p-TsOH处理对硫酸盐竹浆成纸性能的影响

用对甲苯磺酸(p-TsOH)对未漂硫酸盐竹浆进行了处理,将处理后的竹浆进行抄纸,并对成纸性能做了相关分析。发现在p-TsOH浓度25%～50%、温度70℃、时间30～60 min的温和反应条件下,木质素脱除率可达60%,竹浆纤维的得率超过87%,得到的纤维形态基本完整,纤维平均长度未发生明显变化,官能团种类未发生改变。p-TsOH处理后的硫酸盐竹浆成纸亮度提升了47%～74%,抗张指数没有降低。当温度超过80℃,p-TsOH浓度超过50%时,虽脱木质素率进一步增加,但浆料得率降低,纤维开始断裂成碎片,无法成纸。在温和条件下,p-TsOH对未漂硫酸盐竹浆有较好的脱木质素效果,且具有一定的漂白功能。     

蔗渣硫酸盐浆次氯酸盐漂白中有害物质的研究

本文对蔗渣硫酸盐浆次氨酸盐漂白中有机氯及三氯甲烷的形成情况进行了研究，结果表明：这些有害物质的生成量与漂白用氟量、漂白浓度、温度和时间等条件有关；在次氨酸盐漂白时加入少量H2O2,可以有效地减少三氯甲烷的生成量，通过GC及ESR分析阐明H2O2能减少废液中三氯甲烷含量的机理。     

Co-salen型仿酶系统催化漂白竹浆最优化工艺条件的研究

采用正交试验方法对竹浆Co-salen型仿酶系统催化漂白竹浆最优工艺条件及影响因素进行了研究。用白度、硬度、黏度和选择性这四个指标评价仿酶预处理的效果,并通过计算确定了各因子的影响程度及最佳因子组合。结果表明,竹浆Co-salen仿酶催化预处理较适宜的条件为:NaOH用量3.0%,H2O2用量1.0%,Co-salen用量0.03%,吡啶用量0.007%,温度90℃,时间5 h,氧压0.2 MPa,浆浓5%。     

桉木硫酸盐浆DMD漂白工艺条件的研究

使用新漂剂二甲基二环氧乙烷（Dimethyldioxirane,简称DMD）漂白桉木硫酸盐浆时,应严格控制反应的pH值为7．0~7．5;过氧硫酸盐和丙酮用量增加,二甲基二环氧乙烷的漂白能力随之增强;5％用量的DMD漂浆经碱抽提后脱木素能力与氧脱水素相当,但前者漂浆得率高,脱木素选择性好。     

漆酶和聚木糖酶协同漂白蔗渣硫酸盐浆的研究

进行了蔗渣硫酸盐浆漆酶 /介体 (LMS)生物漂白的研究 ,分析了漆酶 /介体体系和聚木糖酶在漂白流程中作为前后漂段或在同一段中同时使用对漂白效果的影响。漆酶 /介体体系与聚木糖酶同时或前后处理蔗渣硫酸盐浆 ,在一定程度上提高了纸浆的漂终白度和强度 ,说明生物漂白改善了漂白选择性     

E—An—76对桦木硫酸盐浆无氯漂白流程的影响

本文研究了半纤维素酶E—An—76对桦木硫酸盐浆无氯漂白流程的影响．研究结果表明：在桦木硫酸盐浆OEDP漂白过程中插入E－An－76组成的OXEDP流程与原漂程比较，可节省大量化学漂剂的用量而保持白度和得率。     

用于二氧化氯制浆漂白系统中FRP设备的耐蚀树脂的检测

本文针对二氧化氯漂白系统的介质条件,检测与验证了四种耐蚀树脂,得出了国产乙烯基酯树脂可满足试验条件的结论。     

二氧化氯在棉织品漂白中的应用研究

二氧化氯是一种强氧化剂,与双氧水和次氯酸钠相比,用于棉织品漂白可有效降解棉织物中的色素和杂质,而且不会降低织物强力,也不会造成水体的严重污染。讨论了二氧化氯对棉织品的漂白机理,并通过单因素实验和正交实验研究了二氧化氯漂白法的影响因素。     

