Radiotracer Technique in Adsorption Study XVI*: an Efficient Removal of Cadmium Ions by Sodium Titanate from Aqueous Solutions

摘要

The uptake of Cd(Il) ions on synthesized sodium titanate at different pH values (3.5-10.2), adsorbate concentrations (10↑(-2)-10↑(-8) M) and temperatures (303-333 K) has been studied using the radiotracer technique. The results show that the uptake follows first order rate law and equilibrium data fitted well for Freundlich adsorption isotherm. A change in temperature does not affect markedly the uptake of Cd(II) ions; however, it is greatly influenced by the presence of diverse ions like Ba↑(2+), Ca↑(2+), Sr↑(2+), Hg↑(2+), Zn↑(2+), Na↑(+), K↑(+) and complexing agents like acetate, phosphate, oxalate and EDTA. Radiation stability of sodium titanate was also assessed by exposing it to neutrons and gamma rays from a 11.1 GBq (Ra-Be) neutron source having an integral neutron flux of 3.85 ×10↑(6) n/cm↑(2)/s associated with y-dose of 1.72 Gy/h as also using a Gamma cell (4.66 kGy/h). The increasing presence of acids (HCI and H↓(2)SO↓(4)) decreases the uptake of Cd(II) ions, however, practically no desorption takes place into the bulk at the studied pH (5.2) and temperature (303-333 K) which suggest irreversibility of the uptake of Cd(II) ions. # 1997 Elsevier Science Ltd. All rights reserved