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Wyświetlanie 1-4 z 4
Tytuł:
Arrheniusan activation energy of separation for different parameters regulating the process
Autorzy:
Drzymała, J.
Powiązania:
https://bibliotekanauki.pl/articles/109713.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation
activation energy
separation
Gibbs potential
Arrhenius plot
Opis:
The Arrhenius model, that relates the activation energy with the kinetic constant and process temperature, was applied for flotation as a separation process, and next was extended to other incentive parameters such as the frother concentration, NaCl content and hydrophobicity. It was shown that determination of the activation energy caused by other incentive parameters (i.e. particle size, surface potential) was also possible. The units of the activation energy depend on the type of the separation process and incentive parameter. For contact angle regulating flotation the activation energy unit is mJ/m2, while for the frother concentration is J. It is known that instead in joules, the activation energy can also be expressed in J/mol and in kT or RT units, where k is the Boltzmann constant, R gas constant and T is absolute temperature in kelvins. Even though different formulas of the specific Gibbs potential were used for calculation of activation energy caused by various incentive parameters, there was generally a good agreement between the extend of changes of the first order kinetic constants of the process and activation energy value. It was found that for flotation of copper-bearing carbonaceous shale the activation energy was equal to 1.1 kT for NaCl as the incentive parameter, 3.0 kT for temperature and 32.7 kT for butyl diethylglycol ether used as a flotation frother. For methylated quartz the hydrophobicity-induced activation energy was 42 mJ/m2 for contact angle as the incentive parameter.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1152-1158
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A procedure of Arrhenius activation energy determination for salt flotation of particles in the vicinity of one molar salt aqueous solutions
Autorzy:
Ratajczak, Tomasz
Kurkiewicz, Szymon
Drzymala, Jan
Powiązania:
https://bibliotekanauki.pl/articles/1450643.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
activation energy
salt flotation
Arrhenius equation
Gibbs potential
Opis:
A modified Arrhenius equation, in which thermal energy is replaced with chemical (Gibbs) potential, and a special calculation procedure were used to evaluate the flotation activation energy for salt solutions in the one molar range of concentrations. The proposed formula overcomes the difficulties of calculating the salt flotation activation energy caused by mathematical problems of finding 1/(ln($c$/$c_o$)) for the standard salt concentration $C_o$ =1 M (1 kmol/m3 and when the applied salt concentration c is in the vicinity of 1 M. The salt flotation activation energy was calculated for flotation of copper-bearing carbonaceous shale in the 0.25, 0.50, 1.00 and 2.00 M NaCl solutions performed in a laboratory machine as equal to 1.9 RT for standard salt solution equal to 1 M.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 6; 1-5
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control of glass surface wettability via esterification with n-alkyl alcohols
Autorzy:
Kruszelnicki, Mateusz
Polowczyk, Izabela
Kowalczuk, Przemyslaw B.
Powiązania:
https://bibliotekanauki.pl/articles/2146948.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
hydrophobicity
surface free energy
contact angle
zeta potential
roughness
Opis:
Surface wettability plays an essential role in many processes and materials applications. It depends mainly on the surface roughness and chemical composition, thus through a controlled modification of these parameters, the wettability can be restrained. Glass is an inorganic solid material, composed mainly of amorphous silica, which surface, due to the presence of reactive hydroxyl groups, can be quite easily chemically modified. This feature can be used to control the wettability of glass by reaction with organic compounds. In this study, the esterification of glass silanol groups with n-alkyl alcohols (Cn/H2n+1/OH, n=3, 4, 6, 8, 10) was employed to modify its wettability. The effect of such modification on the physicochemical properties of glass surface was comprehensively investigated and characterised by the water contact angle, surface free energy, zeta potential, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) measurements. We demonstrate that the wettability of the esterified glass surface is strongly dependent on both the chain length of used alcohol and modification time. The alcohol molecule binds to the glass surface through a Si-O-C bond, leading to the formation of a monolayer that does not significantly affect the surface morphology and zeta potential. Conducted studies provided a broader view of the influence of this technique for modifying surface wettability on its physicochemical properties.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 2; art. no. 145147
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrokinetic and surface properties of some methacrylate-based copolymers
Autorzy:
Ersoy, Bahri
Çiftçi, Hakan
Evcin, Atilla
Merdivenci, Yılmaz
Powiązania:
https://bibliotekanauki.pl/articles/2146940.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
methacrylate copolymer
zeta potential
contact angle
hydrophobicity
surface free energy
Opis:
In this study, some electrokinetic and surface properties of MBAOM-GMA copolymers synthesized from 2-[(methoxy-1,3-benzothiazole-2-yl) amino]-2oxoethyl methacrylate (MBAOM) and glycidyl methacrylate (GMA) monomers were investigated. Accordingly, (i) pH-dependent zeta (ζ) potential changes of the copolymers were investigated under a constant ionic strength (in 1.10-3mol/dm3 NaCl) and the corresponding isoelectric points (iep) were determined, (ii) zeta potential changes depending on the salt concentration in the presence of mono-, di- and tri-valent metal salts were examined, (iii) contact angles (θ) of the copolymers with water were measured and their wetting behavior was assessed, and (iv) surface free energies (SFE) of the copolymers were determined by Acid-Base approach using Van Oss-Chaudhury-Good method. The compositions of the copolymers were 77% MBAOM - 23% GMA, 45% MBAOM - 55% GMA, and 19% MBAOM - 81% GMA. FeCl3, CaCl2, and KCl salts were used for the salt solutions for the zeta potential measurements. As a result, (i) it was determined that the chemical structure of methacrylate copolymers showed a decisive effect on both electrokinetic and surface properties, (ii) the hydrophobic character of copolymer increased with the increase of the GMA ratio, and correspondingly, the SFE decreased, and (iii) the iep of the copolymers varied between pH 3.1-3.7 depending on composition.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 5; art. no. 152162
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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