Abstract The delignification of kraft pulp with sodium dithionite was studied to remove lignin content in the pulp. The sodium dithionite dissolves the chromophoric groups and residual lignin present in the pulp. The increase in dosage of sodium dithionite and reaction temperature of delignification has positive effect on kappa reduction of pulp. X ray diffraction was used to determine the crystallinity index of bleached pulp. The crystallinity increased from 83.3% for unbleached pulp to 86.7% after delignification. Fourier transform infrared spectroscopy shows the reduction in hydrogen bonding in bleached pulp and also the conversion of cellulose I to cellulose II. FT-Raman spectra shows that the fluorescence observed in the spectra of unbleached pulp reduced significantly in comparison to the spectra of bleached pulp resulting in removal of residual lignin and chromophoric groups present in the pulp. Scanning electron imaging shows the smoothening of fiber surface after bleaching. The delignification reaction followed first-order kinetics and activation energy is 33.57kJ/mol.

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使用连二亚硫酸钠作为漂白剂的牛皮纸浆脱木素特性

摘要 研究了硫酸盐纸浆用连二亚硫酸钠脱木素以去除纸浆中的木质素含量。连二亚硫酸钠溶解纸浆中存在的发色团和残留木质素。增加连二亚硫酸钠用量和脱木素反应温度对降低纸浆κ值有积极作用。X射线衍射用于测定漂白纸浆的结晶度指数。结晶度从未漂白纸浆的 83.3% 增加到脱木素后的 86.7%。傅里叶变换红外光谱显示漂白纸浆中氢键的减少以及纤维素 I 向纤维素 II 的转化。FT-拉曼光谱表明，与漂白纸浆的光谱相比，未漂白纸浆光谱中观察到的荧光显着降低，导致纸浆中残留的木质素和发色基团被去除。扫描电子成像显示漂白后纤维表面光滑。脱木素反应遵循一级动力学，活化能为33.57kJ/mol。