Cr(VI) removal from contaminated waters using ultra-thin layered meixnerite

Area of Science:

• Environmental Science
• Materials Science
• Chemistry

Background:

• Hexavalent chromium (Cr(VI)) poses significant risks to public health and the environment due to its high toxicity.
• Effective and low-cost methods for Cr(VI) removal from aqueous solutions are crucial for environmental safety.

Purpose of the Study:

• To develop a novel, low-cost, and highly efficient material for aqueous Cr(VI) removal.
• To investigate the properties and performance of ultra-thin layered meixnerite (UTLM) for Cr(VI) remediation.
• To explore the mechanisms and temperature-dependent effectiveness of UTLM in Cr(VI) removal.

Main Methods:

• Preparation of ultra-thin layered meixnerite (UTLM) through a delamination process.
• Characterization of UTLM morphology using techniques like XRD and TEM (implied by thickness measurement).
• Sorption experiments to determine Cr(VI) removal capacity and analyze removal mechanisms (electrostatic attraction, anion exchange, inner-sphere complexation) using XPS.

Main Results:

• UTLM nanoparticles exhibited a thickness of approximately 7 nm, indicating successful delamination.
• UTLM demonstrated a significantly higher maximum sorption capacity for Cr(VI) (480.9 mg g⁻¹) compared to ordinary meixnerite (OM) (196.9 mg g⁻¹).
• Cr(VI) removal efficiency increased with temperature, with higher Cr-O bond formation observed at elevated temperatures (85 °C).

Conclusions:

• Ultra-thin layered meixnerite is a highly efficient adsorbent for aqueous Cr(VI) removal with low secondary pollution.
• The unique morphology of UTLM enhances dispersion and active sorption sites, leading to superior performance.
• UTLM shows great potential for treating industrial wastewaters, particularly those at elevated temperatures.