偶氮染料刚果红在水中的光催化降解过程

Photocatalytic Degradation Process of Azo Dye Congo Red in Aqueous Solution

通过研究在间歇悬浮体系中直接偶氮染料刚果红在水中的光催化降解过程 ,确定了最佳降解条件 .同时测定了染料溶液的脱色率、COD去除率和矿化率以考察降解过程中脱色与矿化的关系 .另外 ,对降解过程中溶液 pH值的变化及反应的可能中间体进行分析 ,结果表明 :刚果红染料分子的光催化降解过程分为脱色和矿化两个阶段 .矿化主要发生在脱色结束以后 ,并且伴随着脱色溶液的酸化现象 .脱色过程进行较快 ,完全脱色后形成的中间产物需要较长时间才能被逐步矿化 .

The photocatalytic degradation process of azo dye Congo Red was investigated in aqueous suspension of TiO2, and the optimum reaction conditions were determined. Meanwhile, the relationship between the decolorization and mineralization of Congo Red molecules was studied by measuring the decolorization rate, chemical oxygen demand (COD) removal and CO2 yield. The change in pH of aqueous solution as a function of irradiation time was monitored, and the possible intermediates formed during the photocatalytic degradation process of Congo Red were analyzed by using HPLC. The results suggested that the molecule of Congo Red was photocatalytically degradated via decolorization and mineralization sequentially. The mineralization occurred after the decolorization, accompanied by the acidification of the solution. Decolorization is faster than the mineralization. It would take a long time to mineralize the intermediates formed in the stage of decolorization.