufacture of MCC from bleached Kraft bamboo pulp.