Nanoparticles | Uses for Supercritical Fluids

The use of nanoparticles in all areas is ever increasing. While the existence of nanoparticles is not new, using Supercritical Fluids (SCF) to create them is.

Using Supercritical Fluids

 

The use of Supercritical Fluids to make particles eliminates the shortcomings of traditional methods. There are number of SCF techniques to produce particles of controlled size and morphology for organic molecules in the sub micron range:

 

RESS-Rapid Expansion of a Supercritical Solution

With RESS, material is dissolved in the SCF and then depressurized though a nozzle.

 

GAS- Gas Anti-Solvent

Here the compound is dissolved in an organic solvent, a supercritical fluid is introduced, expanding the volume and lowering the solvents solvent strength causing the compound to precipitate under controlled conditions of particle formation.

 

PCA- Precipitation by Compressed Fluid Anti-Solvent

With PCA, the compound dissolved in an organic solvent is sprayed into a SCF, casuing supersaturation and solute precipitation.

 

SEDS -Solution Enhanced Dispersion of Supercritical Fluids

Using SEDS, the compound is dissolved in an aqueous solution and the simultaneously sprayed through a coaxial nozzle with an organic solvent into the supercritical fluid. The water is dissolved into the solvent and SCF causing supersaturation and precipitation.

 

Nanoparticles of inorganic compounds can also be produced using supercritical fluids and sub-critical fluids. Thermal decomposition and hydrothermal syntheses are but two ways to accomplish this.

 

Applied Separations can provide you with the means to make both organic and inorganic particles.

Traditional means

 

Traditional means of making specifically sized material involves several techniques. These include:

  • Milling
  • Grinding
  • Crushing

 

Unfortunately, each of these traditional techniques has problems such as thermal and chemical degradation. Crystallization by adjusting supersaturation, using anti-solvents, or employing reactions and precipitations also have shortcomings:

  • Product contamination
  • High energy requirements
  • Waste solvents
  • Low yields
  • Non-uniform particles

RESS collector mounted on Helix system

Which Supercritical System is Right for My Application?

You've got your method down and it's time to start production.

When you're ready to go, and need a mid-sized system to make it happen.

You have small amounts to process, or you need to perfect your method.

Applied Separations, Inc.     930 Hamilton St., Allentown, PA 18101     610-770-0900