Sequestration of (CH3)Hg+ by amino‐polycarboxylic chelating agents

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Abstract

The speciation of mono-methylmercury(II) cation (MeHg+) in the presence of Nitrilotriacetate (NTA), Ethylenediamine-N,N,N′,N′-tetraacetate (EDTA), diethylenetriamine-N,N,N′,N″,N″-pentaacetate (DTPA) and (S,S)- Ethylenediamine-N,N′-disuccinic acid (S,S-EDDS) was investigated at I=0.1 mol L−1 (NaCl) with the aim to assess a trend of sequestering capacity of the amino‐polycarboxylic (APCs) ligand class towards this cation in aqueous solution. The results obtained gave evidence for the formation of a mononuclear[MeHg(APC)] complex species, differently protonated MeHg(HiL) species (i=1 to 3, depending on the APC considered), a mixed hydroxo species [MeHg(APC)(OH)] and a binuclear [(MeHg)2(APC)] species in all thesystems investigated. The results obtained in this work show that the stability of MeHg–APC complex species is very similar for DTPA, EDTA and S,S-EDDS (e.g., logKMeHg(APC)=10.14, 10.03, 10.14 for DTPA, EDTA and S,SEDDS, respectively) whereas, as expected, MeHg–NTA complexes are less stable (logK(MeHg)(NTA)=9.04). The sequestering ability of APCs towards MeHg+ ion was studied by calculating the sequestering parameter pL0.5in the pH range (3 to 11) investigated, in NaCl medium and also by simulating the presence of a non interacting medium, at the same ionic strength of the experiments. On the basis of the quite high pL0.5 values itcan be asserted that APCs can be used as sequestering agents for the remediation of contaminated soils and water. Of particular interest, from the environmental point of view, is the very good sequestering capacityof the S,S,-EDDS which is, among the APCs considered, the highest biodegradable chelating agent.
Lingua originaleEnglish
pagine (da-a)46-52
Numero di pagine7
RivistaJournal of Molecular Liquids
Volume172
Stato di pubblicazionePublished - 2012

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ethylenediamine
Pentetic Acid
ethylenediaminetetraacetic acids
Ethylenediaminetetraacetic acid
Chelating Agents
Chelation
Edetic Acid
Sequestering Agents
Positive ions
cations
acids
Acids
Ionic strength
Remediation
Cations
soils
Ligands
Ions
aqueous solutions
Soils

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Materials Chemistry

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@article{a9924f2a2d2d499b8fe061071538cda3,
title = "Sequestration of (CH3)Hg+ by amino‐polycarboxylic chelating agents",
abstract = "The speciation of mono-methylmercury(II) cation (MeHg+) in the presence of Nitrilotriacetate (NTA), Ethylenediamine-N,N,N′,N′-tetraacetate (EDTA), diethylenetriamine-N,N,N′,N″,N″-pentaacetate (DTPA) and (S,S)- Ethylenediamine-N,N′-disuccinic acid (S,S-EDDS) was investigated at I=0.1 mol L−1 (NaCl) with the aim to assess a trend of sequestering capacity of the amino‐polycarboxylic (APCs) ligand class towards this cation in aqueous solution. The results obtained gave evidence for the formation of a mononuclear[MeHg(APC)] complex species, differently protonated MeHg(HiL) species (i=1 to 3, depending on the APC considered), a mixed hydroxo species [MeHg(APC)(OH)] and a binuclear [(MeHg)2(APC)] species in all thesystems investigated. The results obtained in this work show that the stability of MeHg–APC complex species is very similar for DTPA, EDTA and S,S-EDDS (e.g., logKMeHg(APC)=10.14, 10.03, 10.14 for DTPA, EDTA and S,SEDDS, respectively) whereas, as expected, MeHg–NTA complexes are less stable (logK(MeHg)(NTA)=9.04). The sequestering ability of APCs towards MeHg+ ion was studied by calculating the sequestering parameter pL0.5in the pH range (3 to 11) investigated, in NaCl medium and also by simulating the presence of a non interacting medium, at the same ionic strength of the experiments. On the basis of the quite high pL0.5 values itcan be asserted that APCs can be used as sequestering agents for the remediation of contaminated soils and water. Of particular interest, from the environmental point of view, is the very good sequestering capacityof the S,S,-EDDS which is, among the APCs considered, the highest biodegradable chelating agent.",
author = "Alberto Pettignano and Salvatore Cataldo and Antonio Gianguzza and {De Stefano}, Concetta",
year = "2012",
language = "English",
volume = "172",
pages = "46--52",
journal = "Journal of Molecular Liquids",
issn = "0167-7322",
publisher = "Elsevier",

