title: Arsenic and fluoride removal from groundwater by electrocoagulation using a continuous filter-press reactor.
abstract: We investigated simultaneous arsenic and fluoride removal from ground water by electrocoagulation (EC) using aluminum as the sacrificial anode in a continuous filter-press reactor. The groundwater was collected at a depth of 320 m in the Bajío region in Guanajuato Mexico (arsenic 43 µg L(-1), fluoride 2.5 mg L(-1), sulfate 89.6 mg L(-1), phosphate 1.8 mg L(-1), hydrated silica 112.4 mg L(-1), hardness 9.8 mg L(-1), alkalinity 31.3 mg L(-1), pH 7.6 and conductivity 993 µS cm(-1)). EC was performed after arsenite was oxidized to arsenate by addition of 1 mg L(-1) hypochlorite. The EC tests revealed that at current densities of 4, 5 and 6 mA cm(-2) and flow velocities of 0.91 and 1.82 cm s(-1), arsenate was abated and residual fluoride concentration satisfies the WHO standard (CF < 1.5 mg L(-1)). Spectrometric analyses performed on aluminum flocs indicated that these are mainly composed of aluminum-silicates of calcium and magnesium. Arsenate removal by EC involves adsorption on aluminum flocs, while fluoride replaces a hydroxyl group from aluminum aggregates. The best EC was obtained at 4 mA cm(-2) and 1.82 cm s(-1) with electrolytic energy consumption of 0.34 KWh m(-3).
authors.affiliation: Universidad de Guanajuato, Departamento de Química, Cerro de la Venada s/n, Pueblito de Rocha, 36040 Guanajuato, Guanajuato, Mexico.
authors.forename: Athziri
authors.initials: A
authors.lastname: Guzmán
authors.affiliation: Universidad de Guanajuato, Departamento de Ingeniería Geomática e Hidráulica, Av. Juárez 77, Zona Centro, 36000 Guanajuato, Guanajuato, Mexico. Electronic address: jlnm@ugto.mx.
authors.forename: José L
authors.initials: JL
authors.lastname: Nava
authors.affiliation: Universidad de Guanajuato, Departamento de Ingeniería Civil, Av. Juárez 77, Zona Centro, 36000 Guanajuato, Guanajuato, Mexico.
authors.forename: Oscar
authors.initials: O
authors.lastname: Coreño
authors.affiliation: Universidad Autónoma de San Luis Potosí, Facultad de Ingeniería-Instituto de Metalurgia, Av. Sierra Leona 550, 78210 San Luis Potosí, San Luis Potosí, Mexico.
authors.forename: Israel
authors.initials: I
authors.lastname: Rodríguez
authors.affiliation: Universidad de Guanajuato, Departamento de Química, Cerro de la Venada s/n, Pueblito de Rocha, 36040 Guanajuato, Guanajuato, Mexico.
authors.forename: Silvia
authors.initials: S
authors.lastname: Gutiérrez
mesh_terms: D000327:Adsorption; D000535:Aluminum / Q000737:chemistry*; D001151:Arsenic / Q000737:chemistry*; D004566:Electrodes; D004572:Electrolysis / Q000295:instrumentation / Q000379:methods*; D005459:Fluorides / Q000737:chemistry*; D060587:Groundwater / Q000737:chemistry; D008800:Mexico; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D000535:Aluminum; D001151:Arsenic; D005459:Fluorides
keywords: Aluminum sacrificial anode; Arsenic removal; Electrocoagulation; Fluoride removal; Groundwater treatment; Sulfate removal