Removal of Chromium from Tannery Wastewater Using Modified Fish Scales as Adsorbent
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Date
2017-11
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Addis Ababa University
Abstract
Industrialization activities have brought many troublesome changes in the environment due to the disposal of huge amount of liquid and solid wastes. However, the presence of a heavy metal such as chromium in the industrial wastewater is a potential hazard to aquatic, animal, and human. Biosorption of heavy metal is an effective technology for the treatment of industrial wastewater because of its low cost and high metal binding capacity. This research study has been focused on the removal of specific metal ion chromium (III) using modified fish scales as sorbents. The collected sample (raw FS) was washed, crushed, chemically modified, and sieved to a range of particle size(125-200μm) and the biosorbent was characterized by FTIR spectroscopy and XRD analysis. A batch adsorption experiment was conducted using model pollutant of tannery wastewater. The adsorption efficiency of MFS was evaluated as the function of adsorbent dosage, pH and contact time and effects of those variables on biosorption efficiency were analyzed. The residual Cr(III) concentrations after biosorption were analyzed using AAS. The results illustrated that the maximum removal efficiency of Cr (III) ion by MFS is 99.7518 % at adsorbent dosage 0.8g, pH of the solution 5 and contact time 90 min, initial concentration 150mg/l chromium ion. The adsorption isotherms data fitted well with Langmuir isotherm model with R2= 0.9998, qmax= 18.3486mg/g, and RL= 0.00007325. Also, adsorption kinetics model was analyzed (pseudo-first-order and pseudo-second-order) for the description of adsorption of Cr (III) using MFS and Pseudo-Second-order model (R2=1) fitted well for adsorption kinetics.
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Keywords
Cr(III) biosorption, modified fish scales, Tanning industry, adsorption isotherm, kinetics model