A Study Aimed at Understanding the Use of Nanomaterial-Treated Filters for the Uptake of Heavy Metals from Water Sources

We describe the synthesis and optical properties of ligand-modified gold nanoparticles in solution and grown on stainless-steel wool filters. Their efficiency with regard to heavy metal uptake from water found at or near DOE facilities was also tested. Two different sequestration technologies for heavy metals were developed based on the surface functionalization of gold nanoparticles with either citrate or L-cysteine. Citrate-capped gold nanoparticles in solution show a greater heavy metal loading capacity than L-cysteine-functionalized gold nanoparticles. It was also found that the citrate-capped gold nanoparticles have a greater sensitivity for copper (II) than zinc (II) ions. L-cysteine-capped gold nanoparticles are more sensitive toward gradual uptake of zinc (II) ions making them valuable for sensing and sequestration applications. L-cysteine-capped gold nanoparticle stainless-steel wool filters are also efficient at the uptake of heavy metal ions. The nanomaterial-treated stainless-steel wool filters are advantageous because they serve as inactive supports allowing efficient flow of the contaminated water and can be easily replaced after heavy metal uptake. They are also comparable to nanomaterials free in solution with regard to the effectiveness of remediation of contaminated water resources.