Use of Sorption Materials for Removing Cadmium from Water

Groundwater and surface water sometimes contain substances that do not occur frequently in such water. Such substances include some of the metals. Increased iron and manganese content is expected in groundwater; however, metals such as cadmium, nickel or arsenic in high quantities are not typical of this water. Still, there are sources where the occurrence of cadmium, arsenic and other metals is in concentrations exceeding the prescribed values for drinking water. Because of the toxicity of heavy metals, authors dealt with the possibilities of removing cadmium from water. There are many ways to remove heavy metals, however today iron hydroxide based granulated sorption materials are used due to their simplicity, efficiency and low economic demands. The laboratory experiments of the removal of cadmium from water were carried out at the Institute of Municipal Water Management, Faculty of Civil Engineering in Brno as part of a specific university research project. The aim of the experiment was to compare the ability of three sorption materials CFH 0818, Bayoxide E33 and GEH on the removal of cadmium from water. These materials were primarily designed to remove arsenic from water. Filtration columns filled with the mentioned sorbents were used for filtration. Drinking water was used as raw water during the measurement from the municipal water supply system in which increased cadmium concentration was achieved artificially by adding a chemical solution. During the experiment, the flow rate was set to reach the required retention time of 2.5, 5, 10 and 20 minutes taking into account the porosity of the media. The results of the laboratory measurement show that all three materials were able to reduce the concentration of cadmium deep below the limit laid down by Decree No. 252/2004 Coll. already at the shortest delay time. Contact filtration occurred unequivocally in all sorption materials during the removal of the cadmium.