Removal of trace cadmium(II) by EDTA‐coated granular activated carbon

Abstract

Abstract The factors influencing the uptake of trace cadmium by an ethylenediaminetetraacetate‐coated granular activated carbon (ECGAC) have been examined and optimum conditions determined. Variables investigated include agitation time, adsorbent dose (or suspension density), Cd(II) concentration and pH. At a substrate suspension density of 200 mg/L, pH of 5.4 and an agitation time of 18 h, uptake was approximately 90% from a solution of 25 μg Cd(II)/L. In comparison, the amount sorbed by uncoated granular activated carbon of 1.0–1.4 mm size fraction under the same conditions was only 5%. The maximum sorption capacity of ECGAC was about 0.4 mg Cd(II)/g (i.e., 3.6 μM/g). Under optimum conditions, it is possible to lower the Cd(II) level to below the maximum acceptable concentration of 5 μg/L specified in the Guidelines for Canadian Drinking Water Quality.