Abstract
A hydrodynamic cavitation method was used to maximize the effect of destructuration of a honeycomb monolithic support of a spent Selective Catalyst Reduction (SCR) catalyst—V2O5-WO3/TiO2-type—for extracting crystalline titanium and tungsten oxides from the cordierite surface. A high relative inlet pressure of 40 MPa was applied to a divergent nozzle for obtaining high shear stresses of the submerged cavitating jets and intensive micro- and nano-jets and shock waves acting on the particle surface of the milled catalyst. Scanning Electron Microscopy (SEM) analysis indicated the compact morphology of the thin metal oxide layer at the surface of the cordierite support and the high content of Ti and W elements in the sample. Energy dispersive spectroscopy (EDAX) performed along with TEM investigations on different nano-zones from the sample established the elemental composition of WO3-TiO2 agglomerates separated after hydrodynamic cavitation processing and identified as independent nanocrystalline structures through Bright Field Transmission Electron Microscopy (BF-TEM) and High Resolution Transmission Electron Microscopy (HR-TEM) measurements. The tetragonal anatase phase of TiO2 and cubic phase of WO3 were established by both interplanar d spacing measurements and X-ray diffraction analysis. The photoelectrochemical results showed the possible second life application of automotive catalysts.
Highlights
Selective catalyst reduction (SCR) catalysts proved to be an excellent technology for the reduction of nitrogen oxide (NOx ) emissions in diesel exhausts, due to a wide window of operating temperatures, the durability of deactivation, and high conversion rate of NOx [1,2]
The results presented in the work at-hand entangle hydrodynamic cavitation with photoelectrochemistry to presented in the work at-hand entangle hydrodynamic cavitation with photoelectrochemistry generate a second-life application for metal oxide-based automotive catalysts
A hydrodynamic cavitation method was designed for extracting the crystalline titanium and tungsten oxides from the cordierite surface of a spent Selective Catalyst Reduction (SCR) catalyst
Summary
Selective catalyst reduction (SCR) catalysts proved to be an excellent technology for the reduction of nitrogen oxide (NOx ) emissions in diesel exhausts, due to a wide window of operating temperatures, the durability of deactivation, and high conversion rate of NOx [1,2]. 2% WO3 /TiO2 catalyst prepared by the sol–gel method with a calcination stage developed at 500 ◦ C for 4 h represents a promising material for the solar photocatalytic treatment of water contaminated by pesticides [12]. A soda roasting process offered the possibility of increasing the leaching efficiency of tungsten from catalyst waste by increasing Na2 CO3 content, roasting time, and temperature [20] Another hydrometallurgical technique for the recovery of W in the form of synthetic CaWO4 through roasting, acidic decomposition (using an HCl solution), leaching (with NaOH), and precipitation was reported as a successful. A test chamber for hydrodynamic cavitation with diverging nozzles is used for the extraction of crystalline titanium and tungsten oxides from the cordierite surface of the V2 O5 -WO3 /TiO2 spent catalyst. The second life application is proven by the photoelectrochemical activity under illumination
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
