| Fabrication free-standing TiO2 nanotube membranes with both ends open: Investigation the photocatalytic property for degradation of 2,4-dichlorohenol |
| Paper ID : 1142-UFGNSM-FULL |
| Authors: |
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Javad Vahabzadeh Pasikhani *1, Neda Gilani2, Azadeh Ebrahimian Pirbazari3 17th unit, Mohsen Bldg., Laleh Dead end, Banafsheh Alley, Noghre dasht St., Sardare gangal Ave., Rasht city, Gilan Province, Iran 2Assistant professor, Fouman Faculty of Engineering, College of Engineering, University of Tehran 3Assistant professor, Fouman Faculty of Engineering, College of Engineering, University of Tehran |
| Abstract: |
| Highly ordered TiO2 nanotubes have attracted a lot of attention for the photocatalytic degradation of organic pollutants. A few studies demonstrated that the tubes structural features play a key role on the photocatalytic activity. However, no studies have been performed to explain the photocatalytic activity of free-standing TiO2 nanotubes membranes with a shorter length than 10 micrometer. In the present study, free-standing open-ended TiO2 nanotube membranes with a length of 8 micrometer were fabricated by two-step anodization process in the fluorine-containing ethylene glycol, followed decreasing voltage at the end of anodization and chemical treatment as a detachment method. The surface morphology, phase structure and surface chemistry of the free-standing TiO2 nanotubes membranes were characterized by FESEM, XRD and FTIR analysis, respectively. The result demonstrated that by immersion the free-standing close-ended TiO2 nanotube in diluted HF solution, the barrier layer at the back of the TiO2 nanotubes completely disappears and the nanotubes become open at both ends. Moreover, the photocatalytic activity of free-standing TiO2 nanotube membranes for degradation of 2,4-dichlorophenol was compared with those of free-standing TiO2 nanotubes with close-end. The photocatalytic tests indicated that the reactions follow first-order kinetics for both samples. Further, the apparent rate constant of 2,4-dichlorophenol photocatalytic degradation by free-standing TiO2 nanotube membranes was 1.33 times as great as those of the free-standing TiO2 nanotubes with close-end. The result also revealed that TiO2 nanotube membranes with opened bottoms exhibited superior photocatalytic activity due to its better access for 2,4-dichlorophenol molecules as well as the enhanced light harvesting and electron collection efficiencies. To sum up, the free-standing open-ended TiO2 nanotube membranes had the best photocatalytic activity (with 72% degradation of 2,4-dichlorophenol) as compared to the free-standing TiO2 nanotubes with close-end and increased the photocatalytic efficiency up to 14%. |
| Keywords: |
| TiO2 nanotubes, Free-standing membranes, Open-ended, Photocatalytic degradation, 2,4-dichlorophenol |
| Status : Paper Accepted (Poster Presentation) |
