Removal Of Fluorescence In Cotton Linter Pulp

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.