A new material based on montmorillonite and Cu(II)-phenanthroline complex for effective capture of ammonia from gas phase

• Published in: Applied clay science Vol. 184; p. 105386
• Main Authors: Castellini, Elena, Malferrari, Daniele, Bernini, Fabrizio, Bighi, Beatrice, Mucci, Adele, Sainz-Díaz, Ignacio Claro, Serrano, Aida, Castro, German R., Brigatti, Maria Franca, Borsari, Marco
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-01-2020
• Subjects: Copper complexes; Gas trapping; Intercalation; Interlayer; Montmorillonite; Mt-CuPhensat-NH3; Montmorillonite; Mt-CuPhensat; Mt-CuPhensemisat; Mt; CuPhen; Mt-CuPhen; Interlayer; Mt-CuPhensemisat-NH3; Intercalation; Gas trapping; Copper complexes
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2019.105386

The intercalation of [Cu(Phen)(H2O)2]2+ (CuPhen) in montmorillonite (Mt) produces a stable hybrid material that is very efficient in removing NH3 from gas phase even at extremely low pressures.
The process was studied by elemental analysis, X-ray powder diffraction, thermal analysis coupled with evolved gas mass spectrometry and DR UV–Vis, NMR and X-ray absorption spectroscopy. The adsorption of CuPhen on Mt consists of two consecutive steps. During the first one, CuPhen intercalates alone into Mt through a cation exchange process, afterwards CuPhen and SO42− ions entry jointly into the mineral interlayer. The two-steps adsorption process is described by a VI-type isotherm, successfully fitted by two independent Frumkin isotherms. NH3 trapping is long-lasting, easy, fast even at extremely low gas pressure and reversible under mild conditions. Mt containing CuPhen always results well performant in removing ammonia from gas phase, but an appreciably higher adsorption capacity of NH3 is obtained when SO42− ion is absent from the interlayer. This hybrid montmorillonite is thus a promising material to be used in industrial or environmental contexts, as an efficient air-cleaner.
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•[Cu(Phen)(H2O)2]2+ intercalates into montmorillonite interlayer following a two steps mechanism.•The resulting hybrid material is very efficient in removing NH3 from gaseous phase.•Gaseous NH3 can be entrapped by the Mt-CuPhen hybrid material also at extremely low pressures.•NH3 adsorption process is fast and does not involve redox processes.•The hybrid material can be easily regenerated under mild conditions.