Elaboration of balance through adsorption of cadmium and selenium between water and underlying sediments via their analysis in drinking, wastewater and sediment samples

Abstract

a b s t r ac tThere is a very delicate balance between water and the underlying sediments as far as adsorption/ desorption is concerned. The toxicity of heavy elements (HEs) in water is significant because of their non-biodegradability. The nature mostly takes care of this as HEs tend to remain adsorbed in the underlying sediments as compared with the water column above them. In the present work, cadmium (Cd) and selenium (Se) . g -1 , respectively. To elaborate the balance between water and sediments, the immobilization of Cd and Se has been studied on Sawaan River's sand. The rate constant for the sorption of Cd(II) and Se(IV) onto the Sawaan River sand is (2.13 ± 0.8) × 10 -1 min -1 and (3.75 ± 0.12) × . 10 -2 min -1 , respectively. The sorption energy E for the sorption of Cd(II) is 11.80 ± 0.25 kJ . mol -1 while the sorption of Se(IV) is 8.93 ± 0.04 kJ . mol -1 . The results of analysis, kinetic and thermodynamic data from adsorption procedure show that sands can effectively be used as preconcentrating agents as well as adsorbents for removal of toxic elements from water and also nature has its own system of minimizing pollutants from the environment.