Method for promoting polychlorinated biphenyl degradation by zero-valent iron

Abstract

The invention belongs to the technical field of soil or sediment repair, in particular to a method for promoting polychlorinated biphenyl degradation by zero-valent iron. According to the method, a compounded formula of an anionic surfactant and a nonionic surfactant such as polyoxyethylene is added, mobility of the hydrophobic pollutants, namely polychlorinated biphenyl, in the soil or the bottommud can be improved, so that the polychlorinated biphenyl is promoted to be in contact with the zero-valent iron and is degraded by the zero-valent iron. Compared with the treatment that no surfactant is added and only the anionic or polyoxyethylene nonionic surfactants are added, and degradation efficiency of the polychlorinated biphenyl can be remarkably improved by adding the mixed surfactant;and compared with other improved zero-valent iron technologies, the method is simple and feasible, is low in cost and is suitable for repairing a large amount of the polluted soil or the bottom mud.

Description

technical field [0001] The invention relates to the technical field of soil or sediment remediation, in particular to a method for promoting zero-valent iron to degrade polychlorinated biphenyls. Background technique [0002] As an efficient and easy-to-obtain repair material, zero-valent iron has strong reducibility, and can be used as an electron donor to reduce and degrade halogenated organic compounds such as polychlorinated biphenyls, polybrominated diphenyl ethers, and simple chlorinated hydrocarbons under anaerobic or low-oxygen conditions. , has been widely used in groundwater and soil remediation. However, there are some restrictive factors in this remediation method, especially for hydrophobic organic pollutants (such as polychlorinated biphenyls, etc.), factors such as insufficient contact between pollutants and zero-valent iron have greatly restricted its application. [0003] At present, the existing technology uses cationic or non-ionic surfactants to improve ...

AI Technical Summary

Problems solved by technology

However, there are some restrictive factors in this repair method, especially for hydrophobic organic pollutants (such as polychlorinated biphenyls, etc.), factors such as insufficient contact between pollutants and zero-valent iron limit its application.

[0003] At present, the existing technology uses cationic or non-ionic surfactants to improve the mobility of pollutants, but in the process of use, the affinity between cationic surfactants, zero-valent iron and soil media is strong, and desorption and recovery are difficult. The amount of application is large, which is not conducive to the control of restoration costs; anionic and nonionic surfactants have strong elution capabilities for PCBs, especially the former can promote the dissolution of PCBs by solubilizing soil organic matter

However, the auxiliary effect of the surfactant formulations in the prior art on the degradation of PCBs by zero-valent iron is not very satisfactory.

Images