Preparação de carvão ativado de bagaço de cana-de-açúcar e sua aplicação na adsorção de Cd(II) e Cu(II)

Abstract

This work presents a study that aims the removal of metal ions present in synthetic wastewater through adsorption process. The heavy metals evaluated were cadmium and copper and as adsorbent was used activated carbon prepared from sugar cane bagasse, produced by chemical activation with zinc chloride (ZnCl 2). The activated carbon was characterized by thermogravimetric analysis, by scanning electron microscopy and by nitrogen adsorption/desorption isotherms. The adsorption of metal ions was measured with the aid of Langmuir and Freundlich isotherms. The kinetic tests were conducted to study the effect of contact time between the adsorbent and the solution containing the metal ions, determining the equilibrium time of the adsorption process. The effect of pH on the adsorption was evaluated by determining its influence on the process. Subsequently, a test was done using granular activated carbon in the removal of metal ions studied for comparison and verification of the effectiveness of the adsorbent produced. The chemically activated carbon showed a considerable increase in microporosity and its specific surface area (1185 m 2/g). The pH determined for the coal produced was 4,62, characterized as a material property acidic and fit to the adsorption of metal ions. Concerning the initial pH of the solutions, those that promote greater amount of adsorbed metal, and is more effective was 6 for copper and 4 for cadmium. The maximum amount of metal adsorbed per gram of adsorbent was 28.04 mg/g for cadmium ions and 27.98 mg/g for copper ions. The synthesized activated carbon adsorption capacity presented next to the activated carbon.