Solid-state polymer membranes for simple, sensitive, and low-cost monitoring of mercury in water

Nikolaos Kallithrakas-Kontos; Spyros Foteinis; Eleftheria M Vazgiouraki; Andreas G Karydas; János Osán; Efthalia Chatzisymeon

doi:10.1016/j.scitotenv.2019.134099

Solid-state polymer membranes for simple, sensitive, and low-cost monitoring of mercury in water

Sci Total Environ. 2019 Dec 20:697:134099. doi: 10.1016/j.scitotenv.2019.134099. Epub 2019 Aug 24.

Authors

Nikolaos Kallithrakas-Kontos¹, Spyros Foteinis², Eleftheria M Vazgiouraki¹, Andreas G Karydas³, János Osán⁴, Efthalia Chatzisymeon⁵

Affiliations

¹ Technical University of Crete, Laboratory of Analytical and Environmental Chemistry, University Campus, GR-73100 Chania, Greece.
² Technical University of Crete, Laboratory of Analytical and Environmental Chemistry, University Campus, GR-73100 Chania, Greece; Public Power Corporation (PPC) Renewables S.A., Attica, Greece. Electronic address: sfoteinis@ppcr.gr.
³ Nuclear Science and Instrumentation Laboratory (NSIL), IAEA Laboratories, Friedensstrasse 1, Seibersdorf A-2444, Austria; Institute of Nuclear and Particle Physics, NCSR "Demokritos", 15310 Aghia Paraskevi, Athens, Greece.
⁴ Nuclear Science and Instrumentation Laboratory (NSIL), IAEA Laboratories, Friedensstrasse 1, Seibersdorf A-2444, Austria; Hungarian Academy of Sciences, Centre for Energy Research, Konkoly-Thege M. út 29-33, H-1121 Budapest, Hungary.
⁵ School of Engineering, Institute for Infrastructure and Environment, University of Edinburgh, Edinburgh EH9 3JL, United Kingdom.

PMID: 32380604
DOI: 10.1016/j.scitotenv.2019.134099

Abstract

Solid-state Hg(II) selective membranes were produced and assessed by means of X-ray absorption near edge structure in the total reflection X-ray fluorescence (TXRF-XANES) setup and by the energy dispersive X-ray fluorescence (EDXRF) technique. Membranes were functionalized using four promising ligands for mercury complexation, i.e.: i) 4-(2-Pyridylazo) resorcinol (PAR), ii) thiourea, iii) calconcarboxylic acid (CCS), and iv) dithizone. A simple analytical procedure was followed, using miniscule reagent quantities, thus suggesting the process is also cost-effective. TXRF-XANES revealed that mercury complexes with the ligands, and is not simply adsorbed onto the PVC matrix, while the complexation was found to not be affected by the matrix existence. Mercury exhibited an increased oxidation grade and was covalently bound to the ligand functional groups, via a strong chemical bond. EDXRF revealed that the solid-state membranes can be used for mercury speciation and trace analysis from environmentally relevant matrices, such as tap water. The membranes could be a promising alternative to polymer inclusion membranes (PIMs), due to their simple configuration and high Hg (II) selectivity in aqueous media, but more research is needed. PAR appears to be the most promising ligand, followed by dithizone and thiourea. CCS had a minuscule preconcentration efficiency since it was preferably bound with Cu in tap water, indicating limited usefulness for mercury preconcentration. However, results suggest that, depending on the ligand, the solid-state membranes could be also possibly used for multi-elemental heavy metals analysis in water.

Keywords: Divalent mercury; Elettra Sinchrotron Trieste (EST); Heavy metal pollution; Mercury complexation; Synchrotron radiation-induced XANES; The International Atomic Energy Agency (IAEA).