Heavy metals in soils are receiving increased attention due to the greater understanding
of their toxicological importance in ecosystems and for human health. In a polluted soil,
the heavy metals tend to adsorb mainly in the fine fraction due to the large surface area. If
a solution is forced to flow through a soil by pressure, the solution will flow in the larger
pores. Oppositely to a hydraulic flow, an applied electric field will tend to pass the soil in
the micropores due to the lower electric resistance here, and thus, the electric current will act exactly where the heavy metals are mainly found. This means that the electrochemical
soil remediation methods that are based on an applied electric field as cleaning agent, are
particularly useful for fine grained soils where pump-and-treat technologies or soil washing
methods are impractical or impossible to use [1].
Different electrochemical soil remediation methods are under development for removal
of heavy metals from polluted soils. The methods are based on the two electrokinetic
phenomena: electroosmosis and/or electromigration. In order to be mobile in the electric
field, the heavy metals must be present in the dissolved phase of the soil. The desorption
and mobilization of most heavy metals during the remediation process is catalyzed by an
acidic front that is developing from the anode end of the soil [2,3], and when the acidic
front reaches all through the soil, the remediation action is finished [4].
Heavy metals in soils are receiving increased attention due to the greater understandingof their toxicological importance in ecosystems and for human health. In a polluted soil,the heavy metals tend to adsorb mainly in the fine fraction due to the large surface area. Ifa solution is forced to flow through a soil by pressure, the solution will flow in the largerpores. Oppositely to a hydraulic flow, an applied electric field will tend to pass the soil inthe micropores due to the lower electric resistance here, and thus, the electric current will act exactly where the heavy metals are mainly found. This means that the electrochemicalsoil remediation methods that are based on an applied electric field as cleaning agent, areparticularly useful for fine grained soils where pump-and-treat technologies or soil washingmethods are impractical or impossible to use [1].Different electrochemical soil remediation methods are under development for removalof heavy metals from polluted soils. The methods are based on the two electrokineticphenomena: electroosmosis and/or electromigration. In order to be mobile in the electricfield, the heavy metals must be present in the dissolved phase of the soil. The desorptionand mobilization of most heavy metals during the remediation process is catalyzed by anacidic front that is developing from the anode end of the soil [2,3], and when the acidicfront reaches all through the soil, the remediation action is finished [4].
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