Heavy metal removal from aquatic systems by northern Anatolian smectites

Competitive adsorption of the heavy metal ions Cu(II), Cd(II) and Pb(II) fr om aqueous media onto northern Anatolian smectites with a mean particle dia meter of 200 mu m, was investigated. The adsorption rate and capacity of th e smectite for the selected heavy metal ions, containing different amounts of these ions (5-900 mg/L) at values ranging from pH 1.0 to 7.0 were studie d. Very high adsorptions rates were observed at the beginning, and adsorpti on equilibria were then gradually achieved in about 30 minutes. The maximum adsorption of metal ions onto the smectite were found to be 41.46 mg Cd(II ), 36.11 mg Pb(II) and 18.72 mg Cu(II) per gram of smectite. The order of a ffinity based on weight uptake by smectite was Cd(II)>Pb(II)>Cu(II). When t he metal ions competed (in the case of adsorption from their mixture), the amounts of Cd(II), Pb(II) and Cu(II) ions adsorbed were 11.86 mg, 11.23 mg and 16.76 mg per gram of smectite, respectively Desorption of the metal ion s from smectite was studied in 0.5 M HNO3 and very high desorption rates, g reater than 95%, were achieved in all cases.