Peroxo and gold modified titanium nanotubes for effective removal of methyl orange with CWPO under ambient conditions.

Titanium dioxide based nanotubes (TN) were synthesized through hydrothermal synthesis route followed by acid washing under ambient conditions. The as-prepared TN with high specific surface area and titanate layered structure were subsequently functionalized with titanium (IV) peroxo groups (TNp) and gold (TN/Au) to examine an influence of non-metal/metal presence in the CWPO of aqueous methyl orange (MO) solution under ambient conditions. The obtained results showed higher activity and mineralization extent of MO over TNp catalyst in comparison to TN/Au at ambient conditions. The 50 ppm MO solution containing 2 g/L of TNp catalyst and stoichiometric amount of hydrogen peroxide was purified up to 68% of TOC during 4 h of CWPO process. As far as TN/Au is concerned, high TOC removal (83%) was only witnessed when the CWPO process was conducted at elevated temperatures (T = 80 °C). Moreover, comparing the simplicity of the synthesis routes and catalytic activities of obtained solids, the metal-free catalyst showed greater potential for the degradation of MO solution under ambient conditions without deprivation of its activity, as demonstrated in successive 4-cycle oxidation runs conducted in the presence of a surplus amount of H 2 O 2 . [ABSTRACT FROM AUTHOR]