A mixed-ligand complex of nickel trimesinate with 1,10-phenanthroline as an adsorbent for organic dyes and a precursor of nanostructured materials

Metal-organic frameworks based on nickel and cobalt trimesinates were synthesized according to a modified procedure by the interaction of nickel acetate or cobalt nitrate and trimesic acid in the presence of alkali. They have been used to extract the organic Congo red and methylene blue dyes from their aqueous solutions. The degree of adsorption depends on temperature and reaches 97 % for Congo red, while for methylene blue it is about 83 %. The mechanisms and characteristic parameters of the adsorption process are analyzed using empirical models of the isotherms of Langmuir, Temkin, and Freundlich, of which the most optimal adsorption process is described by the Freundlich model. The calculated thermodynamic parameters indicate a spontaneous process in the case of nickel trimesinate, while for cobalt trimesinate the adsorption of Congo red is spontaneous, and the adsorption of methylene blue is a forced process.