Dye-sensitized Photocatalyst of Sepiolite for Organic Dye Degradation
Dye-sensitized Photocatalyst of Sepiolite for Organic Dye Degradation
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DOI：
10.3390/catal9030235
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发表时间：
2019-03-04
期刊：
影响因子：
3.9
通讯作者：
Sasaki, Keiko
中科院分区：
文献类型：
--
作者：
Chuaicham, Chitiphon;Pawar, Radheshyam;Sasaki, Keiko
考察了海泡石在可见光照射下降解几种染料化合物的光催化活性。阳离子染料（罗丹明B和亚甲基蓝）在海泡石上的吸附能力和光催化性能均高于阴离子染料（橙II和台锥蓝）。阳离子染料在光催化活性方面的优势是由于阳离子染料分子具有很强的静电吸引力和光敏性。海泡石在120 min内降解了45.3%的罗丹明B，与其他染料相比，光催化降解效率最高。随后，通过可见光照射下对台泮蓝的降解，评价了吸附罗丹明B后废海泡石的可重复使用性。吸附罗丹明B后的废海泡石对台锥蓝的光催化降解性能提高了约2倍，说明染料敏化光催化工艺可以增强海泡石的光催化降解能力。通过自由基清除剂试验，发现一种超氧自由基是罗丹明B降解的主要原因。提出了可见光下罗丹明B降解的可能机理。海泡石可作为一种潜在的催化剂，在日光下降解废水中的有机污染物。
The photocatalytic activity of sepiolite was examined for degradation of several dye compounds under visible light irradiation. Higher adsorption capacities and greater photocatalytic performance of cationic dyes (rhodamine B and methylene blue) were observed on sepiolite, in comparison with anionic dyes (orange II and trypan blue). Superiority in the photocatalytic activity of cationic dyes is attributed to the strong electrostatic attraction and photosensitization properties of cationic dye molecules. Sepiolite has degraded 45.3% rhodamine B within 120 min, which is the greatest photocatalytic degradation efficiency when compared with other dyes. Subsequently, the reusability of spent sepiolite after adsorption of rhodamine B was evaluated by the degradation of trypan blue under the visible light irradiation. The photocatalytic degradation performance of trypan blue by spent sepiolite after adsorption of rhodamine B increased about twice as much as with pristine sepiolite, indicating that the dye-sensitized photocatalytic process could enhance the photocatalytic degradation ability of sepiolite. Through radical scavenger tests, it was found that a superoxide radical is mainly responsible for rhodamine B degradation. The possible mechanism of rhodamine B degradation under visible light irradiation was proposed. The sepiolite could be a potential catalyst for the degradation of organic pollutants in wastewater under solar light.