Arsenic and fluoride removal from groundwater by electrocoagulation using a continuous filter-press reactor. (February 2016)

• Record Type: Journal Article
• Authors: Guzmán, Athziri; Nava, José L.; Coreño, Oscar; Rodríguez, Israel; Gutiérrez, Silvia
• Is Part Of: Chemosphere. Volume 144(2016)
• Page Start: 2113
• Page End: 2120
• Publication Date: 2016-02
• Subjects: Arsenic removal -- Fluoride removal -- Sulfate removal -- Aluminum sacrificial anode -- Electrocoagulation -- Groundwater treatment; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2015.10.108
• Languages: English
• ISSNs: 0045-6535

Abstract

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 ( C F < 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 . Highlights: Arsenic and fluoride removal from real groundwater by electrocoagulation. Aluminum as sacrificial anodes. Electrolyzes at different flow velocities and current densities. Electrocoagulation led to 100% arsenic removal (43 µg L −1 ) with 0.34 KWh m −3 . Fluoride depletion from 2.5 to 0.15 mg L −1 meet the WHO standard (<1.5 mg L −1 ).