Abstract
In the present study ion exchange of Pb2+, Cu2+, Fe3+ and Cr3+ on natural clinoptilolite is examined at 27±1°C and initial concentration of 10meq/dm3. Equilibrium is favorable for Pb2+, unfavorable for Cu2+ and sigmoid for Cr3+ and Fe3+. Selectivity series deduced from equilibrium isotherms is Pb2+>Cr3+>Fe3+>Cu2+, while when maximum exchange levels (MELs) are considered, selectivity series is Pb2+>Cr3+≅Cu2+≥Fe3+. Cu2+ manifests the higher value of diffusion coefficient in the clinoptilolite particles among the metals studied, equal to 1.40×10-9cm2/s. According to the fixed bed experiments the upflow rate (5-15 Bed Volumes (BV)) is influencing the breakthrough point for all metals studied. The breakthrough point varies between 12.3BV for Pb2+ and 1.18 for Cu2+. Flow rate is also influencing the operating capacity, giving values between 0.433meq/gclinoptilolite for Pb2+ and 0.053 for Fe3+. Breakthrough point values confirm the selectivity order deduced from the equilibrium isotherms, while operating capacity values confirm the selectivity order deduced from MEL experiments.
Original language | English |
---|---|
Pages (from-to) | 2784-2792 |
Number of pages | 9 |
Journal | Water Research |
Volume | 36 |
Issue number | 11 |
DOIs | |
Publication status | Published - 2002 |
Keywords
- Clinoptilolite
- Fixed beds
- Heavy metals
- Ion exchange
ASJC Scopus subject areas
- Ecological Modelling
- Water Science and Technology
- Waste Management and Disposal
- Pollution