【作者】 吉兴香；

【导师】 陈嘉川；

【作者基本信息】 广西大学 ， 制糖工程， 2013， 博士

【摘要】 本论文以我国北方速生杨木为原料,选择了三种新型木聚糖酶分别对速生杨KP浆和NaOH-AQ浆进行预处理,研究不同木聚糖酶对两种化学浆氧脱木素、ECF和TCF漂白的影响,并分析了木素的溶出机理、漂后纸浆的纤维性质、打浆性能和成纸的物理性能等,为速生杨化学浆的清洁生产提供技术支持和理论依据。研究了三种木聚糖酶(X1,X2,X3)对速生杨KP浆氧脱木素的影响。通过探讨酶处理因素(时间、pH值、反应温度、酶用量等)对速生杨KP浆氧脱木素效果的影响,优化得出适宜的工艺条件如下：X1：酶用量8IU/L,温度50-55℃,pH8,时间120min；X2：酶用量6IU/g,温度55-60℃,pH8-9,时间120min;X3：酶用量8IU/g,温度50℃,pH8-9,时间120min。研究了三种木聚糖酶(X1,X2,X3)对速生杨NaOH-AQ浆氧脱木素的影响。通过探讨酶处理因素(时间、pH值、反应温度、酶用量等)对速生杨NaOH-AQ浆氧脱木素效果的影响,优化得出适宜的工艺条件如下：X1：酶用量10IU/L,温度50-55℃,pH8-9,时间90-120min；X2：酶用量8IU/g,温度55-60℃,pH8-9,时间90-120min；X3：酶用量10IU/g,温度50-55℃,pH8-9,时间120min。研究了三种木聚糖酶对速生杨KP浆ECF漂白结果的影响,具体如下：XODED漂序可实现的最高白度为88.1%ISO;ODED漂序为85.1%ISO,经酶处理后白度高出2.5-3%ISO；XODQP漂序最高为87.0%IS0；ODQP漂序是84.5%ISO,经过酶处理后白度高出2.0-2.5%ISO；XOPDQP漂序最高为89.7%ISO； OPDQP漂序是87.2%ISO,经过酶处理白度高出2.1-2.5%ISO；XO1O2PDQP漂序最高为89.6%ISO；01O2PDQP漂序为87.1%ISO,经过酶处理后白度高出2.1-2.5%ISO；经过酶处理的漂白浆粘度升高,卡伯值降低,返黄值减小,耐折度、耐破度和裂断长得以改善。研究了三种木聚糖酶对速生杨KP浆TCF漂白结果的影响,具体如下：XOPQP漂序可实现的最高白度为83.3%ISO,OPQP漂序为81.2%ISO,经酶处理后白度高出1.9-2.1%ISO；XO1O2PQP漂序最高为82.7%ISO; O1O2PQP漂序为80.6%ISO,经过酶处理后白度高出1.8-2.1%ISO；XO1PO2PQP漂序最高为83.5%ISO；O1PO2PQP漂序是81.6%ISO,经过酶处理后白度高出1.8-2.1%ISO.经过酶处理的漂白浆粘度升高,卡伯值降低,物理性能得以改善。研究了三种木聚糖酶对速生杨NaOH-AQ浆ECF漂白结果的影响,具体如下：XODED漂序最高白度为88.6%ISO；ODED漂序是85.3%ISO,经过酶处理后白度高出2.9-3.3%ISO；XODQP漂序最高为87.7%ISO；ODQP漂序是84.7%ISO,经过酶处理后白度高出2.5-3.0%ISO；XOPDQP漂序最高为88.5%ISO；OPDQP漂序是85.3%ISO,经过酶处理后白度高出2.8-3.2%ISO； XO1O2PDQP漂序最高为88.2%ISO；O1O2PDQP漂序为85.0%ISO,经过酶处理后高出2.8-3.2%ISO。酶处理可以改善漂后浆的粘度、卡伯值和物理性能。研究了三种木聚糖酶对速生杨NaOH-AQ浆TCF漂白结果的影响,具体如下：XOPQP漂序最高为83.5%ISO；OPQP漂序是81.0%ISO,经过酶处理后白度高出2.2-2.5%ISO；XO1O2PQP漂序最高为83.3%ISO；O1O2PQP漂序是80.8%ISO,经过酶处理后高出2.2-2.5%ISO；XO1PO2PQP漂序最高为84.0%ISO；O1PO2PQP漂序是81.8%ISO,经过酶处理后提高1.8-2.2%ISO。酶处理可以改善漂后浆的粘度、卡伯值及物理性能。分析纸浆的红外谱图得出：三种木聚糖酶处理并未从根本上改变木素结构,但可以降解部分木聚糖,促进木素的溶出,进而在氧脱木素过程中能进一步脱除纸浆中的木素,降低卡伯值,提高白度；经过木聚糖酶处理的速生杨KP浆和NaOH-AQ浆氧脱木素中碱溶木素,在280nm处的紫外吸光度略低些,这可能是处理过程中降解了一少部分木聚糖,破坏了木素-碳水化合物复合体的结构,溶出了分子量较小和亲水性的木素,进一步说明木聚糖酶的处理对纸浆氧脱木素产生了有利于木素脱除的作用。分析纸浆中残余木素的核磁共振波谱得出,经过木聚糖酶处理的纸浆氧脱木素后与单纯氧脱木素后纸浆中的残余木素相比,脂肪族羟基、缩合酚羟基、紫丁香基酚羟基以及羧基含量都有所减少,但对酚羟基增加。酶处理后氧脱木素浆中木素各羟基、羧基的含量较未处理的氧脱木素浆的含量的增加和递减趋势是一致的。进一步说明木聚糖酶的处理有利于氧脱木素,但不同的木聚糖酶作用机理可能存在一定差异。SEM观察发现：酶处理后纤维表面空洞增加,变得柔软,纤维表面细纤维化现象比较明显。AFM观察发现：木聚糖酶处理后,单根纤维表面有无数根比较柔软的微细纤维群,单根纤维表面的凹凸程度明显,纤维表面更疏松、纤维比表面积更大。综上可知,木聚糖酶具有明显的、有效的助漂作用。更多还原

【Abstract】 Fast-grown poplar was used as the raw material and three novel xylanase was selected to pretreated KP and NaOH-AQ pulp in this thesis. The influence of xylanase treatment on oxygen delignification, ECF and TCF bleaching was investigated. Furthermore, the mechanism of lignin dissolution, fiber properties of bleached pulp, beating performance and physical properties of paper sheet was analyzed. In summary, the results above would provide technical support and theoretical basis for clean production of fast-grown poplar chemical pulp.The impact of three kinds of xylanases treatment on oxygen delignification of fast-grown poplar KP pulp was studied. Based on the results