Adsorción de As en 4-Na-Mica sintética y su porducto de tratamiento mecánico

L. LORENZO; E. M. FARFÁN TORRES; P. NARANJO; R. M. TORRES SANCHEZ

Mar del Plata, Argentina

Congreso; V Congreso Iberoamericano de Física y Química Ambiental; 2008

Sociedad Iberoamericana de Física y Química Ambiental

Arsenic is a natural element of the earth´s crust that in some regions of the world can be present in waters. In particular, in Argentina, it is present in groundwater in quantities superior to the admitted ones by the national and international norms (10 µg L-1). Its removal from water has been proved using low cost materials, in which the presence of Fe and Al seems to be fundamental. The synthetic mica 4-Na-Mica with high cationic exchange capacity and four Na ions for cell unit, and his product of mechanical treatment, where the structure was altered moving to the surface aluminum ions, might act as good sorbents for arsenic. In this work, the raw kaolin and the synthesis products were characterized and the arsenic adsorption capacity was evaluated on the two last materials. The results obtained show that both materials adsorb arsenic. The 4-Na-Mica grinded sorbs more arsenic than 4-Na-Mica. 4-Na-Mica grinded attains maximal adsorption capacity, after six days contact, while 4-Na-Mica needs only 2 h. This could be due to the fact that 4-Na-Mica grinded presents higher quantity of edge negatively charged sites than 4-Na-Mica, which adsorb protons of the solution and produces a continued increase of pH. As the time of contact increases (up to 6 h), 4-Na-Mica grinded diminishes its charge and consequently its electrostatic repulsion, being able to adsorb a higher quantity of arsenic species than 4-Na-Mica. The arsenic remotion capacities were: 60.7 % for 4-Na-Mica and 96.5 % for 4-Na-Mica grinded. These results showed the potential application of 4-Na-Mica products in the treatment of arsenic contaminated waters.-1). Its removal from water has been proved using low cost materials, in which the presence of Fe and Al seems to be fundamental. The synthetic mica 4-Na-Mica with high cationic exchange capacity and four Na ions for cell unit, and his product of mechanical treatment, where the structure was altered moving to the surface aluminum ions, might act as good sorbents for arsenic. In this work, the raw kaolin and the synthesis products were characterized and the arsenic adsorption capacity was evaluated on the two last materials. The results obtained show that both materials adsorb arsenic. The 4-Na-Mica grinded sorbs more arsenic than 4-Na-Mica. 4-Na-Mica grinded attains maximal adsorption capacity, after six days contact, while 4-Na-Mica needs only 2 h. This could be due to the fact that 4-Na-Mica grinded presents higher quantity of edge negatively charged sites than 4-Na-Mica, which adsorb protons of the solution and produces a continued increase of pH. As the time of contact increases (up to 6 h), 4-Na-Mica grinded diminishes its charge and consequently its electrostatic repulsion, being able to adsorb a higher quantity of arsenic species than 4-Na-Mica. The arsenic remotion capacities were: 60.7 % for 4-Na-Mica and 96.5 % for 4-Na-Mica grinded. These results showed the potential application of 4-Na-Mica products in the treatment of arsenic contaminated waters.