Hydrolysis of hemicellulose catalyzed by hierarchical H-USY zeolites - The role of acidity and pore structure

Hierarchical H-USY zeolite prepared by oxalic acid treatment was demonstrated to be an effective catalyst for the hydrolysis of hemicellulose. The yield of total reducing sugars (TRS) increased remarkably to 55.7% over hierarchical H-USY compared with 5.8% yield of TRS over H-USY-parent under the same reaction conditions. Mesopores/macropores created by oxalic acid treatment played a main role in elevation of the yield of TRS, which not only improved the accessibility of the acid sites, but also facilitated the product to diffuse out the catalyst and thus restrained its further conversion to byproducts. Conditions of oxalic acid treatment for preparation of hierarchical H-USY zeolite and hydrolysis of hemicellulose were optimized to obtain high yield of TRS. Furthermore, hierarchical H-USY zeolite showed good activity in the selective hydrolysis of hemicellulose in lignocellulosic biomass. (C) 2012 Elsevier Inc. All rights reserved.