IJSRP, Volume 5, Issue 9, September 2015 Edition [ISSN 2250-3153]
Shifare Berhe, Dejene Ayele, Abi Tadesse, Abrha Mulu
This study was carried out to investigate the efficiency of Ethiopian coffee husk (husk of coffee Arabica) to adsorb Pb(II) from industrial effluents using batch experiment. During the batch experiment effects of some parameters such as pH, dose of coffee husk, contact time, initial concentration(Pb(II)), and agitation speed were evaluated and the results indicate that optimum condition for Pb (II) adsorption were pH, 5; contact time, 90 minutes; dose of coffee husk, 2 g; initial concentration, 50 mg/L and agitation speed, 200 rpm. The coffee husk yielded a maximum adsorption efficiency of 95.14%. The residual metallic ion concentrations were determined using Atomic Absorption Spectrometer (AAS). Surface properties of the adsorbent were studied using Fourier Transform Infra-red (FTIR) spectrometer. The linear form of langmuire and Freudlich models were applied to represent adsorption data. The calculated equilibrium data of Pb(II) were well fitted to both Langmuir and Freudlich isotherm models with maximum adsorption capacity (qmax ) of 50 mg/g. Two kinetic models were used to determine the adsorption mechanism and the kinetic data were correlated (R2 =0.99) well with the pseudo second order kinetic model for the adsorption study of Pb(II) which implies that adsorption follows second order kinetics. To evaluate the practical applicability of the coffee husk, adsorption study was also carried out using real samples collected from waste water generated auto-garage and battery charging workshop.