Department of Environmental Engineering, Kyungpook National University, Daegu 702-701, South Korea.
Department of Environmental Engineering, Kyungpook National University, Daegu 702-701, South Korea.
J Hazard Mater. 2015;283:680-8. doi: 10.1016/j.jhazmat.2014.09.067. Epub 2014 Oct 15.
This study was conducted under visible-light exposure to investigate the photocatalytic characteristics of a multiwalled carbon nanotube/titania (TiO2) composite nanofiber (MTCN) using a continuous-flow tubular reactor. The MTCN was prepared by a sol-gel process, followed by an electrospinning technique. The photocatalytic decomposition efficiency for limonene on the MTCN was higher than those obtained from reference TiO2 nanofibers or P25 TiO2, and the experimental results agreed well with the Langmuir-Hinshelwood model. The CO concentrations generated during the photocatalysis did not reach levels toxic to humans. The mineralization efficiency for limonene on the MTCN was also higher than that for P25 TiO2. Moreover, the mineralization efficiency obtained using the MTCN increased steeply from 8.3 to 91.1% as the residence time increased from 7.8 to 78.0s, compared to the increase in the decomposition efficiencies for limonene from 90.1 to 99.9%. Three gas-phase intermediates (methacrolein, acetic acid, and limonene oxide) were quantitatively determined for the photocatalysis for limonene over the MTCN, whereas only two intermediates (acetic acid and limonene oxide) were quantitatively determined over P25 TiO2. Other provisional gas-phase intermediates included cyclopropyl methyl ketone and 2-ethylbutanal.
本研究在可见光照射下进行，使用连续流动管式反应器考察了多壁碳纳米管/二氧化钛（TiO2）复合纳米纤维（MTCN）的光催化特性。MTCN 通过溶胶-凝胶法制备，然后通过静电纺丝技术制备。MTCN 对柠檬烯的光催化分解效率高于参考 TiO2 纳米纤维或 P25 TiO2，实验结果与 Langmuir-Hinshelwood 模型吻合较好。光催化过程中生成的 CO 浓度未达到对人类有毒的水平。MTCN 对柠檬烯的矿化效率也高于 P25 TiO2。此外，与柠檬烯的分解效率从 90.1%增加到 99.9%相比，当停留时间从 7.8 秒增加到 78.0 秒时，MTCN 的矿化效率从 8.3%急剧增加到 91.1%。在 MTCN 上进行的柠檬烯光催化反应中，定量确定了三种气相中间体（甲基丙烯醛、乙酸和柠檬烯氧化物），而在 P25 TiO2 上仅定量确定了两种中间体（乙酸和柠檬烯氧化物）。其他暂定的气相中间体包括环丙基甲基酮和 2-乙基丁醛。
