In Situ FT-IR Analysis of a Composite Curing Reaction Using a Mid-Infrared Transmitting Optical Fiber

The use of a mid-infrared transmitting fiber to carry the infrared beam of an FT-IR spectrometer outside of the optical bench is reported. In addition it is demonstrated that it is possible to analyze samples using the fiber as an internal reflection element. The fiber is covered with a protective coating which can be removed for a short region, to allow contact with the sample over a controlled length. Two examples of the use of an optical fiber for remote sampling are discussed. The first shows that a spectrum of a liquid sample (2-butanone) can be easily measured, and the second shows how a fiber can be used to monitor the progress of curing reactions in thermoset composite materials. The spectrum of a resin was recorded before the cure by embedding the optical fiber in the graphite fiber/polyimide matrix resin prepreg, and then the progress of the cure was monitored during the curing process. This type of remote sampling shows tremendous potential for opening totally new areas of usage for FT-IR spectrometry, including the studies of hazardous materials, enclosed reactions, and processes that do not allow samples to be taken inside the spectrometer.

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In situ attenuated total reflectance FT-IR analysis of an enzyme-modified mid-infrared fiber surface using crystalline bacterial surface proteins

Analytical Chemistry ◽

10.1021/ac00073a008 ◽

1994 ◽

Vol 66 (1) ◽

pp. 35-39 ◽

Cited By ~ 27

Author(s):

K. Taga ◽

R. Kellner ◽

U. Kainz ◽

U. B. Sleytr

Keyword(s):

Fiber Surface ◽

Surface Proteins ◽

Attenuated Total Reflectance ◽

Mid Infrared ◽

Total Reflectance ◽

Bacterial Surface ◽

Ft Ir ◽

Ir Analysis

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Characterization of the Physical, Chemical, and Adsorption Properties of Coal-Fly-Ash–Hydroxyapatite Composites

Minerals ◽

10.3390/min11070774 ◽

2021 ◽

Vol 11 (7) ◽

pp. 774

Author(s):

Eleonora Sočo ◽

Dorota Papciak ◽

Magdalena M. Michel ◽

Dariusz Pająk ◽

Andżelika Domoń ◽

...

Keyword(s):

Fly Ash ◽

Coal Fly Ash ◽

Thermal Power ◽

Synthesis Conditions ◽

High Calcium ◽

Ft Ir ◽

Ir Analysis ◽

Wet Synthesis

(1) Hydroxyapatite (Hap), which can be obtained by several methods, is known to be a good adsorbent. Coal fly ash (CFA) is a commonly reused byproduct also used in environmental applications as an adsorbent. We sought to answer the following question: Can CFA be included in the method of Hap wet synthesis to produce a composite capable of adsorbing both heavy metals and dyes? (2) High calcium lignite CFA from the thermal power plant in Bełchatów (Poland) was used as the base to prepare CFA–Hap composites. Four types designated CFA–Hap1–4 were synthesized via the wet method of in situ precipitation. The synthesis conditions differed in terms of the calcium reactants used, pH, and temperature. We also investigated the equilibrium adsorption of Cu(II) and rhodamine B (RB) on CFA–Hap1–4. The data were fitted using the Langmuir, Freundlich, and Redlich–Peterson models and validated using R2 and χ2/DoF. Surface changes in CFA–Hap2 following Cu(II) and RB adsorption were assessed using SEM, SE, and FT-IR analysis. (3) The obtained composites contained hydroxyapatite (Ca/P 1.67) and aluminosilicates. The mode of Cu(II) and RB adsorption could be explained by the Redlich–Peterson model. The CFA–Hap2 obtained using CFA, Ca(NO3)2, and (NH4)2HPO4 at RT and pH 11 exhibited the highest maximal adsorption capacity: 73.6 mg Cu/g and 87.0 mg RB/g. (4) The clear advantage of chemisorption over physisorption was indicated by the Cu(II)–CFA–Hap system. The RB molecules present in the form of uncharged lactone were favorably adsorbed even on strongly deprotonated CFA–Hap surfaces.

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