Removal of chromium, nickel and cadmium from clays by in‐situ electrokinetic remediation

This article presents the results of a research study that investigated the use of the in situ electrokinetic process for removing chromium, nickel, and cadmium from contaminated clays. For this study, electrokinetic experiments were conducted on two types of clays: kaolin, a commercial‐grade soil consisting mainly of kaolinite clay mineral, and glacial till, a field derived clay that possesses a complex mineralogical composition. Two sets of experiments were performed. The first set of experiments consisted of clays contaminated with both chromium in its hexavalent form, Cr(VI), and nickel, Ni(II). Each of these contaminants was in a concentration of 500 mg/kg. The second set of experiments consisted of clays contaminated with Cr(VI), Ni(II), and cadmium, Cd(II), In concentrations of 500 mg/kg, 500 mg/kg, and 250 mg/kg, respectively. These specific contaminants and contaminant concentration levels were selected to simulate typical electroplating waste conditions. In each test, the contaminated clay was s...