Silver Nanoparticles Impregnated Zeolites Derived from Coal Fly Ash: Effect of the Silver Loading on Adsorption of Mercury (II)

Removal of mercury (II) from aqueous phase is of utmost importance, as it is highly toxic and hazardous to the environment and human health. A promising method for the removal of mercury (II) ions from aqueous solutions is by using adsorbents derived from coal fly ash (CFA), such as synthetic zeolites. In this work we present the hydrothermal production of synthetic zeolites from CFA followed by a modification for impregnation of silver nanoparticles, in solid concentrations from 0.15 to 4.71 wt.%. All produced zeolites and parent materials are characterized by XRD, XRF, BET and PSA to obtain morphological and microstructural data. Moreover, mercury (II) ions removal from aqueous solutions with initial concentration of 10 ppm is studied. According to results, zeolites and Ag-nanocomposites demonstrate much higher removal than parent CFA (up to 98%). In addition to this, we could observe a distinct adsorption behavior depending on the loading of Ag NPs in nanocomposites. A possible removal mechanism for both zeolites and Ag-nanocomposites is discussed.