Adsorption and Recovery Studies of Cadmium and Lead Ions Using Biowaste Adsorbents from Aqueous Solution
The use of low-cost biowaste adsorbents for the removal of toxic metal ions from aqueous solutions offers significant environmental benefits. This research evaluated the adsorption and recovery of Cd<sup>2+</sup> and Pb<sup>2+</sup> ions in batch and column modes with luffa p...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Separations |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2297-8739/12/1/16 |
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| Summary: | The use of low-cost biowaste adsorbents for the removal of toxic metal ions from aqueous solutions offers significant environmental benefits. This research evaluated the adsorption and recovery of Cd<sup>2+</sup> and Pb<sup>2+</sup> ions in batch and column modes with luffa peels and chamomile flowers. The biosorbents were treated with 0.4 M nitric acid or with 0.4 M NaOH base. An FTIR analysis of the sorbents indicated that surface OH, C=O, CO and COO groups played a role in the adsorption process. L-type isotherms were obtained for Pb<sup>2+</sup>, fitting both the Langmuir and Freundlich models, with maximum adsorption capacities of 34.0 mg/g for luffa peels and 49.5 mg/g for chamomile flowers. Adsorption isotherms for Cd<sup>2+</sup> ion fit better with the Freundlich model with smaller adsorption capacity than Pb<sup>2+</sup>. Base-treated sorbents have higher adsorption capacity. The adsorption kinetic for both ions are fast and followed a pseudo-second order chemosorption model. Fixed-bed column dynamic adsorption with luffa peels obtained a Thomas dynamic adsorption capacity of 32.9 mg/g for Pb<sup>2+</sup> and 25.8 mg/g for Cd<sup>2+</sup>. The recovery efficiency was 87 to 90% over three adsorption–regeneration cycles. |
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| ISSN: | 2297-8739 |