酸度及酸介质对硫酸盐掺杂的含钛高炉渣光催化还原Cr(Ⅵ)的影响

Effect of acidity and acidic medium on photocatalytic reduction of Cr(Ⅵ) by sulfate modified titanium-bearing blast furnace slag

利用高能球磨法制备了钙钛矿型硫酸盐掺杂的含钛高炉渣光催化剂,探讨了该催化剂的光催化原理,并系统地研究了不同酸度及酸介质对钙钛矿型硫酸盐掺杂的含钛高炉渣光催化还原Cr(Ⅵ)效率的影响。结果表明,酸度以及酸介质对六价铬的光催化还原效率都有十分重要的影响。在强酸性条件下(pH=1.5),六价铬的光催化还原效率最高;且随着pH值的增大,六价铬的光催化还原效率显著降低。不同酸根离子对STBBFS催化剂光催化还原六价铬的促进作用按PO43-<NO3-<Cl-<SO42-逐渐增强;在光催化反应8h后,六价铬的还原率差别显著,分别为9.32%、48.73%、100%、100%。因此,为了获得较高的光催化效果,必须控制六价铬废水的pH值以及用硫酸调节溶液的酸度。

The photocatalysts of perovskite type sulfate modified titanium-bearing blast furnace slag were prepared by the high energy ball milling method. With the aid of FT-IR, the photocatalysis mechanism of sulfate modified titanium-bearing blast furnace slag was discussed. The effect of different acidities and acidic media on the photocatalytic reduction of Cr （Ⅵ） by sulfate modified titanium-bearing blast furnace slag was investigated. The results showed that acidity and acidic medium affected the photoeatalytic reduction efficiency of Cr （Ⅵ） in aqueous solution. Under strong acid condition （pH = 1.5）, the photocatalytic reduction efficiency of Cr（Ⅵ） reached a maximum. With increasing pH of the solution, the photocatalytic reduction efficiency of Cr（Ⅵ） decreased obviously. The order of the stimulative effect of different acidic media was PO^3-4〈NO^-3〈Cl^-〈SO^2-4 after photocatalytic reduction of Cr（Ⅵ） in aqueous solution after 8 h, the maximum photocatalytic reduction efficiency of Cr（Ⅵ） was 9.32%, 48.73%, 100% and 100% for PO^3-4,NO^-3,Cl^- and SO^2-4, respectively. Based on the research results, effectively keeping the acidity of solution and selecting a suitable acidic medium in the photocatalytic reduction of Cr（Ⅵ） process can further enhance the photocatalytic activities of sulfate modified titanium-bearing blast furnace slag photocatalysts.