May 2014 Vol. 1(2), pp. 009-016
Copyright © 2014 Transcontinental Publishers
Full Length Research Paper
Adsorptive Removal of Pb(II) and Cr(VI) from Wastewater using Acid Untreated Coffee Husk
Haftu G. Alemayehu, Abiyu K.Burkute and Asnake G.Ede*
Arba Minch University, College of Natural Sciences, Chemistry Department, P.O.Box 21
Accepted 08 May, 2014
This study reports the biosorption of Pb (II) and Cr(VI) on surface of cleaned, sundried and powdered but acid untreated normal coffee husk. The functional groups identified at the surface of the coffee husk were OH-, -COOH, and -NH. A contact time of 6 hours assured attainment of equilibrium for both metal ions. The maximum adsorption capacity of Pb (II) and Cr (VI) was 50.54 ± 0.63 and 49.21 ± 0.74 mg g-1, respectively. As the dose increased, removal efficiency increased with statistical significance (p<0.05). The optimum pH for Pb(II) and Cr(VI) removal was 5.5 ± 0.01 and 2.2 ±0.01, respectively. The optimum temperature for removal of Pb(II) and Cr (VI) was 27.5 ± 0.02ºC and 37.5 ± 0.2ºC, respectively. The experimental sorption equilibrium followed both Langmuir (R2=0.944) and Freundlich (R2=0.930) relatively more of Langmuir. The experimental data fitted pseudo first (R2=-0.930) and second (R2=0.955) order kinetic models, being relatively better described by the pseudo-second-order. The reaction was spontaneous as ∆Go (-5.63 kJ/mol).This showed coffee husks are suitable candidates for use as biosorbents in the removal of heavy metals from aqueous solutions.
Keywords: Biosorption, adsorption isotherms, coffee husks, kinetics model, spontaneous, optimum
Cite this Reference:
Alemayehu HG, Burkute AK, Ede AG (2014). Adsorptive Removal of Pb(II) and Cr(VI) from Wastewater using Acid Untreated Coffee Husk. Interlink Continental J. Environ. Sci. Toxicol. 1(2): 009-016.