针阔混合化学浆漂白过程中木素增效溶出机制

This research is a new discovery of the applier when the experiments of mixed bleaching hardwood and softwood pulp was carried out, that is, with the same dosage of bleaching agent, the brightness obtained by mixed bleaching is 2%ISO higher than that by respective bleaching. To obtain the same whiteness, 10% dose of bleaching agent can be saved by mixed bleaching, compared to respective bleaching, while related mechanism are not clearly and definitely identified. Therefore, a new concept of “the efficiency strengthening dissolution.” is presented in the research, in which fractionation and purification was used for the lignin in key bleaching sequence with the method of acid hydrolysis and enzyme-weak acid hydrolysis. HPLC、LC-MS、MS/MS、APCI-MS、NMR and other means were applied for the qualitative analysis and quantitative analysis for the exploration of dissolved degradation of lignin in the mixed bleaching sequence simulated by monomeric and dimeric lignin model compound. Through the analysis of the obtained rate and degree of the reaction between lignin and bleaching agent, and the sequence, ways during mixed bleaching of the pulp, theoretically the reason for reduction of bleaching agent dosage, factors of decreased degree of fiber degradation can be found out to build the lignin dissolved degradation mechanism and thus to clarify the related dissolved degradation mechanism, which can provide a guide and theoretical reference for mixed bleaching technique of hardwood and softwood pulp. The result is significantly meaningful to systematically explain the mechanism of mixed bleaching and promote the industrial process of mixed bleaching.

本项目源于申请者研究阔叶木和针叶木化学浆混合漂白效果好于分别进行漂白的新发现，在达到相同白度时，混合漂白可节约10%的漂剂用量，而对于其相关机理与作用机制目前仍不清晰和明确。因此，本项目提出了“针阔混合漂白木素增效溶出”新概念，利用酸水解和酶-弱酸水解法对混合漂白过程中关键漂段中的木素进行抽提纯化，采用HPLC、LC-MS、MS/MS、APCI-MS、NMR等方法对木素单体和二聚体模型物模拟混合漂段木素的溶出进行定性和定量分析，通过针阔混合化学浆漂白过程中木素降解溶出的顺序、方式、木素与漂剂的反应速度和程度，分析混合漂白较分别漂白效果好的原因，弄清楚其增效溶出的相关机理，为阔叶木和针叶木化学浆混合漂白技术的发展提供理论依据，对阐明混合漂白机理以及推动混合漂白技术的工业化进程具有重要意义。

本项目主要研究了阔叶木和针叶木化学浆混合漂白效果与分别进行漂白效果的比较，研究表明，在达到纸浆达到相同白度时，混合漂白可节约10%左右的漂剂用量；在采用相同的漂剂用量时，针阔混合漂白纸浆的白度明显高于分别漂白纸浆的白度，且纸浆保持良好的强度。本项目通过大量的试验研究，提出了“针阔混合漂白木素增效溶出”新理论新概念，利用混合漂白和分别漂白的氧脱木素段对木素进行抽提纯化，采用了红外、核磁等系列现代仪器检测方法对木素进行了定性和定量分析，通过针阔混合化学浆漂白过程中木素降解溶出的顺序、方式、木素与漂剂的反应速度和程度，分析了混合漂白较分别漂白效果好的原因，弄清楚其增效溶出的相关机理，为阔叶木和针叶木化学浆混合漂白技术的发展提供了理论依据，对阐明混合漂白机理以及推动混合漂白技术的工业化进程具有重要意义。