Multiwalled carbon nanotube deposition on model environmental surfaces

Area of Science:

• Environmental Science
• Materials Science
• Physical Chemistry

Background:

• Understanding nanoparticle deposition is crucial for environmental remediation and material science.
• Maltiwalled carbon nanotubes (MWNTs) are widely used in various applications, necessitating studies on their environmental behavior.
• Surface properties significantly influence nanoparticle-surface interactions.

Purpose of the Study:

• To investigate the deposition behavior of MWNTs on different model environmental surfaces.
• To elucidate the roles of electrostatic and hydrophobic interactions in MWNTs deposition.
• To explore the relationship between deposition kinetics and the nature of MWNTs-surface association.

Main Methods:

• Quartz crystal microbalance with dissipation monitoring (QCM-D) was employed to study MWNTs deposition.
• Model surfaces with varying surface charges (positive, negative, hydrophobic) were utilized.
• Solution ionic strength (IS) was systematically varied to assess its impact on deposition.

Main Results:

• MWNTs deposition on charged surfaces aligned with Derjaguin-Landau-Verwey-Overbeek (DLVO) theory.
• Hydrophobic interactions were dominant for MWNTs deposition on a hydrophobic polystyrene surface.
• Initial deposition rates (rf) and attachment efficiencies (αD) were dependent on IS and surface electrostatics.
• Deposition was insensitive to surface morphology at constant IS.
• The ratio of changes in dissipation to frequency (|ΔD/Δf|) varied, indicating different MWNTs-surface association characteristics.

Conclusions:

• Both DLVO theory and hydrophobic interactions govern MWNTs deposition on environmental surfaces.
• Surface charge and ionic strength are key factors controlling MWNTs deposition rates and efficiencies.
• While deposition kinetics can be similar, the nature of nanoparticle-surface association can differ significantly.