Effect of chloride ions on the adsorption of cadmium from leachate onto kaolinite

The amount of Municipal Solid Waste (MSW) produced in Canada was 12.6 million tonnes in 1980. Cadmium, which is one heavy metal characteristically present in leachate from MSW, is an extremely toxic metal to all living organisms. Clay liners are used to contain contaminants such as heavy metals (aluminum, mercury, manganese, lead, and zinc) present in leachate from landfill sites containing MSW. Consequently, an investigation into the mechanisms of cadmium adsorption from leachate onto clay was pursued.Characteristically, such leachates contain trace quantities of heavy metals and abundant quantities of chloride ions. For this study, leachate samples were collected from the Meloche landfill site in Kirkland, Quebec. This leachate is characteristic of other leachates, and in one monitoring well it contained cadmium (Cd) at 0.069 mg/L (ppm) and chloride ions (Cl$ sp-$) at 677 mg/L (ppm). Under these conditions, the formation of complex ions between cadmium and chloride has the potential to interfere with the adsorption of cadmium by clay minerals