High-efficient nanoemulsions separation by surface manipulation of sands

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Oil-in-water (O/W) nanoemulsions are widely used but pose environmental risks upon release.
• Their stability due to nanoscale droplets and interfacial films makes separation challenging.
• Economical and efficient nanoemulsion removal methods are needed as alternatives to traditional techniques.

Purpose of the Study:

• To develop a cost-effective and high-flux method for nanoemulsion separation.
• To investigate the efficacy of a novel sand filtration system integrating specialized sands.

Main Methods:

• A sand filtration system was designed using oleophilic and oleophobic sands.
• Oleophilic sands were treated with hydrophobic silane and given a rough surface for oil absorption.
• Oleophobic sands utilized a hydration layer for anti-oil adhesion and water permeation.

Main Results:

• The mixed rough sand filter (MRSF) achieved a separation flux over 2519 L.m⁻².h⁻¹ under gravity.
• Separation efficiency reached up to 98.7% for oil-in-water nanoemulsions.
• The synergistic properties of treated sands enabled efficient and rapid separation.

Conclusions:

• The developed sand filtration system provides a promising approach for high-flux and efficient nanoemulsion separation.
• This method offers a cost-effective and energy-saving alternative for environmental remediation.
• The integration of specifically treated sands is key to the system's performance.