Desorption of cadmium from suspended particles in a turbulence tank

Sediment is responsible for the fate and transport of many toxic metals in the aquatic environment. It is important to understand the reactivity of toxic metals in aquatic sediment for environmental planning and assessment. This paper presents the experimental results of Cadmium (Cd) desorption from artificially contaminated sediment particles in a turbulence tank. The turbulence is generated by harmonic grid stirred motion. The turbulence intensity is quantified in terms of eddy diffusivity which is equal to 9.84F, where F is the harmonic vibration frequency. In the present of turbulence, it is found that Cd contaminated sediment particles in suspension gradually release Cd into the water. The metal releasing behavior well conforms with a one-dimensional unsteady water-sediment-metal transport-transformation equation formulated for the turbulence tank. The determination of the equation’s parameters for sediment adsorption-desorption of metals in the tank is discussed. With the help of the equation, the variations of the total and dissolved metal concentrations with time and the metal adsorption-desorption abilities in the present of suspended sediment particles in natural waters can be investigated.