Theoretical study on the adsorption ability of (ZnO)6 cluster for dimethylmercury removal and the influences of the supports and other ions in the adsorption process

In this work a number of computational methods have been applied to study the adsorption of dimethylmercury (DMM) on the (ZnO)(6) cluster and the influences of the supports (MgO, SBA-15) and external ions (Cl-, OH-) on the adsorption process: the energy and electronic properties were calculated using Geometry, Frequency, Noncovalent, eXtended Tight Binding method; global minimum was found by using the Artificial Bee Colony algorithm; the Growing String Method was used to scan the potential energy surface to determine the transition states, and the stability of the adsorption products was investigated via molecular dynamic simulations. The calculated results show that the interaction between (ZnO)(6) and DMM are both kinetically and thermodynamically favorable. The strong chemisorption of DMM on the (ZnO)(6)/MgO and (ZnO)(6)/SBA-15 is the consequence of the interaction between (ZnO)(6) cluster and the supports. The higher adsorption affinity toward DMM of (ZnO)(6)/MgO, compared to (ZnO)(6)/SBA-15, is due to the synergistic effect of MgO with (ZnO)(6). However, in the OH(-)ion environment, (ZnO)(6)/SBA-15, reversely, seemed to be a better adsorbent for DMM molecules. [GRAPHICS] .