The Behaviour of ¹³⁴Cs, ⁶⁰Co, and ⁸⁵Sr Radionuclides in Marine Environmental Sediment

Abstract

This work describes experimental investigations and modelling studies on the sorption of radionuclides ¹³⁴Cs, ⁶⁰Co, and ⁸⁵Sr by certain marine sediments within Egypt. The chemical composition of the marine sediments was determined. The soluble salts were measured for the sediments and the concentrations of the released cations, Al³⁺, Fe³⁺, and Si⁴⁺, were measured for the sediment materials in 0.1 M NaClO₄ aqueous solution at different hydrogen ion concentrations. The two main factors that control the uptake of the radionuclides onto the sediment are the pH and the exchangeable capacities of the sediment materials. Surface complex model was used to estimate the surface charge densities and the electric surface potential of the marine sediment materials. These two parameters were calculated at the surface capacity sites of the sediment materials. The desorption of the adsorbed cations was determined by means of selective consecutive extraction tests using different chemical reagents including (1) 1 M MgCl₂ (pH 7), (2) 1 M ammonium oxalate (pH 3-5), (3) 0.04 M NH₂OH,HCl in 25% acetic acid (pH 3-4), (4) H₂O₂ in 5% HNO₃(pH 2-3), and (5) digestion with nitric acid followed by hydrofluoric and perchloric acids (pH 2).