of oxygen delignification by varying key parameters (including time, pH, temperature, enzyme dosage), the optimal condition was proposed as followed: X1:enzyme dosage8IU/L, temperature50-55℃, pH8, time120min; X2:enzyme dosage6IU/L, temperature55-60℃, pH8-9, time120min; X3:enzyme dosage8IU/L, temperature50℃, pH8-9, time120min.The impact of three kinds of xylanases treatment on oxygen delignification of fast-grown poplar NaOH-AQ pulp was studied. Based on the results of oxygen delignification by varying key parameters (including time, pH, temperature, enzyme dosage), the optimal condition was proposed as followed: X1:enzyme dosage10IU/L, temperature50-55℃, pH8-9, time90-120min; X2:enzyme dosage8IU/L, temperature55-60℃, pH8-9, time90-120min; X3:enzyme dosage10IU/L, temperature50-55℃, pH8-9, time120min.The influence of three kinds of xylanases on the ECF bleaching of KP pulp was studied, and the results as followed:The XODED bleaching sequence can provide the highest brightness of88.1%ISO. ODED can provide brightness of85.1%ISO, which can higher2.5-3%ISO when employed xylanases pretreatment. XODQP bleaching sequence can provide the highest brightness of87.0%ISO. ODQP can provide brightness of84.5%ISO, which can higher2.0-2.5%ISO when employed xylanases pretreatment. The XOpDQP bleaching sequence can provide the highest brightness of89.7%ISO. OpDQP can provide brightness of87.2%ISO, which can higher2.1-2.5%ISO when employed xylanases pretreatment. The XO1O2pDQP bleaching sequence can provide the highest brightness of89.6%ISO. O1O2pDQP can provide brightness of87.1%ISO, which can higher2.1-2.5%ISO when employed xylanases pretreatment. The viscosity, Kappa Number, p.c. Number, and physical properties could get improved by xylanases pretreatment.The influence of three kinds of xylanases on the TCF bleaching of KP pulp was studied, and the results as followed:The XOPQP bleaching sequence can provide the highest brightness of83.3%ISO. OPQP can provide brightness of81.2%ISO, which can higher1.9-2.1%ISO when employed xylanases pretreatment. XO1O2pQP bleaching sequence can provide the highest brightness of82.7%ISO. O1O2pQP can provide brightness of80.6%ISO, which can higher1.8-2.1%ISO when employed xylanases pretreatment. The XO1pO2pQP bleaching sequence can provide the highest brightness of83.5%ISO. O1pO2pQP can provide brightness of81.6%ISO, which can higher1.8-2.1%ISO when employed xylanases pretreatment. The viscosity, Kappa Number, p.c. Number, and physical properties could get improved by xylanases pretreatment.The influence of three kinds of xylanases on the ECF bleaching of NaOH-AQ pulp was studied, and the results as followed:The XODED bleaching sequence can provide the highest brightness of88.6%ISO. ODED can provide brightness of85.3%ISO, which can higher2.9-3.3%ISO when employed xylanases pretreatment. XODQP bleaching sequence can provide the highest brightness of87.7%ISO. ODQP can provide brightness