The adsorption of soluble Sn(TV) species on goethite (FeOOH), a naturally
occurring mineral, was investigated in 0.01 M NaCl solution at ambient
temperature. The sequential spike method was used to obtain the distribution
coefficient (Kd). Kd values of higher than 1×107 ml/g at neutral
pH, and 3×105 ml/g at pH 11 were obtained. It is observed that Kd
values decrease with increasing pH. In the desorption experiment, the
sequential extraction method was applied. The extractants such as 0.1 M
NaOH, Tamm's acid oxalate and Coffin's reagent were used. The result
indicates that the adsorption consists of both reversible and irreversible
reactions, and that the most of fractions in adsorption of Sn on goethite
correspond to the irreversible adsorption or a stable fixation. Moreover, it
is suggested that the reversible adsorption converts to the irreversible
adsorption with time.