Synthesis and characterization of a microporous copper triazolate as a water vapor adsorbent

To better understand the water vapor adsorption behavior of metal organic frameworks, a microporous copper triazolate was synthesized and used as a substrate to evaluate water vapor adsorption isotherms at four different temperatures (293, 303, 323 and 343 K). Samples of [Cu3II(triazolate)3(OH)3(H2O)4]·4.5H2O were obtained as powders by partially modifying a procedure reported in the literature and characterized by means of X-ray diffraction, scanning electron microscopy, particle size distribution, thermogravimetry and microporosimetric analysis. The experimental data for the water vapor adsorption were submitted to non-linear regression using the semiempirical Sips equation, which led to a good correlation between model curves and experimental points. Moreover, the dependence of the isosteric heat on the fractional coverage of the adsorbent was successfully calculated by the van’t Hoff equation and Sips theoretical isotherms.

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► Optimized synthesis which leads to high-sized, morphologically well-defined crystals.
► Successful modeling of water vapor adsorption isotherms on synthesized samples.
► Estimation of the isosteric heat of adsorption starting from theoretical isotherms.
► Correlation of the isosteric heat with forces involved in the adsorption process.