Highly Efficient Adsorption of Pb(II) by Magnesium-Modified Zeolite: Performance and Mechanisms

Area of Science:

• Materials Science
• Environmental Chemistry
• Chemical Engineering

Background:

• Lead (Pb(II)) contamination in water poses significant environmental and health risks.
• Conventional water treatment methods for lead removal can be inefficient or costly.
• Natural zeolites, like clinoptilolite, are abundant but often require modification for enhanced contaminant adsorption.

Purpose of the Study:

• To synthesize and characterize magnesium-modified clinoptilolite (MZ) for efficient Pb(II) removal.
• To investigate the adsorption kinetics, isotherms, and mechanisms of Pb(II) onto MZ.
• To evaluate the stability and performance of MZ under various conditions relevant to water treatment.

Main Methods:

• Synthesis of MZ via precipitation and calcination.
• Characterization using BET, XRD, SEM-EDX, FT-IR, and XPS.
• Adsorption experiments to determine kinetics, isotherms, and effect of pH and competing ions.

Main Results:

• MZ exhibited pseudo-second-order kinetics (R² = 0.9956) and Langmuir isotherm behavior (R² = 0.9686).
• Achieved a high maximum adsorption capacity (q_m) of 1656 mg/g for Pb(II).
• Demonstrated stable performance across pH 3.0-5.5 and in the presence of high salt concentrations.

Conclusions:

• Magnesium modification transforms clinoptilolite into a highly efficient adsorbent for Pb(II).
• The primary removal mechanism involves surface complexation and chemical conversion of Pb(II).
• MZ presents a promising, stable, and high-capacity material for treating lead-contaminated water.