Highlights
- Electrocoagulation is a process able to treat and remove fluoride and arsenic simultaneously from drinking water.
- Critical factors in the electrocoagulation process for simultaneous removal are pH, current density and treatment time.
- Acidic pH is more favorable for fluoride removal
- Arsenic removal is less complex than fluoride removal, high removal efficiencies were reached without initial pH adjustment.
Abstract
The co-occurrence of fluoride and arsenic in groundwater presents a problem in many, mostly arid, regions of Latin America and the world. These pollutants cause significant health problems and are difficult to remove simultaneously from drinking water. In this study, the electrocoagulation process for the simultaneous removal of fluoride and arsenic was evaluated in well from the state of Durango, Mexico, in order to both solve the local problem and determine how to apply the method generally. Tests were carried out with different times, concentrations, initial pH values, and electric current densities, with iron and aluminum as electrode materials. The removal efficiencies in simultaneous presence were 85.68% for fluoride and approximately 100% for arsenic. The final concentrations for both pollutants were below the drinking water limits established by the World Health Organization (WHO) and Mexican regulations. The optimum conditions of the electrocoagulation process found were a current density of 4.5 mA/cm2, an initial pH of 5, and a treatment time of 15 min, considering initial fluoride and arsenic concentrations of 5 mg/L and 80 µg/L, respectively.
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