Ni supported on Mg–Al oxides for continuous catalytic wet air oxidation of Crystal Violet

The continuous catalytic oxidation of aqueous Crystal Violet (CV) solutions has been investigated using a nickel catalysts (7 wt%) supported over Mg–Al mixed oxides in a trickle-bed reactor. The influence of the temperature, pressure, gas flow and dye initial concentration were studied in the catalytic wet air oxidation of CV. The catalyst showed a very stable activity up to 350 h on stream with an average total organic carbon (TOC) conversion of 64%. CV and TOC removal were very sensitive to the temperature. Dye conversion augmented from 44.7% at 120 °C to 86.1% at 180 °C. Dye conversion varied from 62.6 to 18.4%, TOC from 59.5 to 18.7% and TN from 66.6 to 14.0% within 10 to 50 ppm of initial dye concentration. The leaching of Ni was 6 wt% of the initial metal present in the catalyst and a 0.59% of carbonaceous deposit was formed onto the catalyst surface.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Ni/MgAlO catalyst. ► Catalytic wet air oxidation in trickle-bed reactor for Crystal Violet removal. ► Effect of the reaction variables was tested. ► The catalyst proved to be stable and efficient for the dye degradation.