Application of ion chromatography for the assessment of cadmium adsorption in simulated wastewater by activated carbon

Abstract

A separation for Cd2+ and its interferences of common cations (Na+, NH+, K+, Mg2+, and Ca2+) was performed. Cation-exchange ion chromatography for Cd2+ and common cations separation on a weakly acidic H+ forming cation-exchange resin was investigated and applied to test the efficacy of activated carbon in the removal of Cd2+ from simulated wastewater. The difference of retention volumes between Ca2+ and Cd2+ was 0.45 mL for oxalic acid with a concentration of 1.75 mM, and the retention volume drastically decreased when the oxalic acid concentration increased in the eluent. Considering the prevailing conditions for TOSOH TSK gel Super IC A/C at 40°C with a least pH limit of 2.0, 1.75 mM of oxalic acid was selected for rapid analysis with pH of 2.3. Applying 50 μL sample injection, the calibration curve was linear for tested standard samples ranging from 0.05 to 2.0 mg/L, the detection limit (S/N = 3) was 0.066 mg/L (0.583 μM), and the analysis was applicable with coexisting Ca2+ up to 10.0 mg/L (250 μM) while other cations did not interfere. It was possible to analyze three samples within an hour. The application of this method on Cd2+ adsorption indicated the effectiveness of the method for heavy metals' analysis.