title: Electro-Fenton decolourisation of dyes in an airlift continuous reactor using iron alginate beads.
abstract: In this study, electro-Fenton dye degradation was performed in an airlift continuous reactor configuration by harnessing the catalytic activity of Fe alginate gel beads. Electro-Fenton experiments were carried out in an airlift reactor with a working volume of 1.5 L, air flow of 1.5 L/min and 115 g of Fe alginate gel beads. An electric field was applied by two graphite bars connected to a direct current power supply with a constant potential drop. In this study, Lissamine Green B and Reactive Black 5 were selected as model dyes. Fe alginate gel beads can be used as an effective heterogeneous catalyst for the degradation of organic dyes in the electro-Fenton process, as they are more efficient than the conventional electrochemical techniques. At optimal working conditions (3 V and pH 2), the continuous process was performed. For both dyes, the degree of decolourisation increases when the residence time augments. Taking into account hydrodynamic and kinetic behaviour, a model to describe the reactor profile was obtained, and the standard deviation between experimental and theoretical data was lower than 6%. The results indicate the suitability of the electro-Fenton technique to oxidise polluted effluents in the presence of Fe alginate gel beads. Moreover, the operation is possible in a continuous airlift reactor, due to the entrapment of iron in the alginate matrix.
authors.affiliation: Department of Chemical Engineering, University of Vigo, Isaac Newton Building, Campus As Lagoas, Marcosende, 36310 Vigo, Spain.
authors.forename: O
authors.initials: O
authors.lastname: Iglesias
authors.forename: E
authors.initials: E
authors.lastname: Rosales
authors.forename: M
authors.initials: M
authors.lastname: Pazos
authors.forename: M A
authors.initials: MA
authors.lastname: Sanromán
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry*; D055664:Electrochemical Techniques; D005782:Gels; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D057446:Hydrodynamics; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D008086:Lissamine Green Dyes / Q000737:chemistry; D008956:Models, Chemical; D009282:Naphthalenesulfonates / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D000464:Alginates; D004396:Coloring Agents; C045076:Fenton's reagent; D005782:Gels; D006603:Hexuronic Acids; D008086:Lissamine Green Dyes; D009282:Naphthalenesulfonates; D014874:Water Pollutants, Chemical; D020723:Glucuronic Acid; C024537:green 5; D006861:Hydrogen Peroxide; D007501:Iron; C063421:Remazol black B