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WEB Multivalent Magnetic Nanoaggregates with Unified Antibacterial Activity and Selective Uptake of Heavy Metals and Organic Pollutants

Thursday (24.09.2020)
17:05 - 17:20 Z: Special Symposia I
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Covalently functionalized magnetite (Fe3O4) nanoaggregates carrying an imidazolium-derivative (1-hexadecyl-3-vinyl imidazolium bromide, HDVI), L-cysteine (L-Cys) and polyacrylic acid (PAA) as surface ligands were generated to overcome the obstruction of organic and inorganic pollutants as well as harmful microbes in waste and drinking water. These bimodal water-treatment particulate agents (HDVI@L-Cys@PAA@Fe3O4) showed high antibacterial efficacy and specific surface adsorption properties for heavy metals, e.g. Ni(II) cations, and the organic model pollutant methylene blue (MB). For covalent conjugation of HDVI the polyacrylic acid (PAA) coated magnetite nanocrystals (PAA@Fe3O4) were functionalized with L-cysteine via carbodiimide coupling (L-Cys@PAA@Fe3O4) having terminal -SH groups that were used for thiol-ene click chemistry. After micrographic characterization, carefully performed series of water-remediation tests with these magnetically separable HDVI@L-Cys@PAA@Fe3O4 nanoaggregates demonstrated their high efficiency in the concomitant removal transition metal ions and organic pollutant without losing the antibacterial effect. Time-dependent batch adsorption experiments showed a high degree (> 90 %) of trapping and removal activity for both tested species – MB and Ni(II) ions. There was still a removal efficiency of more than 82 % obtained after three desorption-regeneration cycles for both adsorbates. Antibacterial tests were conducted against E. coli and B. subtilis and exhibited antibacterial activity against both types of bacteria. The high antibacterial action of the HDVI@L-Cys@PAA@Fe3O4 nanoaggregates is originated from the surfactant-like structure of HDVI groups capable of penetrating and perturbating the bacterial cell walls. Our results developed here demonstrate that nanoaggregates are highly effective in unifying bactericidal activity against different microorganism with heavy metal and organic pollutant removal properties.

Annika Szymura
University of Cologne
Additional Authors:
  • Dr. Shaista Ilyas
    University of Cologne
  • Prof. Dr. Ines Neundorf
    University of Cologne
  • Prof. Dr. Sanjay Mathur
    University of Cologne