CALIBRATION COEFFICIENTS OF CONNECTION BETWEEN THE LANGMUIR ADSORPTION EQUATION AND V.N. OPARINA’S KINEMATIC EXPRESSION FOR PENDULUM-TYPE WAVES ACCORDING TO LOCAL MEASUREMENTS AT THE COAL DEPOSITS OF KUZBASS

The article shows that at present there are experimental and theoretical prerequisites for establishing formalized relationships between deformation-wave and physicochemical processes occurring in real multiphase rock massifs. The calibration coefficients of the relationship in the correspondence operator between the adsorption equation and the kinematic expression for pendulum waves were established, verified in comparison with the available measurements in laboratory and field experiments for coals of the entire metamorphic series: quantitative values of the physicochemical invariant were determined for coals of different stages of metamorphism and structural parameter of the geomedium, as well as the velocity of propagation of a longitudinal wave in geoblocks-carriers of pendulum waves and translational movement of "colliding" geoblocks for different stages of metamorphism. It is shown that the values of the obtained dispersion allow one to take into account all the variety of the main stages of metamorphism of Kuzbass coal deposits in the theory and forecast of outburst hazard, i.e. take into account the real qualities of coal seams.

Adsorption and Migration Characteristics of Fluorine in Ash-Sluicing Water in Soils

The excessive fluorine content in ash-sluicing water has become one of the main environmental pollution problems in the thermal power generation industry. This study selected 5 representative soil types and used fluoride ions (F-) as the pollution control factor. The experimental results showed that the isotherms of the F- solutions prepared by deionized water (adsorbed by Jianbi clay and Fengrun sandy soil) and ash-sluicing water all conformed to the Langmuir isothermal adsorption equation. In terms of the F- solution prepared with ash-sluicing water, the adsorption isotherm of Tianshengqiao red clay conformed to the Langmuir isothermal adsorption equation; the adsorption isotherms of Beijing silty soil and Fen River loess conformed to the Henry isothermal adsorption equation. In terms of the maximum adsorption capacity, Tianshengqiao red clay > Jianbi clay > Beijing silty soil ? Fen River loess > Fengrun sandy soil. Through the experiments, we also found that the adsorption capacity decreased with increasing pH, and the pH buffering effects of the 5 soils, from high to low, were Tianshengqiao red clay > Jianbi clay > Beijing silty soil > Fen River loess > Fengrun sandy soil.

Some Questionable Approaches in Interfacial Electrochemistry—The Charged State of Adsorbed Species and Their Involvement in Redox Processes

On the basis of a survey on the relevant literature it can be stated that some views and approaches concerning the charged state of adsorbed species and the charge transfer processes occurring with them are far from being unambiguous even in some respect they contradict fundamental physical and physicochemical principles. The meaning of the electrosorption valency, the misleading formulation of the Gibbs adsorption equation, and the interpretation of redox processes occurring with adsorbed species, is discussed in detail. It has been concluded that although the electrosorption valency of an adsorbed species as usually defined is an extra-thermodynamic and self-contradictory concept, experimental determined formal partial charge numbers can be a useful tool for scientists investigating adsorption phenomena, since the observed deviation between its value and the charge number of the same species in the solution phase unequivocally indicates a non-simple mechanism of the adsorption process, which should be taken into account in theoretical interpretation of the experimental data. It has been emphasized that the evaluation of voltammetric curves obtained in the presence of adsorbed redox partners requires a cautious analysis of the accompanying chemical transformations. In the framework of a critical analysis it is demonstrated that probably one of the most important sources of the misinterpretations and misunderstandings is the inadequate approach to the concept of electrode charge. The possibility of a general and straightforward presentation of the Gibbs adsorption equation has also been discussed.

The Issue of the Free Surface of Adsorbent in the Description of a Monolayer Mobile Gas Adsorption on Solids

This paper characterises the concept of monolayer mobile gas adsorption on a homogeneous surface of a solid. The theoretical basis of the phenomenological variant of the description of adsorption equilibrium in the system in question are discussed. The essential features of the solutions to date are discussed, and the effect of the free surface of adsorbent on the form of the final adsorption equation is stressed.An alternative concept of the free surface based on the modified two-dimensional analogue of Reiss, Frisch and Lebowitz equations is also presented. The obtained adsorption equation was tested for critical parameters of two-dimensional condensation of the adsorption layer, and then used to describe the experimental data available in literature. The verification carried out confirmed the correctness and usefulness of the proposed concept.

Molecular Dimerisation in a Multilayer Adsorption Phase on Homogeneous Surfaces of a Solid Adsorbent

Continuing the discussion on the description of adsorbate-adsorbate association on homogeneous surfaces of solids, an attempt was made to formulate an analytical form of adsorption equation for a multilayer adsorption phase. The validity of Berezin’s and Kiselev’s assumptions concerning the independence of adsorption in further layers from the model of the phenomenon in the first of them was discussed. The fundamental validity of this assumption has been demonstrated, simultaneously ridding it of its arbitrary character. The main aim of the study was to demonstrate the possibility of formulating a description assuming molecule association in the entire adsorption phase (and not only in the first layer). Theoretical considerations are confined to the case of dimerisation in the concentration range thus warranting the approximation characteristic of the Berezin and Kiselev model. The obtained final adsorption equation exhibits physically acceptable boundary properties; with adequate assumptions it amounts to the Brunauer, Emmett and Teller equation, the equation formulated earlier by one of the authors of this paper or the Langmuir equation.

The equivalence of quasi-chemical and statistical description of adsorbate molecule association in a localised adsorption monolayer on a homogeneous solid surface

The analysis of Berezin and Kiselev’s concept assuming linear association of molecules in a localised adsorption monolayer on the homogeneous surface of a solid adsorbent was carried out. An inconsistency due to the lack of consideration of equilibrium concentration of free adsorption sites in the formulation of the expression for the association constant has been pointed out. It was shown that the correct form of this function leads to the final adsorption equation being identical to the specific case of the Fowler-Guggenheim equation. The obtained result has been generalised to cases of branched adsorbateadsorbate associations. A new adsorption equation limiting the association to at most the dimers has been introduced. Critical conditions for the two-dimensional condensation of the adsorption layer were determined. By applying the formalism of canonical ensemble, full equivalence of the phenomenological and statistical methods was demonstrated in the description of the intermolecular interactions in the localised adsorption monolayer.