Department of Chemistry, Faculty of Science, University of Mohaghegh Ardabili, Ardabil, Iran.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Oct 15;81(1):228-35. doi: 10.1016/j.saa.2011.05.109. Epub 2011 Jun 14.
The photocatalytic degradation of methylene blue is investigated in aqueous solution containing CoS/nanoAl-MCM-41 photocatalyst under visible light. The catalyst is characterized by X-ray diffraction (XRD), UV-vis diffused reflectance spectra (UV-vis DRS) and transmission electron microscopy (TEM) techniques. The effect of CoS, nanoAl-MCM-41 support and different wt% of CoS over the support on the photocatalytic degradation and influence of parameters such as CoS loading, catalyst amount, pH and initial concentration of methylene blue on degradation are evaluated. Hypsochromic effects (i.e. blue shifts of spectral bands) resulting from N-demethylation of the dimethylamino group in methylene blue occurs in presence of CoS/nanoAl-MCM-41 under ambient condition. Meanwhile, the bleaching of methylene blue MB, by sulfide ion, in an aqueous solution is studied in the presence nanoAl-MCM-41 catalyst. In the presence of sulfide ions, MB is bleached to its colorless leuco (LMB) and MBH(2)(+) forms. In an acidified solution (pH<2) the bleaching process generates LMB and by changing pH between 2.0 and 7.0 bleaching of MB dye to MBH(2)(+) form is observed. Using nanoAl-MCM-41 with encapsulated CoS nanoparticles only causes demethylation of MB in aqueous solution.
在含有 CoS/nanoAl-MCM-41 光催化剂的水溶液中，通过可见光研究了亚甲基蓝的光催化降解。通过 X 射线衍射（XRD）、紫外可见漫反射光谱（UV-vis DRS）和透射电子显微镜（TEM）技术对催化剂进行了表征。考察了 CoS、nanoAl-MCM-41 载体和载体上不同 wt%的 CoS 对光催化降解的影响，以及 CoS 负载量、催化剂用量、pH 值和亚甲基蓝初始浓度等参数对降解的影响。在 CoS/nanoAl-MCM-41 的存在下，亚甲基蓝的二甲基氨基发生 N-脱甲基反应，导致光谱带发生蓝移。同时，研究了在纳米 Al-MCM-41 催化剂存在下，水溶液中亚甲基蓝 MB 与硫离子的漂白作用。在有硫离子存在的情况下，MB 被漂白成无色的 LMB 和 MBH(2)(+)形式。在酸化溶液（pH<2）中，漂白过程生成 LMB，通过在 2.0 和 7.0 之间改变 pH 值，可以观察到 MB 染料向 MBH(2)(+)形式的漂白。使用包封 CoS 纳米粒子的 nanoAl-MCM-41 仅在水溶液中导致 MB 的脱甲基。
