Application of alginate extraction residue for Al(III) ions biosorption: a complete batch system evaluation

Abstract

The residue derived from the alginate extraction from S. filipendula was applied for the biosorption of aluminum from aqueous medium. The adsorptive capacity of the residue (RES) was completely evaluated in batch mode. The effect of pH, contact time, initial concentration and temperature was assessed through kinetic, equilibrium and thermodynamic studies. The biosorbent was characterized prior and post-Al biosorption by N2 physisorption, Hg porosimetry, He picnometry and thermogravimetry analyses.Equilibrium was achieved in 60 minutes. Kinetics obeys pseudo-second order model at aluminum higher concentrations. Isotherms followed Freundlich model at low temperature (293.15 K) and D-R or Langmuir model at higher temperatures (303 and 313 K). Data modeling indicated the occurrence of both chemical and physical interactions in the aluminum adsorption mechanism using RES. The maximum adsorption capacity obtained was of 1.431 mmol/g at 293 K. The biosorption showed a spontaneous, favorable and exotherm character. A simplified batch design was performed, indicating that the residue is a viable biosorbent, achieving high percentages of removal using low biomass dosage.