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Poster Presentation 1-10
Effects of Carbonic Acid on Endogenous Acid Accumulation in Pretreatment Hydrolysates.
Robert McWilliams, and G. Peter van Walsum
Department of Environmental Studies, Baylor University PO Box 97266, Waco, TX 76798-7266
Telephone: (254) 710-6552; Fax: (254) 710-2309; E-mail: Gpeter_van_Walsum@Baylor.edu
Comparison of Carbonic Acid (H2CO3) and Liquid Hot Water Pretreatment (LHWP) hydrolysates has shown that the evidence of hydrolytic activity in the two systems, such as sugar accumulation and degree of degradation, is largely the same. However, the carbonic acid pretreatment system appears to result in a higher final pH, indicating a reduced accumulation of acid species in the hydrolysate.
Samples produced by the pretreatment of biomass with carbonic acid were compared to samples produced using only liquid hot water. Pretreatment temperatures tested ranged from 180oC to 220oC; reaction times were varied between 2.5 and 30.5 minutes; and initial room temperature CO2 pressures ranged from 0 to 800 psig. Substrates tested included aspen wood and corn stover, which have relatively high and low concentrations of acetyl groups, respectively. Measurements of acid concentrations in the hydrolysates were carried out using High Pressure Anion Exchange chromatography (HPAE). Correlations between final pH, reaction severity, acetate concentrations and biomass source are presented.
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