Lignin-intercalated WS₂ with synergistic adsorption for efficiency lead removal

Area of Science:

• Materials Science
• Environmental Science
• Nanotechnology

Background:

• Tungsten disulfide (WS₂) is a 2D material effective for removing lead ions (Pb²⁺) from water.
• WS₂ nanosheets tend to aggregate, reducing their adsorption efficiency.
• Current methods using synthetic polymers for dispersion lack inherent adsorption properties.

Purpose of the Study:

• To develop highly dispersible Lignin/WS₂ composites for synergistic lead ion adsorption.
• To enhance the adsorption efficiency of WS₂ through lignin intercalation.
• To explore a novel strategy for water remediation using bio-based adsorbents.

Main Methods:

• Intercalating lignin from walnut shells into bulk WS₂ to create Lignin/WS₂ composites.
• Utilizing lignin's steric hindrance and electrostatic repulsion for WS₂ exfoliation and dispersion stabilization.
• Investigating adsorption kinetics and isotherms to understand the adsorption mechanism.

Main Results:

• The Lignin/WS₂ composites exhibited significantly enhanced Pb²⁺ removal capacity (∼66.9 mg/g).
• This capacity was 1.7 times higher than pure lignin and 25.0 times higher than bulk WS₂.
• Adsorption followed pseudo-second-order kinetics and Freundlich isotherm models, indicating chemisorption.

Conclusions:

• Lignin intercalation effectively exfoliates and disperses WS₂ nanosheets, preventing aggregation.
• Synergistic adsorption by lignin and WS₂ offers superior Pb²⁺ removal efficiency.
• This work presents a promising, sustainable approach for heavy metal remediation in water.