Algal-based biomaterials for environmental remediation of heavy metals

Algal based biomaterials that can remediate heavy metals include dried algal biomass, algal biochar and algal cell wall polymers. The major cell wall polymers include sulfated polysaccharides like carrageenan, alginates and fucoidans. The ability of sulfated polysaccharides to bind bivalent metal ions has been discussed. The cell wall polysaccharides various negatively charged functional groups like COO−, OSO3−, -NH2, etc., that help bind heavy metal ions. The mechanism of biosorption of metals includes the ion exchange process, electrostatic process and the formation of weak Van der Waals and strong covalent bonds. The properties of the biomaterials and the mechanism of sorption have been explained in detail.