| 高指数晶面TiO2对铬的吸附及光催化去除 |
| 摘要点击 1460 全文点击 532 投稿时间：2018-06-10 修订日期：2018-07-30 |
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| 中文关键词 铬污染 TiO2{201} 吸附去除 光催化还原 表面沉淀 |
| 英文关键词 chromium contamination TiO2{201} adsorption removal photocatalytic reduction surface precipitation |
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| 中文摘要 |
| 由工业生产引起的铬污染是环境领域面临的一大挑战.二氧化钛（TiO2）材料因其吸附催化的双重作用在铬的去除方面具有潜在应用前景.利用溶剂热法合成高指数晶面TiO2{201}，对其进行SEM、TEM、XRD及XPS表征，并用于Cr（Ⅲ/Ⅵ）的吸附及Cr（Ⅵ）的光催化还原，以达到从水体中去除铬的目的.所合成的TiO2{201}为锐钛矿相，呈蒲公英状的层级结构.Langmuir吸附等温线结果表明，TiO2{201}对Cr（Ⅲ）和Cr（Ⅵ）的最大吸附量分别为22.7 mg·g-1和13.2 mg·g-1，Freundlich模型拟合结果表明TiO2{201}对Cr（Ⅲ）和Cr（Ⅵ）的吸附均易于进行，其1/n均小于0.5.在紫外光照条件下，TiO2{201}作为光催化剂可将毒性较强且吸附去除效果较差的Cr（Ⅵ）还原成Cr（Ⅲ），并以Cr（OH）3及Cr2O3的形式沉淀在TiO2表面，XPS表征结果进一步证实了表面沉淀的存在.为探明TiO2{201}光催化还原Cr（Ⅵ）的机制，分别研究光生空穴淬灭剂（EDTA-2Na）和光生电子淬灭剂（KBrO3）对Cr（Ⅵ）还原效率的影响，证明Cr（Ⅵ）的还原是由光生电子引起. |
| 英文摘要 |
| Chromium (Cr) contamination caused by industrial manufacturing poses a severe challenge in the environment. Titanium dioxide (TiO2) has potential application in Cr removal due to its adsorption and photocatalytic performance. High-index TiO2 with exposed {201} facet was synthesized using the solvothermal method and characterized by SEM, TEM, XRD, and XPS. The adsorption of Cr(Ⅲ/Ⅵ) and photocatalytic reduction of Cr(Ⅵ) on TiO2{201} was examined for the removal from water. The synthesized TiO2{201} was constructed by a dandelion-like hierarchical structure. The adsorption isotherms of Cr(Ⅲ) and Cr(Ⅵ) on TiO2{201} conformed to the Langmuir model, with maximum adsorption capacities of 22.7 mg·g-1 and 13.2 mg·g-1, respectively. The best fitted results from the Freundlich model show that the adsorption of Cr(Ⅲ) and Cr(Ⅵ) on TiO2{201} were favorable with the parameter of 1/n less than 0.5. The results of photocatalytic reduction show that TiO2{201} can reduce Cr(Ⅵ) to Cr(Ⅲ) under UV irradiation, and Cr(Ⅲ) was further precipitated on the surface of TiO2 in the form of Cr(OH)3 and Cr2O3, which was evidenced by XPS characterization. To explore the mechanism of photocatalytic reduction of Cr(Ⅵ), the effect of scavengers for photogenerated holes (EDTA-2Na) and electrons (KBrO3) on Cr(Ⅵ) reduction was studied, and the results suggested that photogenerated electrons were the main reductant. |
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