| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 85 === Electrokinetic processing has been used in the soil reclamation by the mechanisms: electroosmosis and electrolysis. The H+ ion produced by electrolysis from the anode is the key point to remove the heavy metals adsorbed on the clay surface. When an electrical field is applied, the cations move toward the cathode. There is a flow which is called electroosmotic flow occurred inside the porous medium. The pH of pore fluid decides the direction of electroosmotic flow. Higher pH takes the pore fluid moving to the cathode, lower pH takes it to the anode instead.
In this thesis Cadmium was selected to be the model pollutant for studying the reclamation efficiency under low hydraulic and potentiostatic gradient situation. It was found that no matter normal or reverse electroosmotic flow gets the ability to remove heavy metals from the kaolinite clay. We also found that the precipitates due to high pH circumstance do not concentrate in the soil near the cathode, but they focus on the place standing between the soil specimen and the cathode room. We also discuss the effects when a cation exchanging membrane is set to the specimen and the difference of running time, length of the specimen....etc.
The feasibility of removing Cadmium from kaolinite specimen has been investigated. According to our experiments, the residual concentration percentage can be reduced to 5% or less.
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