BIOMASS CHAR SULFONIC ACIDS (BC-SO3H)-CATALYZED HYDROLYSIS OF BAMBOO UNDER MICROWAVE IRRADIATION

Abstract

A heterogeneous process for the hydrolysis of bamboo into reducing sugars, a process catalyzed by biomass char sulfonic acids (BC-SO3Hs), was carried out under microwave irradiation. This transformation technology was nearly ineffective with regards to the hydrolysis of fresh bamboo because of the impeding lignin that was wrapped around the cellulose, but the hydrolysis proceeded efficiently when the hemicellulose, and especially the lignin in bamboo, were partly removed through pretreatment with an aqueous ZnCl2 solution under microwave irradiation. The BC-SO3H catalyst bearing –SO3H, OH, and COOH groups showed much higher turnover numbers (TON, 0.64 to 1.07) for the hydrolysis of the pretreated bamboo than did the dilute H2SO4 solution (TON, 0.08). This is likely due to its strong affinity for Beta-1,4-glycosidic bonds of cellulose. The microwave irradiation resulted in much higher hydrolytic efficiency than did conventional heating. This likely resulted from the microwave irradiation’s unique role in activating the cellulose molecules and heightening particle collisions, effects that can remarkably accelerate this process of heterogeneous catalysis.