海藻酸铁微球对偶氮染料降解反应的光催化作用

PHOTOCATALYTIC EFFECT OF FERRIC ALGINATE GEL BEADS ON OXIDATIVE DEGRADATION OF AZO DYES

使用海藻酸钠与氯化铁制备了海藻酸铁微球,在过氧化氢存在的条件下将其作为非均相光催化剂应用于不同结构偶氮染料的氧化降解反应,考察了微球数量、光辐射强度、pH值和偶氮染料结构等对染料脱色率的影响,并使用紫外可见光谱和总有机碳(TOC)研究了海藻酸铁微球对偶氮染料降解和矿化反应的光催化效应。结果表明:海藻酸铁微球数量的增加和光辐射强度的增大都可以显著提高染料脱色率,尽管pH值的提高会导致染料脱色率有所下降,但是在pH值为中性条件下染料60min脱色率仍保持在60%以上,在相同反应条件下海藻酸铁微球的存在使得活性染料比酸性染料更容易发生脱色反应。海藻酸铁微球不仅对染料结构中偶氮键的断裂具有催化作用,而且还能催化其中芳香环结构的降解和矿化过程。

Ferric alginate gel beads were prepared with ferric chloride and sodium alginate, and then used as the hetero- geneous photocatalysts for the oxidative degradation of azo dyes with different structure in the presence of H2O2. Some factors effecting decoloration of azo dyes such as dosage of gel beads, irradiation intensity, pH level and dye nature were also investigated in this work. Meanwhile, the effect of photocatalysis of ferric alginate gel beads on degradation and min- eralization were studied by using UV-Vis spectrum method and total organic carbon （TOC） measured. The results indi- cated that increasing the dosage of gel beads and enhancing irradiation led to high decoloration level. dyes in the presence of ferric alginate gel beads was reduced with pH level increasing, but more than 60% azo dyes were decomposed at neutral condition. Moreover, reactive dyes were decomposed more easily than acid dyes in the presence of ferric alginate gel beads and tt2 02 in solution at the same conditions. It is summarized that ferric alginate gel beads could significantly promote the all decomposition processes including decoloration, degradation and mineralization of azo dyes.