Hydrogen peroxide bleaching of cellulose pulps obtained from brewer’s spent grain

Brewer’s spent grain (BSG) was evaluated for bleached pulp production. Two cellulose pulps with different chemical compositionswere produced by soda pulping: one from the original raw material and the other from material pretreated by dilute acid. Both of them were bleached by a totally chlorine-free sequence performed in three stages, using 5% hydrogen peroxide in the two initial, and a 0.25 NNaOHsolution in the last one. Chemical composition, kappa number, viscosity, brightness and yield of bleached and unbleached pulps were evaluated. The high hemicellulose (28.4% w/w) and extractives (5.8% w/w) contents in original BSG affected the pulping and bleaching processes.However, soda pulping of acid pretreated BSG gave a celluloserich pulp (90.4% w/w) with low hemicellulose and extractives contents (7.9% w/w and