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Development for In-Situ Remediation of Contaminated Groundwater by Zero-Valent iron Nanoparticles and RIP Method

Absrtact	Remediation of sites contaminated by dense non-aqueous phase liquids (DNAPLs), especially chlorinated organic compounds, is a significantly priority in the environmental field because of their widespread use in many applications. DNAPLs usually can penetrate groundwater and reach aquifer. The condensed DNAPLs may be immobilized and further penetrate down to deeper aquitard zone that can not be easily removed by pumping. The persistent-contaminated DNAPLs may also pollute the soil and groundwater simultaneously during moving in the groundwater slowly. High activity and surface area of zero-valent iron nanoparticles (ZVINs) can be suspended in water by surface-modification with PEI polymeric films. The suspended ZVINs can be further injected into the wells and reach the plume of DNAPLs down with the flowing groundwater. Finally the plume may be catalyzed and decomposed to nontoxic species on highly active ZVINs. Experimentally, the ZVINs of 20-50 nm in size were synthesized by a hydrothermal method and then the PEI-coated ZVINs are easily and stably suspended in water. The water-soluble PEI coating of ZVINs may flow with the groundwater and the completely fresh ZVINs were observed while approaching the DNAPLs plumes. The data of in-situ remediation indicated that concentrations of DNAPLs after using well-injection method were notably reduced. By using resistivity image profiling (RPI), the conductivity data of modified ZVINs solution and sampling groundwater were similar. It indicated that lower conductivity of FeO species was found. In addition, RPI can elucidate complex subsurface DNAPLs structures by dense sampling of resistivity variation at shallow depth. The combinative technology of floating surface-modified ZVINs and RPI technique would be economically and environmentally attractive. Furthermore, the simulation calculation, basic engineering design, and economic estimation of this in-situ remediation technique were also performed to develop a domestic in-situ remediation technology in the near future.
Keyword	Zero-valent iron nanoparticle, Resistivity image Profiling, Dense non-aqueous phase liquid chlorohydrocarbons, Directly injection method, Reductive decomposition, In-situ remediation.

Absrtact

Remediation of sites contaminated by dense non-aqueous phase liquids (DNAPLs), especially chlorinated organic compounds, is a significantly priority in the environmental field because of their widespread use in many applications. DNAPLs usually can penetrate groundwater and reach aquifer. The condensed DNAPLs may be immobilized and further penetrate down to deeper aquitard zone that can not be easily removed by pumping. The persistent-contaminated DNAPLs may also pollute the soil and groundwater simultaneously during moving in the groundwater slowly. High activity and surface area of zero-valent iron nanoparticles (ZVINs) can be suspended in water by surface-modification with PEI polymeric films. The suspended ZVINs can be further injected into the wells and reach the plume of DNAPLs down with the flowing groundwater. Finally the plume may be catalyzed and decomposed to nontoxic species on highly active ZVINs. Experimentally, the ZVINs of 20-50 nm in size were synthesized by a hydrothermal method and then the PEI-coated ZVINs are easily and stably suspended in water. The water-soluble PEI coating of ZVINs may flow with the groundwater and the completely fresh ZVINs were observed while approaching the DNAPLs plumes. The data of in-situ remediation indicated that concentrations of DNAPLs after using well-injection method were notably reduced. By using resistivity image profiling (RPI), the conductivity data of modified ZVINs solution and sampling groundwater were similar. It indicated that lower conductivity of FeO species was found. In addition, RPI can elucidate complex subsurface DNAPLs structures by dense sampling of resistivity variation at shallow depth. The combinative technology of floating surface-modified ZVINs and RPI technique would be economically and environmentally attractive. Furthermore, the simulation calculation, basic engineering design, and economic estimation of this in-situ remediation technique were also performed to develop a domestic in-situ remediation technology in the near future.

Keyword

Zero-valent iron nanoparticle, Resistivity image Profiling, Dense non-aqueous phase liquid chlorohydrocarbons, Directly injection method, Reductive decomposition, In-situ remediation.