coagulation, flocculation, disinfection, etc.) or their use in a combination with other
agents, which will assist in achieving the expected effectiveness in remediation
practice. One of the options is their combination with hydrogen peroxide, where
nanostructured ferric/ferrous sludge is formed by the reduction of ferrates. This
sludge can act as an effective catalyst for radical decomposition of hydrogen
peroxide. The aim of this study was to test the combination of ferrates with hydrogen
peroxide in laboratory conditions and then to realize a field pilot application. The
proposed combination showed a relatively high efficiency during remediation of
even heavily contaminated water. Ferrates were finally reduced to naturally occurring forms of iron and the final products of the hydrogen peroxide degradation were
oxygen and water. Thus, no other contaminants were discharged into the aqueous
environment. No increase in salinity of the water was observed either. The reaction
proceeded rapidly even without pH value adjustment or other parameters of the
reaction being changed. In addition to this, the formed iron sludge acted as an
effective flocculant. The presence of this sludge in purified water is the necessary
condition for the successful remediation by subsequent hydrogen peroxide application. Comparing ex situ and in situ applications, the removal efficiency is high in
both cases, but significant difference consists in the rapid run of the reaction. In the
case of water remediation by an ex situ method, this is an advantage as the effective
remediation during short time is required. Conversely, in the case of water remediation by an in situ method, this is a disadvantage because the contamination returns
rapidly to the initial level as a consequence of contamination of the soil surrounding.
In this case, rather long-term remediation reactions are required.
References
Bartzatt R, Cano M, Johnson L, Nagel D (1992) Removal of toxic metals and nonmetals from
contaminated water. J Toxicol Environ Health 35(4):205–210. https://doi.org/10.1080/
15287399209531611
Che H, Bae S, Lee W (2011) Degradation of trichloroethylene by Fenton reaction in pyrite
suspension. J Hazard Mater 185(2–3):1355–1361. https://doi.org/10.1016/j.jhazmat.2010.10.
055
Filip J, Yngard RA, Siskova K, Marusak Z, Ettler V, Sajdl P, Sharma VK, Zboril R (2011)
Mechanisms and efficiency of the simultaneous removal of metals and cyanides by using
ferrate(VI): crucial roles of nanocrystalline iron(III) oxyhydroxides and metal carbonates.
Chem Eur J 17(36):10097–10105. https://doi.org/10.1002/chem.201100711
Goodwill JE, Jiang Y, Reckhow DA, Gikonyo J, Tobiason JE (2015) Characterization of particles
from ferrate preoxidation. Environ Sci Technol 49(8):4955–4962. https://doi.org/10.1021/acs.
est.5b00225
Hara J (2012) Chemical degradation of chlorinated organic pollutants for in situ remediation and
evaluation of natural attenuation. In: Puzyn T, Mostrag-Szlichtyng A (eds) Organic pollutants
ten years after the Stockholm convention – environmental and analytical update. InTech, Rijeka,
pp 345–364. https://doi.org/10.5772/31775
Hrabák P (2012) Kritické studium sanačního využití modifikovaného Fentonova činidla (A critical
study of remedial utilization of modified Fenton reagent). Dissertation, Technical University of
Liberec
14 Field Study V: Combined Oxidation Technology Using Ferrates (Fe
IV–VI
). . .
329
agents, which will assist in achieving the expected effectiveness in remediation
practice. One of the options is their combination with hydrogen peroxide, where
nanostructured ferric/ferrous sludge is formed by the reduction of ferrates. This
sludge can act as an effective catalyst for radical decomposition of hydrogen
peroxide. The aim of this study was to test the combination of ferrates with hydrogen
peroxide in laboratory conditions and then to realize a field pilot application. The
proposed combination showed a relatively high efficiency during remediation of
even heavily contaminated water. Ferrates were finally reduced to naturally occurring forms of iron and the final products of the hydrogen peroxide degradation were
oxygen and water. Thus, no other contaminants were discharged into the aqueous
environment. No increase in salinity of the water was observed either. The reaction
proceeded rapidly even without pH value adjustment or other parameters of the
reaction being changed. In addition to this, the formed iron sludge acted as an
effective flocculant. The presence of this sludge in purified water is the necessary
condition for the successful remediation by subsequent hydrogen peroxide application. Comparing ex situ and in situ applications, the removal efficiency is high in
both cases, but significant difference consists in the rapid run of the reaction. In the
case of water remediation by an ex situ method, this is an advantage as the effective
remediation during short time is required. Conversely, in the case of water remediation by an in situ method, this is a disadvantage because the contamination returns
rapidly to the initial level as a consequence of contamination of the soil surrounding.
In this case, rather long-term remediation reactions are required.
References
Bartzatt R, Cano M, Johnson L, Nagel D (1992) Removal of toxic metals and nonmetals from
contaminated water. J Toxicol Environ Health 35(4):205–210. https://doi.org/10.1080/
15287399209531611
Che H, Bae S, Lee W (2011) Degradation of trichloroethylene by Fenton reaction in pyrite
suspension. J Hazard Mater 185(2–3):1355–1361. https://doi.org/10.1016/j.jhazmat.2010.10.
055
Filip J, Yngard RA, Siskova K, Marusak Z, Ettler V, Sajdl P, Sharma VK, Zboril R (2011)
Mechanisms and efficiency of the simultaneous removal of metals and cyanides by using
ferrate(VI): crucial roles of nanocrystalline iron(III) oxyhydroxides and metal carbonates.
Chem Eur J 17(36):10097–10105. https://doi.org/10.1002/chem.201100711
Goodwill JE, Jiang Y, Reckhow DA, Gikonyo J, Tobiason JE (2015) Characterization of particles
from ferrate preoxidation. Environ Sci Technol 49(8):4955–4962. https://doi.org/10.1021/acs.
est.5b00225
Hara J (2012) Chemical degradation of chlorinated organic pollutants for in situ remediation and
evaluation of natural attenuation. In: Puzyn T, Mostrag-Szlichtyng A (eds) Organic pollutants
ten years after the Stockholm convention – environmental and analytical update. InTech, Rijeka,
pp 345–364. https://doi.org/10.5772/31775
Hrabák P (2012) Kritické studium sanačního využití modifikovaného Fentonova činidla (A critical
study of remedial utilization of modified Fenton reagent). Dissertation, Technical University of
Liberec
14 Field Study V: Combined Oxidation Technology Using Ferrates (Fe
IV–VI
). . .
329