Adsorption of Pb (II) Ions from Aqueous Solution by Citric Acid Modified and Unmodified Cucumeropsis manii (Melon) Pod Husks


  • J. I. Opurum
  • G .A. Cookey
  • C. C. Obunwo


In this study, the biosorption of Pb(II) ion was studied in a batch sorption  method using 1.0M citric acid modified (CA-CM) and unmodified (UCM) Cucumeropsis manii  pod husk as low cost adsorbent. The influence of different parameters such as pH of the solution, initial concentration of metal ion and contact time was observed. The optimum pH was 6. The percentage removal of Pb(II) ion increased with increase in initial concentration of the metal ions. For the effect of contact time, the CA-CM adsorbent removed higher percentage (97%) of Pb (II) ion than the UCM adsorbent (77%) within an interval of 10 mins. Langmuir isotherm fitted the adsorption data better than Freundlich and Dubinin-Radushkevsich adsorption models and suggests physisorption. The adsorption capacity values determined from the three isotherm modelled were higher for the CA-CM than the UCM adsorbent. The result obtained show that the citric acid modified melon pod husk biomass is a good adsorbent for Pb(II) ion in aqueous solution.