Solid-phase interaction mechanism

Sodium reduction development directions, 336 diluted melts, 331-332 of K-Salt, 327-328 principals, 326 Solid-phase interaction mechanism, 34-37 niobium oxyfluorides, 26-31 tantalum oxyfluorides, 32-34 Solubility diagrams (NH4)5Nb3OF18, 22 K2NbF7 in HF solutions, 14 K2TaF7 in HF solutions, 14 RbsNbjOF,, 22-23 Solubility of peroxides, 307 Specific conductivity, 153, 164 Spontaneous polarization, 223 Structural characteristics for X Me=8, 61,... 

The Handbook of Environmental Chemistry Vol. 5 Part E Pollutant-Solid Phase Interactions Mechanism, Chemistry and Modeling (by T. A.T. Aboul-Kassim, B. R. T. Simoneit)... 

Abdul-KassimT. A. T. and Simoneit B. R. T. (2001) Pollutant-Solid phase Interactions mechanism, chemistry and Modeling. In The Handbook of Environmental Chemistry. Springer, Berlin, vol. 5, part E, 314pp. 

Kassim TA, Simoneit BRT (2001) Pollutant-solid phase interactions Mechanisms, chemistry and modeling. The Handbook of Environmental Chemistry (Water Pollution Series), vol 5/Part E. Springer, Berlin Heidelberg New York, p 435... 

Independent of the molecular properties of contaminants, the subsurface solid phase constituents are a major factor that control the adsorption process. Both the mineral and organic components of the solid phases interact differentially with ionic and nonionic pollutants, and in all cases, environmental factors, such as temperature, subsurface water content, and chemistry, affect the mechanism, extent, and rate of contaminant adsorption. 

Adsorption is a physicochemical process whereby ionic and nonionic solutes become concentrated from solution at solid-liquid interfaces.3132 Adsorption and desorption are caused by interactions between and among molecules in solution and those in the structure of solid surfaces. Adsorption is a major mechanism affecting the mobility of heavy metals and toxic organic substances and is thus a major consideration when assessing transport. Because adsorption is usually fully or partly reversible (desorption), only rarely can it be considered a detoxification process for fate-assessment purposes. Although adsorption does not directly affect the toxicity of a substance, the substance may be rendered nontoxic by concurrent transformation processes such as hydrolysis and biodegradation. Many chemical and physical properties of both aqueous and solid phases affect adsorption, and the physical chemistry of the process itself is complex. For example, adsorption of one ion may result in desorption of another ion (known as ion exchange). 

Solid phase extraction (SPE) involves the separation of components of samples in solution through their selective interaction with and retention by a solid, particulate sorbent. SPE depends on differences in the affinities of the various components of the sample for the sorbent. The mechanisms of the interactions are virtually identical to the sorption processes that form the basis of liquid chromatographic separations (p. 80). The choice of solvent, the pH and ionic strength of aqueous solutions, and the chemical nature of the sorbent surface, especially its polarity, are all of importance in controlling the selectivity and efficiency of an extraction. 

In order to better investigate the relationship between sensor response and interaction mechanism it is useful to consider the way in which each volatile compound is expected to interact when in contact with a solid phase. These interactions can be modelled using the linear sorption energy relationship approach (LSER) [23]. 

A primary role of crystallization is to purify the desired product and exclude impurities. Such impurities are frequently related in chemical structure to the desired product, through the mechanisms of competitive reaction and decomposition. Where the impurities are similar in structure it is likely that their interactions with the solvent in the liquid phase will also be similar. In this instance the selectivity of crystallization is mainly attributed to the difference between the respective pure solid phases. The ideal solubility equation can be applied to such systems [5, 8] on a solvent free basis to predict the eutectic composition of the product and its related impurities. The eutectic point is a crystallization boundary and fixes the available yield for a single crystallization step. 

CNT can markedly reinforce polystyrene rod and epoxy thin film by forming CNT/polystyrene (PS) and CNT/epoxy composites (Wong et al., 2003). Molecular mechanics simulations and elasticity calculations clearly showed that, in the absence of chemical bonding between CNT and the matrix, the non-covalent bond interactions including electrostatic and van der Waals forces result in CNT-polymer interfacial shear stress (at OK) of about 138 and 186MPa, respectively, for CNT/ epoxy and CNT/PS, which are about an order of magnitude higher than microfiber-reinforced composites, the reason should attribute to intimate contact between the two solid phases at the molecular scale. Local non-uniformity of CNTs and mismatch of the coefficients of thermal expansions between CNT and polymer matrix may also promote the stress transfer between CNTs and polymer matrix. 

It is intended that the review of the different aspects and goals in this chapter provides an up-to-date background for the succeeding chapters in this volume. This will clarify the discussions about the different interaction mechanisms between organic pollutants and various solid phases, their chemistry, and applicable modeling techniques that are presented in the subsequent chapters. 

Interaction Mechanisms Between Organic Pollutants and Solid Phase Systems... 

Keywords. Sorption, Interaction mechanisms, Organic pollutants, Solid phases, Adsorption, Partitioning, Humic substances, Humus, Organic matter... 

Interaction Mechanisms at the Pollutant-Solid Phase Interface. . 129... 

The main objectives of the present chapter are to (1) discuss in detail the compositions of the different solid phase systems covered in this volume which include soils, sediments, suspended matter, colloids, and biocolloids/biosolids, (2) review the various interaction mechanisms between organic pollutants and... 

Before discussing the various interaction mechanisms between organic pollutants and solid phase systems, it is important to describe briefly the compositions of such solids mentioned in this chapter and throughout the volume. This can provide insight about the possible interaction mechanisms and their mode of chemical interactions. These phases include soils, sediments, suspended solids, colloids, and biocolloids (i. e., biosolids). 

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