Retention of toxic chromium from aqueous phase by H3PO4-activated lignin: Effect of salts and desorption studies

Ahmad B. Albadarin*, Ala'a H. Al-Muhtaseb, Gavin M. Walker, Stephen J. Allen, Mohammad N.M. Ahmad

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


In this study, the feasibility of using H3PO4-activated lignin for hexavalent chromium adsorption has been investigated. The composite of activated lignin was characterized using FTIR, XRD and SEM with EDAX analysis. It was observed that the pH had a strong effect on the adsorption capacity; adsorption of Cr(VI) was more favorable at acidic pH with maximum uptake at pH 2. The adsorption equilibrium data were best represented by Koble-Corrigan isotherm. The monolayer sorption capacity obtained from the Langmuir model was found to be 77.85mg/g. Adsorption showed pseudo-second order rate kinetics and the process involving the rate-controlling step is complex as it involves both film and intraparticle diffusion processes. The NaOH desorbing agent was able to release approximately 84% of metal ions. Thermodynamic parameters showed that the sorption process is exothermic and non-spontaneous. The overall Cr(VI) retention on the activated lignin surface perhaps includes both the physical adsorption of Cr(VI) and the consequent reduction of Cr(VI) to Cr(III).

Original languageEnglish
Pages (from-to)64-73
Number of pages10
Issue number1-3
Publication statusPublished - Jul 1 2011
Externally publishedYes


  • Activated lignin
  • Chromium (VI)
  • FTIR
  • Isotherm
  • Reduction
  • Thermodynamic parameters

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • General Materials Science
  • Water Science and Technology
  • Mechanical Engineering


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