Catalytic oxidation of aqueous methyl and dimethylamines by activated carbon

Abstract

The catalytic wet air oxidation (CWAO) of methyl and dimethylamines was studied. A commercial peach stones activated carbon and its oxidized and reduced forms were used as catalysts. The observed catalytic behavior is related to the presence of oxygenated surface functional groups on the activated carbons. The N-compounds were selectively oxidized to nitrogen, water and carbon dioxide using these activated carbon catalysts. It is proposed that the quinonic surface groups are responsible for the selective catalytic oxidation of these amines. Carboxylic, lactonic and anhydride groups strongly adsorb the amine compounds producing inhibition of the catalytic activity of the activated carbon in the CWAO process.

Chemical-activated carbons from peach stones for the adsorption of emerging contaminants in aqueous solutions

“…In order to enhance the quantity of oxygenated surface functional groups, the original PC material was modified by a liquid phase oxidation treatment reported in other previous works [19]: the solid was kept in contact to a HNO 3 solution (6 mol/L) for 1 h at 80°C in a 250 mL round-bottom flask, using a ratio of 10 mL of acid solution/1.0 g of carbon. The recovered solids was washed with deionized water until neutrality and further dried in oven for 24 h at 110°C, resulting in O-PC material.…”

Study of the Catalytic Conversion and Adsorption of Abietic Acid on Activated Carbon: Effect of Surface Acidity

“…The untreated samples were denoted as CGRAN and DARCO, while the Hetreated samples were denoted as CGRAN-He and DARCO-He. ) at 80 °C for 1 h following a procedure reported by Aguilar et al 12 . The samples were then thoroughly washed with water until a neutral pH of the filtrate was obtained, and then dried at 110ºC for 10 h. The samples were denoted as Darco-N3 and Darco-N6 according to the concentration of HNO 3 used (3 mol L -1 and 6 mol L -1 , respectively).…”

Catalytic properties of carbon materials for wet oxidation of aniline

“…The overall efficiency of both carbon materials should reflect a combined effect of their mesoporous character and surface oxygen functionality (as measured by the CO/CO 2 ratio obtained by TPD). In CWAO of aqueous methyl and dimethylamines using activated carbons as catalysts, the observed catalytic activity was related to the presence of oxygenated functional groups on the activated carbons, being proposed that the quinone surface groups (releasing CO by TPD) were those responsible for the catalytic activities, while carboxylic, lactone and anhydride groups, releasing CO 2 , were responsible for a catalytic activity inhibition [19]. In a recent study [26] we discovered that the CX catalyst undergoes surface modification (decrease of the CO/CO 2 ratio) when used in the CWAO process, supporting our interpretation on the catalytic role of the groups releasing CO by TPD.…”

“…Interestingly, we have noticed that the aniline removal efficiency and the selectivity to non-organic compounds obtained with such supported Pt catalysts were dependent on the mesoporous character and on the concentration of surface oxygen functional groups of the corresponding support. Other research groups also reported on carbon materials as promising catalysts for the CWAO of aromatic compounds, such as phenol and aniline [14][15][16][17] and of nitrogen containing compounds, such as ammonia and amines [18,19]. The development of carbon materials and their application in CWAO, either as a catalyst support or directly as a catalyst, was recently reviewed [20].…”