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。     

DMD在纸浆漂白中的应用进展

综述了二甲基二环氧乙烷（DMD）的制备方法、结构特点、选择性氧化的化学特性、与木质素的相关反应机理及DMD在纸浆漂白中的作用.DMD作为一种强的亲电氧化试剂,具有良好的脱木质素能力和选择性.DMD作为漂白剂单独用于纸浆漂白,可以使纸浆达到较高的白度;DMD作为多段漂段间的活化剂,可提高后续漂白的效果.不同于传统含氯漂白的污染性,DMD的低污染和高漂白效率的特点,使其在纸浆全无氯漂白方面有着良好的应用前景.     

国外将氯代品和臭氧用于纸浆漂白

目前在欧洲纸浆市场上,客户们普遍看好漂白纸浆用TCF-pulps。这是一种不含元素氯或二氧化氯的微透明、低强度漂白用新产品。另据预计,ECF-pulps将成为90年代纸浆工业标准漂白用最佳产品。该产品与二氧化氯一并使用,但不含元素氯。上述产品在质     

蔗渣硫酸盐浆漆酶/介体生物漂白流程与工艺的研究

进行了蔗渣硫酸盐浆漆酶 /介体 (LMS)生物漂白流程与工艺的研究。讨论了漆酶的存在和纯化、表面活性剂对LMS的影响 ,分析了碱抽提、螯合处理、酸处理以及压力过氧化氢漂白对漂白结果的影响。检测了含LMS处理的纸浆漂白流程的纸浆性质     

二噁英及纸浆漂白剂的发展趋势

制浆造纸工业采用氯来漂白纸浆已有很多年的历史了,但是,这种漂白方法的应用即将被取缔。自1980年以来,人们对有机氯化物的生成,尼其是用赢漂白纸浆后产生的二嚷英(dioxin)引起的致癌性越来越受到环保部门的关注。纸浆生产者正在承受来自几个方面的压力。     

改进紙浆漂白工艺的新措施

最近美国Weyerhaeuser Co.取得了一项关于改进纸浆漂白工艺的专利权(美国专利3,177,111)。新措施是在次氯酸盐漂白过程中加入一些氨基磺酸,这样,不仅纸浆漂白工本可以大大降低(每吨降低1元美金),而且更重要的是纸浆的强度可以提高很多,次氯酸盐的用量也可以比不用氨基磺酸时减少20～60%。由于使用氨基磺酸的关系,纸浆的碱度经较低,因     

过氧酸和DMD的性能及其在纸浆漂白中的应用

过氧酸和二氧环丙酮是类强的亲电氧化试剂 ,在反应中可有效转移氧原子。文章综述了这类氧化剂的性能及在纸浆漂白中的作用 ,作为可替代传统氯气漂白的最有希望的无污染漂剂 ,采用过氧酸和二氧环丙酮可实现纸浆的全无氯漂白     

瑞典纸浆工业用氯量减少

瑞典是欧洲主要的纸浆生产国家,为了减少对环境的污染,该国纸浆工业漂白工艺的用氯量在过去10年中逐渐下降,生产过程中排放的污染环境的有机氯化物已经减少了一半。目前每吨漂白纸浆只用氯     

日本学者开发生物漂白技术

日本神户制钢所的生物研究所和九叶大学合作,用高活性木素分解菌,成功地进行了硫酸盐纸浆的漂白,从而开发出实用的生物漂白技术.据称,用木素分解菌的生物漂白技术与非氯系药剂结合,就可得到白度为85％的全漂白纸浆,并可避免氯系漂白剂漂白所造成的环境污染。新技术包括用酶素漂白、用木素分解菌的生物漂白和同非氯系     

中高浓度纸浆无氯漂白效益佳

华南理工大学日前研发出中浓度化学浆全无氯漂白技术,使漂后纸浆具有更高的白度及强度。目前利用该成果建成的生产线规模已从5万t/a向10万t/a（非木浆）升级,创建了我国具有自主知识产权的第一条中浓纸浆全无氯漂白生产线,也是国际上第一条草类原料化学浆全无氯漂白生产线。该技术成果使我国纸浆漂白这一重要生产单元不产生有毒有害的可吸附有机氯化物AOX,     

Optimization of Parameters for Microwave-Assisted Foam Mat Drying of Blackcurrant Pulp

Both analysis and optimization of parameters of microwave-assisted foam mat drying (MAFM), viz. microwave power, pulp load, drying time, and pulp thickness, for the dehydration process of blackcurrant pulp were performed in a household microwave oven. During MAFM drying, microwave power, pulp load, and drying time have positive effects on both vitamin C and anthocyanin content of blackcurrant pulp up to a certain level then a negative trend is observed. The increase of microwave power and decrease of pulp load accelerate the dehydration of blackcurrant pulp. The pulp thickness has a significant positive effect on both vitamin C and anthocyanin content of blackcurrant pulp. The optimum parameters valid for MAFM drying of blackcurrant pulp are as follows: microwave power of 560 W, pulp load of 65 g, drying time of 8 min, and pulp thickness of 4.46 mm. MAFM drying is a potential method for dehydrating blackcurrant pulp.     

