Monday, April 29, 2013
Exhibit Hall
The use of chemicals and solvents has been widely investigated to pretreat lignocellulosic biomass. The inter and intra-molecular bonds can be broken or solvated by them opening up the matrix of lignin, cellulose and hemicellulose. In recent years, increasing attention has been paid to the effect of ions on the dissolution of cellulose and wood, mostly within the frame of investigating the use of ionic liquids. Acetate anion is as efficient in cellulose dissolution, while organic cations are reported as more effective with decreasing sizes. Although the perspective of using a solvent to dissolve the lignocellulosic is very attracting, the ionic liquids that have been tested till now are generally characterized by high cost, recycling difficulties, low yields, toxicity. However, the search for new solvents is very active and is pushed by the advantages that such ideal liquid medium could provide. Although ammonia has been largely investigated as chemical for pretreatment, lack of information has been highlighted about the role of the ammonium cation. The efficiency on solubility and enzymatic digestibility of ammonium acetate has been not yet systematically investigated. In this work, we report about experiments carried out on straw loaded with ammonium acetate at different concentrations in water and treated at different severities, i.e. 121-220°C for 5 - 300 min. It has been achieved the solubilization of about one third of the biomass and a dramatic increase of the enzymatic digestibility of the solid residue.