Manganese-Functionalized Bentonite for Efficient Cadmium Ion Removal from Aqueous Systems
Silvia Dolinská1, Ingrid Znamenáčková1, Věra Valovičová2
1Institute of Geotechnics of the Slovak Academy of Sciences, 040 01 Košice, Slovakia.
Materials (Basel, Switzerland)
|June 12, 2026
Summary
Manganese oxide modification significantly enhances bentonite
Area of Science:
- Materials Science
- Environmental Science
- Geochemistry
Background:
- Bentonite's sorption properties are influenced by mineral phases and chemical modifications.
- Manganese oxides are known for their affinity towards heavy metal cations.
Purpose of the Study:
- To investigate the impact of manganese oxides and quartz sand on bentonite's sorption properties.
- To characterize the surface chemistry of modified bentonite using X-ray photoelectron spectroscopy (XPS).
Main Methods:
- Systematic investigation of bentonite from Stará Kremnička.
- Surface characterization using X-ray photoelectron spectroscopy (XPS), X-ray diffraction, FTIR spectroscopy, and zeta potential measurements.
- Analysis of manganese oxidation states and surface functional groups.
Main Results:
- Manganese was predominantly in the Mn(IV) oxidation state (MnO2-type phases).
- Modified bentonite showed increased adsorption capacity: BMn (103.09 mg/g) and MMn (116.28 mg/g) compared to natural bentonite (63.29 mg/g).
- Sorption is governed by ion exchange and Mn oxide surface interactions.
Conclusions:
- Manganese oxide modification enhances bentonite's heavy metal adsorption capacity.
- Surface chemical states, particularly Mn(IV) species, are crucial for efficient metal binding.
- Modified bentonites show promise as effective sorbents for environmental remediation.
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