Nanobubble Formation by Flow Regime Switching Using a Tesla Valve

Area of Science:

• Materials Science
• Fluid Dynamics
• Nanotechnology

Background:

• Nanobubbles (NBs) are gas cavities in solution with diameters around 200 nm, exhibiting unique properties for diverse applications.
• Current laboratory-scale methods for NB generation include ultrasonication and pressure cycling, each with limitations.

Purpose of the Study:

• To introduce and evaluate a novel, cost-effective method for nanobubble generation using flow regime cycling through a Tesla valve.
• To compare the performance of the Tesla valve method with existing techniques (ultrasonication, pressure cycling) in terms of bubble characteristics.

Main Methods:

• Nanobubbles were generated using CO2 or N2 via flow regime switching through a Tesla valve, ultrasonication, and pressure cycling.
• Bubble diameter was measured using Nanoparticle Tracking Analysis (NTA).
• Bubble concentration and zeta potential were also quantified for comparative analysis.

Main Results:

• The Tesla valve method produced CO2 nanobubbles with an average diameter of 110 nm, comparable to sonication.
• Bubble concentration for the Tesla valve method was 3.8 × 10^8 bubbles/mL, higher than sonication but lower than pressure cycling.
• Zeta potential was measured at -33 mV, indicating favorable surface charge characteristics.

Conclusions:

• Flow cycling through a Tesla valve is an effective method for generating nanobubbles in the 100-200 nm range.
• This technique demonstrates favorable comparison to alternative laboratory methods, with potential for low energy consumption and scalability.
• The Tesla valve method presents a promising alternative for cost-effective and scalable nanobubble production.