Remediation and Restoration of Petroleum Hydrocarbon Containing Alcohol-Contaminated Soil by Persulfate Oxidation Activated with Soil Minerals
2017
Satapanajaru, Tunlawit | Chokejaroenrat, Chanat | Sakulthaew, Chainarong | Yoo-iam, Maneekarn
Petroleum hydrocarbon, a complex mixture including aliphatic and aromatic hydrocarbons, is known to have negative effects on the environment. We determined the effectiveness of persulfate (PS) (5% w/w) activated using 1% (w/w) of various types of soil minerals, goethite (α-FeOOH), hematite (Fe₂O₃), magnetite (Fe₃O₄), maghemite (γ- Fe₂O₃), manganese oxide (MnO₂), and zeolite (clinoptilolite) to treat petroleum hydrocarbon-contaminated soil. Total petroleum hydrocarbon (TPH) was 4200 ± 124 mg kg⁻¹. The TPH removal efficiency was in the order: Fe₃O₄ > MnO₂ > γ-Fe₂O₃ > Fe₂O₃ > α-FeOOH > clinoptilolite. When the PS dosage and the moisture content of the soil increased, the degradation rate (k ₒbₛ) of TPH removal increased; on the other hand, lowering the pH increased the k ₒbₛ of TPH removal. The PS oxidation of TPH was optimized using response surface methodology (RSM). The interactive effects of three factors, namely, persulfate dosage (X ₁), pH (X ₂), and soil moisture content (X ₃), were investigated. The optimum removal of TPH by PS oxidation activated using 1% (w/w) magnetite was obtained at 5.5% (w/w) PS and 85% (w/w) moisture content at an initial pH of 4.5. However, the soil treated by PS showed a negative effect on soil health. The germination of mung bean (Vigna radiata (L.) R. Wilczek) and the CO₂ release for the treated soil were low, indicating that toxicity had occurred in the treated soil. To restore the treated soil, adding a soil amendment, like CaCO₃, fly ash, or crop residue, was able to improve plant growth and soil microbial activity.
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