Abstract
Observations were made of copper-polluted soil to see, if any
changes in the bonding type of copper in the soil were made during
electrodialytic soil remediation. Three different fractions of the
copper-polluted soil were used for investigation with infrared
spectroscopy (IR), X-ray diffraction (XRD), transmission electron
microscope (TEM) and observations with scanning electron
microscope (SEM), the last two combined with an EDX analysis unit.
The three soil fractions were extracted with am-monia for
observa-tion of the copper removal when copper forms
copper-tetra-ammine complexes with am-monia. Ammonia was chosen
because it forms strong complexes with copper and to keep the soil
basic, so that the carbonates were not dissolved. The bulk soil
was treated by electrodialytic reme-dia-tion, and soil treated for
seven months was investigated with XRD, TEM and SEM.Malachite was
found by use of XRD measurements in one of the untreated soil
samples. These measurements were supported by EDX measurements
(combined with either SEM or TEM), where almost pure copper
particles were found. The EDX measurements do not include
hydrogen, carbon and oxygen, which make the figures of all other
elements higher than it should be. Two other groups of
copper-containing particles were found in the soil by EDX. One
group was a mineral also containing magnesium, aluminium, silicon,
potassium, calcium and iron. This was probably a copper and
iron-containing clay mineral, and the other group had a high
content of calcium (approximately 30%). Some particles from this
latter group also had a high content of iron (approximately
10%).Extraction experiments with ammonia showed that some of the
copper was highly soluble in ammo-nia. This means that it would be
advantageous to treat the soil fractions separately because of the
big difference in the degree of pollution and the way copper is
bound within the soil.The speciation of copper in the soil from a
small pilot plant did not show any measurable change during the
first seven months of operation. It seems that the number of
particles with very a high concentration of copper, approximately
90%, decreased and the number of particles with copper in the same
range as iron increased. No group of copper-containing particles
was seen to disappear or to change into a different type.
Original language | English |
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Title of host publication | Heavy Metals in the Environment and Electromigration Applied to Soil Remediation |
Place of Publication | Lyngby |
Publisher | Technical University of Denmark, Environmental Electrochemistry |
Publication date | 1999 |
Pages | 121-128 |
Publication status | Published - 1999 |
Event | 2nd Symposium Heavy Metals in the environment and Electromigration Applied to Soil Remediation - Lyngby, Denmark Duration: 7 Jul 1999 → 9 Jul 1999 Conference number: 2 |
Conference
Conference | 2nd Symposium Heavy Metals in the environment and Electromigration Applied to Soil Remediation |
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Number | 2 |
Country/Territory | Denmark |
City | Lyngby |
Period | 07/07/1999 → 09/07/1999 |