Utilização da macroalga Sargassum sp. como adsorvente natural no controle de poluição por cobre em meio aquoso

Abstract

The deposition of heavy metals in aquatic environments is a growing phenomenon related to industrial processes and dump domestic use, whose production has increased significantly to meet the great demand today. The purpose of this study was to evaluate the adsorption capacity of copper in aqueous solutions by macroalgae "Sargasso" collected on the beaches of the north coast of Pernambuco. These were washed, dried in the greenhouse at ambient temperature (37 ± 1.0 ° C), crushed in a grinder of knives and classified. To optimize the process we used a 23 factorial design, in duplicate, with the central point in triplicate, to assess the influence of the amount of algae (0.05 to 0.25 g) of contact time (2 to 6 h) and pH buffer (3.0 to 5.0) with a particle size of 35 mesh seaweed and agitation at 200 rpm at biorretenção Copper. The tests were performed biosorption by placing the alga in contact with 25 mL of a solution containing 50 mg.L-1 for Cu2 + in acetate buffer 0.1 mol L-1 under the conditions of the experimental design. The concentration of Cu2 +, before and after the tests were determined by Atomic Absorption Spectrometry in Flame. The amount of copper adsorbed in mg per gram of adsorbent varied from 3.11 to 19.38. All the main variables were significant in a 95% level of confidence. From the linearization of the Langmuir equation, we obtained a maximum adsorption capacity of 1.248 mg.g-1 and an adsorption constant of 0.335 L.mg-1. The correlation coefficient (R2) between the data and the model was satisfactory (0.9645). The breakthrough curves were obtained until the entire bed was saturated by ions of the solution. The time was set according to the flow, using a time of 8 hours with a flow rate of 2.0 mL min-1 when there was a stabilization process. Algae Sargasso shown to have a high potential to remove copper from aqueous solutions. This way they can be used to control pollution of copper in aqueous media.