A Novel Fluidized Bed Technique for Measuring UV Raman Spectra of Catalysts and Adsorbates

Fluidised bed characterisation using Raman spectroscopy: Applications to pharmaceutical processing

“…Surprisingly little work has been carried out on Raman probing of fluidised beds, the only previous studies had no control of the sampling volumes and recorded data from at a single fixed position which it was assumed would give representative data for the entire sample (Hausman et al, 2005a,b;Chua and Stair, 2000). Here we show an important new use of the technique which allows in situ measurement of the composition of the material within the fluidised bed in three spatial dimensions and as a function of time.…”

Mechanistic and Adsorption Studies of Relevance to Photocatalysts on Titanium Grafted Mesoporous Silicalites

“…The 5 mW doubled output of the laser passed through the quartz window of a fluidized bed reaction cell and irradiated the sample which rested on a quartz frit. The fluidized bed minimizes heating and possible effects due to absorption of multiple photons and allowed us to monitor the initial adsorption of the reactants [26][27][28]. Raman and Rayleigh scattered light was collected using an ellipsoidal mirror focused onto a fiber bundle coupled to a Spex Triax 550 single grating spectrometer with a UV-enhanced CCD detector.…”

Influence of absorption on quantitative analysis in Raman spectroscopy

“…Gas flow and mechanical vibration were adjusted to produce stirring of the catalyst powder without lifting the powder bed off the porous disk. Detailed information on the measurement is provided in previous papers [23,28]. The Raman spectra of V/d-Al 2 O 3 were normalized to the same integration time of 5500 s. All Raman spectra were collected using a laser power of 2 mW at the sample position.…”

“…An integration time of 15 s with two accumulations was used for the measurements of liquid samples. The Raman spectra of dehydrated V/d-Al 2 O 3 were measured in a fluidized bed reactor on the UV Raman instrument described previously [23,25,27,28]. The V/Al 2 O 3 samples were heated in the fluidized bed reactor in flowing 5% O 2 /N 2 (60 ml/min) at 823 K for 2 h to remove adsorbed moisture.…”