Abstract:

Catalytic decomposition of hydrogen peroxide in alkaline solutions in the presence of different states of Fe（Ⅲ）, free Fe（Ⅲ） in solution and adsorbed Fe（Ⅲ） with cellulose, was studied.The individual and combined roles of DTPA, magnesium sulphate, and sodium silicate as stabilizers for alkaline hydrogen peroxide were also investigated.The most effective way to control decomposition of hydrogen peroxide induced by Fe（Ⅲ） under conventional hydrogen peroxide brightening conditions was examined.The results showed that free Fe（Ⅲ） in solution was present in the form of Fe₂O₃ crystal structure.Adsorbed Fe（Ⅲ） with cellulose was formed when free Fe（Ⅲ） in solution adsorbed on the surface of cellulose fiber or filled into hollow fiber.Free Fe（Ⅲ） in solutions stabilized hydrogen peroxide, while adsorbed Fe（Ⅲ） with cellulose activated the decomposition of hydrogen peroxide.In the presence of free Fe（Ⅲ） under alkaline condition, DTPA and MgSO4 were effective in reducing the catalytic decomposition of peroxide and the decomposition rates of hydrogen peroxide were decreased to 25% and 50%, respectively.In the presence of adsorbed Fe（Ⅲ） with cellulose, DTPA, magnesium sulphate, and sodium silicate did not have any protective influence to hydrogen peroxide, and the decomposition rate of peroxide was over 80% within 1 h.

Key words:

差异态铁, 过氧化氢, 催化分解, 保护剂

摘要： 通过制备差异态铁,研究了差异态铁对碱性过氧化氢的催化分解行为,考察了硫酸镁、硅酸钠及DTPA在差异态铁存在下的功能效果.研究发现,游离态铁以Fe₂O₃晶体颗粒形式存在,通过吸附在纤维表面或者填充在纤维“孔腔”内形成纤维素吸附态铁;游离态铁减弱了过氧化氢碱性分解,吸附态铁强化了过氧化氢碱性分解.DTPA、硫酸镁显著抑制游离态铁催化分解碱性过氧化氢,将过氧化氢分解率分别降至25%,50%.DTPA、硫酸镁对抑制纤维素吸附态铁的催化分解无效,1 h内碱性过氧化氢分解率达到80%以上.

关键词:

差异态铁, 过氧化氢, 催化分解, 保护剂