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Updated: Jun 8, 2025

On-chip Isotachophoresis for Separation of Ions and Purification of Nucleic Acids
Published on: March 2, 2012
Selective single-atom adsorption for precision separation of lead ions in tap water via capacitive deionization
Zhenwei Gao1, Luqing Wang2, Xingkang Huang1
1Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois, 60637, United States; Chemical Sciences and Engineering Division, Physical Sciences and Engineering Directorate, Argonne National Laboratory, Lemont, Illinois, 60439, United States.
Abstract:
Capacitive deionization (CDI) offers a cost-effective and low-energy method for selective removal of Pb2+ from drinking water. Modifying CDI electrode surfaces with functional groups presents a versatile approach to enhancing selective ion adsorption capacity. However, a comprehensive understanding of the selectivity and removal efficiency of Pb2+ among diverse functional groups remains unexplored. Here, we investigated the effects of different functional groups (-SH, -COOH, and -NH2) attached to the graphene oxide (GO) electrode surfaces on Pb2+ selectivity and removal efficiency. Surprisingly, GO-COOH demonstrated single-atom adsorption of Pb2+, displaying superior removal efficiency and selectivity compared with -SH and -NH2, although -SH possesses significant chelation capability for Pb2+. Both density functional theory (DFT) calculations and X-ray pair distribution function (PDF) analyses confirmed that Pb2+ exhibits a theoretically higher affinity to -COOH. This research deepens our understanding of the interactions between functional groups and heavy metal ions, enabling selective and rapid separation of target cations for water purification.
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