Complex Permittivity to Detect Lead in Soil with Various Salt Forms and Combinations

Samer Al Martini,Julie Q Shang,M.J Zainorizuan,L Alvin John Meng Siang,L Yee Yong,A Mohd Shalahuddin,O Mohamad Hanifi,R Siti Nazahiyah

doi:10.1051/matecconf/201710307007

Abstract

The response of soil-water systems to an external electric field can be described as polarization and conduction. Polarization represents the electric charges stored in a material, whereas conduction is the ability of a material to conduct free charges. The combined effects of polarization and conduction can be expressed in terms of complex permittivity. Since the complex permittivity of a soil-water system is a function of soil properties, this research was undertaken to detect soil contamination using the complex permittivity measurements. The system used in this investigation to measure the complex permittivity of a lead contaminated soil consisted of an Automatic Network Analyzer (ANA), a set of coaxial cables, a personal computer (PC) for data processing and a coaxial sample holder. Two sample holders were first used: long holder and short holder. It was found that the short holder can give reliable and close measurement to the long holder. The short holder was later adopted. Soil samples were prepared in the lab and mixed with lead nitrate solutions and with hybrid blend of lead nitrate and lead chloride solutions. The relationship between the complex permittivity and lead concentration was investigated. A chemical analysis of the pore fluids for all lead contaminated soil samples was conducted to trace the presence of lead in soil. It was found that the complex permittivity is affected by lead concentration in soil, as the real part decreased and the imaginary part increased with an increase in lead concentration. Lead was not detected in the soil pore water for the soil tested, which suggested that lead was immobilized by precipitation and the adsorption mechanism.

Highlights

The last century witnessed vast industrial revolution that resulted in global environmental contamination problems
3.2 Complex permittivity of soil samples mixed with lead nitrate solutions
This permittivity is known as the static dielectric constant. After these frequencies the relative permittivity decreased until it reached the lowest values (ε ’∞).These Fig.s show that the dielectric dispersion for the short holder occurred at higher frequencies than for the long holder

Summary

Introduction

The last century witnessed vast industrial revolution that resulted in global environmental contamination problems. Many industries all over the world, and especially in developed countries, generate wastewater daily, which contains high levels of metals. At the start of the industrial revolution, any damage that heavy metals could have caused to the environment was not known. Many industries discharged their wastewaters directly to rivers and lakes causing pollution of water and soil. The environmental problem has become an important issue in the world. Researchers recently focused on research contamination issues and monitoring systems [1,2,3,4]

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