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More on Characterization. Qualitative size distribution dynamics Particle chemistry Particle chemical characterization. Size distributions may change over time. Starter size distribution: . Processes in which volume is conserved. Coagulation, communition or breakup, restructuring .

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More on characterization
More on Characterization

  • Qualitative size distribution dynamics

  • Particle chemistry

  • Particle chemical characterization


Size distributions may change over time
Size distributions may change over time

Starter size distribution:


Processes in which volume is conserved

Coagulation, communition or breakup, restructuring


Processes in which volume not conserved

Condensation, evaporation, nucleation, sedimentation,



Chemical composition not always same

  • Varying degrees of chemical homogenaity in particle mixtures

  • Particles all of one chemical species (ie salt granules) – chemically homogeneous

  • Particles are all of one chemical species, but the particles are mixed – externally mixed

  • Particles are of two or more chemical components, but composition of each particle is same – internally mixed

  • Individual particles have different compositions


Chemical composition may vary with size

Pharmaceutical powders for inhalation - want small drug particles mixed with and loosely bound to larger inert particles

Emissions from incinerators – some high volatility compounds evaporate in high temperature zone and nucleate downstream forming ultrafine high surface area particles

More examples


How to measure chemical composition?

Many techniques – survey of analytical chemistry

Some need large sample of material, so need to take average over whole size distribution, and/or time

Some need extremely small amounts of material so representative sampling is crucial

Some can tell you composition on-line or nearly on-line

Some require off-line analysis


SADK – secret acronym decoder kit

  • Atomic absorption spectroscopy (AAS)

  • Inductively coupled plasma- atomic emission spectroscopy (ICP-AES)

  • Laser induced breakdown spectrometry (LIBS)

  • Time of Flight Mass spectrometry of aerosols (TOF-MS)

  • X-ray Fluorescence (XRF)

  • Proton Induced X-Ray Emission (PIXE)

  • Neutron activation analysis (NAA)

  • X-ray photoelectron spectroscopy (XPS)

  • Auger spectroscopy

  • X-ray diffraction (XRD)

  • Energy dispersive X-ray spectroscopy (EDX or EDS)

  • Electron energy loss spectrometry (EELS)



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