https://chemical.eng.usm.my/bassim/PDF/adsorption%20isotherm.pdf

Insights into the modeling of adsorption isotherm systems

1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Surface and Colloid Science

The article focuses on adsorption of heavy metal ions on soils and soils constituents such as clay minerals, metal (hydr)oxides, and soil organic matter. Empirical and mechanistic model approaches for heavy metal adsorption and parameter determination in such models have been reviewed. Sorption mechanisms in soils, the influence of surface functional groups and surface complexation as well as parameters influencing adsorption are discussed. The individual adsorption behavior of Cd, Cr, Pb, Cu, Mn, Zn and Co on soils and soil constituents is reviewed.

Adsorption of heavy metal ions on soils and soils constituents

Guidelines for the use and interpretation of adsorption isotherm models: A review.

Colloid mobilization and transport in groundwater

Multisite proton adsorption modeling at the solid/solution interface of (hydr)oxides: A new approach: II. Application to various important (hydr)oxides

Adsorption on heterogeneous surfaces may be influenced not only by the heterogeneity but also by lateral interactions. For multicomponent solutions competition increases the complexity even further. In practice such complex systems frequently occur and to investigate the behavior of these systems it is rather useful to have analytical equations available which can describe the adsorption. Existing analytical mono- and multicomponent binding equations for heterogeneous surfaces are briefly reviewed. These equations are based on a high degree of ideality with respect to both the local isotherm and the affinity distribution for the different components. A new more generally valid analytical competitive binding equation is derived, using a nonideal local isotherm equation. In this local isotherm all component-specific nonideality is incorporated; i.e., it includes both lateral interactions and component-specific heterogeneity contributions. Under these conditions the remaining adsorbate-surface interactions can be characterized by an "intrinsic" affinity distribution that applies for all components. The features of the new equation are discussed and illustrated on the basis of some model calculations. The model is tested in practice using cadmium ion binding to fulvic acid at various pH values (data of Saar and Weber, Can. J. Chem. 57, 1263, 1979). These data cannot be modeled satisfactorily with the classical equation for multicomponent adsorption on heterogeneous surfaces. The newly derived equation gives excellent results.

Analytical Isotherm Equations for Multicomponent Adsorption to Heterogeneous Surfaces

Ion binding to humic substances is influenced by the chemical heterogeneity and by the variable charge behavior of the humics. In this paper, we concentrate on the variable charge effects. To study these effects, acid/base titration data of 11 humic substances measured at a series of salt levels are analyzed. In a first-order approach, the organic matter molecules are treated as an ensemble of small rigid and impermeable cylindrical or spherical particles of a certain size and a variable surface charge density depending on pH and salt concentration. With double-layer models for such particles, the electrostatic effects on the proton binding can be described reasonably well. When the density of the humic material is used as a constraint, the radius of the spheres or the cylinders is the only adjustable parameter in the model

Proton binding to humic substances. 1. Electrostatic effects

Analysis of proton binding by a peat humic acid using a simple electrostatic model

Comprehensive study on interactions between livestock production systems and the environment. Management of waste from animal product processing is the main subject

J.C.M. de Wit

Papers

Multisite proton adsorption modeling at the solid/solution interface of (hydr)oxides: A new approach: II. Application to various important (hydr)oxides

Analytical Isotherm Equations for Multicomponent Adsorption to Heterogeneous Surfaces

Proton binding to humic substances. 1. Electrostatic effects

Analysis of proton binding by a peat humic acid using a simple electrostatic model

Livestock and the environment : finding a balance