Polisaccaridi estratti da alghe marine invasive come biosorbenti di metalli pesanti per una strategia di bioremediation

Heavy metal pollution is one of the major concerns for environmental and human health. Invasive macroalgae produce large amounts of biomass often treated as waste, that could be transformed into an economic and eco-friendly resource. In this contest, we evaluated the biosorbent ability of polysaccharides (100 μg/ml) extracted from Agardhiella subulata (κ-carrageenan), Sargassum muticum (alginate) and Ulva ohnoi (ulvan) to remove arsenite (AsIII), mercury (HgII) and vanadium (VV) (100 ppm) from aquatic solutions. All extracts negligibly adsorbed arsenite, κ-carrageenan showed the highest adsorption level of VV (52.5%), whereas alginate and ulvan adsorbed moderately HgII (about 30%). The biosorption mechanisms were attributed to electrostatic attractions between functional groups of alginate or ulvan and HgII, and between alginate or κ-carrageenan and VV. For their ability to adsorb both HgII and VV, κ-carrageenan and alginate could be proposed to develop bioremediation strategies alternative to physical or chemical techniques currently used for heavy metal removal.