MnO₂-loaded microorganism-derived carbon for U(VI) adsorption from aqueous solution

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Uranium contamination in wastewater poses significant environmental and health risks.
• Effective and low-cost adsorbents are needed for uranium removal from radioactive effluents.

Purpose of the Study:

• To synthesize carbon/MnO2 composites (MMCs) using Saccharomyces cerevisiae as a precursor for U(VI) adsorption.
• To investigate the adsorption capacity, mechanism, and regeneration of MMCs for U(VI).

Main Methods:

• Synthesis of MMCs via oxidation-reduction and one-step carbonization of Saccharomyces cerevisiae.
• Characterization using scanning electron microscopy and nitrogen adsorption.
• Batch adsorption experiments to determine U(VI) adsorption capacity and kinetics.
• FTIR and X-ray photoelectron spectroscopy for mechanism elucidation.

Main Results:

• MMCs exhibited a porous structure with increased specific surface area after carbonization.
• Maximum U(VI) adsorption capacity reached 207 mg g⁻¹ at pH 4.5.
• Adsorption process was endothermic, spontaneous, and followed chemisorption kinetics.
• Surface hydroxyl groups were identified as key adsorption sites.
• Over 95% uranium desorption was achieved using 0.5 mol L⁻¹ HNO₃, with good material reusability.

Conclusions:

• Carbon/MnO2 composites derived from Saccharomyces cerevisiae are effective adsorbents for U(VI).
• MMCs demonstrate high adsorption capacity, favorable kinetics, and efficient regeneration.
• This study presents a sustainable and cost-effective approach for U(VI) removal from radioactive wastewater.