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Wyszukujesz frazę "Langmuir adsorption" wg kryterium: Temat


Wyświetlanie 1-10 z 10
Tytuł:
Hydrocarbons removal from underground coal gasification water by organic adsorbents
Autorzy:
Lutynski, M.
Suponik, T.
Powiązania:
https://bibliotekanauki.pl/articles/110448.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
underground coal gasification
permeable reactive barrier
Langmuir adsorption isotherm
Opis:
The main problems in the case of the undergorund coal gasificiation process is the possible pollution of surrounding aquifers. The underground gasification cavity is a source of both gaseous and liquid pollutants and these are mainly aromatic hydrocarbons, phenols, heavy metals and others. In order to prevent underground water from pollution a permeable reactive barrier was proposed. The filling was granulated activated carbon and SPILL-SORB (peat) – two commonly available sorbents adequate for hydrocarbons removal. The wastewater (synthetic solution which simulated groundwater contaminated with the UCG products) was prepared by mixing distilled water with desired amounts of substances such as phenols, benzene, toluene, xylene, naphthalene etc. Batch tests were performed in order to measure sorption of phenols and benzene from the post-UCG water on the mentioned sorbents. Experimental results were fitted with linear and non-linear Freundlich and Langmuir isotherm models. The obtained data showed that removal of phenols and benzene in case of GAC was much more efficient. However, sorption was lower than in the case of literature data and can be explained by complex composition of the solution and pre-treatment of the samples. The Langmuir model gave a better fit in the case of GAC, whereas Freundlich isotherm model was matching the data better in case of SPILL-SORB.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 289-298
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of Cr(VI) using a novel adsorbent modification. Ultrasonic method with apricot kernel shells
Autorzy:
Kalipci, E.
Namal, O. O.
Powiązania:
https://bibliotekanauki.pl/articles/207440.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adsorption
isotherms
ultrasonics
Langmuir adsorption
Langmuir isotherm
adsorpcja
izotermy
ultradźwięki
adsorpcja Langmuira
izoterma Langmuira
Opis:
Raw apricot kernel shells (AKS) and ultrasound-modified apricot kernel shells were used as adsorbents for the removal of Cr(VI) from aqueous solutions. For raw and modified AKS, the experimental data well fitted to the Langmuir isotherm and adsorption kinetics was suited to pseudo-second order kinetic model indicating chemisorption as the rate-limiting step. For raw and modified AKS, maximum adsorption capacities obtained from the Langmuir adsorption model were 6.5 mg/g and 9.9 mg/g, respectively. Maximum Cr(VI) adsorption was obtained at a pH 2 and optimum stirring speed was determined as 250 rpm. After ultrasound modification, an increase for Cr(VI) adsorption was observed. Raw AKS as low-cost natural biomaterial can be preferred for the removal of Cr(VI) when compared to other adsorbents. Ultrasonic modification can be used to improve the efficiency of Cr(VI) removal.
Źródło:
Environment Protection Engineering; 2018, 44, 3; 79-93
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamics and adsorption studies of dye (rhodamine-b) onto natural diatomite
Autorzy:
Koyuncu, M.
Kul, A. R.
Powiązania:
https://bibliotekanauki.pl/articles/110287.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
diatomite
rhodamine B
adsorption
thermodynamics
Langmuir isotherm
Freundlich isotherm
Opis:
Thermodynamics and adsorption studies were conducted with a dye of rhodamine-B on natural diatomite. Adsorption of the dye was investigated with an initial dye concentration at pH 8±0.2, 303, 313 and 323 K. The adsorption experiments were carried out isothermally at three different temperatures. The Langmuir and Freundlich isotherm models were used to describe the equilibrium data and the results were discussed in details. The kinetic data agreed with the pseudo-first order model with rate constants (k2) in the range of 3.05–1.59.10–1 g/mg min. The thermodynamic parameters such as standard free energy, entropy change and enthalpy were calculated for natural diatomite. These values showed that adsorption of rhodamine-B on natural diatomite was a spontaneous and endothermic process.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 631-643
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption of sodium/calcium poly(acrylic acid) salts on anatase: effect of the polyelectrolyte molecular weight and neutralization
Autorzy:
Jacquemet, Christian
Powiązania:
https://bibliotekanauki.pl/articles/1449765.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adsorption
free energy
Langmuir isotherm
sodium-calcium poly(acrylic acid) salts
anatase
Opis:
