Quantification of Zeolite phases

Zeolites are commonly used in a vast variety of industrial applications, including environmental clean-up, petroleum cracking, filtering/separations and cation exchange. These materials can be mined from natural sources or can be commercially synthesized. A basic structure of five silicon and aluminum tetrahedra result in a cage-like structure with large open spaces or "pores". These pores have charged regions which attract or exchange cations. For effective activity and specific cation incorporation, the zeolites need to be very specific and pure. X-ray diffraction is the preferred method for impurity identification (phase identification) and quantification.


Figure 1: Diffraction pattern from the MiniFlex shows two samples of zeolites: S7
5 and S79. Red lines indicate the presence of sodalite phase and the blue lines indicate the presence of a LTA zeolite type.

Generally for RIR, the entire pattern does not need to be integrated or profile fit, only the region containing the strongest intensity peaks from all phases. Profile fitting provides area information, both of individual peaks and the entire pattern. After profile fitting, the peak areas are assigned to the individual phases present by color. Easy Quant, the RIR quantitative feature in MDI's Jade software, uses the peak area information along with the phase identification to calculate the weight percents of each identified phase.


Figure 2: Results of Relative Intensity Ratio method (RIR) quantification of sample S75 from diffraction pattern. Pie chart indicates 3.5 weight percent of sodalite phase.


Figure 3: Results of RIR method quantification of sample S79 from diffraction pattern. Pie chart indicates 1.6 weight percent of sodalite phase.

New sixth generation MiniFlex X-ray diffractometer (XRD) is a multipurpose analytical instrument that can determine: phase identification and quantification, percent (%) crystallinity, crystallite size and strain, lattice parameter refinement, Rietveld refinement, and molecular structure. It is widely used in research, especially in material science and chemistry, as well as in industry for research and quality control. It is the newest addition to MiniFlex series of benchtop X-ray diffraction analyzers from Rigaku, which began with the introduction of the original MiniFlex system decades ago. Read more...

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