International Journal of Chemical Studies
Vol. 5, Issue 4 (2017)
Isotherm studies on biosorption of some heavy metal ions from aqueous solution onto orchid Malabar (Piliostigma malabaricum) seed pod
Author(s): Amadi OK, Ekuma FK and Okwunodulu FU
Abstract: The adsorption of the following heavy metals; Cd(II), Co(II) and Cr(III) from aqueous solution using Orchid Malabar has been investigated with the aim of assessing the potential of the adsorbent in detoxifying industrial effluents before their safe disposal into land or water bodies. The study involves the application of different isotherm models to assess their suitability to the observed equilibrium adsorption data. Effect of pH on the adsorption process was investigated and results obtained show that the optimum pH for adsorption of the metal ions: Cr(lll), Co(ll) and Cd(ll) occurred at pHs 4.0, pH 7.0 and pH 4.0 respectively. The equilibrium experimental data were tested using five different isotherm models, namely; the Langmuir, Freundlich, Dubinin-Radushkevich, Harkins-Jura and Halsey isotherms. The correlation coefficients (R2 values) obtained from the five isotherm plots were used to assess their suitability to the experimental adsorption data. Results obtained from the isotherm plots show that Halsey and Freundlich isotherms provided best fits to the adsorption data. Comparison of the maximum amount of each of the metal ions adsorbed onto the adsorbent shows that Cr(III) and Cd(II) were better adsorbed onto the adsorbent than Co(II) ions. The trend of adsorption of the metal ions generally follows: Cr(III) > Cd(II) > Co(II). The results from this study indicate that the biosorbent could be employed as a low cost alternative for the removal of the studied metal ions from dilute aqueous solutions.
Pages: 161-167 | 760 Views 15 Downloads
How to cite this article:
Amadi OK, Ekuma FK, Okwunodulu FU. Isotherm studies on biosorption of some heavy metal ions from aqueous solution onto orchid Malabar (Piliostigma malabaricum) seed pod. Int J Chem Stud 2017;5(4):161-167.