[Show abstract][Hide abstract] ABSTRACT: Multi-walled carbon nanotubes (MWCNTs) functionalized by different oxidants (HNO(3)/H(2)SO(4), H(2)O(2), O(3) and air) have been used as catalysts for the wet air oxidation of phenol. To investigate the effect of the oxidation conditions on the structure of the functionalized MWCNTs, various characterization techniques, e.g., scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) have been used. The MWCNTs treated with O(3) and H(2)O(2) show higher amounts of oxygen-containing functional groups and carboxylic acid groups, and a weaker acidic nature, in comparison with those treated with other oxidizing agents. All the functionalized MWCNTs exhibit good activity in the catalytic wet air oxidation (CWAO) of phenol. However, the MWCNTs treated with O(3) show the highest activity with desirable stability in comparison with other functionalized MWCNTs, indicating that the functionalization of carbon nanotubes with O(3) is a very promising strategy in synthesizing efficient catalysts for CWAO.
No preview · Article · Jul 2012 · Journal of hazardous materials
[Show abstract][Hide abstract] ABSTRACT: Ru catalysts, supported on TiO2, CeO2, and CeO2-TiO2, were prepared by the impregnation method. The effect of the structure of the supports on the activity of Ru catalysts was
investigated in the catalytic wet air oxidation (CWAO) of acetic acid under 230°C and 5 MPa in a batch reactor. Physical properties
including the surface area, crystalline phase, and surface components of the Ru catalysts were characterized by N2 adsorption, X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The CeO2-based Ru catalysts had good activity, and the prepared RuO2/CeO2 catalyst showed markedly higher activity than the RuO2/CeO2-TiO2 catalyst. The surface structure, the high amount of chemisorbed oxygen on the catalyst surface, and the suitable pHpzc value of the supports played an important role in the activity of the Ru catalysts in CWAO of acetic acid.
Keywordscatalytic oxidation–catalysts–ruthenium–ceria–acetic acid