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Column-mode fluoride removal from aqueous solution by magnesia-loaded fly ash cenospheres
1State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, China.
Environmental Technology
|August 4, 2012
Summary
Magnesia-loaded fly ash cenospheres effectively remove fluoride in fixed-bed reactors. Optimal performance is achieved with larger adsorbent masses and higher flow velocities for efficient fluoride adsorption.
Area of Science:
- Environmental Science
- Water Treatment Engineering
- Materials Science
Background:
- Fluoride contamination in water poses significant health risks.
- Developing efficient and cost-effective adsorbents for fluoride removal is crucial.
- Fly ash cenospheres offer a potential low-cost adsorbent material.
Purpose of the Study:
- To investigate the performance of magnesia-loaded fly ash cenospheres (MLC) for fluoride removal in a fixed-bed reactor.
- To evaluate the impact of operational parameters on fluoride adsorption efficiency.
- To assess the regeneration potential of the adsorbent.
Main Methods:
- Column experiments were conducted using a fixed-bed reactor packed with MLC.
- Adsorbent mass, flow velocity, influent concentration, and coexisting anions were varied.
- Bohart and Adams and Thomas models were applied to analyze breakthrough data.
- Regeneration was performed using 0.2 M NaOH.
Main Results:
- Breakthrough time and capacity increased with adsorbent mass and flow velocity.
- Higher influent fluoride concentrations decreased breakthrough and exhaustion times.
- Coexisting anions, particularly phosphate, significantly reduced adsorption capacity.
- Adsorption was found to be reversible with effective regeneration using NaOH.
Conclusions:
- MLC is a promising adsorbent for fluoride removal from water.
- Optimizing adsorbent mass and flow velocity enhances column performance.
- Coexisting anions necessitate careful consideration in real-world applications.
- The reversible nature of adsorption allows for adsorbent regeneration and reuse.
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