Sensitivity of Surface Complexation Modeling to the Surface Site Density Parameter
نویسنده
چکیده
Previous research has shown that adsorption of many inorganic anions on soil mineral surfaces can be described equally well by chemical surface complexation models using either inneror outer-sphere surface complexes. At the same time, goodness of fit of these models to adsorption data has been used to distinguish between innerand outer-sphere adsorption mechanisms. In this study the ability of chemical surface complexation models to describe anion adsorption on goethite using both innerand outer-sphere surface complexes was evaluated and found to be sensitively dependent on the value of the surface site density. Application of a goodness of fit criterion leads to the choice of an inner-sphere adsorption mechanism for small surface site densities and an outer-sphere adsorption mechanism for large values of this parameter. Experimentally determined values of surface site density vary by an order of magnitude depending upon the method used. It is suggested that uncertainty in the value of the surface site density parameter currently invalidates use of surface complexation models to predict anion adsorption mechanisms on soil mineral surfaces. © 1991 Academic Press. Inc.
منابع مشابه
Investingation and Chemisorption study of Oxygen Atoms and Cr (100) surface by DFT calculation
This study concerns about quantum chemical modeling behavior of 02 on Cr (100)surface by using density functional theory (DFT) by LANL2DZ and 6 — 31G* basissets, we presented the results of our first principles electronic structure calculationson the 02 molecules and their interface with Cr (100) surface. The chromium metalhas the body-centered cubic structure, and chromium cluster has five Cr ...
متن کاملApplication of surface complexation models to anion adsorption by natural materials.
Various chemical models of ion adsorption are presented and discussed. Chemical models, such as surface complexation models, provide a molecular description of anion adsorption reactions using an equilibrium approach. Two such models, the constant capacitance model and the triple layer model, are described in the present study. Characteristics common to all the surface complexation models are e...
متن کاملInfluence of Surface Heterogeneities on Complexation of Ethylene with Active Sites of NiMCM-41 Nanocatalyst: A Density Functional Theory Study
Consecutive adsorption of ethylene molecules on different nanoclusters as representatives of the active sites of NiMCM-41 catalyst was investigated with respect to structural, topological, and energetic properties at the B3LYP/6-311+G* and M06/Def2-TZVP levels of theory. The dimeric adsorption of the ethylene molecules was found to be exothermic on all sites (adsorption enthalpies ranging from ...
متن کاملStatistical physics modeling of equilibrium adsorption of cadmium ions onto activated carbon, chitosan and chitosan/activated carbon composite
The adsorption ability of activated carbon, chitosan, and chitosan/activated carbon composite for cadmium separation from aqueous solution was analyzed via statistical physical modeling. The equilibrium data were analyzed by Langmuir, Hill, double layer model, and the multi-layer model with saturation isotherm models. Results showed that the multi-layer model with saturation could well describe...
متن کاملPlane-wave Pseuclopotential Density Functional Theory periodic Slab Calculations of NO Adsorption on Co(111) Surface
Plane-wave pseudopotential Density Functional Theory (OFT) periodic slab calculations were performed usingthe giteralized gradient approximation (GHA) to investigate the adsorption of nitric oxide(NO) on the (I II)surface of Cu. Copper rface was stimulated using th P 'odic Slab Method consisting of Five atomic Layers.Four different adsorption saes (Atop. Bridge, RCP Hollow, and FCC Hollow) were...
متن کامل