Selenium adsorption on activated carbon by using radiotracer technique

Selenium (Se) is an essential trace element for human beings and plays important roles in human health but it is also toxic at concentrations above 1 mg of selenium per kg of body weight. Therefore, elimination of selenium ions from aqueous solutions is important. Se can be eliminated by using activated carbon as an adsorbent. Radiotracer concept is applicable for observation of elimination mechanism. For this reason, selenium radioisotope can be used as tracer. Selenium dioxide is irradiated in the central thimble of ITU TRIGA Mark II Training and Research Reactor for radiotracer production. Radioactivity measurements are carried out by the gamma-ray spectroscopy system to determine the effect of different experimental parameters. The relative importance of test parameters like concentration of adsorbate, pH of the solution, and contact time on adsorption performance of activated carbon for selenium ion is examined. Typical adsorption isotherms (Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin) are determined for the mechanism of sorption process. Evaluation of experiments for different parameters shows possibility of elimination of selenium from aqueous media by using activated carbon.