Long Term Sorption Kinetics of Phenanthrene in Aquifer Materials

Abstract

Most aquifer materials are heterogeneous in terms of grain size distribution and petrography. To understand sorption kinetics, homogeneous subfractions, either separated from heterogeneous sands and gravels (lithocomponents) or fragments of fresh rocks, have to be studied. In this paper we present data on long-term sorption kinetics of phenanthrene for homogeneous samples consisting of one type of lithocomponents or fresh rock fragments in different grain sizes. Diffusion rate constants were determined in batch experiments using a numerical model for retarded intraparticle pore diffusion and correlated to grain size and intraparticle porosity of the lithocomponents. Sorption isotherms were nonlinear for all samples investigated (Kleineidam et al. ()). The numerical model described the sorption kinetics very well for coarse sand and gravels. Tortuosity factors, which were obtained as final fitting factors, agreed with Archie's law predictions based on the intraparticle porosity. The dependency of sorptive uptake on grain size revealed that for smaller grains intrasorbent diffusion may become significant. This is attributed to relatively large particulate organic matter (POM) within the sedimentary rock fragments. Specifically, charcoal and coal particles, which were found in some of the sandstones, controlled the sorptive uptake rates.

A Density Functional Theory Study of the Adsorption of Benzene on Hematite (α-Fe2O3) Surfaces

“…There also exists a large literature on sorption studies conducted with natural minerals and other geosorbents, like sediments or soils, with varying organic matter content [88][89][90][91][92][93][94][95][96][97][98][99][100][101]. For example, the interaction between the (110) goethite surface and acetic acid, acetate, 2,4-dichlorophenoxyacetic acid, 2,4-dichlorophenoxyacetate and benzene have been studied by means of quantum mechanical calculations using the B3LYP approach [88], whereas the interaction of esters and acids with iron oxide surfaces has also been reported [47,89].…”

Sorption Behavior of Dye Compounds onto Natural Sediment of Qinghe River

“…Pignatello and Xing (6) as well as Luthy et al (7) have reviewed the sorption/desorption of organic compounds on the natural particles. Numerous studies have been devoted to sorption kinetics (8)(9)(10)(11), equilibrium modeling, and mechanism (12)(13)(14)(15)(16)(17), as well as to the factors that affect adsorption (18)(19)(20). It has been shown that the sorption of low-polarity, nonpolar, and nonionic organic compounds onto natural particles occurs largely by the partition of these compounds to organic matter involved in the solid (16,(21)(22)(23), and the interface behavior of ionic organic compounds is controlled mainly by the specific chemical and electrostatic interactions (24)(25)(26)(27)(28).…”

Modeling desorption kinetics of a persistent organic pollutant from field aged sediment using a bi-disperse particle size distribution

“…We used a numerical integration method similar to the method described by Rügner (Rugner et al 1999) to 10 [um] 50 [um] 250 [um] 2000 [um] 100 The thick solid line through the symbols was calculated using the bi-disperse model with particle diameters of 10 and 84 μm approximate the solution of Eqs. 3 and 11.…”

“…For example, Freundlich sorption isotherms (Miller and Pedit 1992;Lin et al 1994;Rugner et al 1999;Braida et al 2001;Gamst et al 2004) or linear sorption isotherm (Wu and Gschwend 1986;Steinberg et al 1987;Rijnaarts et al 1990;Ball and Roberts 1991;Brusseau et al 1991;Pignatello et al 1993;Pedit and Miller 1994;Li and Werth 2004) were used to model desorption kinetics. In radial diffusion models, particle-size effects are generally lumped into a single-fit-parameter D a /R 2 , where D a is a diffusion coefficient and R the radius of the spheres.…”