of84.7%ISO, which can higher2.5-3.0%ISO when employed xylanases pretreatment. The XOPDQP bleaching sequence can provide the highest brightness of88.5%ISO. OpDQP can provide brightness of85.3%ISO, which can higher2.8-3.2%ISO when employed xylanases pretreatment. The XO1O2pDQP bleaching sequence can provide the highest brightness of88.2%ISO.0,02pDQP can provide brightness of85.0%ISO, which can higher2.8-3.2%ISO when employed xylanases pretreatment. The viscosity, Kappa Number, p.c. Number, and physical properties could get improved by xylanases pretreatment.The influence of three xylanases on the TCF bleaching of NaOH-AQ pulp was studied, and the results as followed:The XOpQP bleaching sequence can provide the highest brightness of83.5%ISO. OpQP can provide brightness of81.0%ISO, which can higher2.2-2.5%ISO when employed xylanases pretreatment. XO1O2pQP bleaching sequence can provide the highest brightness of83.3%ISO. O1O2pQP can provide brightness of80.8%ISO, which can higher2.2-2.5%ISO when employed xylanases pretreatment. The XO1pO2pQP bleaching sequence can provide the highest brightness of84.0%ISO. OlpO2pQP can provide brightness of81.8%ISO, which can higher1.8-2.2%ISO when employed xylanases pretreatment. The viscosity, Kappa Number, p.c. Number, and physical properties could get improved by xylanases pretreatment.The results of FT-IR showed that:xylanase treatment does not change the structure of lignin fundamentally, but can degraded part of the xylan to promote the lignin dissolution. The lignin can get further removed and lead to decreased Kappa number and improved brightness.The alkali-soluble lignin of oxygen delignification after xylanase treatment of KP and NaOH-AQ pulp has less absorption at280nm, which may caused by part of xylan degradation. The LCC structure was destroyed and low molecular weight and hydrophilic lignin was dissolved during xylanase treatment. The results showed the treatment benefit the delignification.The comparison of residual lignin between pretreated and un-pretreated pulp was carried out, the results showed that:aliphatic hydroxyl group, condensation phenolic hydroxyl group, phenolic hydroxyl and carboxyl in syringyl were decreased, while phenolic hydroxyl increased. The changing tendency of hydroxyl group and carboxyl group of lignin in oxygen delignification was consistent in pretreatment and un-pretreated pulp. The results indicated xylanase pretreatment can improve delignification, despite the different mechanism of varied xylanase.SEM showed:fiber voids was increased, and became softer, and surface fibrillation phenomenon was more obvious with xylanase pretreatment. AFM showed:the single fiber surface has numerous soft fine fiber groups, the unevenness of the surface was obvious, fiber surface was more porous, and surface area was greater after xylanase pretreatment.In conclusion, the xylanase has obviously and effectively effect on bleaching process.更多还原