The mean ionic activity coefficients of NaCl in fructose + water mixtures were experimentally determined at 298.15 K from electromotive force measurements of the following electrochemical cell containing two ion-selective electrodes (ISE):  Na−ISE|NaCl(m),fructose(w),H2O(1−w)|Cl−ISE. The molality (m) varied between (0.005 and 3.5) mol kg-1, while the mass fraction of fructose in the mixture (w) was 0, 0.1, 0.2, 0.3, and 0.4. The emf values were analyzed using different models which employed extended Debye−Hückel equations and those of Pitzer, Scatchard, and Sen for describing the variations in activity coefficients with concentration. Results obtained with the different models were in good agreement. The interaction parameters of each model were comparatively analyzed with those of other similar systems reported in the literature, and discussion is presented concerning their variation with properties of the medium, particularly the dielectric constant. The free energy of transfer of the NaCl from the water to the mixed solvent was determined and its variation with the composition of the solvent is discussed in terms of ion−ion and ion−solvent interactions. Also determined was the primary hydration number of the NaCl, which was compared with results from the literature. Finally, the parameters of interaction g ij and salting constant k s were estimated.

The corrosion behavior of four different preparations of plasma-sprayed hydroxyapatite (HA) coatings on Ti6Al4V substrates in static Hank's balanced salt solution was investigated using dc potentiodynamic and ac impedance techniques. Two different nominal thicknesses, 50 microm and 200 microm, and two different spraying conditions, were considered. The electrochemical impedance experiments proved this technique to be very suitable for the investigation of the electrochemical behavior of surgical implant alloys when they are coated with HA, which is characterized by the dissolution and passivation characteristics of the underlying metal substrate. Because the coatings are porous, ionic paths between the electrolytic medium and the base material can eventually be produced, resulting in the corrosion of the coated metal. Differences in the corrosion resistance of the coated materials were detected, and a relevant model for the description of the coating degradation in the biosimulating solution was proposed. The model consisted of the description of the coated system in terms of a two-layer model of the surface film. Significant differences in electrochemical behavior for similar nominal thicknesses of HA coatings obtained under different spraying conditions were found.

The effects of boron content and preparation methods are studied in this present investigation. Three different methods are employed for the preparation of catalysts. The catalysts are characterized by pore size distribution (PSD), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Thiophene hydrodesulfurization (HDS), cumene hydrocracking (HC), gas oil HDS and Maya heavy crude oil HDS, and hydrodemetallization (HDM) activities are tested. The results show that the specific surface area and PSD are not changed with B loading. The enrichment of metal distribution on the alumina surface is observed from SEM experiments for the 0.6B–NiMo catalyst. More staging of MoS2 active phases is noticed in the B catalyst than the B-free catalyst. It can be stated that boron forms a monolayer on the alumina surface and reduces the metal–support interaction. It facilitates the formation of more staging of active phases. The thiophene HDS activity slightly increases with boron loading up to 0.6 wt % B, and after that, the activity becomes constant or slightly decreases. The cumene cracking of the NiMo–B catalyst shows the highest activity. The overall activity of boron catalysts was found to be the same or marginally higher than that of the boron-free catalyst. The presence of boron may help to reduce catalyst deactivation during hydrotreating of heavy crude oil.

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This article presents the results of an experimental study conducted to evaluate the behavior of two types of andisol soils found in Tenerife, Canary Islands, Spain. The soils were evaluated in relation to their buffering capacity when confronted with acid and alkaline fronts generated during electroremediation treatment. The study was conducted using a cell, which established a continuous flow of distilled water through electrode chambers to remove H ϩ and OH -generated during electrolysis. The results indicate that the soils had sufficient buffer capacity to support variations in pH independent of the maintenance of flow of solution in the electrode chambers.Although the mechanism of migration was not affected, the flow of water favored the movement of ions by diffusion monitoring of the electrolytic current allowed for a real-time parameter to act as an indicator of the quantity of ions available in regions near the electrodes.