Urea-functionalized HKUST-1 metal-organic framework for high-performance lead adsorption.

Area of Science:

• Materials Science
• Environmental Chemistry
• Nanotechnology

Background:

• Heavy metal contamination, especially lead (Pb²⁺), presents significant environmental and health hazards.
• Effective water remediation strategies are crucial for mitigating these risks.

Purpose of the Study:

• To synthesize and compare pristine HKUST-1 and urea-functionalized HKUST-1 (HKUST-1@Urea) for Pb²⁺ removal.
• To investigate the structural, adsorption, and thermodynamic properties of HKUST-1@Urea for lead remediation.

Main Methods:

• Synthesis of pristine HKUST-1 and HKUST-1@Urea.
• Characterization using XRD, FT-IR, and SEM.
• Pb²⁺ adsorption experiments, isotherm and kinetic modeling, and thermodynamic analysis.

Main Results:

• HKUST-1@Urea exhibited enhanced hydrophilicity and increased adsorption sites due to urea functionalization.
• HKUST-1@Urea achieved 98% Pb²⁺ removal in 45 min with a capacity of 400 mg g^-1.
• Adsorption followed pseudo-second-order kinetics and Langmuir isotherm, indicating spontaneous, endothermic, and physisorption-driven processes.

Conclusions:

• HKUST-1@Urea is a highly efficient, stable, and reusable adsorbent for lead removal from aqueous solutions.
• Post-synthetic urea modification significantly enhances the performance of HKUST-1 for water purification.
• HKUST-1@Urea presents a cost-effective and sustainable option for heavy metal remediation.