Abstract
The adsorption of Cr(VI) from aqueous solution by Turkish vermiculite were investigated in terms of equilibrium, kinetics, and thermodynamics. Experimental parameters affecting the removal process such as pH of solution, adsorbent dosage, contact time, and temperature were studied. Equilibrium adsorption data were evaluated by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. Langmuir model fitted the equilibrium data better than the Freundlich model. The monolayer adsorption capacity of Turkish vermiculite for Cr(VI) was found to be 87.7mg/g at pH 1.5, 10g/L adsorbent dosage and 20C. The mean free energy of adsorption (5.9kJ/mol) obtained from the D-R isotherm indicated that the type of sorption was essentially physical. The calculated thermodynamic parameters (Go, Ho and So) showed that the removal of Cr(VI) ions from aqueous solution by the vermiculite was feasible, spontaneous and exothermic at 20-50C. Equilibrium data were also tested using the adsorption kinetic models and the results showed that the adsorption processes of Cr(VI) onto Turkish vermiculite followed well pseudo-second order kinetics.
| Original language | English |
|---|---|
| Pages (from-to) | 3563-3581 |
| Number of pages | 19 |
| Journal | Separation Science and Technology |
| Volume | 43 |
| Issue number | 13 |
| DOIs | |
| State | Published - Jan 2008 |
| Externally published | Yes |
Bibliographical note
Funding Information:The authors are grateful for the financial support of the Unit of the Scientific Research Projects of Gaziosmanpasa University. The authors also would like to thank Demirhan CITAK for his helps in experimental studies.
Keywords
- Adsorption
- Cr(VI)
- Kinetics
- Removal
- Thermodynamics
- Turkish vermiculite
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering
- Process Chemistry and Technology
- Filtration and Separation