Environmental Engineering Reference
In-Depth Information
from the dried sandy soil at certain amount of deionized water and two type of
heavy metal (Fe and Pb). One soil sample was taken and recognized by the deionized
water only (clean soil) while another two samples prepared to evaluate the effect of
heavy metal contamination on saturated sand soil by adding 10 mg/L from the two
type of heavy metals. The total liquid (water and heavy metal) was 40% by volume in
order to saturate the sand soil with porosity 0.4. The soil samples were shacked for
15 min then kept for 3 h in sealed plastic container to avoid any evaporation. Three
impedance measurements were obtained at each frequency and the average value was.
The complex permittivity was deduced from the measured impedance of soil sample.
Electromagnetic Measurements and Test Cells
The test cell of internal dimensions 80 × 80 × 40 mm were used. Copper electrodes
with dimensions 80 × 80 × 2 mm were attached to two opposite faces of the cell.
Copper connections were passed through the cell walls and connected to the
electrodes. All impedance measurements were acquired using the LCR meter, oper-
ating in voltage-drive mode, with the signal voltage being 1,000 mV. A linear
sweep over the frequency range of 100-1,000 kHz was used with the data, recorded
at 21 frequency points within this range.
The connection to the LCR meter was done by means of short, individually
screened coaxial cables to the voltage (V), high/low and current (I) output/input
terminals. Cable impedance, plate impedance and fringing impedance were
determined using an appropriate model circuits. From the measurements, the
impedances of soil sample were calculated and all data is logged by a PC. The complex
permittivity (real part dielectric constant and imaginary part loss factor) of soil
samples were deduced from the impedance of the soil. The setup of the system is
shown in Fig.
2
.
Fig. 2
Schematic diagram of the dielectric measurement system
