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Article Dans Une Revue Separation and Purification Technology Année : 2016

Purification of pentoses from hemicellulosic hydrolysates with sulfuric acid recovery by using electrodialysis

Résumé

The valorization of lignocellulosic biomass as a renewable carbon source is growing in chemical industries, particularly in the agro-industrial sector. Many chemicals compounds and bio-based intermediates can be produced but their production needs to be more cost-competitive. The valorization of pentoses in hemicellulosic hydrolysates, obtained by using dilute sulfuric acid, is of growing interest. However, current downstream processes which involve a partial or complete neutralization of the acid are not satisfactory for economic and environmental reasons. This work presents a method of purification of pentoses with sulfuric acid recovery which reduces water and chemicals consumptions. The results obtained at the laboratory scale with wheat bran hydrolysates are very promising. The process is based on the combination of ultrafiltration, conventional electrodialysis and ion-exchange. A special organic UF membrane (Alpha Laval - UFX10pHt), resistant to acidic conditions, removed totally macromolecules which can damage the electrodialysis unit by precipitation, with good mean permeate flow rate (24 L h−1 m−2 till VCF = 4.4). Then, conventional electrodialysis was performed to recover most of sulfuric acid (>80%) without losing sugars (<1%) with an acceptable faradic yield (70%). The specific energy consumption of the electrodialysis stack was interesting (0.6 kWh per kg of H2SO4 recovered and 4.2 kWh per m3 of hydrolysate). Finally, the complete demineralization (conductivity <10 μS cm−1) and discoloration (420 nm absorbance <0.01) of the pentoses solution was obtained by ion-exchange with about a 10-fold increase of resins capacity (20 BV) compared to conventional processes with a neutralization step (2 BV).
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Dates et versions

hal-01310364 , version 1 (09-11-2016)

Identifiants

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Julien Lemaire, Claire-Line Blanc, Fanny Duval, Marc-André Théoleyre, Dominique Pareau. Purification of pentoses from hemicellulosic hydrolysates with sulfuric acid recovery by using electrodialysis. Separation and Purification Technology, 2016, 166, pp.181-186. ⟨10.1016/j.seppur.2016.04.030⟩. ⟨hal-01310364⟩
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