Persulfate Treatment of Dissolved Gasoline Compounds

• Published in: Journal of hazardous, toxic and radioactive waste Vol. 17; no. 1; pp. 9 - 15
• Main Authors: Sra, Kanwartej S, Thomson, Neil R, Barker, Jim F
• Format: Journal Article
• Language: English
• Published: American Society of Civil Engineers 01-01-2013
• Subjects: Activation; Aquifers; Ethylbenzene; Gasoline; Oxidation; Oxidation rate; Reactors; Strategy; Technical Papers
• ISSN: 2153-5493; 2153-5515
• DOI: 10.1061/(ASCE)HZ.2153-5515.0000143

AbstractBench-scale treatability of an ensemble of gasoline compounds was investigated using unactivated and activated persulfate. The activation strategies explored were chelated-iron, peroxide, alkaline conditions, and the presence of aquifer solids. Batch reactor trials were designed with an initial total petroleum hydrocarbon (TPH) concentration of ∼25  mg/L, and nine organic compounds were monitored over a 28-day reaction period. First-order oxidation rate coefficients (kobs) were estimated for all experimental trials. Unactivated persulfate at a concentration of 20  g/L resulted in almost complete oxidation of benzene, toluene, ethylbenzene, and xylenes (BTEX) (>99%), trimethylbenzenes (>95%), and significant oxidation of naphthalene (∼70%). Oxidation rate coefficients were enhanced by 2–15 times using the peroxide or chelated-iron activation strategy. Alkaline activation at pH 11 or 13 yielded kobs that were ∼2 times higher than the unactivated case, except for the kobs for benzene, toluene, and ethylbenzene, which were reduced by 50% at pH 13. Natural activation by two aquifer materials resulted in kobs similar to the unactivated case. Significant oxidant strength (60–85%) was observed in all 20  g/L persulfate reactors, implying significant persulfate persistence under gasoline-contaminated conditions. The overall bulk gasoline stoichiometry for these experimental trials varied from 120 to 340 g-persulfate/g-TPH.