【作者】 孙保国；

【导师】 徐立新；

【作者基本信息】 天津科技大学 ， 制浆造纸工程， 2004， 硕士

【摘要】 棉浆是一种基本工业原料，由于各种原因其内常含有一些荧光物，尤其一些低等棉短绒含量更多，而有价证券和一些食品包装纸对所用棉浆中的荧光物含量是严格控制的。 造纸中常用的还原剂，例如连二亚硫酸钠和甲脒亚磺酸(FAS)等不能除去荧光；荧光抑制剂可用于消荧光，但不能在分子结构上对其进行破坏；某些常用氧化剂对消荧光有着较好的效果，我们研究了过醋酸、二氯异氰脲酸钠、二氧化氯的脱除效果、影响因素及一些结论。发现过醋酸用量为3％，温度80℃，pH值8左右，浆浓为10％，反应时间2h后可以脱除90％多的荧光物；二氯异氰脲酸钠脱荧光的适宜条件为：用氯量为1.2％～2.2％，温度40～50℃，pH值6。浆浓为10％，反应时间90min；药品用量为2％，温度90℃，反应初始pH值4～5，浆浓为10％，反应时间2～2.5h时二氧化氯消荧光的效果也较好；由于CEH仍然是目前一些工厂中的主要漂白方法，因此我们在第五章探讨了在CEH三段漂中荧光物的变化情况，其中氯气对荧光的消除有一定的效果，提高该段温度或加入一定量的二氧化氯，可促进荧光的脱除，另外，提高漂白段(H)反应温度或适当降低反应初始pH值都可对荧光的脱除有一定的促进作用。 目前国内外测定固体中荧光物的含量仅限于通过一些方法间接来表示。本论文的第七章探讨了测定棉短绒浆中荧光物含量的三种方法：目测法、白度差值法、荧光分光光度计法。其中目测法简便、直接，但受人为因素和室内光线明暗的影响很大，很难得到准确的结果；白度差值法仪器简单且易于操作，但只适用浆料中荧光物含量比较大的情况，荧光物含量的较小差别并不能在白度上明显显示出来；荧光分光光度计法具有高灵敏性、相对荧光强度可调性等优点，是适用本实验的较为理想的方法。更多还原

【Abstract】 These years people have paid more and more attention to the removal of the fluorescence in cotton linter for the sake of getting better cotton linter pulp. Cotton linter is a kind of basic industry material used to make many products, but usually there are much impurity emitting fluorescence in them and some pulp i s asked not to contain fluorescence especially.General reducing agents, such as hyposulphite and FAS, cannot remove fluo- rescence; Depressor can depress fluorescence, but it cannot destroy molecular str- ucture; Some oxidants can destroy molecular structure of fluorescence and remove it.We study main effect factors of peracetic acid and pulp property indexes’varieties when we remove the fluorescence in cotton linter pulp. And finally the ideal technic condition is got when removing fluorescence: Heating the pulp at pH 8 and 80 C with 3% peracetic acid, and about 90% removal after 2h.Dichloroisocyanuric acid salts (DCCNa) is a kind of general product in chlorinalkali industry, but we nearly do not use it in papermaking industry. The paper describes DCCNa’s main effect factors and indexes’varieties when we remove the fluorescence in cotton linter pulp. And finally we get the ideal technic condition: 1.2% - 2.2% available chlorine, 40~50C, pH6, 10% pulp concentration and 1.5h.We also study main effect factors and indexes’varieties when we remove the fluorescence by ClO2 . And in the bleaching by CEH we study the fluorescence variety in every stage.Now we only can determining the content of fluorescence in solid sample by some indirect way. In this paper we describe three methods determining fluorescence in cotton linter pulp in our experiment: mensurating by eyes, mensurating by whiteness meter and mensurating by fluorescence spectrophotometry. The first one is very simple, but different people usually get different judgements of the same sample; The apparatus of the second one is simple and easy to manipulate, but for whiteness meter’s sensitivity is not very high,it cannot determine the content exactly if fluorescence is weak; Fluorescence spectrophotometry used by the last one is very sensitive to fluorescence and relative fluorescence intensity can be regulated according to our needs.更多还原