Single and binary biosorption of Cu(II), Ni(II) and methylene blue by raw and pretreated Spirogyra sp.: Equilibrium and kinetic modeling

The raw and pretreated Spirogyra sp. were used for the single and binary removal of Cu(II), Ni(II) and methylene blue (MB) from aqueous solution. The effects of pH, contact time, initial pollutant concentration, biosorbent dosage and ionic strength (NaCl) on removal efficiency were investigated. The biosorption capacity of Cu(II), Ni(II) and MB onto raw and pretreated Spirogyra sp. was found as the following order: MB > Cu > Ni and Ni > MB > Cu. The pseudo-first order, pseudo-second order and the intraparticle diffusion models were applied to the experimental data. The thermodynamic parameters (ΔH, ΔS, ΔG) were calculated. Desorption studies was also done. The structural characteristics of biosorbent were determined through FT-IR spectrums and SEM images. Also, binary biosorption studies showed that removal efficiency of dominant pollutant reduced by the presence of the other ion in aqueous solution.