title: Ni/MgAlO regeneration for catalytic wet air oxidation of an azo-dye in trickle-bed reaction.
abstract: Active nickel catalysts (7 wt%) supported over Mg-Al mixed oxides have been recently developed and it has also been demonstrated that they are also highly selective in Catalytic Wet air Oxidation (CWAO) of dyes. CWAO of Chromotrope 2R (C2R) has been studied using a trickle bed reactor employing temperatures from 100 to 180 °C, liquid flow rates from 0.1 to 0.7 mL min(-1) and initial dye concentration from 10 to 50 ppm. Total pressure and air flow were 25 bar and 300 mL min(-1), respectively. The catalyst showed a very stable activity up to 24 h on stream with an average TOC conversion of 82% at 150 °C and T(r)=0.098 g(Ni) min mL(-1). After the reaction, a 1.1 wt% C of carbonaceous deposit is formed onto the catalyst and a diminution of 30% of the surface area with respect of the fresh catalyst was observed. An increase in the space time gave higher TOC conversions up to T(r)=0.098 g(Ni) min mL(-1), attaining values of 80% at 180 °C. The performance of TOC and dye removal does not decrease after two regeneration cycles. In total, a 57 h effective reaction has been carried out with no loss of catalytic activity.
authors.affiliation: Grupo de Catálisis y Procesos de Separación (CyPS), Departamento de Ingeniería Química, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Vallet
authors.forename: Gabriel
authors.initials: G
authors.lastname: Ovejero
authors.forename: Araceli
authors.initials: A
authors.lastname: Rodríguez
authors.forename: José A
authors.initials: JA
authors.lastname: Peres
authors.forename: Juan
authors.initials: J
authors.lastname: García
mesh_terms: D000388:Air; D000536:Aluminum Hydroxide / Q000737:chemistry*; D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry*; D008276:Magnesium Hydroxide / Q000737:chemistry*; D009282:Naphthalenesulfonates / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D009282:Naphthalenesulfonates; D014874:Water Pollutants, Chemical; C010467:hydrotalcite; C070620:chromotrope 2R; D000536:Aluminum Hydroxide; D009532:Nickel; D008276:Magnesium Hydroxide