Abstract: Interactions of poly(acrylic acid)s (PAAs) of two different molecular weights (Mw = 9,560 g×$mol^{-1}$ and 4,220 g×$mol^{-1}$) with surfaces of an untreated anatase $TiO_2$ were assessed through adsorption isotherm measurements. Those dispersants were tested under different sodium-calcium neutralization states (molar ratio $r = Ca^{2+}$ / $CO_{2-}$ varying from 0 to 0.35). Their behavior towards the $TiO_2$ surfaces can be described by the Langmuir adsorption model. For both polymers, surface coverage ($Γ_max$) evolves linearly with the molar ratio $r$. For a given r value, a lower surface coverage was observed with the polymer having the highest molecular weight. The free energy of adsorption ($/DeltaG_{ads}$) of PAAs was estimated from adsorption experiment data. This calculation indicates that sorption occurs spontaneously and is unlikely to be of chemical nature. The absolute values of $/DeltaG_{ads}$ are higher for the highest molecular weight polymers suggesting that they are more strongly adsorbed to anatase surfaces. The absolute values of $/DeltaG_{ads}$ per mole of sodium-calcium macromolecules are found to be lower than those calculated for their homologues 100% sodium neutralized suggesting that they are bound with the solid by a fewer number of segments.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 1; 113-123
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface modification of fly ash spheroidal particles and their application in the adsorption of phosphorus and chromium(VI) from single and competitive solute systems
Autorzy:
Chen, Chen
Cheng, Ting
Zhang, Xiao
Zhang, Minte
Lv, Ruiyang
Powiązania:
https://bibliotekanauki.pl/articles/2032957.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fly ash
Langmuir isotherm
adsorption phosphorus
popiół lotny
izoterma Langmuira
adsorpcja fosforu
Opis:
This work focuses on the surface modification of fly ash spheroidal particles and their application in phosphorus and chromium(VI) adsorption. The results show that through surface modification, amorphous silica-alumina gels precipitated on the spheroidal particle surface (by which the microsurface area of the reaction products is effectively enlarged) and the surface zeta potential was changed to fit for adsorbing anions. During the adsorption experiment (single and competitive solute systems), chromium(VI) was easier to adsorb. The surface zeta potential and the existence of competitive ions should be recognized as two important factors affecting adsorption efficiency. A higher temperature could improve the adsorption efficiencies of the two solute systems. The fitting results of the pseudo-second-order model (single and competitive solute systems) show better agreement than those of the pseudo-first-order model at every temperature. The Langmuir adsorption isotherm equation can better simulate the adsorption process in single solute sy039stems, but only the chromium(VI) adsorption process can be fitted by the competitive Langmuir adsorption isotherm in competitive solute systems.
Źródło:
Environment Protection Engineering; 2020, 46, 3; 39-59
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption of reactive dyes and their mixtures on activated carbon. Kinetics, equilibrium and thermodynamic evaluation
Autorzy:
Kouhail, Meriem
Elahmadi, Zakia
Benayada, Abbes
Dewil, Raf
Powiązania:
https://bibliotekanauki.pl/articles/206912.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adsorption efficiency
adsorption kinetics
Langmuir isotherm
reactive dye
COD
efektywność adsorpcji
kinetyka adsorpcji
izoterma Langmuira
barwnik reaktywny
ChZT
Opis:
The adsorption of three reactive dyes (Reactive Bezactiv Yellow (RBY), Reactive Bezactiv Blue (RBB) and Reactive Bezactiv (RBR)) on a commercially available activated carbon (CAC) has been evaluated. It was shown that CAC is capable to effectively remove these dyes from a solution. The adsorption increased with higher contact time, adsorbent dose, and initial dye concentration. The data indicated that the adsorption kinetics of dyes on CAC followed a pseudo-second order model. The adsorption isotherms followed the Langmuir isotherm model. Evaluation of thermodynamic parameters revealed that the adsorption process is endothermic for all dyes and spontaneous in a single system and became spontaneous in mixture systems at high temperature, expect RBY and RBB in the ternary mixture. Adsorption was higher for RBY, followed by RBB, and was lowest for RBR. The total adsorption efficiency was confirmed by chemical oxygen demand (COD) measurements.
Źródło:
Environment Protection Engineering; 2020, 46, 2; 5-24
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ferric hydroxide-based media for removal of toxic arsenic species. Kinetic, equilibrium and thermodynamic studies
Autorzy:
Szlachta, M.
Wójtowicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/207931.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Freundlich isotherm
Langmuir isotherm
arsenic
adsorption
sewage
izoterma Freundlicha
izoterma Langmuira
arsen
adsorpcja
ścieki
Opis:
Adsorption studies were conducted to assess the feasibility of ferric hydroxide-based material for treatment of highly arsenic-contaminated effluents. The experiments were performed in a batch adsorption regime using a synthetic aqueous solution. The contact time between arsenic ions and the adsorbent, initial concentration of arsenic in treated solution, temperature of solution and adsorbent dose had a significant effect on the adsorption performance in the system. Both the mechanism of the process involved and the rate of As(III) and As(V) adsorption were analyzed based on pseudo-firstand pseudo-second order kinetic models. The adsorption data at constant temperature were described by the Langmuir and Freundlich isotherm equation, and the theoretical adsorption capacity of ferric hydroxide was determined to be 43.75 mg/g and 44.04 mg/g for arsenic(III) and (V), respectively. The estimated thermodynamic parameters, including changes in free energy, enthalpy and entropy, revealed that the adsorption is spontaneous and endothermic under applied experimental conditions.
