An efficient catalytic process for the treatment of genotoxic aniline wastewater using a new granular activated carbon-supported titanium dioxide composite

Abstract

This work presents an efficient catalytic ozonation process for the treatment of aniline wastewater as a model pollutant. The process uses a granular activated carbon-supported titanium dioxide catalyst with environmentally-friendly and sustainable characteristics. Titanium dioxide composites were prepared by precipitation of alcoholic titanium tetrachloride solutions on two different carbon supports: Norit® GAC 1240 Plus and Norit® ROX 0.8. This method is an improvement on other composite preparation methods such as hydrothermal and impregnation by immersion techniques, which were also carried out for comparison. It characterised our composites by Brunauer–Emmett–Teller analysis, scanning electron microscopy-energy dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy to assess the influence of the carbon support. Composites synthesised via this novel precipitation method presented a 25% increase in their initial specific surface area and a 9.1% increase in titanium dioxide loading. It compared the catalytic activity of the different titanium dioxide composites on different aniline solutions, and studied the optimal pH and ozone dose. Norit® GAC 1240 Plus-supported titanium dioxide composite prepared by the precipitation method gave the highest removal yield with 80.24% mineralisation of total organic carbon in 45 min. With respect to the costs associated with the treatment, the composite achieved a removal yield of 26.8 mg ozone/mg total organic carbon.