Biosorption performance of red and green marine macroalgae for removal of trace cadmium and nickel from wastewater

The ability of red (Corallina officinalis L., Porphyra columbina) and green (Codium fragile) marine macroalgae to remove Cd(II) ions from dilute aqueous solutions, mimicking wastewaters with low metal concentrations, was explored. Under pre-established equilibrium conditions, Corallina and Porphyra attained almost complete removal at 1 g/100 mL. Equilibrium sorption isotherms of cadmium were determined and modelled. As judged from the estimated maximum sorption capacities, Porphyra showed the highest cadmium-binding ability, followed by Corallina and Codium. Furthermore, the three algae proved less effective in capturing nickel than cadmium ions at low dosages, attaining quite similar removal for 1 g/100 mL.

Keywords: wastewater treatement, biosorption, red marine macroalgae, green marine macroalgae, heavy metals, metal removal, cadmium, nickel, biosorption, equilibrium sorption isotherms, modelling