Gymnogongrus torulosus as a new biosorbent for heavy metal removal.

MARIA DEL MAR ARECO; ERIKA VALDMAN; MARIA DOS SANTOS AFONSO

Rio de Janeiro, Brasil

Conferencia; XIII International Conference on Heavy Metal in the Environment; 2005

Center for Mineral Technology, Ministry of Science and Technologfy of Brazil

Heavy metals are one of the major pollutants in the aquatic environment. The increasing concentration of trace metals in rivers and lakes during the past decades is related with the establishment of different industries around the world. This situation is forcing scientists to study new technologies to remove trace metals from polluted waters. Biosorption, known as sorption of heavy metals onto biological materials, is becoming a potential alternative that is both more economic and less hazardous to the environment. Gymnogongrus torulosus (Rhodophyta) is a seaweed with great commercial interest in Argentina because it produces carrageenan, a polysaccharide commonly used in hydrocolloid industries. In this study, this seaweed collected from the South Atlantic Ocean was selected to be used as a biosorbent for Zn(II), Cd(II), Cu(II) and Pb(II) because they are the more common heavy metals presented in wastewater. The adsorption isotherms and the thermodynamic parameters for the selected metals adsorption were obtained under different experimental conditions for dried Gymnogongrus torulosus. Results have shown that this seaweed biosorbs Zn (II), Cd(II), Cu(II) and Pb(II) equally in lower solution concentrations, while at concentrations higher than 100 mg/L it biosorbs in the way Pb>Cd>Cu>Zn. The biosorption of these heavy metals increased linearly with an increasing pH. As some polysaccharides are being revealed to be excellent biosorbents for heavy metals, the importance of the aqueous extraction residues from the G. torulosus on the metal uptake is also under investigation.