Pretreatment of Corn Stover Using Supercritical CO2 with Water-Ethanol as Co-solvent

Supercritical fluids as a green technology for the pretreatment of lignocellulosic biomass

“…Additionally, the ethanol as polar co-solvent (with polar characteristics) can promote the pretreatment based on the cleavage of the lignocellulosic matrix. The last statements agree with those discussed by other authors (Lü et al, 2013;Puech et al, 1990). Moreover, an intensification effect on the hydrolysis reactions should be expected.…”

“…Other types of pretreatments have been explored as alternatives to reduce operational conditions in terms of reactions severity, residence time, equipment deterioration and its associated costs. Supercritical pretreatment (Lü et al, 2013) among others are innovative proposals recently discussed. This paper studies the effect of supercritical pretreatment as a green technology (based on an inexpensive solvent as CO 2 ) on the cellulose crystallinity and lignin removal in rice husk.…”

“…Water in the biomass combined with supercritical carbon dioxide generates a carbonic acid mixture which generates a kind of weak acidic environment preliminary promoting the hemicellulose hydrolysis and intensifying the mass transfer conditions (Narayanaswamy et al, 2011). Additionally, when water is mixed with other type of solvents the delignification capability is enhanced; for instance, ethanol improves the solubility of lignin fragments (Lü et al, 2013).…”

“…The literature reports huge ranges of temperatures and pressures of 100-198°C and 7-300 bar (Gao et al, 2010;Lü et al, 2013;Narayanaswamy et al, 2011;Pasquini et al, 2005a,b). Indeed, in those works the increase of the pressure gave higher delignification yields and an increase in surface area was also observed (Narayanaswamy et al, 2011).…”

Sub- and supercritical fluid technology applied to food waste processing

“…Using the mentioned conditions, they found the delignification value of around 96%, which shows good agreement between the experimental and predicted data. LÜ [61] used supercritical CO 2 with water-ethanol as co-solvent to pretreat corn stover and enhance its enzymatic hydrolysis. The authors observed that the highest sugar yield (77.8%) was achieved for the corn stover pretreated with CO 2 /water-ethanol at 15 MPa and 180 • C for 1 h. After the pretreatment the percentage of cellulose increased 33% and the percentages of lignin and hemicellulose reduced 4 and 23%, respectively.…”