This paper investigates the potential of alginate-immobilised
Chlorella sorokiniana for removing Cu
2+, Ni
2+ and Cd
2+ ions from drinking water solutions. The effects of initial metal concentrations, contact times and temperatures on the biosorptions and removal efficiencies of the tested metals were investigated at initial pH values of 5, and pH effects were studied within the range of 3–7. When studying the effects of initial metal concentrations, the highest experimental removal yields achieved for Cu
2+, Ni
2+ and Cd
2+ ions were 97.10, 50.94 and 64.61 %, respectively. The maximum biosorption capacities obtained by the Langmuir isotherm model for the biosorptions of Cu
2+, Ni
2+ and Cd
2+ ions by alginate-immobilised
C. sorokiniana were found to be 179.90, 86.49 and 164.50 mg/g biosorbent, respectively. The experimental data followed pseudo-second-order kinetics. At an initial metal concentration of 25 mg/L, immobilised algae could be used in at least 5 successive biosorption–desorption cycles. SEM and EDS analyses revealed that the metals bonded to the biosorbent. Bi- and multi-metal systems of Cu
2+, Ni
2+ and Cd
2+ were investigated at initial metal concentrations of 30, 50 and 100 mg/L. The removal of Cd
2+ as well as Ni
2+ in such systems was negatively affected by the presence of Cu
2+. The removal efficiency for Cu
2+ in multi-metal systems decreased by 5–7 %, whilst in the cases of Cd
2+ and Ni
2+ the efficiencies decreased by up to 30 %. Nevertheless, the results obtained show that alginate-immobilised
C. sorokiniana can efficiently remove the metals tested from polluted drinking water sources.
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