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Updated: Jan 23, 2026
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A Scalable Balz-Schiemann Reaction Protocol in a Continuous Flow Reactor
Published on: February 10, 2023
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Selenium removal by activated alumina in batch and continuous-flow reactors
Yuxia Ji1, Lin Li2, Yi-Tin Wang1
1Department of Civil Engineering, University of Kentucky, Lexington, Kentucky.
Summary
Activated alumina effectively removes selenium species, with higher capacity for selenite (Se(IV)) than selenate (Se(VI)). This material shows promise for selenium remediation in water treatment, especially in continuous-flow systems.
Area of Science:
- Environmental Science
- Water Treatment Technologies
- Adsorption Processes
Background:
- Selenium contamination in water poses significant environmental and health risks.
- Activated alumina (AA) is a potential adsorbent for removing selenium species from aqueous solutions.
- Understanding the behavior of different selenium forms (Se(VI) and Se(IV)) is crucial for effective remediation.
Purpose of the Study:
- To investigate the efficiency of activated alumina (AA) for selenium removal in batch and continuous-flow systems.
- To compare the adsorption capacities of AA for selenate (Se(VI)) and selenite (Se(IV)).
- To evaluate the impact of bicarbonate on selenium adsorption and the performance of AA in a bioreactor.
Main Methods:
- Batch adsorption experiments to determine adsorption kinetics and isotherms.
- Continuous-flow reactor studies using AA and inoculated with Shigella fergusonii.
- Analysis of adsorption data using pseudo-first/second order and Langmuir/Freundlich models.
- Investigation of the effect of sodium bicarbonate on Se(VI) and Se(IV) adsorption.
Main Results:
- Adsorption kinetics followed pseudo-first and pseudo-second order models, with equilibrium times of 8 and 12 hours for Se(VI) and Se(IV), respectively.
- AA exhibited significantly higher adsorption capacity for Se(IV) compared to Se(VI).
- Se(VI) adsorption was inhibited by NaHCO3, whereas Se(IV) adsorption was unaffected.
- Continuous-flow bioreactors achieved substantial Se(VI) removal (70-74%) and insignificant Se(IV) effluent concentrations.
Conclusions:
- Activated alumina is effective for removing both Se(VI) and Se(IV) from water.
- AA demonstrates superior performance for Se(IV) removal and is less affected by common water constituents like bicarbonate.
- AA-packed bioreactors show promise for comprehensive selenium remediation, with potential for enhanced efficiency through optimized liquid retention time.
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