Źródło:
Environment Protection Engineering; 2018, 44, 4; 117-129
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Activated bio-carbons prepared by physical activation of residues after supercritical extractionof raw plants
Autorzy:
Bazan-Woźniak, Aleksandra
Pietrzak, Robert
Powiązania:
https://bibliotekanauki.pl/articles/110368.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bio-sorbents
physical activation
toxic gas removal
adsorption from liquid phase
Langmuir and Freundlich isotherm
Opis:
A series of activated bio-carbons has been obtained by physical activation of residues after supercritical extraction of blackberries, raspberries and blackcurrants. The effects of different temperatures of activation and different starting materials on the physicochemical and sorption properties of the bio-carbon samples obtained were evaluated. The physicochemical properties of the activated bio-carbons were characterized by elementary analysis, low-temperature nitrogen sorption and Boehm titration. All materials were tested as adsorbents of pollutants from gas (nitrogen dioxide) and liquid (iodine, methylene blue) phase. The sorption properties of the activated bio-carbons were tested at 23°C. The materials obtained were activated bio-carbons of surface area ranging between 303 and 442 m2/g and showing basic character of the surface. The content of elemental carbon in the obtained samples was in the range of 73.4-82.1 wt. %. The maximum adsorption capacities of the materials towards nitrogen dioxide were 65 mg/g, methylene blue -207 mg/g, and iodine 1001 mg/g. According to the adsorption tests towards nitrogen dioxide, the sorption capacities of the adsorbents studied were increased if a mixture of nitrogen dioxide and air had a humidity of 70 %. The mechanism of methylene blue adsorption involved the formation of adsorptive multilayer. The most effective adsorbent of organic and inorganic pollutants proved to be the activated bio-carbon obtained from the residues after supercritical extraction of blackcurrants.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 6; 1357-1365
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of reactive blue 29 dye by adsorption on modified chitosan in the presence of hydrogen peroxide
Autorzy:
Naghizadeh, A.
Nabizadeh, R.
Powiązania:
https://bibliotekanauki.pl/articles/208197.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adsorption isotherms
copper compounds
isotherms
sewage
adsorption capacities
Langmuir isotherm
natural water systems
izotermy adsorpcji
związki miedzi
ścieki
izotermy kanalizacyjne
ścieki przemysłowe
izoterma Langmuira
Opis:
Industrial effluents that carry dyestuff into natural water systems are serious environmental concern. Complex aromatic structures of dyes make them more stable and more difficult to remove from the effluents discharged into water bodies. In the present study, removal of reactive blue 29 dye with chitosan and modified chitosan with Cu complexes from aqueous solution was investigated in a batch adsorption system with respect to the changes in the contact time, pH of solution and chitosan dosage. Adsorption isotherms of the dye onto chitosan were also studied. The results revealed that the adsorption capacity of chitosan with Cu complexes is lower than that of chitosan without Cu complexes. Also effect of H2O2 on adsorption when we used chitosan without Cu complexes is more considerable. The results also demonstrated that adsorption capacity of reactive blue 29 dye on chitosan was higher at lower pHs. Finally, the Langmuir isotherm showed the best conformity to the equilibrium data.
Źródło:
Environment Protection Engineering; 2016, 42, 1; 149-168
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of titanium dioxide/attapulgite composites and their application in treating Reactive Black KN-B wastewater
Autorzy:
Xie, A.
Luo, S.
Chaoyao, Y.
Powiązania:
https://bibliotekanauki.pl/articles/207828.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wastewater treatment
titanium dioxide
X ray diffraction
adsorption capacities
adsorption kinetics
Langmuir models
photocatalytic effect
oczyszczanie ścieków
dwutlenek tytanu
dyfrakcja promieniowania X
zdolności adsorpcyjne
kinetyka adsorpcji
modele Langmuira
efekt fotokatalityczny
Opis:
Removal of water soluble Reactive Black KN-B from aqueous media by means of titanium dioxide/attapulgite (TiO2/ATP) composites was studied in a batch system. The composites were investigated using X-ray diffraction and surface area analysis. Under UV irradiation, the photocatalytic effect of TiO2/ATP composites, pH and reaction temperature on the decolorization rate of Reactive Black KN-B were investigated in detail. The adsorption experiments of TiO2/ATP composites showed that the isotherms and adsorption kinetics were well followed by the Langmuir model and the zero order equation, respectively. The maximum adsorption capacity of TiO2/ATP composites for Reactive Black KN-B calculated by the Langmuir model was 20.08 mg g-1. It can be concluded that the TiO2/ATP composites could be good photocatalysts/adsorbents for treating Reactive Black KN-B wastewater.
Źródło:
Environment Protection Engineering; 2014, 40, 1; 45-56
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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