An adsorption-desorption (or parking-lot) model can reproduce qualitatively the densification kinetics and other features of a weakly vibrated granular material. Here we study the the two-time correlation and response functions of the model and demonstrate that their behavior is consistent with recently observed memory effects in granular materials. Although the densification kinetics and hyste...

Directly measuring the rate of a surface chemical reaction remains a challenging problem. For example, even after more than 30 years of study, there is still no agreement on the kinetic parameters for one of the simplest surface reactions: desorption of CO from Pt(111). We present a new experimental technique for determining rates of surface reactions, the velocity-selected residence time metho...

The adsorption of catechol (1,2-dihydroxybenzene) on graphene nanoplatelets (GNPs) is investigated electrochemically and spectroscopically. The reversible adsorption of catechol on GNPs is Langmuirian with an adsorption constant of (0.2 ± 0.002) mM-1 at low adsorbate concentrations (≤100 mM). At higher concentrations (>100 mM) the adsorption of catechol on GNPs is shown to undergo a flat to ver...

studies on adsorption, desorption and reaction kinetics of carbendazim in grey-brown podzolic soil derived from loamy sand (Albic luvisls), grey-brown podzolic soil derived from silt (Haplic luvisols) and brown soil derived from sandy clay loam (Haplic Cambisols) were carried out. Five concentrations of carbendazim (5.0, 3.8, 2.6, 1.0 and 0.2 μg ⋅ cm-3) in 0.01 mol ⋅ dm-3 CaCl2 were used for th...

The drying kinetics were examined in four cross-linked polymers that form hydrogels: 2,3-Dihydroxypropyl methacrylate (DHPMA) and 2-hydroxyethyl methacrylate (HEMA) and two random copolymers, with one-to-one and three-to-one HEMA-to-DHPMA molar ratios. The hydrogels were saturated with buffered, isotonic saline solution and deionized water; weight loss kinetics were monitored at temperatures fr...

The contribution of variable grain sizes to uranium adsorption/desorption was studied using a sediment from the US DOE Hanford site. The sediment was wet sieved into four size fractions: coarse sand (1-2 mm), medium sand (0.2-1 mm), fine sand (0.053-0.2 mm), and clay/silt fraction (<0.053 mm). For each size fraction and their composite (sediment), batch and flow-cell experiments were performed ...

The effects of adsorbate lateral interactions on the kinetics of surface diffusion and desorption are studied by means of kinetic and thermodynamic Monte Carlo simulations. This study is motivated by recent diffusion and desorption experiments on the NH3/Re~001! system, which show that the activation energies of these processes decrease ~in different fashions! with increasing surface coverage, ...

A thermally enhanced pump-and-treatment method for pentachlorophenol (PCP)-contaminated soil and groundwater has shown potential advantages over the traditional pump-and-treatment method. Studies on the desorption kinetics of PCP from aquifer soil are the first step toward quantitative assessment of the newly proposed method. Five series of desorption batch tests were conducted at different tem...

The host xanthenol compound forms a 1:1 clathrate with dioxane, namely 9-(1-naphthyl)-9H-xanthen-9-ol-1,4-dioxane, C23H16O2.C4H8O2. The structure of this clathrate is reported, along with a study of the kinetics of desolvation and the determination of an activation energy. The guest molecules are stabilized by O(host)-H...O(guest) hydrogen bonds [O-H = 0.968 (2) A, O...O = 2.7532 (13) A and O-H...

The kinetics of K exchange were investigated in Ca-saturated samples from the Ap horizon of an Evesboro soil from Delaware. Biphasic kinetics characterized the first-order plots for K adsorption and desorption at 283 and 298K with the two simultaneous reactions being attributed to exchange sites with varying reactivity for K and Ca ions. The rapid reaction was ascribed to exchange sites of the ...