RESEARCH ON THE PROCESS OF CELLULOSE PURIFICATION FROM WHEAT STRAW ETHANOL PULP

摘要

Cotton pulp and wood pulp were commonly served as raw materials to produce microcrystalline cellulose, whereas wheat straw has not been reported for being used as the raw material. This research focused on cellulose purification from wheat straw ethanol pulp by a QZPX pollution-free process, which was one of the primary processes for MCC preparation. Chelating treatment (Q) used EDTA at the dosage of 0.4% (oven dry base, similarly hereinafter). The optimal ozone treatment (Z) was found to be at the dosage of 1.2% when the pulp consistency was 45% and pH was 2. After the Z treatment, the KMnO4 value of the pulp was decreased from 18.2 to 3.7, the brightness was increased from 26.4%ISO to 55.6%ISO, and the degree of polymerization (DP) was decreased from 675 to 646. The optimal H2O2 (P) process conditions were: pulp consistency 12%, C6H5Na3O7 dosage 1%, H2O2 dosage 3%, NaOH dosage 1.8%, temperature 70°C, and time 120min. The suitable xylanase (X) process conditions were enzyme dosage 1.5 IU/g, pulp consistency 5%, temperature 50 °C, and time 150 min. The properties of the final product after QZPX treatment were: acellulose content 94.67%, brightness 85.6% ISO, and DP 615.