Glucose and 5-hydroxymethylfurfural production from cellulosic waste by sequential alkaline and acid hydrolysis

Glucose and 5-hydroxymethylfurfural production from waste paper towel was evaluated by sequential alkaline and acid hydrolysis. Effects of alkali/acid doses, treatment time and temperature on hydrolysis performance were investigated by using Box-Behnken and Box-Wilson statistical experiment design methods. Operation parameters for alkaline hydrolysis were percent NaOH, treatment time and temperature and for acid hydrolysis percent acid and treatment time. Total paper conversion of the sequential process was 72% indicating significant waste reduction beside glucose and 5-hydroxymethylfurfural formation. The maximum yields for glucose and 5-hydroxymethylfurfural were 61.23% and 19.70% in acid and alkaline hydrolysis, respectively. Main products in the effluent of alkaline hydrolysis were glucose and 5-hydroxymethylfurfural. Highest glucose concentration (25.2 gL−1) in alkaline hydrolysis was obtained at 16% NaOH, 119 °C, and 74 min. The 5-hydroxymethylfurfural concentration and paper conversion at this condition was 7.22 gL−1 and 28.47%, respectively. When the solid residue of alkaline hydrolysis was treated with 5% H2SO4 at 135 °C for 120 min then 30.7 gL−1 glucose and 0.87 gL−1 5-hydroxymethylfurfural was obtained with 44.35% paper conversion.