Arsenic removal by adsorption in sand-iron systems

E.M. FARFÁN TORRES; EDGARDO L. SHAM; LILIANA LORENZO

Centro Atómico Constituyentes, Buenos Aires

Taller; Taller de distribución de As en Ibero-América; 2006

RED CYTED IBEROARSEN

  The presence of arsenic in water is a growingproblem at a global scale,because the intake of this element for long periods of time leads to a chronic disease called RegionalChronicEndemicHydroarsenicism(RCEHA). The presenceof arsenic has been detected in groundwaterin the Chaqueña Plain region correspondingto the provinceof Salta. Surfacewaters are not affected. However, the main sourcesofwater for the inhabitantsofthis area are low.availability, temporary lagoons - called "madrejones" by the locals, - since this is a semi-arid region with pluvial seasons increasingly shorter,which prevent swater accumulation. For this reason, the consumption of water from wells has increased, and health problems in the population have increased with it. Arsenic abatement methods that are efficient and easily implemented should therefore be developed,because the socio-culturallevel of the inhabitants of the region is generally low with a considerable degree of  literacy or incomplete literacy. Our laboratoryhas studiedthe implementationof As adsorption- cipitation systems based on the combination of sand and zero-valent iron (Sham and Farfán Torres, 2005). In order to compare this system with other systems reported in the literature, and to detennine the mechanisms that govern the removal process, a series of tests - discussed in this paper - were carried out.detennine the mechanisms that govern the removal process, a series of tests - discussed in this paper - were carried out. The results obtained show that contact times longer than four hours are needed to reach equilibrium. Removal capacity, both of the sand support and the A-Fe-OH-60 adsorbant, is almost non-existent. On the other hand, the A-FeOx-500 adsorbant presents a removal capacity of almost 95%.