Using innovative copper-loaded activated alumina (Cu/AA) as the catalyst for catalytic wet peroxidation (CWPO) of catechol.

In this study, copper-loaded activated alumina (Cu/AA) was synthesized and used for the CWPO of catechol (a representative refractory organic pollutant). Various characterization techniques were deployed to characterize the catalysts, e.g., activated alumina (AA), as well as pristine and spent 1% Cu/AA. The innovative 1% Cu/AA catalyst exhibited good thermal stability up to 1173 K with a marginal weight loss of 13%. The Cu species were well dispersed on the activated alumina framework with no significant cluster formation. Typically, the average copper particle size of 5 nm was dispersed on the AA framework. Catechol removal was observed to be 92% with 87% mineralization at optimized conditions (initial catechol concentration = 200 mg/L, catalyst dose of 1% Cu/AA = 2 g/L; temperature = 323 K; pH = 6; and H2O2/catechol stoichiometric ratio = 0.5). The mineralization of catechol was analyzed using mass spectroscopy, with the associated mechanism has been elucidated. Results of this study indicated that synthesized catalyst has phenomenal advantages in terms of simple separation and high removal efficiency of catechol, suggesting the feasibility of employing Cu/AA as the effective catalyst for the CWPO of catechol.

Wet peroxidation of resorcinol catalyzed by copper impregnated granular activated carbon.

The present article reports the treatment of resorcinol using a catalytic wet peroxidation (CWPO) process in the presence of copper impregnated granular activated carbon (Cu/GAC) with a bench-scale batch reactor. The typical physico-chemical properties of synthesized catalyst were characterized with different equipment and methods. 90% resorcinol removal and 81% of TOC removal was achieved at optimum conditions (pH = 6, the stoichiometric ratio of H2O2/resorcinol = 1.2, catalyst dose = 0.5 g/L, initial concentration of resorcinol = 100 mg/L, temperature = 70 °C and time t = 4 h). Fourier-transform infrared spectroscopy (FTIR) measurements revealed that GAC posses various conjugated hydrocarbon groups including aromatic hydrocarbons, carboxylic groups, carboxyl and carbonate. Cu/GAC catalyst has a surface smoother than that of pristine GAC. At neutral or natural pH (∼6.4) of resorcinol, CWPO of resorcinol is favorable by Cu/GAC catalyst. Catalyst stability study revealed that Cu/GAC sustain its catalytic reactivity to over 76% in the five cycles without any regeneration. The thermogravimetric analysis confirmed that 350 °C temperature found to be optimum for calcination of Cu/GAC without any major losses. The mineralization mechanism was proposed based on intermediates identified during CWPO reaction.