A radiotracer technique has been used to study the removal of Hg(II) ions from aqueous solutions by synthesized and well-characterized hydrous ferric oxide (HFO) and hydrous tungsten oxide (HTO). Adsorptive concentration (10(-4)-10(-8) mol dm(-3)), pH (ca 4.0-10.0) and temperatures (303-333 K) were examined for assessing optimal conditions for removal of these ions. The uptake of Hg(II) ions, fitted well with the Freundlich isotherm, increased with increasing temperature. No significant desorption took place in the present temperature range. The presence of other anions and cations affected the uptake of Hg(II) markedly. Irradiation of hydrous ferric oxide and tungsten oxide by using a 11.1 x 10(9) Bq (Ra-Be) neutron source having a neutron flux of 3.9 x 10(6) cm(-2) s(-1) with the associated gamma-dose rate of 1.72 Gy h(-1) did not influence the extent of adsorption of Hg(II) significantly. (c) 2005 Elsevier Inc. All rights reserved.