title: Methylene blue removal from contaminated waters using O3, natural zeolite, and O3/zeolite.
abstract: This paper compares experimental results on methylene blue (MB) removal systems based on ozone oxidation, zeolite adsorption, and simultaneous adsorption-oxidation using ozone in the presence of natural zeolite. The effect of pH (2-8), and the presence of radical scavengers (sodium acetate) on process rates and removal efficiencies are assessed at laboratory scale. The experimental system consisted of a 1 L differential circular flow reactor and an ozone generator rated at 5 g O3/h. Results show that ozone oxidation combined with zeolite adsorption increases the overall MB oxidation rate with respect to ozonation process and zeolite adsorption. In presence of free radical scavenger, only a 25% of reduction on MB removal rate are observed in the simultaneous treatment, as compared with 70% when ozonation treatment is used, suggesting that MB oxidation reactions take mainly place on the zeolite surface.
authors.affiliation: Facultad de Ingeniería, Universidad Católica de la Santísima Concepción, Caupolicán 491, Concepción, Chile. hvaldes@ucsc.cl
authors.forename: H
authors.initials: H
authors.lastname: Valdés
authors.forename: R F
authors.initials: RF
authors.lastname: Tardón
authors.forename: C A
authors.initials: CA
authors.lastname: Zaror
mesh_terms: D000327:Adsorption; D016166:Free Radical Scavengers / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008751:Methylene Blue / Q000737:chemistry* / Q000302:isolation & purification*; D010126:Ozone / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods*; D017641:Zeolites / Q000737:chemistry*
chemical_list: D016166:Free Radical Scavengers; D014874:Water Pollutants, Chemical; D014867:Water; D017641:Zeolites; D010126:Ozone; D008751:Methylene Blue