天津科技大学学报2004，Vol.19Issue(z1)：179-183,5.
HE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING
HE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING
Yumeng Zhao 1Shuhui Yang 1Liang Sheng 1Yonghao Ni2
作者信息
- 1. Tianjin University of Science & Technology, Tianjin,China
- 2. University of New Brunswick, N.B., Canada
- 折叠
摘要
Abstract
Hydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed under alkaline condition, especially when transition metal ions exit. Experiments show that the valence of transition metal ion is also responsible for the decomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ and Fe3+. They are both catalytically active to hydrogen peroxide decomposition. Because Fe3+ is brown, it can affect the brightness of pulp directly, it can also combine with phenol, forming complexes which not only are stable structures and are difficult to be removed from pulp, but also significantly affect the brightness of pulp because of their color.Sodium silicate and magnesium sulfate, when used together, can greatly decrease hydrogen peroxide decomposition. The optimum dosage of sodium silicate is about 0.1% (on solution) for Fe2+ and 0.25% (on solution) for Fe3+. Adding chelants such as DTPA or EDTA with stabilizers simultaneously can obviously improve pulp brightness. For iron ions, the chelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite and cellulose can reduce Fe3+ to Fe2+ effectively, and pulp brightness is improved greatly. Adding sodium thiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxide solution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxide bleaching, the optimum pH value should be 10.5-12.关键词
Hydrogen peroxide/Bleaching/Transition metal ions/Iron/Stabilizer/Chelant/Reducing agentKey words
Hydrogen peroxide/Bleaching/Transition metal ions/Iron/Stabilizer/Chelant/Reducing agent分类
轻工纺织引用本文复制引用
Yumeng Zhao,Shuhui Yang,Liang Sheng,Yonghao Ni..HE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING[J].天津科技大学学报,2004,19(z1):179-183,5.
