IMPROVED OXYGEN DELIGNIFICATION SELECTIVITY OF OIL PALM (ELAEIS GUINEENSIS) EFB SODA-AQ PULP: EFFECT OF PHOTO- PRETREATMENT AND AQ-AIDED H2O2 REINFORCEMENT

摘要

The kappa number (K_n) reduction of oil palm empty fruit bunch (EFB) soda-anthraquinone (AQ) pulp by oxygen delignification was limited to only 34% to avoid substantial cellulose degradation. Thus, a preliminary study of photo-pretreatment was performed to improve the bleaching selectivity, and its effect was compared with the AQ-aided H2O2 reinforced O-stage (O_p-stage). The results showed that both methods performed better selectivity than the ordinary O-stage. It was suggested that the photo-treatment improved selectivity by diminishing carbonylinduced carbohydrate degradation. Conversely, the AQ-aided O_p-stage delivered higher delignifying power with minimum cellulose degradation. For pulps with the K_n above 6.0, the effectiveness of both methods was about the same, but to achieve lower K_n (5.8 and below), the AQ aided O_p pulps exhibited better selectivity.