Cd(II) biosorption using Lessonia kelps

► Lessonia kelps are efficient sorbents for copper and nickel. ► Characterization of biosorbent by FT-IR spectroscopy and SEM-EDAX. ► Langmuir equation for modeling sorption isotherm. ► Crank equation for fitting uptake kinetics. ► Greater impact of sorbent dosage and metal concentration against particle size and temperature.