Ozone treatment of soil contaminated with aniline and trifluralin
2003
Pierpoint, A.C. | Hapeman, C.J. | Torrents, A.
Column studies were conducted to determine the ability of ozone to degrade aniline and trifluralin in soil. Ozone rapidly degraded aniline from soil under moist soil conditions, 5% (wt). Removal of 77-98% of [UL-14C]-aniline was observed from soil columns (15 ml, i.d.=2.5 cm), exposed to 0.6% O3 (wt) at 200 ml/min after 4 min. Initial ozonation products included nitrosobenzene and nitrobenzene, while further oxidation led to CO2. Ring-labeled-[UL-14C]-trifluralin removal rates were slower, requiring 30 min to achieve removals of 70-97%. Oxidation and cleavage of the N-propyl groups of trifluralin was observed, affording 2,6-dinitro-4-(trifluoromethyl)-aniline, 2,6-dinitro-N-propyl-4-(trifluoromethyl)-benzamine, and 2,6-dinitro-N-propyl-N-acetonyl-4-(trifluoromethyl)-benzamine. Base solutions revealed that trifluralin was similarly oxidized to CO2, where 72-83% of the activity recovered comprised 14CO2. Use of ozone-rich water improved contaminant removal in trifluralin-amended soil columns, but did not improve removal in aniline, pentachloroaniline, hexachlorobenzene amended soil columns, suggesting that ozonated water may improve contaminant removal for reactive contaminants of low solubility.
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