含氧类自由基与过氧化氢脱木素

Oxygen-Containing Radicals and Hydrogen Peroxide Delignification

介绍了纸浆过氧化氢漂白中的含氧类自由基,如羟基自由基、过氧阴离子自由基和氢过氧自由基,以及自由基与过氧化氢脱木素及漂白的关系。讨论了这些自由基的产生、自由基与木素反应的特点、羟基自由基的脱木素选择性以及pH值对其影响,提出通过控制漂白体系中的压力、温度和过氧化氢用量来调控过氧化氢的传递、自由基的产生以及自由基浓度,合理地利用自由基反应来提高过氧化氢的脱术素能力,改善漂白效果。

The oxygen-containing radicals, including hydroxyl radicals, superoxide anion radicals and hydroperoxyl radicals, in peroxide bleaching and the relationship between the radicals and hydrogen peroxide delignification are introduced. The way of the radicals producing, the radicals reaction with lignin, the delignification selectivity of hydroxyl radicals and the pH effect on the selectivity are discussed. It is con- sidered that the transfer of hydrogen peroxide, the producing and concentration of the radicals can be controlled by controlling the pressure, temperature and hydrogen peroxide charge in the bleaching system. The delignification ability of hydrogen peroxide can be strengthened and the bleaching results can be improved with the aid of radicals reaction.