Organophosphorus pesticide contaminated sites have been categorized as a global priority contaminated site type for remediation due to the excessive accumulation of persistent organic pollutants. This study investigated the removal effect of phorate (PHR) in polluted soil through co-solvent-assisted alkaline activation of persulfate (PS) system, and evaluated the contribution of the co-solvent to the desorption behavior and solubilizing effect of PHR. Results showed that a high PHR degradation rate of 56.1% was obtained on the second day under the following conditions: 40% (v/v) acetonitrile (ACN) as co-solvent, CPS = 382 mmol L–1, pH 12, and a WL/Ws ratio of 1:2. It was a significant improvement over the system without co-solvent (19.9%). Moreover, a degradation rate of PHR was up to 93.9% on the 21st day under the optimized operating conditions, which was significantly higher than that observed in the persulfate oxidation system (13.1%) and the alkaline hydrolysis system (33.6%). The critical active species, including sulfate radicals <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11270_2025_8705_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="43" /> </InlineMediaObject> <EquationSource Format="TEX">$S{O}_{4}^{\bullet -}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>S</mi> <msubsup> <mi>O</mi> <mrow> <mn>4</mn> </mrow> <mrow> <mo>∙</mo> <mo>-</mo> </mrow> </msubsup> </mrow> </math></EquationSource> </InlineEquation> and hydroxyl radicals (•OH) for the oxidation of PHR in contaminated soil during the alkaline-activated persulfate system were identified using electron spin resonance (ESR) and radical quenching experiments. The degradation pathways involved both hydrolytic pre-activation and radical mineralization. Furthermore, the luminescent bacteria tests demonstrated that the luminescence inhibition rate of the PHR-contaminated soil decreased from an initial value of 100% (highly toxic) to 16.2% (low toxicity) after remediation. In summary, this study offers a promising approach for the remediation of organophosphorus pesticide-contaminated soils.

Enhanced Removal of Phorate in Polluted Soil by Co-Solvent-Augmented Alkaline Activation of Persulfate

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发表日期：

2025年10月13日

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Tingting Lv,
Hong Wang,
Ding Li,
Ruihai Li,
Chengliang Yang,
Wei Zhao,
Zhenyu Cui,
Jianxin Li

摘要

Organophosphorus pesticide contaminated sites have been categorized as a global priority contaminated site type for remediation due to the excessive accumulation of persistent organic pollutants. This study investigated the removal effect of phorate (PHR) in polluted soil through co-solvent-assisted alkaline activation of persulfate (PS) system, and evaluated the contribution of the co-solvent to the desorption behavior and solubilizing effect of PHR. Results showed that a high PHR degradation rate of 56.1% was obtained on the second day under the following conditions: 40% (v/v) acetonitrile (ACN) as co-solvent, C_PS = 382 mmol L^–1, pH 12, and a W_L/W_s ratio of 1:2. It was a significant improvement over the system without co-solvent (19.9%). Moreover, a degradation rate of PHR was up to 93.9% on the 21st day under the optimized operating conditions, which was significantly higher than that observed in the persulfate oxidation system (13.1%) and the alkaline hydrolysis system (33.6%). The critical active species, including sulfate radicals $S{O}_{4}^{\bullet -}$ $S O_{4}^{∙ -}$ and hydroxyl radicals (•OH) for the oxidation of PHR in contaminated soil during the alkaline-activated persulfate system were identified using electron spin resonance (ESR) and radical quenching experiments. The degradation pathways involved both hydrolytic pre-activation and radical mineralization. Furthermore, the luminescent bacteria tests demonstrated that the luminescence inhibition rate of the PHR-contaminated soil decreased from an initial value of 100% (highly toxic) to 16.2% (low toxicity) after remediation. In summary, this study offers a promising approach for the remediation of organophosphorus pesticide-contaminated soils.