Equilibrium and Kinetic Study of Cu(II) Ions Biosorption on Biochars Obtained from Marine Algae Biomass

Due to their dangerous effects, persistence and tendency to accumulate, heavy metals can present a hazard to the environment and human health. Hence, the elimination of heavy metals from aqueous solutions is crucial. Biosorption is a viable alternative that can be used for this purpose. To emphasize this aspect, biochars obtained by pyrolysis of marine algae biomass (Ulva lactuca) at three different temperatures (320, 450 and 550 °C) were used as biosorbents for the removal of Cu(II) ions from aqueous effluents. The biosorption of Cu(II) ions on biochar biosorbents reached the equilibrium after 60 min, for an initial concentration of 25 mg Cu(II)/L. All biosorption kinetic data are described by the pseudo-second-order model. Furthermore, the Langmuir model best fits the equilibrium data of Cu(II) ions biosorption onto biochars. The maximum biosorption capacity followed the order: BC-550 (32.15 mg/g) > BC-450 (31.95 mg/g) > BC-320 (16.83 mg/g). All experimental observations support the potential use of biochars obtained from algae biomass as promising alternative biosorbents for the removal of Cu(II) ions.