}

TY - JOUR

T1 - Sequestration of (CH3)Hg+ by amino‐polycarboxylic chelating agents

AU - Pettignano, Alberto

AU - Cataldo, Salvatore

AU - Gianguzza, Antonio

AU - De Stefano, Concetta

PY - 2012

Y1 - 2012

N2 - The speciation of mono-methylmercury(II) cation (MeHg+) in the presence of Nitrilotriacetate (NTA), Ethylenediamine-N,N,N′,N′-tetraacetate (EDTA), diethylenetriamine-N,N,N′,N″,N″-pentaacetate (DTPA) and (S,S)- Ethylenediamine-N,N′-disuccinic acid (S,S-EDDS) was investigated at I=0.1 mol L−1 (NaCl) with the aim to assess a trend of sequestering capacity of the amino‐polycarboxylic (APCs) ligand class towards this cation in aqueous solution. The results obtained gave evidence for the formation of a mononuclear[MeHg(APC)] complex species, differently protonated MeHg(HiL) species (i=1 to 3, depending on the APC considered), a mixed hydroxo species [MeHg(APC)(OH)] and a binuclear [(MeHg)2(APC)] species in all thesystems investigated. The results obtained in this work show that the stability of MeHg–APC complex species is very similar for DTPA, EDTA and S,S-EDDS (e.g., logKMeHg(APC)=10.14, 10.03, 10.14 for DTPA, EDTA and S,SEDDS, respectively) whereas, as expected, MeHg–NTA complexes are less stable (logK(MeHg)(NTA)=9.04). The sequestering ability of APCs towards MeHg+ ion was studied by calculating the sequestering parameter pL0.5in the pH range (3 to 11) investigated, in NaCl medium and also by simulating the presence of a non interacting medium, at the same ionic strength of the experiments. On the basis of the quite high pL0.5 values itcan be asserted that APCs can be used as sequestering agents for the remediation of contaminated soils and water. Of particular interest, from the environmental point of view, is the very good sequestering capacityof the S,S,-EDDS which is, among the APCs considered, the highest biodegradable chelating agent.

AB - The speciation of mono-methylmercury(II) cation (MeHg+) in the presence of Nitrilotriacetate (NTA), Ethylenediamine-N,N,N′,N′-tetraacetate (EDTA), diethylenetriamine-N,N,N′,N″,N″-pentaacetate (DTPA) and (S,S)- Ethylenediamine-N,N′-disuccinic acid (S,S-EDDS) was investigated at I=0.1 mol L−1 (NaCl) with the aim to assess a trend of sequestering capacity of the amino‐polycarboxylic (APCs) ligand class towards this cation in aqueous solution. The results obtained gave evidence for the formation of a mononuclear[MeHg(APC)] complex species, differently protonated MeHg(HiL) species (i=1 to 3, depending on the APC considered), a mixed hydroxo species [MeHg(APC)(OH)] and a binuclear [(MeHg)2(APC)] species in all thesystems investigated. The results obtained in this work show that the stability of MeHg–APC complex species is very similar for DTPA, EDTA and S,S-EDDS (e.g., logKMeHg(APC)=10.14, 10.03, 10.14 for DTPA, EDTA and S,SEDDS, respectively) whereas, as expected, MeHg–NTA complexes are less stable (logK(MeHg)(NTA)=9.04). The sequestering ability of APCs towards MeHg+ ion was studied by calculating the sequestering parameter pL0.5in the pH range (3 to 11) investigated, in NaCl medium and also by simulating the presence of a non interacting medium, at the same ionic strength of the experiments. On the basis of the quite high pL0.5 values itcan be asserted that APCs can be used as sequestering agents for the remediation of contaminated soils and water. Of particular interest, from the environmental point of view, is the very good sequestering capacityof the S,S,-EDDS which is, among the APCs considered, the highest biodegradable chelating agent.

UR - http://hdl.handle.net/10447/63522

UR - http://www.sciencedirect.com/science/article/pii/S0167732212001584

M3 - Article

VL - 172

SP - 46

EP - 52

JO - Journal of Molecular Liquids

JF - Journal of Molecular Liquids

SN - 0167-7322

ER -