硫酸盐蒸煮过程中溶出木质素特性的变化

用化学和波谱分析研究了常规硫酸盐制浆过程中溶出木质素化学结构特性的变化。结果表明 ,溶出木质素的缩聚程度较高 ,其共轭双键的增加主要发生在蒸煮前期。蒸煮过程中木质素的降解溶出伴随着甲氧基的脱除反应 ,木质素溶出之后基本不存在脱甲氧基反应。随着蒸煮反应的进行 ,溶出木质素的醇羟基不断减少 ,而酚羟基则不断增加     

二氧化氯的漂白及制备方法

我国大多数造纸厂生产漂白纸浆均采用含氯漂白技术,应用这些漂白剂漂白后的纸浆废液中含有很多的有毒甚至剧毒的有机氯化合物。本文介绍的二氧化氯是一种新的对环境污染少、对纸张漂白效果好、不影响纸张质量的漂白剂。阐述二氧化氯用于纸浆漂白原理及其优势,介绍二氧化氯的几种常见制备方法。     

Behavior of Eucalyptus Kraft Pulp Extractives Components across ECF Bleaching and Their Impact on Brightness Reversion

Abstract

This study investigated the chemical composition of the dichloromethane and acetone extracts of eucalypt pulp across D(EP)DP and AZDP bleaching sequences by gas chromatography-mass spectrometry (GC-MS). The bleaching stages led to the partial removal and to several oxidative transformations of fatty acids and sterols, the main lipophilic extractives found in the unbleached pulp. The pulp samples were bleached to 90–91% ISO by D(EP)DP and AZDP sequences and their brightness stability and chemical characteristics determined. The effect of aging on brightness was investigated. The AZDP bleaching sequence resulted in pulps of higher brightness stability. Furoic structures representing the main acid degradation products of HexA are suggested as the actual intermediates that cause yellowing by forming colored compounds. The AZDP process removed larger amounts of HexA across bleaching.     

Effects of the Preferential Oxidation of Phenolic Lignin Using Chlorine Dioxide on Pulp Bleaching Efficiency

Chlorine dioxide is widely used for pulp bleaching because of its high delignification selectivity. However, efficient and clean chlorine dioxide bleaching is limited by the complexity of the lignin structure. Herein, the oxidation reactions of phenolic (vanillyl alcohol) and non-phenolic (veratryl alcohol) lignin model species were modulated using chlorine dioxide. The effects of chlorine dioxide concentration, reaction temperature, and reaction time on the consumption rate of the model species were also investigated. The optimal consumption rate for the phenolic species was obtained at a chlorine dioxide concentration of 30 mmol·L⁻¹, a reaction temperature of 40 °C, and a reaction time of 10 min, resulting in the consumption of 96.3% of vanillyl alcohol. Its consumption remained essentially unchanged compared with that of traditional chlorine dioxide oxidation. However, the consumption rate of veratryl alcohol was significantly reduced from 78.0% to 17.3%. Additionally, the production of chlorobenzene via the chlorine dioxide oxidation of veratryl alcohol was inhibited. The structural changes in lignin before and after different treatments were analyzed. The overall structure of lignin remained stable during the optimization of the chlorine dioxide oxidation treatment. The signal intensities of several phenolic units were reduced. The effects of the selective oxidation of lignin by chlorine dioxide on the pulp properties were analyzed. Pulp viscosity significantly increased owing to the preferential oxidation of phenolic lignin by chlorine dioxide. The pollution load of bleached effluent was considerably reduced at similar pulp brightness levels. This study provides a new approach to chlorine dioxide bleaching. An efficient and clean bleaching process of the pulp was developed.     

竹材用于生产溶解浆的试验研究

将竹材与木材原料相对比,分析了竹原料的特性,直观地说明了竹材用于溶解浆生产的可行性.结合工厂的现有工艺流程,以造纸竹浆为原料,优化了其蒸煮、漂白等工艺条件,制取了溶解浆.结果表明:所得浆粕甲种纤维素含量高、白度高、反应性能较好,适用于黏胶纤维用浆粕的生产.     

