Effect of coating on the environmental applications of zero valent iron nanoparticles: the lindane case.
Commercial stabilized slurry of zero-valent iron nanoparticles (nZVI) as well as laboratory-synthesized polymer-stabilized NZVI nanoparticles were used for lindane (γ-hexachlorocyclohexane) degradation studies in aqueous solution. In the present study, polymer-stabilized iron nanoparticles were stabilized using polyethylene glycol (PEG, Mn ~400 and ~950-1050) and polytetrahydrofuran (PTHF, Mn ~650). To study the effectiveness of the different nanoparticles, a quantitative monitorization of lindane degradation by using solid-phase extraction (SPE) and a qualitative measurement of generated volatile by-products by headspace-solid phase microextraction (HS-SPME) followed by GC/MS were carried out. The obtained data were compared and contrasted with the results obtained in previous work. Results showed that the nanoparticles studied in this work possess superior dechlorination performance compared with previous observations. The freshly prepared Fe(0)-PEG400, Fe(0)-PEG1050 and Fe(0)-PTHF exhibited high reactivity during the dechlorination process of lindane in a very short time. The results obtained with the synthesized nanoparticles were similar to those obtained with commercial nanoparticles. However, in all cases reactivity decreased at reaction's late stage. Degradation of lindane by the studied nanoparticles removed 99.9% of the lindane initial concentration after 72h, except for Fe(0)-PTHF nanoparticles, for which the reaction stopped after 5min. In all cases, the reaction followed a second order kinetics. Finally, comparing the results from this study with our previous work, where different nature polymers were considered (Fe(0)-CMC, Fe(0)-PAA and Fe(0)-PAP), more gradual degradation profile of lindane was observed for Fe(0)-PAA and Fe(0)-CMC. It should be noted that in the present case, the reaction of lindane was speeded up with commercial and Fe(0)-PEG nanoparticles. Nevertheless, in the later case, the composition of by-products was affected by the presence of partially degraded intermediates. Taking into account the current technologies, the high removal rates obtained and the acceptable degradation times required, the proposed technology is suitable for its aimed purpose.
Analytical Chemistry Department, Faculty of Science and Technology, University of the Basque Country/EHU, Box 644, 48080 Bilbao, Spain.
I
I
San Román
Physical Chemistry Department, Faculty of Science and Technology, University of the Basque Country/EHU, 48940 Leioa, Spain.
A
A
Galdames
Analytical Chemistry Department, Faculty of Science and Technology, University of the Basque Country/EHU, Box 644, 48080 Bilbao, Spain.
M L
ML
Alonso
Central Analysis Service, Faculty of Science and Technology, University of the Basque Country/EHU, Box 644, 48080 Bilbao, Spain.
L
L
Bartolomé
Physical Chemistry Department, Faculty of Science and Technology, University of the Basque Country/EHU, 48940 Leioa, Spain.
J L
JL
Vilas
Analytical Chemistry Department, Faculty of Science and Technology, University of the Basque Country/EHU, Box 644, 48080 Bilbao, Spain.
R M
RM
Alonso
D001556:Hexachlorocyclohexane / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D000071228:Polyelectrolytes / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
D007306:Insecticides; D000071228:Polyelectrolytes; D014874:Water Pollutants, Chemical; D001556:Hexachlorocyclohexane; D007501:Iron
HS-SPME; Lindane; Polymer coating; SPE; Zero-valent iron nanoparticles