亚硫酸盐对偶氮染料橙黄Ⅱ的脱色效能及机理研究

Decolorization Efficiency and Mechanism of Azo Dyes Orange Ⅱ by Sulfite

利用亚硫酸盐对典型偶氮染料--橙黄Ⅱ(AO7)进行脱色,发现亚硫酸盐浓度升高有助于AO7的快速去除,在90 min内降解率达到95%以上。通入空气会造成部分SO^2-3被氧化,降低了AO7的降解率。温度升高和中性p H值条件有利于AO7的降解;高浓度亚硫酸盐条件下AO7初始浓度对其降解影响不大,低浓度亚硫酸盐对AO7的降解率则随AO7初始浓度的升高而降低。亚硫酸盐是一种亲核试剂,它对AO7的脱色是迈克尔加成的结果,并且在亚硫酸盐过量时能达到不可逆的脱色效果。

Sulfite was used to decolorize the typical azo dyes-Orange Ⅱ (AO7). Results showed that,the increase of sulfite concentration contributed to the rapid removal of AO7 whose degradation rate reached above 95% within 90 min. Aeration caused oxidization of the SO^2-3,and reduced the degradation rate of AO7. The increase of temperature and neutral p H conditions were favorable to the degradation of AO7. Under high sulfite concentration condition,the initial concentration of AO7 had limited effect on the degradation rate;however,the degradation rate decreased with the increase of initial concentration of AO7 under low sulfite concentration condition. Sulfite was a nucleophilic agent which decolorized AO7 as a result of Michael addition and achieved an irreversible decolorization effect in excess of sulfite.