芳纶浆粕技术指标的分析

在芳纶浆粕的3种主要制备方法基础上,分析了Dupont与Teijin两家公司的商品浆粕的技术指标,然后分别对芳纶浆粕的7种指标——表面形貌、比表面积、长度及其分布、抓附力、滤水性能、保水值和比浓对数黏度进行了分析讨论。最后指出:芳纶浆粕最重要的技术指标是比表面积和纤维长度及其分布,以及由两者综合决定的浆粕有效比表面积。     

废胶粉和锯末对废纸浆性能的影响

试验研究废胶粉和锯末对废纸浆性能的影响.结果表明:废胶粉/废纸浆、锯末/废纸浆和废胶粉/锯末/废纸浆复合材料的物理性能提高,且废胶粉/废纸浆复合材料的物理性能优于废胶粉/锯末/废纸浆复合材料,因此以废胶粉改性废纸浆效果较好.废胶粉/废纸浆复合材料的最佳配方为:废纸浆100(干基计),废胶粉8,防老剂D 0.2,硫黄0.2,促进剂M 0.2;最佳固化条件为150℃/10 MPa×30 min.此时材料表面比较光滑,结构紧密,排列比较均匀,废胶粉与废纸浆的相容性较好.     

Relationship between the included levels of coffee pulp and the protein content in rations for monogastric animals

The purpose of this research was to determine the effect of including fresh and ensilaged coffee pulp in rations for monogastric animals, and find the best protein and coffee pulp levels in rations for rats. Fresh coffee pulp and pulp ensilaged for 12 months were used; both kinds of pulp were sun-dried before incorporating them into the rations. The chemical analyses of the pulps revealed a lower content in caffeine, tannins, chlorogenic acid and caffeic acid in the ensilaged pulp than in fresh coffee pulp. Thirty-two experimental rations were prepared, 16 with fresh coffee pulp and 16 with the ensilaged by-product, distributed into four different protein levels (10, 15, 20 and 25%), and three levels of pulp (15, 30 and 45%) for each protein level. The rations thus prepared were fed to Wistar albino rats for a six-week period. The parameters used to measure the effect of the two types of pulp were mortality rate, food consumption, weight gain, food conversion and apparent digestibility of the rations. Ensilaged pulp had a higher nutritive value, lower toxicity and better digestibility than fresh pulp. The increase in the protein level of the ration resulted in partial protection against the negative effects of coffee pulp on the performance of animals, since this improved as the protein level of the ration increased.     

Soft measurement of pulp suspension flow velocity based on wavelet transform

A soft measurement technique is presented, which the pulp suspension flow velocity (PSFV) can be obtained by analysis of pulp fibre consistency signal without using the flow sensor or flow meter. Doppler Effect in pulp fibre consistency signal, which is caused by the relative motion between pulp suspension flowing in pulp pipe and consistency sensor fixed in the pipe, is discovered on the basis of studying the structure of pulp suspension and the properties of pulp fibre consistency signal, and it is proved by wavelet transform (WT) in this paper. WT are used to analyse pulp fibre consistency signal based on Doppler Effect. PSFV can be determined by the average period of WT which is used to analyse pulp fibre consistency signal based on Doppler Effect. The corresponding tests indicate that the measurement technique is feasible with high precision and better dynamic characteristics.     

A modified method of nitric acid pulping of bagasse

Pulping of bagasse by a rapid and mild nitric acid process was successfully carried out to produce different grades of pulp. Nitric chemimechanical bagasse pulp was produced in a high yield of 91 % on pulping depithed bagasse with 4% HNO₃ for a period of 30 min at 80°C, followed by alkali pulping with 2% NaOH at 95°C for 30 min. The pulp had a satisfactory strength and high opacity. On increasing the strengths of nitric acid to 7% and alkali to 7% a nitric semichemical pulp of 65% yield was obtained. The pulp had a superior strength and high opacity. The pulp was easily bleached to 71% general electric brightness (GE) with the chlorination-alkali-extraction-hypochlorite (CEH) sequence. With 15% HNO₃ and 8% NaOH, nitric chemical bagasse pulp was produced. The pulp was easily bleached to a high brightness of 82% GE with one stage hypochlorite. The pulp had a higher strength than kraft bagasse pulp. A satisfactory newsprint paper was produced on an experimental paper machine with a furnish composed of 80% bleached nitric semichemical bagasse pulp, 10% bleached softwood pulp and 10% clay.     

