Biosorption of Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II) using different residual biomass

Abstract

The sorption behaviour of a biomass sample collected in an irrigation pond has been investigated. The biomass sample was selected from several ones collected in different eutrophised habitats of the Community of Madrid (Spain). The selection was made based on its effectiveness in the recovery of heavy metals from aqueous solution. The biomass sample selected was mainly composed of several Chlorophyta algae species and deciduous plants, and was tested to evaluate its behaviour in the biosorption of Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II), metals commonly found in industrial effluents. Preliminary studies were started in monometallic systems to determine the optimum values of pH, biomass concentration and sorption kinetics. The quantification of the sorption process was accomplished with sorption isotherms by fitting the experimental data to two mathematical models. The Langmuir model gave the best fit. Copper and lead were adsorbed in higher proportions, followed by nickel and zinc and, finally, cadmium. The metals more easily adsorbed in monometallic systems were also preferentially adsorbed in bimetallic systems. FTIR and acid-base titration were the analytical techniques used to establish sorption mechanisms, and carboxylic groups were identified as the main functional groups involved in the process.

Keywords:

• biosorption
• heavy metals
• Langmuir
• Freundlich
• residual biomass

Acknowledgements

The authors wish to express their gratitude to the Spanish Ministry of Science and Technology for funding this work.