Method for remediation of heavy metal-organic complex contaminated soil

By using microwave irradiation pretreatment and sodium lignosulfonate dispersion, the problems of low activation efficiency of persulfate and ferric hydroxide colloid inhibition were solved, achieving efficient remediation of soils contaminated with heavy metals and organic matter, and improving the degradation efficiency of organic matter and the fixation effect of heavy metals.

CN122099054APending Publication Date: 2026-05-29CENT SOUTH SAFETY & ENVIRONMENTAL TECH RES INST CO LTD
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Patent Information

Application Number
CN202610501941.6
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-04-16
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

In the remediation of soils contaminated with heavy metals and organic matter, existing technologies have low activation efficiency of persulfate oxidants, hinder the contact between phosphates and heavy metals due to ferric hydroxide colloids, and result in uneven distribution of ferrous ions, leading to incomplete degradation of organic matter and low heavy metal fixation efficiency.

Method used

Iron-modified biochar hotspots are formed through microwave irradiation pretreatment. Persulfate is activated by microwave residual heat. Sodium lignosulfonate is added to disperse ferrous oxalate. Ferrous oxalate reacts rapidly with persulfate to generate ferric ions. Sodium dihydrogen phosphate is used to precipitate ferric ions in time to generate ferric phosphate precipitate, thus achieving efficient degradation of organic matter and long-term stability of heavy metals.

Benefits of technology

It significantly improves the degradation efficiency of organic pollutants, ensures the full progress of phosphate precipitation reaction, achieves uniform fixation of heavy metals, and improves the utilization rate of oxidant and the long-term stability of heavy metals.

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Abstract

The application discloses a remediation method for heavy metal-organic compound contaminated soil, and belongs to the technical field of contaminated soil remediation. The method comprises the following steps: mixing the compound contaminated soil with iron modified biochar and zero-valent iron reducing agent, adding water step by step to obtain pretreated soil, placing the pretreated soil into a microwave reaction cavity for microwave irradiation treatment, transferring the soil to a turning machine after the irradiation is completed, and adding, in sequence, a persulfate oxidant, a sodium lignosulfonate aqueous solution, ferrous oxalate and a sodium dihydrogen phosphate aqueous solution after cooling, mixing by turning and placing for maintenance to obtain remediated soil. The iron modified biochar and the zero-valent iron are activated by microwave irradiation, combined with persulfate oxidation and phosphate precipitation fixation, efficient degradation of organic matter in the soil and stabilization of heavy metals are realized, and the method can be used for ex-situ remediation of heavy metal-organic compound contaminated soil.
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