芦苇浆纳米纤维素的制备及其尺寸均一性制备方法初探

采用硫酸水解芦苇浆和乙酸预处理芦苇浆制备纳米纤维素（NCC）,并对NCC尺寸和形貌进行测定和分析,探究均一纳米纤维素的制备方法。结果表明芦苇浆NCC得率为61．50％,3次重复实验的乙酸预处理芦苇浆NCC得率分别为63．13％（NCC-1）、62．30％（NCC-2）和62．15％（NCC-3）;乙酸预处理芦苇浆NCC乙酸回收率分别为75．00％（NCC-1）、78．15％（NCC-2）和77．56％（NCC-3）。NCC尺寸分析表明芦苇浆NCC和3次重复实验的乙酸预处理芦苇浆NCC平均尺寸均有差异,其中只有乙酸预处理芦苇浆NCC-1尺寸分布较均匀,平均尺寸185．3nm。透射电子显微镜（TEM）下观察所制备的芦苇浆NCC和乙酸预处理芦苇浆NCC-1均呈棒状。     

高性能芳纶浆粕/HNBR复合材料的制备及性能研究

试验研究预处理方法对芳纶浆粕在橡胶基体中分散性及芳纶浆粕／HNBR复合材料性能的影响。结果表明，芳纶浆粕预处理改善了其在复合材料中的分散效果；白炭黑预处理复合材料的定伸应力和拉伸强度提高，拉断伸长率减小，高温下物理性能稍有改善；共沉法预处理改善效果不明显；白炭黑预处理芳纶浆粕用量增大，混炼时间不变，复合材料物理性能提高，但高温下撕裂强度减小；芳纶浆粕／HNBR复合材料中，芳纶浆粕容易取向；芳纶浆粕用量增大，复合材料挤出性能改善。     

Graftability of beaten pulps and acetylated pulps

Ce(IV)-induced polymerization of acrylonitrile with acetylated bagasse and wood pulps, having different acetyl contents, has been investigated. The graft yield is dependent on the acetyl content as well as the origin of the pulp. Increasing the acetyl content of pulps caused a significant decrease in the polymer loading. However, the rate of polymerization of acetylated wood pulp is much higher than that of acetylated bagasse pulp. The ceric consumption during grafting decreases as the acetyl content of the pulp increases. The effect of beating of the pulps, to various degrees of freeness, on their reactivity toward grafting process has also been studied. Generally, the state of cellulose, as defined by its degree of beating, and the origin of the pulp strongly influenced the graft yield. In creasing the beating degree of bagasse pulp resulted in a decrease in graft yield, while beating of wood pulp, to a definite degree, inhibits the polymerization reaction. The consumption of Ce(IV) by the beaten pulps during oxidation is somewhat greater than that consumed by the unbeaten pulps, whereas the consumption during grafting of acrylonitrile onto beaten pulps depends on the initial concentration of ceric solution. Also, the effect of grafting of acrylonitrile onto acetylated wood and bagasse pulps on their strength properties as well as the effect of grafting onto beaten pulps on their properties has been investigated. Grafting of acrylonitrile onto acetylated bagasse pulp decreased its strength properties, but improved its beatability comparatively to those of original pulp (0 acetyl content). On the other hand, grafting of acrylonitrile onto acetylated wood pulp resulted in a great improvement in its strength properties compared to those of grafted unacetylated pulp. Grafted unbeaten pulps gave thinner and weaker paper than the original pulp (without grafting). Beating of bagasse pulp before grafting gave pulp which possessed a higher strength properties, at low °SR, than those of pulp beaten after grafting. Raising the °SR by rebeating the pulp after reaction up to the original value had an adverse effect on the strength. Beating of bagasse pulp before grafting did not accelerate the reaction rate, but it saved some power consumption, since the time required for beating of grafted pulp to a given °SR was lower than that of ungrafted pulp.     

抗菌蔗渣浆纤维的制备及其性能研究

以漂白蔗渣浆为原料、3-氯-2-羟基丙基三甲基氯化铵为抗菌剂,在碱性条件下发生醚化反应,制备具有广谱抗菌性能的抗菌蔗渣浆纤维。研究了接枝率、接触时间、菌液浓度、洗涤次数对抗菌蔗渣浆纤维抑菌率的影响,试验表明:当接枝率为3%时,抗菌蔗渣浆纤维对大肠埃希菌、金黄葡萄球菌、白念珠菌的抑菌率均为100%;且经过20次洗涤后,抗菌蔗渣浆纤维的抑菌率仍在90%以上,耐洗涤性能好。抗菌蔗渣浆纤维可用于制备具有抗菌性能的食品包装纸,进而实现蔗渣浆纤维的高值化利用。