Decrease of arsenic in water by calcium salts addition

CACCIABUE, LUCÍA; DIETRICH, SEBASTIÁN; WEINZETTEL, PABLO; BEA, SERGIO ANDRÉS; SIERRA, LEONARDO

Environmental Arsenic in a Changing World: Proceedings of the 7th International Congress and Exhibition on Arsenic in the Environment

CRC Press

Lugar: Florida; Año: 2019; p. 422 - 424

Arsenic (As) presence in groundwater from Argentinean pampean plain is favored by high pH and Na-HCO3- type waters. Our hypothesis was that by adding Ca to the aquifer system, pH could decresed and As may be retained in solid phase (sediments). Batch experiments were performed on natural sediments in contact with a Na-HCO3- solution, where CaSO4 or CaCl2 was added. Ca salts addition decreased up to 0.3 points of pH solution and as a result, As concentration in solution decreased. Two mechanisms are proposed. One is that a small decrease in pH enhanced As adsorption on Fe oxides. The second is that calciteprecipitated and could trap As inside its structure.