Interfacial interactions between plastic particles in plastics flotation.

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Plastic waste recycling is crucial, with flotation emerging as a key industrial technology.
• Understanding interfacial interactions is vital for optimizing plastic flotation efficiency.

Purpose of the Study:

• To investigate the interfacial interactions governing plastic particle behavior in flotation systems.
• To elucidate the role of van der Waals forces and Lewis acid-base interactions.
• To analyze the impact of wetting agents on plastic particle dispersion and floatability.

Main Methods:

• Calculated Lifshitz-van der Waals (LW) and Lewis acid-base (AB) Gibbs functions.
• Utilized extended Derjaguin-Landau-Verwey-Overbeek (DLVO) potential energy profiles.
• Examined the relationship between hydrophobic attraction and surface properties.

Main Results:

• Van der Waals forces contribute to attraction between plastic particles.
• Hydrophobic attraction, driven by AB Gibbs function, is the dominant interparticle force.
• Wetting agent adsorption enhances particle dispersion and reduces floatability.
• A three-order polynomial relationship was found between AB Gibbs function and Lewis base component.

Conclusions:

• Hydrophobic attraction is the primary mechanism in plastic flotation.
• Wetting agents negatively impact floatability by promoting dispersion.
• Pneumatic flotation offers potential for improved plastic recovery and purity via selective wetting agent adsorption.