Biosorption of copper ions onto wheat straw | Biosorpcija jona bakra korišćenjem pšenične slame kao adsorbensa
2011
Gorgievski, M., Institut za rudarstvo i metalurgiju, Bor (Serbia) | Božić, D., Institut za rudarstvo i metalurgiju, Bor (Serbia) | Stanković, V., Tehnicki fakultet u Boru, Bor (Serbia) | Trujić, V., Institut za rudarstvo i metalurgiju, Bor (Serbia)
The paper presents the results of the adsorption of copper ions from synthetic solutions onto wheat straw used as an adsorbent in this study. Physical and chemical characterization of the wheat straw was performed in order to estimate their adsorption abilities, as: total oxygen demand (TOD), which was determined volumetrically by means of KMnO4 solution. The consumption of oxygen was 18 mg/L. Besides the TOD, the total cation exchange capacity (CEC) of wheat straw, (the ability of the adsorbent to exchange alkali and alkaline earth metals in the reaction with NH4Cl), was also determined. The determined total CEC was 1.86 mmol Mez+/g wheat straw. Here, Mez+ denotes exchanged alkali and alkaline earth metal ions. The content of alkali and alkaline earth metals, before and after rinsing of wheat straw with water and after saturation with copper was presented, too. The change in the initial pH value as well as the adsorption kinetics of copper ions were both investigated and considered. The adsorption of copper ions onto wheat straw was found to be a fast process. The equilibrium was reached for less than 40 minutes. Kinetic studies indicated that copper adsorption followed the pseudo-second order model. The maximum adsorption capacity was 5 mg/g. Adsorption isotherms showed that the adsorption equilibrium follows Langmuir adsorption model. The adsorption of copper ions on the wheat straw occurs via an ion exchange mechanism, where copper ions are exchanged with both calcium and hydrogen atoms from the wheat straw molecular structure. The results show that wheat straw could be used as a cheap, natural adsorbent for the adsorption of copper ions from industrial effluents.
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