Rapid and efficient removal of heavy metal ions from aqueous media using cysteine-modified polymer nanowires

We report the development of a novel, simple, and highly effective polymeric material with nanoscale dimensions for use in removal of heavy metal ions from aqueous media. The nanomaterial was ∼ 200 nm in diameter and several microns long and was fabricated in the form of nanowires via template-directed electrochemical polymerization. The nanowires were covalently modified by cysteine, a nonessential amino acid with very high binding constants for selected toxic heavy metal ions, such as, As ³⁺ , Cd ²⁺ , Pb ²⁺ , and Cu ²⁺ . We demonstrated rapid and efficient removal of As ³⁺ , Cd ²⁺ , Pb ²⁺ , and Cu ²⁺ ions from natural water samples. The arsenic removal capacity was found to be ∼ 160 mg As ³⁺ per gram of the material, a substantially greater removal capacity than other materials reported to date. The removal capacity of other heavy metals ions was also rapid and effective, their concentrations becoming undetectable in a matter of minutes after treatment with the nanowires. These nanowires have demonstrated potential that could lead to a low cost, novel, and highly effective technique for use in treatment of drinking water and for other environmental remediation purposes.