TY - THES

T1 - Laboratory Scale Experiments for the Development of an Electrokinetic in-situ Soil Remediation Method Using Diamond Electrodes

AU - Schmale, Julia

N1 - no embargo

PY - 2007

Y1 - 2007

N2 - This master thesis presents the outcome of laboratory pre-assays leading to the development of a new electrokinetic in-situ remediation method for elimination of organic compounds in soil. This method aims to chemically oxidize phenol and diesel in soil with peroxodisulfate. The oxidant is generated in an electro synthesis process with diamond electrodes from a sulfate solution. The peroxodisulfate rich solution is then distributed electrokinetically within the contaminated area by means of an electric gradient generated by field electrodes in order to reach the pollutant. The overall outcome of the laboratory study suggests that the elimination of diesel and phenol in soil matrix by means of this technique is possible. Experiments with a bipolar mechanically implanted diamond electrode at 200 mA/cm resulted in a linear peroxodisulfate production curve with a slope of 1.1 (Ah/l vs mmol/l). Under these conditions, 54 mmol of the oxidant can be generated in about 16 h. This is the amount needed to eliminate one mmol sodium phenolate (0.1 g) to over 99 % in sandy loam soil during four weeks in presence of bivalent iron as catalyst. One mmol of diesel oil (0.2 g) can be decomposed up to 84 % in twelve weeks with 285 mmol of catalyzed peroxodisulfate. Under the influence of an electric gradient of 4 V/cm, peroxodisulfate can travel 4 cm/h from the cathode towards the anode in loamy sand.

AB - This master thesis presents the outcome of laboratory pre-assays leading to the development of a new electrokinetic in-situ remediation method for elimination of organic compounds in soil. This method aims to chemically oxidize phenol and diesel in soil with peroxodisulfate. The oxidant is generated in an electro synthesis process with diamond electrodes from a sulfate solution. The peroxodisulfate rich solution is then distributed electrokinetically within the contaminated area by means of an electric gradient generated by field electrodes in order to reach the pollutant. The overall outcome of the laboratory study suggests that the elimination of diesel and phenol in soil matrix by means of this technique is possible. Experiments with a bipolar mechanically implanted diamond electrode at 200 mA/cm resulted in a linear peroxodisulfate production curve with a slope of 1.1 (Ah/l vs mmol/l). Under these conditions, 54 mmol of the oxidant can be generated in about 16 h. This is the amount needed to eliminate one mmol sodium phenolate (0.1 g) to over 99 % in sandy loam soil during four weeks in presence of bivalent iron as catalyst. One mmol of diesel oil (0.2 g) can be decomposed up to 84 % in twelve weeks with 285 mmol of catalyzed peroxodisulfate. Under the influence of an electric gradient of 4 V/cm, peroxodisulfate can travel 4 cm/h from the cathode towards the anode in loamy sand.

KW - Remediation

KW - electrokinetic Sites

KW - contaminated Oxidation

KW - in-situ Diamond electrodes Peroxodisulfate

KW - Altlastensanierung Elektrokinetik Oxidation

KW - in-situ Diamantelektroden Peroxodisulfat

M3 - Master's Thesis

ER -