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4191977 - Adsorptive and desorptive behavior of metal cations on iron oxyhydroxide nanoparticles under varying salinity conditions | Poster Board #700
3:00 PM - 5:00 PM EDT
Wednesday, March 26, 2025Room: Hall B2/C (San Diego Convention Center)Parent Session
Fundamentals of Structure and Reactivity at Mineral-Water Interfaces:
Room: Hall B2/C (San Diego Convention Center)
DIVISION/COMMITTEE: [ENVR: Division of Environmental Chemistry] [GEOC: Division of Geochemistry]
Credits
0.00 CE
Organizers
- Jacquelyn Bracco, Queens College
- Benjamin Legg, University of Washington
- Thomas Underwood, Pacific Northwest National Laboratory
Nanoscience
Poster - In-person
ENVR: Division of Environmental Chemistry
GEOC: Division of Geochemistry
Overview
Metal contaminants in aquatic systems can be effectively sequestered from the dissolved phase through adsorption to mineral particle surfaces such as those of iron oxyhydroxides. However, the variable salinity of natural waters can complicate the adsorption, desorption, and retention of metal ions to such sorbents. This study aims to characterize the adsorptive and desorptive properties of zinc and copper metals in multiple saline conditions at concentrations ranging from those in freshwater to saltwater systems. This allows for the identification of which metal demonstrates greater retention or higher adsorption efficiency and which salt most effectively facilitates the binding of metals to iron oxyhydroxides.
FeOOH (goethite) nanoparticles were synthesized through an established flash microwave method, washed in 1000 MWCO dialysis tubing against DI water for 5 days, then stored in suspension at 4°C at their as-synthesized pH between 4.5 and 5.0. The nanoparticle suspensions were then exposed to 0.5 mM Cu (II) or Zn (II) with the pH adjusted upwards to 6.5 and 7.5, respectively, to induce metal cation adsorption to the nanoparticles. After a 24-hour adsorption period, the sorbed nanoparticle suspensions were exposed separately to sulfate, chloride, sulfate + chloride, or artificial sea water (ASW) at concentrations representing the range from freshwater to seawater. After an additional 18 hours, the suspension pH was reduced to 5.0 to induce metal cation desorption from the nanoparticles. The suspensions were then centrifuged, filtered through a 0.45 µm filter, and acidified to a pH less than 2 before the supernatants were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The percentage of metals absorbed and retained in the separate environments were calculated from the ICP-OES data. The results suggest that the salt conditions examined enhance the adsorption and retention of both metals in the following order: sulfate < chloride < sulfate + chloride < ASW, and that Zn (II) exhibits higher retention than Cu (II) in all environments.
FeOOH (goethite) nanoparticles were synthesized through an established flash microwave method, washed in 1000 MWCO dialysis tubing against DI water for 5 days, then stored in suspension at 4°C at their as-synthesized pH between 4.5 and 5.0. The nanoparticle suspensions were then exposed to 0.5 mM Cu (II) or Zn (II) with the pH adjusted upwards to 6.5 and 7.5, respectively, to induce metal cation adsorption to the nanoparticles. After a 24-hour adsorption period, the sorbed nanoparticle suspensions were exposed separately to sulfate, chloride, sulfate + chloride, or artificial sea water (ASW) at concentrations representing the range from freshwater to seawater. After an additional 18 hours, the suspension pH was reduced to 5.0 to induce metal cation desorption from the nanoparticles. The suspensions were then centrifuged, filtered through a 0.45 µm filter, and acidified to a pH less than 2 before the supernatants were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The percentage of metals absorbed and retained in the separate environments were calculated from the ICP-OES data. The results suggest that the salt conditions examined enhance the adsorption and retention of both metals in the following order: sulfate < chloride < sulfate + chloride < ASW, and that Zn (II) exhibits higher retention than Cu (II) in all environments.
