Adsorption and degradation processes of tributyltin and trimethyltin in landfill leachates treated with iron nanoparticles.
Biotic and abiotic degradation of toxic organotin compounds (OTCs) in landfill leachates is usually not complete. In this work adsorption and degradation processes of tributyltin (TBT) and trimethyltin (TMeT) in leachate sample treated with different iron nanoparticles (FeNPs): Fe(0) (nZVI), FeO and Fe3O4 were investigated to find conditions for their efficient removal. One sample aliquot was kept untreated (pH 8), while to the others (pH 8) FeNPs dispersed with tetramethyl ammonium hydroxide (TMAH) or by mixing were added and samples shaken under aerated conditions for 7 days. The same experiments were done in leachates in which the pH was adjusted to 3 with citric acid. Size distribution of TBT and TMeT between particles >5 µm, 0.45-5 µm, 2.5-0.45 µm, and <2.5 nm was determined by sequential filtration and their concentrations in a given fraction by gas chromatography coupled to inductively coupled plasma mass spectrometry (GC-ICP-MS). Results revealed that most of the TBT or TMeT was present in fractions with particles >2.5 or <2.5 nm, respectively. At pH 8 adsorption of TBT to FeNPs prevailed, while at pH 3, the Fenton reaction provoked degradation of TBT by hydroxyl radicals. TBT was the most effectively removed (96%) when sequential treatment of leachate with nZVI (dispersed by mixing) was applied first at pH 8, followed by nZVI treatment of the aqueous phase, previously acidified to pH 3 with citric acid. Such treatment less effectively removed TMeT (about 40%). It was proven that TMAH provoked methylation of tin, so mixing was recommended for dispersion of nZVI.
Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
Kelly
K
Peeters
Equipe de Chimie Analitique Bio-Inorganique et Environnement, IPREM CNRS UMR 5254, Université de Pau et des Pays de l'Adour, Hélioparc, 64053 Pau, France.
Gaëtane
G
Lespes
Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
Radmila
R
Milačič
Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia. Electronic address: janez.scancar@ijs.si.
Janez
J
Ščančar
D000327:Adsorption; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D015203:Reproducibility of Results; D013054:Spectrophotometry, Atomic; D014220:Trialkyltin Compounds / Q000032:analysis* / Q000737:chemistry; D014298:Trimethyltin Compounds / Q000032:analysis* / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
C045076:Fenton's reagent; D058185:Magnetite Nanoparticles; D014220:Trialkyltin Compounds; D014298:Trimethyltin Compounds; D014874:Water Pollutants, Chemical; C046488:trimethyltin; C011559:tributyltin; D006861:Hydrogen Peroxide; D007501:Iron
Adsorption; Degradation; Fenton-type process; Iron nanoparticles; Landfill leachate; Tributyltin; Trimethyltin