Rapid synthesis of Ti-MCM-41 by microwave-assisted hydrothermal method towards photocatalytic degradation of oxytetracycline.
This study employed microwave-assisted hydrothermal method to synthesize Ti-MCM-41, which are mesoporous materials with a high surface area and excellent photocatalytic ability. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) were employed. The XRD findings showed that Ti-MCM-41 exhibited a peak at 2θ of 2.2°, which was attributed to the hexagonal MCM-41 structure. The BET (Brunauer-Emmett-Teller) results agreed with the TEM findings that Ti-MCM-41 has a pore size of about 3-5nm and a high surface area of 883m(2)/g. FTIR results illustrated the existence of Si-O-Si and Si-O-Ti bonds in Ti-MCM-41. The appearance of Ti 2p peaks in the XPS results confirmed the FTIR findings that the Ti was successfully doped into the MCM-41 structure. Zeta (ζ)-potential results indicated that the iso-electric point (IEP) of Ti-MCM-41 was at about pH3.02. In this study, the photocatalytic degradation of oxytetracycline (OTC) at different pH was investigated under Hg lamp irradiation (wavelength 365nm). The rate constant (K'obs) for OTC degradation was 0.012min(-1) at pH3. Furthermore, TOC (total organic carbon) and high resolution LC-MS (liquid chromatography-mass spectrometry) analyses were conducted to elucidate the possible intermediate products and degradation pathway for OTC. The TOC removal efficiency of OTC degradation was 87.0%, 74.4% and 50.9% at pH3, 7 and 10, respectively. LC-MS analysis results showed that the degradation products from OTC resulted from the removal of functional groups from the OTC ring.
College of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
Hanlin
H
Chen
Department of Environmental Science and Engineering, Tunghai University, Taichung 40704, Chinese Taipei. Electronic address: yppeng@thu.edu.tw.
Yen-Ping
YP
Peng
Department of Civil Engineering, "National" Chi Nan University, Nantou 54561, Chinese Taipei.
Ku-Fan
KF
Chen
Department of Safety, Health and Environmental Engineering, Central Taiwan University of Science and Technology, Taichung 40601, Chinese Taipei.
Chia-Hsiang
CH
Lai
Department of Electrical Engineering, Cheng Shiu University, Kaohsiung 83347, Chinese Taipei.
Yung-Chang
YC
Lin
D046529:Microscopy, Electron, Transmission; D008872:Microwaves; D008956:Models, Chemical; D010118:Oxytetracycline / Q000737:chemistry*; D055668:Photochemical Processes; D056951:Photoelectron Spectroscopy; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
C509968:MCM-41; D012822:Silicon Dioxide; D014025:Titanium; D010118:Oxytetracycline
Microwave hydrothermal synthesis; Oxytetracycline; Photocatalytic degradation; Ti-MCM-41