Estudio de adsorción y desorción de Cadmio (II) por un andosol rico en alofán tomado de un yacimiento ubicado en la provincia de Santo Domingo de los Tsáchilas.

Abstract

It was studied the adsorption and desorption process of cadmium (Cd 2+ ) on a soil of volcanic origin. Some collected samples of soil from San José de Achotillo at Santo Domingo de los Tsáchilas Province, through the physicochemical characterization of them examples it is determined that the soil not presented any pollution. To determine the adsorption conditions, parameters that were studied were pH, amount of adsorbent, ionic strength and mixing time. Isotherms of cadmium adsorption to the soil was in the range from 1 to 10 parts per million (ppm) of cadmium by adding standard from 1000 ppm cadmium, to a controlled pH of 10±0,1 in 1 g of andosol and 0.005 mg.L -1

NaNO 3 as ionic strength, with a time of 60 minutes mixing and concentration of cadmium measurement by Atomic spectrophotometry and it was compared with models mathematicians of Freundlich and Langmuir. For the desorption were used waste of trials adsorption on the soil by the application NaNO 3, and it was determined the concentration by spectrophotometry. Soil records the presence of cadmium from 0,0223 ppm to 0,5341 ppm whit an adsorption an adsorption from 94,6% to 98,6%. The results showed that the model of Langmuir is which best describe the adsorption and it is determined that the process is performed on a monolayer. The percentage of desorption of varies from 9,55% to 20,99% of cadmium recovery which indicates that it is strongly retained in the soil. It is concluded the soil has a high adsorption capacity, so it could be used for processes of elimination of cadmium in contaminated waters. It is recommended to extend the study of andosol adsorption with solutions containing different pollutants simultaneously.