Ectodermis of paddle cactus (Opuntia spp.) as biosorbent of chromium (VI) from aqueous solutions

Abstract

The adsorption behaviour of chromium ( and/or ) from aqueous solutions on ectodermis of Opuntia in a batch system is presented. Modification of the biosorbent, contact time, concentration of chromium in solution and pH and temperature of the aqueous media were the studied parameters. Chromium anion uptake was higher at pH 2 for biosorbents treated with formaldehyde or HCl. The adsorption data were fitted to the Freundlich and Langmuir isotherms. The thermodynamic parameters Δ H ⁰, Δ G ⁰ and Δ S ⁰ were estimated and the obtained results showed that the adsorption reaction was endothermic and spontaneous for both biomaterials.

Keywords:

• chromium
• adsorption
• Opuntia
• biomaterial
• water pollution
• heavy metals

Acknowledgements

The authors acknowledge financial support from ININ and CONACyT (Project: 131174-Q). The authors are also grateful to the Technicians of the Chemistry Department for experimental support.