Impact of Carbonate and Carbonate Elimination on the Efficiency of Pb Removal from Carbonated Kaolinite in Electrokinetics Process with Special Attention to the XRD Analysis

Electrokinetics is one of the important methods for soil remediation. Due to workability of this method, it has widely being used for contaminant removal from fine grain soils. On the other hand, the presence of carbonate in clayey soils causes a reduction in the efficiency of electrokinetics method. On the fundamental of microstructural aspects of this method, there are only limited researches. Therefore, the main objective of this research is to investigate the impact of carbonate and carbonate elimination on the efficiency of Pb removal from carbonated kaolinite in electrokinetics process with special attention to the XRD analysis. In electrokinetics experiments, natural kaolinite samples were air dried and passed through number #10 sieve. Then, kaolinite samples were mixed in 1:10 soil: electrolyte ratio with 10 cmol/kg-soil lead nitrate. Samples were kept for a week to achieve equilibrium. Then, they were compacted on the electrokinetics cell in 5 layers with similar density of 1.7 g/cm3. Finally, the electrokinetics experiments were performed. At the end of electrokinetics experiments, soil sample was removed from cell and was sliced in 5 sections. Each section was dried separately and was analyzed by AA and XRD experiments. The results of this research show that for decarbonated kaolinite sample, a 162% increase in electrokinetics efficiency was observed. Base on the results of this research the efficiency of the electrokinetics method for heavy metal contaminant removal is a function of three factors which include heavy metal transformation towards cathode compartment, pH variations, and soil water content.