Natural Persulfate Activation for Anthracene Remediation in Tropical Environments
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Data
2017
Autores
Ferreira, Ieda D.
Prieto, Tatiana
Freitas, Juliana G.
Thomson, Neil R.
Nantes, Iseli L.
Bechara, Etelvino J. H. [UNIFESP]
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Resumo
In situ chemical oxidation using persulfate is one alternative to remediate polycyclic aromatic hydrocarbon-contaminated soil
however, oxidation can lead to the formation of toxic and persistent by-products, and treatment efficiency can be dependent on environmental conditions. Temperature and soil matrix properties can dictate reaction rates and pathways, promoting oxidant activation or scavenging the free radicals generated. This research investigated the ability of persulfate to degrade anthracene in tropical environmental conditions. Batch tests were conducted for various persulfate systems (naturally and chelated-iron-activated), with an Oxisol contaminated with anthracene. Electron paramagnetic resonance (EPR) was used to identify free radicals formed. Naturally activated persulfate degraded more than 96% of the anthracene and its byproduct anthraquinone after 90 days, considered more toxic and persistent, while the chelated-iron-activated persulfate system used was able to remove 70% of the anthracene. EPR measurements showed the coexistence of SO4 center dot- and (OH)-O-center dot radicals. Sulfate radicals were formed by thermal activation at ambient temperatures (mean of 23.7 degrees C), and (OH)-O-center dot was formed by propagation reactions and hydrolysis in acidic conditions that lead to peroxide formation. In the naturally activated system, anthracene degradation was observed and SO4 center dot- radicals were abundant, indicating that this treatment system can be effective in a typical tropical soil environment.
however, oxidation can lead to the formation of toxic and persistent by-products, and treatment efficiency can be dependent on environmental conditions. Temperature and soil matrix properties can dictate reaction rates and pathways, promoting oxidant activation or scavenging the free radicals generated. This research investigated the ability of persulfate to degrade anthracene in tropical environmental conditions. Batch tests were conducted for various persulfate systems (naturally and chelated-iron-activated), with an Oxisol contaminated with anthracene. Electron paramagnetic resonance (EPR) was used to identify free radicals formed. Naturally activated persulfate degraded more than 96% of the anthracene and its byproduct anthraquinone after 90 days, considered more toxic and persistent, while the chelated-iron-activated persulfate system used was able to remove 70% of the anthracene. EPR measurements showed the coexistence of SO4 center dot- and (OH)-O-center dot radicals. Sulfate radicals were formed by thermal activation at ambient temperatures (mean of 23.7 degrees C), and (OH)-O-center dot was formed by propagation reactions and hydrolysis in acidic conditions that lead to peroxide formation. In the naturally activated system, anthracene degradation was observed and SO4 center dot- radicals were abundant, indicating that this treatment system can be effective in a typical tropical soil environment.
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Water Air And Soil Pollution. Dordrecht, v. 228, n. 4, p. -, 2017.