Functionalized Metal-Organic Frameworks for the Efficient Removal of Low Concentrations of Ammonia.

The excellent ammonia adsorption properties of [Cu(bpy)2 (OTf)2 ]n (ELM-12; bpy=4,4'-bipyridine, OTf=trifluoromethanesulfonate) make it unique for the removal of ammonia at low concentrations, but its instability under humid conditions restrict its practical applications. Herein, a functionalized ELM-12@PDMS (PDMS=polydimethylsiloxane) composite was prepared by coating a nanoscale PDMS layer on the ELM-12 surface, which significantly increased its hydrophobicity. The dynamic ammonia adsorption properties of ELM-12 and ELM-12@PDMS were explored by means of kinetic breakthrough measurements under dry and humid conditions. ELM-12@PDMS can effectively capture ammonia at 100 ppm when maintained under 80 % relative humidity, which makes it promising for real applications.