Biosorption of chromium by red algae Polysiphonia nigrescens

LUIS F. SALA; SEBASTIÁN E. BELLÚ; PATRICIA BLANES; JUAN C. GONZÁLEZ; SILVIA I. GARCÍA; MARÍA INÉS FRASCAROLI; FLORENCIA MANGIAMELI; REGINA TRIPALDI; VERÓNICA ANDREU; ANA M. ATRIA; JULIO FERRÓN; JUAN M. SALAS PEREGRIN; EMILIO RUBIN DE CELIS; LIDIA PIEHL; CRISTINA MATULEWICZ; HÉCTOR PRADO

Bariloche, Río Negro, Argentina

Simposio; 18th International Biohydrometallurgy Simposium; 2009

CINDEFI-CETMIC (CONICET) Universidad Nacional de la Plata / Universidad Nacional del Comahue

The presence of toxic heavy metals in contaminated streams, arising from the dischargeof untreated effluent, is one of the most important environmental issues. Their presencein aquatic ecosystem causes a harmful effect to living organisms. CrVI is known to becarcinogenic and has an adverse potential to modify the DNA transcription process. Onthe other hand, CrVI can be reduced to CrIII by a wide variety of biological and chemicalreductants (1,2).The application of traditional treatment techniques implies a high cost and a continuousinput of chemicals which cause further environmental damage. The high level ofsulfation of the polysaccharides from Polysiphonia nigrescens suggests that thisinexpensive red seaweed could be used as an important biomass for removing heavymetals. This study focuses on the biosorption of chromium onto algae biomass fromaqueous solution.Native P. nigrescens was collected in Cabo Corrientes (Mar del Plata, Buenos Aires,Argentina). Experimental parameters affecting biosorption process such as pH, contacttime and biomass dosage were studied. The biosorption capacity (mg Cr / g biomass) ofP. nigrescens for CrIII in the study preliminary was 50.0 mg/g at pH 4.0 and 11.6 g/Lbiomass dosage, 19 h equilibrium time and 20.0 ºC. EPR and XPS spectroscopy frommixtures CrVI/ biomass, pH = 1, shows the presence of CrV + CrIII bound to the surfaceof the red algae at short contact times and CrIII at long contact times. This resultsindicate that, at pH = 1, P. nigrescens can completely remove CrVI from aqueoussolution through an adsorption-coupled reduction mechanism to yield adsorbed CrIII andthe less toxic aqueous CrIII, which can be further removed at pH = 4.0.References:(1) Juan C. Gonzáleza, Silvia I. Garcíaa, Sebastián Bellúa, Ana María Atriab, JuanManuel Salas Pelegrínc, Antal Rockenbauerd, Lazlo Koreczd, Sandra Signorellaa* andLuis F. Salaa,*, Oligo and Polyuronic acids interactions with hypervalent chromium,submited to Polyhedron, 2009.(2) Sebastián Bellú, Juan C. González, Silvia García,Sandra Signorella*, Luis F. Sala*,Kinetics and mechanism of oxidation of apple pectin by Cr(VI) in aqueous acid mediumJ. Phys. Org. Chem., 2008, 21, 1059-1067.