模糊控制技术在纸浆漂白过程中的应用

针对漂白过程干扰因素多、大滞后的特点 ,采用模糊控制技术研究并开发了氯气流量模糊控制器来修正氯气流量设定值 ;应用该控制器不仅使白度提高了 2 .2 % ,而且使得每吨浆可以节约氯气 2 .3 9kg     

漆树漆酶催化甘蔗渣纸浆漂白的研究

利用漆树漆酶在无介体存在条件下对甘蔗渣纸浆进行生物漂白,初步探索了反应时间、漆树漆酶用量、温度及酸度对甘蔗渣纸浆白度的影响。结果表明,在浆浓为3%,漆树漆酶用量1.6 mL/g(对干浆),漂白时间20 min,反应温度20~50℃,pH值为6.1~8.1时,甘蔗渣纸浆白度可提高4%~5%ISO。     

木聚糖酶对马尾松KP浆漂白机理的探索

采用常规分析方法对纸浆卡伯值、粘度和戊聚糖含量等进行分析 ,又采用紫外光谱、高效液相色谱、凝胶渗透色谱及扫描电镜等仪器分析方法分别对酶解浆、酶解液及酶解浆稀碱抽出液进行了分析。结果认为 ,木聚糖酶用于化学浆漂白的机理是其降解了残余木质素中的LCC结构和部分木聚糖 ,从而节省了后序化学漂剂的用量 ,提高了纸浆白度     

漂白纸浆质量的模糊评判

介绍模糊评判的基本步骤并将其应用于纸浆漂白过程中,实现了对漂白纸浆质量的在线评判,方法简单可行。     

高纯耐热耐碱木聚糖酶预处理对杨木KP浆漂白特性的影响

研究了耐热耐碱木聚糖酶X对杨木硫酸盐浆预处理的选择性及其对无元素氯(ECF)漂白特性的影响。结果表明:该木聚糖酶预处理具有高的助漂选择性,预处理对纸浆的得率及黏度影响不大;该木聚糖酶对温度及pH的适应范围较广,在温度为75～80℃、pH 8.0～9.5范围内都可以发挥有效的助漂作用,尤其在温度80℃、pH 8.0、酶用量2 IU/g的条件下更能发挥酶效;耐热耐碱木聚糖酶X预处理可减少漂白ClO2用量,当达到对照浆相同白度(90%ISO)时可减少D0段26%～27%的ClO2用量(相当于总用氯量的16%)。     

Use of a Novel Extremophilic Xylanase for an Environmentally Friendly Industrial Bleaching of Kraft Pulps

Xylanases can boost pulp bleachability in Elemental Chlorine Free (ECF) processes, but their industrial implementation for producing bleached kraft pulps is not straightforward. It requires enzymes to be active and stable at the extreme conditions of alkalinity and high temperature typical of this industrial process; most commercial enzymes are unable to withstand these conditions. In this work, a novel highly thermo and alkaline-tolerant xylanase from Pseudothermotoga thermarum was overproduced in E. coli and tested as a bleaching booster of hardwood kraft pulps to save chlorine dioxide (ClO₂) during ECF bleaching. The extremozyme-stage (EXZ) was carried out at 90 °C and pH 10.5 and optimised at lab scale on an industrial oxygen-delignified eucalyptus pulp, enabling us to save 15% ClO₂ to reach the mill brightness, and with no detrimental effect on paper properties. Then, the EXZ-assisted bleaching sequence was validated at pilot scale under industrial conditions, achieving 25% ClO₂ savings and reducing the generation of organochlorinated compounds (AOX) by 18%, while maintaining pulp quality and papermaking properties. Technology reproducibility was confirmed with another industrial kraft pulp from a mix of hardwoods. The new enzymatic technology constitutes a realistic step towards environmentally friendly production of kraft pulps through industrial integration of biotechnology.