Temat: adsorpcja kationów - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Adsorpcja dwuwartościowych kationów na granicy faz hydroksyapatyt/roztwór elektrolitu
Adsorption of divalent cations at the hydroxyapatite/electrolyte solution interface
Autorzy:: Janusz, Władysław
Skwarek, Ewa
Powiązania:: https://bibliotekanauki.pl/articles/1853733.pdf
Data publikacji:: 2021
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: hydroksyapatyt
adsorpcja kationów dwuwartościowych
hydroxyapatite
adsorption of divalent cations
Opis:: Functional and composite materials obtained from hydroxyapatite (HAp) are widely used in practice, which results in intensive research of systems containing hydroxyapatite. Doping with divalent ions of hydroxyapatite changes its properties, thus extending its application in material science. Substitution of calcium ions in the surface layer of hydroxyapatite by metal cations is used in the development of new catalysts, sorbents, sensors and materials for other applications. The doping of the surface of the hydroxyapatite with divalent ions may occur as a result of adsorption of metal cations on the surface groups and calcium exchange in the crystal structure of the hydroxyapatite. The paper presents the mechanisms of adsorption of selected bivalent ions Ba2+, Cd2+, Co2+, Fe2+, Sr2+, Zn2+ on hydroxyapatite. The influence of cation adsorption on unit cell parameters, crystallite size and particle size distribution is discussed.
Źródło:: Wiadomości Chemiczne; 2021, 75, 9-10; 1203-1228
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Wpływ pola ultradźwiękowego na adsorpcję kationów kadmu
The Effect of Ultrasonic Field on the Adsorption of Cadmium Ions
Autorzy:: Lach, J.
Okoniewska, E.
Stępniak, L.
Ociepa, E.
Powiązania:: https://bibliotekanauki.pl/articles/1819171.pdf
Data publikacji:: 2013
Wydawca:: Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:: pola ultradźwiękowe
adsorpcja kationów
aqueous solution
activated carbon
sewage sludge
metal ions
removal
surface
Opis:: Adsorption on activated carbon is one of the methods applied for removal of heavy metals from water and wastewater contaminated with these elements. Ion exchange is a predominating mechanism in the process of sorption of ions. In case of sorption of heavy metals cations various surface aggregates are formed. Other processes, such as reduction and oxidation, and precipitation in the pores of insoluble compounds (e.g. hydroxides, carbonates) also occur. The processes behind the formation of aggregates with various degrees of resistance have a particular effect on the selectivity of ion exchange on activated carbons. The chemical composition of activated carbon surface – in particular, the presence of oxygen groups capable of ion exchange – shows the most significant effect during adsorption of heavy metals ions. Typically, the surface of the activated carbons produced with the steam-gaseous method has functional groups both of acidic and alkaline character that are capable of exchanging cations as well as anions. Carbon materials with no functional groups can also sorb protons. This is possible due to the fact that dislocated electrons π in the solutions act as Lewis base. There are a number of methods currently being investigated that would allow for improving the efficiency of adsorption of heavy metals. In the presented work the effect of ultrasonic field on the adsorption of cadmium from the model solutions was analyzed. Various configurations of ultrasonic field applied in the process of adsorption were investigated. Ultrasounds were generated in the UP 400S disintegrator. In the first phase the activated carbon in the form of granules was modified with the ultrasonic field of acoustic power density of 42,5 W/cm2or 85,0 W/cm2, at the amplitude of 30 and 60 µm, and at the exposure time of 5, 10, 15 and 20 min. Modified activated carbons were used for sorption of cadmium ions from the solutions at the initial concentrations ranging from 2,24 do 11,2 mg/dm3. The adsorption of cadmium on the activated carbon modified with ultrasounds (at the amplitude of 30 µm and 60 µm) and at the shortest exposure time (i.e. 5 min.) was higher than on the initial activated carbon. The most favorable results were obtained for the activated carbon modified with ultrasonic field with the acoustic power density of 42,5 W/cm3 and the exposure time of 10 min. The efficiency of cadmium adsorption for the highest concentration increased from 50% (the initial activated carbon) to 63%. Also, the work included the analysis of the effect of ultrasonic field on the cadmium solution with the activated carbon in the form of granules in the first phase of static adsorption. In this case, no significant differences in the adsorption capacities were observed. Also, the effect of ultrasounds on the solution used for the adsorption of cadmium did not have an impact on the efficiency of adsorption. In the final phase of the investigations the effect of sonification on the adsorption of cadmium on the powdery activated carbon was analyzed. The control sample was mechanically mixed for 5 min, and the remaining samples were subjected to the ultrasonic field at various amplitudes but with the same exposure time. The efficiency of adsorption combined with ultrasounds was significantly higher. The final concentrations during the adsorption without ultrasounds were in the range of 0,291 to 1,778 mg/dm3 whereas for the adsorption combined with ultrasounds these concentrations ranged from 0,13 to 0,748 mg/dm3.
Źródło:: Rocznik Ochrona Środowiska; 2013, Tom 15, cz. 3; 2142-2157
1506-218X
Pojawia się w:: Rocznik Ochrona Środowiska
Dostawca treści:: Biblioteka Nauki

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