Adsorption of metal elements onto illite and halloysite was investigated at 25℃ using pollutant water collected from the gold-bearing metal mine. Incipient solution of pH 3.19 was reacted with clay minerals as a function of time: 10 minute, 30 minute, 1 hour, 12 hour, 24 hour, 1 day, 2 day, 1 week, and 2 week. Twenty-seven cations and six anions from solutions were analyzed by AAs (atomic absorption spectrometer), ICP(induced-coupled plasma), and IC (ion chromatography). Speciation and saturation index of solutions were calculated by WATEQ4F and MINTEQA2 codes, indicating that most of metal ions exist as free ions and that there is little difference in chemical species and relative abundances between initial solution and reacted solutions. The adsorption results showed that the adsorption extent of elements varies depending on mineral types and reaction time. As for illite, adsorption after 1 hour-reaction occurs in the order of As〉Pb〉Ge〉Li〉Co, Pb, Cr, Ba〉Cs for trace elements and Fe〉K〉Na〉Mn〉Al〉Ca〉Si for major elements, respectively. As for halloysite, adsorption after 1 hour-reaction occurs in the order of Cu〉Pb〉Li〉Ge〉Cr〉Zn〉As〉Ba〉Ti〉Cd〉Co for trace elements and Fe〉K〉Mn〉Ca〉Al〉Na〉Si for major elements, respectively. After 2 week-reaction, the adsorption occurs in the order of Cu〉As〉Zn〉Li〉Ge〉Co〉Ti〉Ba〉Ni〉Pb〉Cr〉Cd〉Se for trace elements and Fe〉K〉Mn〉Al, Mg〉Ca〉Na, Si for major elements, respectively. No significant adsorption as well as selectivity was found for anions. Although halloysite has a 1:1 layer structure, its capacity of adsorption is greater than that of illite with 2:1 structure, probably due to its peculiar mineralogical characteristics. According to FTIR (Fourier transform infrared spectroscopy) results, there was no shift in the OH-stretching bond for illite, but the ν1 bond at 3695 cm-1 for halloysite was found to be stronger. In the viewpoint of adsorption, illite is characterized by an inner-sphere complex, whereas halloysite by an outer-sphere complex, respectively. Initial ion activity and dissociation constant of metal elements are regarded as the main factors that control the adsorption behaviors in a natural system containing multicomponents at the acidic condition.

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