Efficient Removal of Uranyl Ions Using PAMAM Dendrimer: Simulation and Experiment

Maity, T and Aggarwal, A and Dasgupta, S and Velachi, V and Singha Deb, AK and Ali, SM and Dasgupta, PK (2023) Efficient Removal of Uranyl Ions Using PAMAM Dendrimer: Simulation and Experiment. In: Langmuir .

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Abstract

In this work, using atomistic molecular dynamics (MD) simulations and polymer-assisted ultrafiltration experiments, we explore the adsorption and removal of uranyl ions from aqueous solutions using poly(amidoamine) (PAMAM) dendrimers. The effects of uranyl ion concentration and the pH of the solution were examined for PAMAM dendrimers of generations 3, 4, and 5. Our simulation results show that PAMAM has a high adsorption capacity for the uranyl ions. The adsorption capacity increases with increasing concentration of uranyl ions for all 3 generations of PAMAM in agreement with experimental findings. We find that the number of uranyl ions bound to PAMAM is significantly higher in acidic solutions (pH < 3) as compared to neutral solutions (pH ∼ 7) for all uranyl ion concentrations. Additionally, we find an increase in the number of adsorbed uranyl ions to PAMAM with the increase in the dendrimer generation. This increase is due to the greater number of binding sites present for higher-generation PAMAM dendrimers. Our simulation study shows that nitrate ions form a solvation shell around uranyl ions, which allows them to bind to PAMAM binding sites, including the amide, amine, and carbonyl groups. In polymer-assisted ultrafiltration (PAUF) experiments, the removal percentage of uranyl ions by G3 PAMAM dendrimer increased from 36.3% to 42.6% as the metal ion concentration increased from 2.1 × 10-5 M to 10.5 × 10-5 M at a pH of 2. Our combined experiment and simulation study suggests that PAMAM is an effective adsorbent for removing uranyl ions from aqueous solutions.

Item Type:	Journal Article
Publication:	Langmuir
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society.
Keywords:	Amides; Binding sites; Dendrimers; Metal ions; Molecular dynamics; Ultrafiltration; Uranium compounds, Atomistic molecular dynamics simulations; Binding-sites; High adsorption capacity; Ion concentrations; PAMAM dendrimer; Polyamidoamines; Polymer-assisted ultrafiltration; Simulation studies; Solution pH; Uranyl ions, Adsorption
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	15 Jun 2023 10:20
Last Modified:	15 Jun 2023 10:20
URI:	https://eprints.iisc.ac.in/id/eprint/82059

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