本文以未漂桉木硫酸盐浆为原料,考察了硼氢化钠预处理后过氧化氢漂白纸浆白度、返黄以及废液中残余过氧化氢、溶出木素及甲醇等物质的变化,并在此基础上探讨了硼氢化钠预处理的作用机制。并以葡萄糖作为纸浆羰基基团模拟物,探讨了硅酸钠是否对硼氢化钠与纸浆羰基基团的反应有催化作用。结果表明:Na BH4预处理明显改变了溶出木素的结构(由于羰基的消除)并降低了溶出木素的反应活性,从而减少过氧化氢在与溶出木素反应中的消耗,同时也减少了废液中甲醇的生成。因此,使过氧化氢在纸浆漂白中的功效得到了进一步的提高。同时,硅酸钠对硼氢化钠与纸浆中羰基基团的反应有催化作用。
Based on the eucalyptus kraft pulp, this paper reported the effects of sodium borohydride pretreatment of peroxide bleaching process on the amount of residual hydrogen peroxide, dissolved lignin and methanol in the efflu- ents. The experiment results showed that the structure of dissolved lignin was evidently changed ( due to the remov- al of carbonyl) and thus the activity of dissolved lignin was weakened by sodium borohydride pretreatment. This re- duced both the peroxide consumption in the reaction on the dissolved lignin and the methanol formation in effluent. As a result, the efficiency of peroxide in pulp bleaching could be further improved.