Extremely Low Sulfuric Acid Hydrolysis of Cornstalk and Its Structural Changes

In this study, extremely low acid (ELA, 0.08% w/v of sulfuric acid) was used for the hydrolysis of cornstalk in a reactor at a designed reaction temperature from 130 °C to 170 °C, and the results were compared with hot water hydrolysis and low acid (LA, 0.2% w/v of sulfuric acid) hydrolysis. And the influences of initial sulfuric acid concentration and reaction temperature on the hydrolysis of cornstalk were discussed in details. It was found that pentose is the most abundant sugar, and 6.4 g/L of xylose and 1.5 g/L of arabinose could be obtained at the temperature of 160 °C when hydrolysis with ELA, the pentose yield for hemicellulose in cornstalk was 68.7%. Furthermore, the physicochemical and structural changes for the hydrolyzed and controlled cornstalk were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscope (SEM), and the results were elaborated in detail.