The sorption of 4-nitrophenol (4-NP) in enzymatically isolated cuticles ofLycopersicon esculentum fruits andFicus elastica leaves was studied as a function of temperature and solute concentration. Plots of the concentrations of 4-NP sorbed in the cuticle versus the equilibrium concentrations in the aqueous phase gave linear isotherms at low concentrations that tended to approach plateaus at higher sorbate concentrations (≥ 10 mmol·kg-1). At low concentrations of sorbed 4-NP, cuticles have sorptive properties similar to those of organic solvents which are able to form intermolecular hydrogen bonds, while at higher concentrations their solid nature becomes apparent. During sorption of 4-NP the cutin matrix swells and new sorption sites are successively formed. The partition coefficients of 4-NP in the system cuticle/buffer are functions of temperature and concentration. At high sorbate concentrations (approx. 1 mol·kg-1) they approach a value of 1. Different sorptive properties were observed for the cutin regions normally encrusted with soluble cuticular lipids (SCL) and those without SCL. Increasing temperature augmented the number of sorption sites in the cutin ofLycopersicon while no effect was observed withFicus. The changes of partial molar free energy (ΔG
o
tr), enthalpy (ΔH
o
tr), and entropy (ΔS
o
tr) for the phase transfer of 4-NP also depended on sorbate concentration: ΔH
o
tr and ΔS
o
tr were negative and steeply decreased at high sorbate concentrations. This is due to solute-solute interactions replacing solute-cutin interactions at high concentrations resulting in solid precipitates of solute within the cutin matrix. This formation of ordered solid domaines starting from a small number of nonelectrolyte molecules interacting with the cutin is proposed as a model for the intracuticular deposition of SCL.

Thermodynamic analysis of nonelectrolyte sorption in plant cuticles: The effects of concentration and temperature on sorption of 4-nitrophenol.

Prediction of multicomponent adsorption is still one of the most challenging problems in the adsorption field. Many models have been proposed and employed to obtain multicomponent isotherms from single-component equilibrium data. However, most of these models were based on either unrealistic assumptions or on empirical equations with no apparent definition. The purpose of this investigation was to develop a multicomponent adsorption model based on a thermodynamically consistent equation, and to validate that model using experiment data. Three barbiturates—phenobarbital, mephobarbital, and primidone—were combined to form a ternary system. The adsorption of these barbiturates from simulated intestinal fluid (without pancreatin) by activated carbon was studied using the rotating bottle method. The concentrations, both before and after the attainment of equilibrium, were determined with a high-performance liquid chromatography system employing a reversed-phase column. The proposed equation and the competitive Langmuir-like equation were both fit to the data. A very good correlation was obtained between the experimental data and the calculated data using the proposed equation. The results obtained from the original competitive Langmuir-like model were less satisfactory. These results suggest that the proposed equation can successfully predict the trisolute isotherms of the barbituric acid derivatives employed in this study.

Prediction of adsorption from multicomponent solutions by activated carbon using single-solute parameters. Part II--Proposed equation.

1. Int roduct ion Surface physics and chemistry have become increasingly significant äs distinct subdisciplines because we have recognized that important physical, chemical, and electrical properties and behavior of matter confined to phase boundaries (commonly called "surfaces" or "interfaces") often differ profoundly from the bulk of that same matter. A complete treatment of surface phenomena would far exceed the scope of this presentation (i). It is assumed that this Symposion is essentially interested in the preparation and behavior of surfaces of metals, plastics, glasses, wood or wood-based materials — polycrystalline, polymeric-resinous, glassy, amorphous or heteromorphous — the phase boundaries of which are contiguous to the ordinary atmosphere and are to be functionally involved in some technical process — for example, corrosion or its prevention, lubrication, surface finishing, enameling, electroplating, or adhesive bonding (2). This paper seeks to Interpret the physico-chemical phenomena occurring at the surfaces of such materials and to show their relationship to the subsequent behavior of the surfaces.

Surface Properties as Physico-Chemical Phenomena

Enterosorption properties of algae fiber were studied. Determination of the thermodynamic characteristics of heavy metal sorption showed that the process is endothermic with the prevalence of chemisorption interactions. Algae fiber exhibits high sorption capacity for heavy metals and pathogenic microorganisms.

Enterosorption Properties of Arctic Brown Algae Fiber

https://iopscience.iop.org/article/10.1088/2053-1591/aab565/pdf

Binding affinities of cationic dyes in the presence of activated charcoal and anionic surfactant in the premicellar region

We have calculated the individual adsorption isotherms from solutions of chloroform-carbon tetrachloride on three adsorbents using only the data on adsorption from solutions.

Adsorption from solutions of nonelectrolytes on solid adsorbents

1.

On the basis of formal use of the law of mass action and the adsorption equilibrium we have derived equations for the adsorption isotherms of binary mixtures.




2.

Experimental data of adsorption of mixtures of vapors agree well with our equations.

S. Yu. Elovin

Papers

Adsorption from solutions of nonelectrolytes on solid adsorbents

The application of the mass action law to adsorption equilibria