Measuring of the electromotive force in molten system is used to characterize thermodynamic properties of the system at equilibrium. Values of the electromotive force are very important for the determination of activity and standard electrode potential. Investigation of the electromotive force of Al + TiB2 and Al-Al cell was the main aim of this work leading to the characterization of acid cryolite systems. The measurements were realized using a molten aluminum electrode and the electromotive force of an electrochemical cell was investigated in electrolytes at various molar ratios (NaF/AlF3) at equilibrium. Thermodynamic properties were measured in acid cryolite melts at three different temperatures: 800 °C, 900 °C, and 1000 °C, for all experiments.
The removal of three environmentally harmful and hardly degradable pharmaceuticals, namely sulfamethoxazole, diclofenac, and cetirizine, from aqueous solution by the adsorption onto two types of activated charcoals (WSCl2 and HWOH) was investigated. The volume of micropores and mesopores in two charcoals was the main property affecting removal efficiencies. Using microporous WSCl2 as an adsorbent, higher removal efficiencies were achieved for all chosen pharmaceuticals. The highest removal efficiency was recorded in the case of sulfamethoxazole (79%). A direct correlation between log Kow and removal efficiencies and between the solubility of pharmaceuticals and removal efficiencies was not found. The adsorption behavior of individual pharmaceutical solutions can be described by the pseudo-second order kinetic model. The parameters obtained from the kinetic model show that the adsorption rate on HWOH was higher than on WSCl2. However, the amounts of adsorbed pharmaceuticals were lower on HWOH than on WSCl2, which can be linked to the textural difference between the charcoals. In the mixture consisting of all three compounds, overall removal efficiencies were lower than in the case when individual pharmaceuticals were present in the solution. Results also indicate that a certain fraction of the micropores can only be occupied by the smallest compound in the mixture (sulfamethoxazole).
Novel technologies for organic pollutants degradation have been studied to cope with extensive water pollution. In this work, the use of ultraviolet degradation and potassium ferrate as possible oxidation tools for toluene, a widely used industrial chemical, degradation is proposed. In the experiment with ultraviolet irradiation, a low-pressure mercury lamp was used to generate a single line electromagnetic radiation with the wavelength of 254 nm. Maximal degradation efficiency achieved after 55 minutes of irradiation was 67.1 %. In the experiments with potassium ferrate, the highest degradation efficiency was 71.2 % at the concentration of 10 mg/L of ferrate (VI) anion.
Surface water and groundwater are polluted with pharmaceuticals, detergents, pesticides, and many other substances. Application of ferrates seems to be a perspective option for wastewater treatment as ferrates are not only powerful oxidizing agents but also an excellent disinfecting and coagulating agents decomposing many stable inorganic, organic, and biological compounds. Final products of their decomposition do not include carcinogenic or toxic products. In this paper, stability of electrochemically prepared potassium ferrate encapsulated in packaging materials printed on a 3D printer was monitored. In the experiment, electrochemically prepared potassium ferrate with different purity (21.4 %, 63.5 % and 67.3 %) was used. Stability of potassium ferrate was monitored for one month and that of other ferrates for three months. Different storage conditions of ferrate samples were also compared. Storage conditions had a significant influence on the ferrate stability.
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