The biosorption of zinc from model solution as well as wastewater by Arthrospira (Spirulina) platensis biomass was studied. Adsorption capacity of the biosorbent was investigated as a function of contact time between adsorbent and zinc, the initial metals and sorbent concentration, pH value, and temperature. The ability of Arthrospira biomass for zinc biosorption exhibited a maximum at the pH range 4-8. Equilibrium data fitted well with the Langmuir model as well as the Freundlich model with maximum adsorption capacity of 7.1 mg/g. The pseudo second-order model was found to correlate well with the experimental data. Different thermodynamic parameters, ΔG°, ΔH° and ΔS° were evaluated and it has been found that the sorption was feasible, spontaneous, and endothermic in nature. The process of zinc removal from industrial effluent was studied at different time of sorbat-sorbent interaction and different sorbent dosage. Maximum zinc removal (83%) was obtained at sorbent concentration 60 g/L during 1-h experiment. The results indicate that Arthrospira platensis biomass could be effectively used for zinc removal from industrial effluents.
Keywords: arthrospira platensis; biosorption; industrial effluent; zinc.