MgSO_4、DTPA和Na_2SiO_3对含过渡金属离子的碱性H_2O_2溶液的稳定作用

Stabilizing Effects of Magnesium Sulfate,DTPA and Silicate on Alkaline Hydrogen Peroxide Solution

研究了碱性条件下Al3+及碱土金属离子(Mg2+、Ca2+)对H2O2的稳定作用、过渡金属离子Fe3+、Fe2+、Mn2+和Cu2+对H2O2的催化分解作用及MgSO4、DTPA和Na2SiO3对碱性H2O2溶液的稳定作用。结果表明,碱土金属离子Mg2+、Ca2+可以对碱性H2O2溶液起到很好的稳定作用;Al3+在强碱条件下对H2O2的分解没有影响。过渡金属离子Fe3+、Fe2+、Mn2+和Cu2+在碱性条件下都会快速催化分解H2O2。4种过渡金属离子对H2O2的催化分解作用由强到弱依次为:Cu2+、Fe2+、Mn2+、Fe3+。在过渡金属离子存在的情况下,Mg2+仍然有较好的防分解性能;Mg2+对有Fe2+存在的H2O2碱溶液的稳定效果好于Fe3+。无论H2O2的碱性溶液中是否有过渡金属离子,加入DTPA对H2O2均有一定的稳定作用,但其稳定效果远不如添加Mg2+效果好。Na2SiO3加入不含过渡金属离子的碱性H2O2溶液中时,不能够起到稳定H2O2的作用。

The measures for protecting hydrogen peroxide from decomposition in alkaline solutions vary with the bleaching conditions. Focusing on enhancement of stabilizing effects with normal stabilizers, such as magnesium sulphate, DTPA and silicates and so on, the fundamental investigation on the decomposition behavior of hydrogen peroxide in alkaline solution with higher alkalinity was carried out, the contributions of main types of alkaliearth metals and transition metal ions to the decomposition reactions of hydrogen peroxide were studies. It was found that Mg^2＋ or Ca^2＋ could decrease the decomposition rate of hydrogen peroxide obviously, but there was no obvious effect with presence of Al^3＋ . With presence of the transition metal ions in the solutions,the decomposition rate of H2O2 could be accelerated rapidly. The catalytic effects on H2O2 decomposition of the transition metal ions could be listed with a descending order as： Cu^2＋〉Fe^2＋〉Mn^2＋ 〉 Fe^3＋ . DTPA showed certain stabilizing effect on hydrogen peroxide, which was independent of the existence of the transition metal ions in the hydrogen peroxide alkaline solutions. Comparing their stabilizing effects, magnesium sulphate showed better stabilizing efficiency than DTPA. It must be mentioned that, with absence of transition metal ions in the hydrogen peroxide alkaline solutions, the silicates showed no obvious effect on stabilizing of hydrogen peroxide.