PVC/EVA-based polymer inclusion membranes with improved stability and Cr(VI) extraction capacity: Water...

Area of Science:

• Materials Science
• Environmental Engineering
• Separation Science

Background:

• Polymer inclusion membranes (PIMs) are crucial for extracting heavy metals and organic compounds.
• Polyvinyl chloride (PVC) is a common base polymer for PIMs but requires expensive liquid plasticizers.
• Developing cost-effective and efficient plasticizers for PIMs is an ongoing research area.

Purpose of the Study:

• To investigate poly(ethylene-co-vinyl acetate) (EVA) as a polymer plasticizer for PVC-based PIMs.
• To optimize PIM composition for enhanced chromium(VI) extraction.
• To evaluate the physical-chemical properties and stability of the developed PIMs.

Main Methods:

• Elaboration of PIMs using PVC, EVA, and Aliquat 336.
• Optimization of PVC/EVA ratio and EVA vinyl acetate (VA) content.
• Characterization using SEM and tensile testing.
• Evaluation of PIM performance through Cr(VI) transport measurements.

Main Results:

• Miscible PVC/EVA blends were achieved, with EVA demonstrating a plasticizing effect.
• PIMs with EVA$_{40}$ showed higher Cr(VI) extraction efficiency and permeability compared to PVC-only PIMs.
• Optimized PIMs achieved a high Cr(VI) transport flux of 54.7 µmol·m⁻²·s⁻¹.
• Addition of tetradecanol further improved stability, allowing up to 24 cycles.

Conclusions:

• EVA, particularly EVA$_{40}$, effectively replaces conventional liquid plasticizers in PVC-based PIMs.
• EVA-based PIMs offer improved Cr(VI) extraction and enhanced stability.
• The developed PIMs show significant potential for efficient and stable heavy metal removal from aqueous solutions.