Abstract
The magnetotactic bacteria have the properties of both capturing heavy metal ions and being quickly separated out from the wastewater, which makes them high quality adsorbents. The adsorption of ions usually shows selectivity in the multi component aqueous solutions. This paper investigated the mechanism of adsorption selectivity using the molecular dynamics method on the basis of periodic law of elements. A universal equation with respect to the mass, volume and charge of ions was deduced. Based on the analysis of the surficial properties, a model was built to describe the structure of magnetotactic bacteria using the organic groups. Then, the interface system of bacterium surface, aqueous solutions and heavy metal ions was developed and dynamics simulation was performed. It was found that the ion having smaller charge-mass ratio according to the periodic system of elements might be easier to be adsorbed. The ionic thermal motion could depress the adsorption of ions and might be one of the reasons which cause adsorption selectivity. Furthermore, the larger charge-mass ions were more inclined to be drifting away from the bacteria in the simulation.
Key words: Magnetotactic bacteria, heavy metal, adsorption, charge-mass ratio, periodic law of elements, molecular simulation.
