Using time-perturbed density functional theory the optical activity of metal-thiolate compounds formed by highly symmetric Ag and Au nanoparticles (NPs) and a methyl-thiol molecule is studied after performing atomic optimizations and electronic calculations upon adsorption. Many different sites and orientations of the adsorbed molecule on icosahedral Ag and Au NPs of 55 atoms are considered. Up...

Radionuclide (Sr-90 and Cs-137) behavior in the subsurface environment was evaluated with respect to natural attenuation, sorption and desorption kinetics, and equilibrium. Batch experiments were conducted with synthesized groundwater or acid (NaNO3; pH approximately 3) solutions under different temperature (T=20 and 70 degrees C) and pressure (P=Patm and P=3 MPa) conditions. Samples of sedimen...

CO adsorption on the Pt~111! surface is studied using first-principles methods. As found in a recent study @Feibelman et al., J. Phys. Chem. B 105, 4018 ~2001!#, we find the preferred adsorption site within density functional theory to be the hollow site, whereas experimentally it is found that the top site is preferred. The influence of pseudopotential and exchange-correlation functional error...

The energetics of elementary surface processes relevant for CO oxidation, particularly CO and 02 adsorption, were investigated by a direct calorimetric method on model Pd nanoparticles and on the extended Pd(111) single crystal surface. The focus of this study lies on a detailed understanding of how a nanometer scale confinement of matter affects the binding strength of gaseous adsorbates. We r...

We report 150 ns explicit solvent MD simulations of the adsorption on graphene of albumin (BSA) in two orientations and using two different adsorption protocols, i.e., free and forced adsorption. Our results show that free adsorption occurs with little structural rearrangements. Even taking adsorption to an extreme, by forcing it with a 5 nN downward force applied during the initial 20 ns, we s...

The adsorption of antifreeze glycoproteins (AFGP) from aqueous solution onto two different silicate minerals, muscovite mica and amorphous silica-titania, has been directly observed for the first time in situ using atomic force microscopy (AFM) and optical waveguide lightmode spectroscopy (OWLS). The former yields the lateral distribution and heights of adsorbed single molecules and massed adso...

We develop a model for solute transport in porous media, which takes into account equilibrium and non-equilibrium multiple-site adsorption. Binary ion exchange is included. Adsorption rate formulations and their isotherms are reviewed and their mathematical properties investigated. This forms the basis of the study of travelling wave solutions in the second part of the paper.

The energetics of elementary surface processes relevant for CO oxidation, particularly CO and O2 adsorption, were investigated by a direct calorimetric method on model Pd nanoparticles and on the extended Pd(111) single crystal surface. The focus of this study lies on a detailed understanding of how a nanometer scale confinement of matter affects the binding strength of gaseous adsorbates. We r...

It seems using the Maxwell-Stefan (M-S) diffusion model in combination with the vacancy solution theory (VST) and the single-component adsorption data provides a superior, qualitative, and quantitative prediction of diffusion in zeolites. In the M-S formulation, thermodynamic factor (Г) is an essential parameter which must be estimated by an adsorption isotherm. Researchers usually utilize the ...

Xylene is an aromatic hydrocarbon that is a highly toxic compound. Therefore, it is essential to remove this component from wastewater before discharging it to the environment. In this research work, palm kernel biomass was activated chemically by H3PO4 and synthesized activated charcoal was applied to separate xylene from aqueous media. The prepared activated charcoal was characterized using F...