Adsorption of γ-Valerolactone: An Alternative for Solvent Recovery after Conversion of Lignocellulosic Biomass to Fermentable Sugars

L. G. Coelho, G. Johann, F. Palú, M. G. A. Vieira, R. Guirardello, V. N. T. Júnior and E. A. D. Silva

Abstract
The γ-valerolactone is an effective solvent in solubilizing lignocellulosic biomass fractions, although it inhibits microbial activity. To avoid the negative effects on the metabolism of microorganisms, even small quantities of γ-valerolactone need to be removed. This study examined the adsorption of γ-valerolactone on the commercial resin. The removal efficiency, adsorption equilibrium, pH effects, and fixed-bed column conditions were investigated. The highest removal efficiency of γ-valerolactone from sugar solution was 39.92 %, with 413.78 mg g−1 γ-valerolactone adsorption capacity, observed with commercial resin Dowex Optipore L-493 and pH 4.00. Dual-site Langmuir adsorption isotherm was found to be the best-fitting model for describing the adsorption mechanisms of γ-valerolactone on commercial resin. Thus, this study shows that γ-valerolactone could be removed from sugar solution by adsorption on commercial resin. In addition, the process is a viable alternative for the recovery of solvent and keeping the microbial activity in lignocellulosic biomass fractions.

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Keywords
commercial resin, separation, kinetic, equilibrium, batch, fixed-bed