Adsorption and degradation processes of tributyltin (TBT) and trimethyltin (TMeT) in landfill leachate sample treated with different iron nanoparticles (FeNPs): Fe0 (nZVI), FeO and Fe3O4 were investigated to find conditions for their efficient removal. FeNPs dispersed with tetramethyl ammonium hydroxide (TMAH) or by mixing were added and to leachate samples (pH 8) and 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 colloids and dissolved form was determined by sequential filtration and their concentrations in a given fraction by gas chromatography (GC) coupled to ICP-MS. Results revealed that most of the TBT was present in colloidal fractions, while TMeT in dissolved form. 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.
COBISS.SI-ID: 28962087