Photocatalytic degradation of Rhodamine B by microwave-assisted hydrothermal synthesized N-doped titanate nanotubes

Caiyun Yan; Ku-Fan Chen; Chia-Hsiang Lai; Shiau-Wu Lai; Qing Chang; Yen-Ping Peng

doi:10.1016/j.jes.2014.05.017

Photocatalytic degradation of Rhodamine B by microwave-assisted hydrothermal synthesized N-doped titanate nanotubes

J Environ Sci (China). 2014 Jul;26(7):1505-12. doi: 10.1016/j.jes.2014.05.017. Epub 2014 Jun 10.

Authors

Caiyun Yan¹, Ku-Fan Chen², Chia-Hsiang Lai³, Shiau-Wu Lai⁴, Qing Chang⁵, Yen-Ping Peng⁶

Affiliations

¹ School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China. Electronic address: 499522256@qq.com.
² Department of Civil Engineering, National Chi Nan University, Nanto 54561, Taiwan, Chinese Taibei.
³ Department of Safety, Health and Environmental Engineering, Central Taiwan University of Science and Technology, Taichung 40601, Taiwan, Chinese Taibei.
⁴ College of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
⁵ School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
⁶ College of Environment and Energy, South China University of Technology, Guangzhou 510006, China. Electronic address: yppeng0124@scut.edu.cn.

PMID: 25080000
DOI: 10.1016/j.jes.2014.05.017

Abstract

Microwave-induced nitrogen-doped titanate nanotubes (NTNTs) were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Zeta potential analysis, specific surface area (SBET), and UV-Visible spectroscopy. TEM results indicate that NTNTs retain a tubular structure with a crystalline multiwall and have a length of several hundred nanometers after nitrogen doping. XRD findings demonstrate that the crystalline structure of NTNTs was dominated by anatase, which is favored for photocatalytic application. The Ti-O-N linkage observed in the XPS N 1s spectrum is mainly responsible for narrowing the band gap and eventually enhancing the visible light photoactivity. FT-IR results demonstrated the existence of H₃O⁺, which could be excited by photo-generated holes to form hydroxyl radicals and degrade environmental pollutants. After sintering at 350°C, the UV-Vis absorbance edges of NTNTs significantly shift to the visible-light region, which indicates N atom doping into the nanotubes. Photocatalytic degradation of Rhodamine B (RhB) via NTNTs show good efficiency, with pseudo first-order kinetic model rate constants of 3.7 × 10⁻³, 2.4 × 10⁻³ and 8.0 × 10⁻⁴ sec⁻¹ at pH3, 7, and 11, respectively.

Keywords: Microwave hydrothermal; Photocatalytic degradation; Titanate nanotubes.

MeSH terms

Catalysis
Crystallography, X-Ray
Microscopy, Electron, Transmission
Microwaves*
Nanotubes / chemistry*
Photochemical Processes
Rhodamines / chemistry*
Spectrum Analysis / methods
Titanium / chemistry*

Substances

Rhodamines
Titanium
rhodamine B