Adsorción de mercurio (II) sobre carbón activo funcionalizado en condiciones estacionarias y dinámicas

Abstract

The objective of the present research work consisted of a dynamic and stationary study of mercury removal by adsorption with functionalized activated carbon (CAF). Initially the activated carbon was washed with HCl (37%) and distilled water, then it is functionalized with a solution of CuCl2 at 12% (m/V), subsequently the composition and surface of the CAF was characterized by IR and SEM analysis; the adsorption of Hg+2 was analyzed by stationary tests determining: contact time at three different temperatures and constant concentration; the isotherm analysis was performed at 25°C, 30°C and 35°C at constant mass and seven different Hg+2 concentrations; the pH effect was performed in a range of 2-11 at constant CAF mass and Hg+2 concentration; the isoelectric point was performed with constant CAF mass NaOH and HCl (0.1N); the adsorbent mass effect was carried out in the range of 0.3 - 1.25g CAF at constant mercury concentrations. Dynamic column tests were conducted at different flow rates i.e. 7mL/min - 15mL/min and with a mass of 100g CAF. Using adsorption kinetics models, the maximum adsorption capacity was determined to be 0.1317 mg Hg+2/g CAF at 30°C with a contact time of 240 minutes; the most efficient adsorption is observed at pH=6, and its isoelectric point at pH=9, the increase of the CAF mass is directly proportional to the adsorption capacity and finally, it was found that the CAF was not saturated at the conditions experienced in the dynamic tests, since its adsorption capacity after the established times was very high. From the tests carried out, it is concluded that CAF is a good adsorbent, so it is recommended to use it for Hg+2 adsorption processes in contaminated waters.