Simultaneous Nitrite Resourcing and Mercury Ion Removal Using MXene-Anchored Goethite Heterogeneous Fenton Composite.

Area of Science:

• Environmental Chemistry
• Materials Science
• Catalysis

Background:

• Simultaneous removal of SO2, NO, and Hg0 using gas-phase advanced oxidation and wet absorption is effective but generates challenging nitrite and mercury-rich wastewater.
• Existing methods struggle to produce harmless wastewater, necessitating innovative solutions for pollutant remediation.

Purpose of the Study:

• To fabricate and characterize a bifunctional β-FeOOH@MXene heterogeneous Fenton material for simultaneous nitrite and mercury removal.
• To investigate the material's performance, stability, and the underlying synergistic mechanisms for wastewater treatment.

Main Methods:

• Fabrication of β-FeOOH@MXene heterogeneous Fenton material.
• Characterization using X-ray diffraction, FTIR, SEM-EDS, and TEM.
• Performance evaluation for nitrite oxidation and Hg2+ removal, including cyclic stability tests.
• Radical identification via Electron Spin Resonance (ESR) and mechanistic studies using DFT, XPS, and Raman spectroscopy.

Main Results:

• Achieved 99.5% nitrite oxidation and 99.7% Hg2+ removal with excellent stability over 13 cycles.
• Demonstrated superior Hg2+ adsorption capacity (395 mg/g) and minimal Fe leaching (<0.018 wt%).
• Identified synergistic effects between MXene and β-FeOOH, including enhanced Fenton reaction and inhibited Fe leaching.
• Determined HO• as the primary radical for nitrite oxidation and elucidated the Hg2+ removal pathway.

Conclusions:

• The β-FeOOH@MXene material effectively treats nitrite and mercury-containing wastewater, offering a novel strategy for harmless wastewater resource utilization.
• The synergistic interaction between MXene and β-FeOOH enhances catalytic activity and material stability, paving the way for advanced environmental remediation technologies.