Adsorption characteristics of copper ions using magnetically modified medicinal stones

To improve efficiency of adsorption process, magnetically modified medicinal stones (MMS) were developed by means of entrapment method with iron oxide and urethane. The MMS have the maximum uptake capacity of about 13.6 mg/g-dry mass for copper ions at pH 6. The adsorption mechanism can be explained as ion exchange between alkali earth metals and copper ions. The surface condition and adsorption of copper ions onto MMS were confirmed by ESEM and EDAX. MMS could remove copper ions of about 93% with 1.5 g and the adsorption equilibrium of MMS was faster than that of commercial ion exchange resin (IR-120 plus resin) by about 50 min.