Biosorbents for Removing Hazardous Metals and Metalloids

Area of Science:

• Environmental Science
• Materials Science
• Green Chemistry

Background:

• Aquatic environments are increasingly polluted with hazardous heavy metals and metalloids.
• Effective and economical remediation strategies are crucial for environmental protection.
• Waste valorization offers a sustainable approach to developing novel sorbent materials.

Purpose of the Study:

• To develop low-cost biosorbents from various waste materials for heavy metal and metalloid remediation.
• To investigate the efficacy of these biosorbents in removing specific pollutants like Pb(II), Cr(VI), Sb(III/V), and As(III/V).
• To explore simple and accessible preparation methods for creating functional biosorbents.

Main Methods:

• Preparation of lignophenol and lignosulfonate gels from lignin waste.
• Conversion of pectin-rich fruit residues (orange, apple) into biosorbents using alkali treatment.
• Development of biosorbents from seaweed (alginic acid-rich) and fruit wastes (persimmon, grape).
• Preloading of biosorbents with multi-valent metal ions (Zr(IV), Fe(III)) for enhanced metalloid removal.
• Treatment of specific wastes with concentrated sulfuric acid for Cr(VI) removal.

Main Results:

• Lignocatechol and lignosulfonate gels effectively removed lead (Pb(II)).
• Pectic acid-rich residues efficiently removed Pb(II) after alkali treatment.
• Biosorbents effectively removed antimony (Sb(III/V)) and arsenic (As(III/V)) when preloaded with Zr(IV) or Fe(III).
• Seaweed-derived biosorbents showed efficacy in removing target pollutants.
• Persimmon and grape waste treated with sulfuric acid effectively removed hexavalent chromium (Cr(VI)).

Conclusions:

• Agricultural and industrial wastes can be transformed into effective, low-cost biosorbents for heavy metal and metalloid remediation.
• Simple and accessible preparation methods enable the production of functional biosorbents from diverse waste streams.
• These findings highlight the potential of waste valorization for developing sustainable solutions to aquatic pollution.