New Carbamoyl Surface-Modified ZrO₂ Nanohybrids for Selective Au Extraction from E-Waste

Area of Science:

• Materials Science
• Nanotechnology
• Environmental Chemistry

Background:

• Precious and critical metal ion extraction is crucial for resource management and recycling.
• Zirconia nanoparticles offer a versatile platform for surface modification.
• Developing efficient and selective adsorbents is key for sustainable metal recovery.

Purpose of the Study:

• To investigate the efficient and selective extraction of precious metal ions (Au(III), Pd(II)) using zirconia nanoparticles.
• To explore the impact of different organic carbamoyl phosphonic acid ligands on adsorption efficiency.
• To evaluate the stability, reusability, and adsorption characteristics of modified zirconia for gold recovery.

Main Methods:

• Surface modification of commercial zirconia nanoparticles (ZrO2) with mono- and di-carbamoyl phosphonic acid ligands.
• Characterization of modified nanoparticles using TGA, BET, ATR-FTIR, and 31P-NMR.
• Batch adsorption experiments to assess metal ion extraction efficiency, selectivity, and adsorption kinetics/thermodynamics.

Main Results:

• Di-carbamoyl phosphonic acid ligands demonstrated higher adsorption efficiency compared to mono-carbamoyl ligands.
• Increased ligand hydrophobicity correlated with improved adsorption performance.
• The ZrO2 modified with di-N,N-butyl carbamoyl pentyl phosphonic acid ligand (ZrO2-Lb) showed excellent stability, efficiency, and reusability for gold recovery.
• Adsorption of Au(III) by ZrO2-Lb followed the Langmuir model with a maximum capacity of 6.4 mg/g.

Conclusions:

• Surface modification of zirconia nanoparticles with specific carbamoyl phosphonic acid ligands is an effective strategy for precious metal extraction.
• Di-carbamoyl ligands with higher hydrophobicity are superior for adsorbing metal ions like gold.
• The developed ZrO2-Lb system exhibits significant potential for industrial applications in selective gold recovery and recycling.