麦草生物化机浆木聚糖酶预处理H_2O_2漂白研究

Improvement of H_2O_2 Bleaching of Wheat Straw Bio-Chemimechanical Pulp by Xylanase Pretreatment and Acetic Anhydride Activation

在麦草生物化机浆H2O2漂白时,采用单纯H2O2漂白难以获得较高白度的纸浆,但通过对浆料进行木聚糖酶预处理和在漂白过程中加入醋酸酐进行活化,可以改善H2O2漂白效率,提高漂白浆白度。麦草生物化机浆木聚糖酶预处理和醋酸酐活化处理的适宜条件分别为木聚糖酶用量12IU/g绝干浆、120min和在H2O2漂白150min时加入5%醋酸酐处理10min。采用木聚糖酶预处理、醋酸酐活化和H2O2漂白相结合的XP5aP5a漂白程序,可获得白度为74.6%ISO的漂白麦草生物化机浆。实验对酶预处理和漂白过程中纸浆化学成分的变化也进行了研究。

Improvement of H2O2 bleaching of bio-chemimechanical pulp from wheat straw by xylanase pretreatment and acetic anhydride activation was studied in the paper. It is difficult to obtain high brightness of bleached bio-chemimechanical pulp of wheat straw by using a single stage peroxide bleaching. Pretreatment with xylanase prior to bleaching and activation with acetic anhydride during bleaching lead to improvement of H2O2 bleaching and upgrade of the brightness of the bleached pulp. The suitable conditions of xylanase pretreatment and acetic anhydride activation were xylanase dosage 12 IU/g oven dry wheat straw, 48°C, 120 min, pH 4.8 and 5% acetic anhydride, 10 min. The acetic anhydride was added when peroxide bleaching proceeded 150 min. the ISO brightness of 74.6% could be achieved by using xylanase pretreatment, H2O2 bleaching and acetic anhydride activation. The chemical compositions of the bio-chemimechanical pulp of wheat straw were also analyzed during xylanase-enhanced H2O2 bleaching.