Wyniki wyszukiwania - Biblioteka Nauki

Ten serwis zostanie wyłączony 2025-02-11.

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

Znaleziono wyników: 4

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Adsorpcja dwuwartościowych kationów na granicy faz hydroksyapatyt/roztwór elektrolitu

100%

Janusz W. , Skwarek E.

Wiadomości Chemiczne

2021

tom [Z] 75, 9-10

1203--1228

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.

Preparation of yttrium citrate by the reaction of yttrium hydroxide with sodium citrate

80%

Janusz W. , Skwarek E. , Sternik D.

Physicochemical Problems of Mineral Processing

2020

tom Vol. 56, iss. 6

51--59

A method of obtaining yttrium citrate by transformation of freshly precipitated yttrium hydroxide in the solutions of sodium citrate under hydrothermal conditions has been proposed. To determine the synthesis time, transformation kinetics consisted in by taking the solid samples for the C and H contents analysis after 6, 12, 24, 48 and 72 hours of synthesis. Simultaneously these samples were subjected to the thermogravimetric analysis. As follows from the thermogravimetric analysis adsorption of citrate dihydrate on yttrium hydroxide is observed in the initial period up to 24 hours. Later the yttrium citrate dihydrate is formed. The thermogravimetric analysis of the final product i.e. amorphous yttrium citrate showed that the decomposition/oxidation of the sample occurs in six stages the particle size analysis method of static light scattering showed that 45% of the particles had a diameter of 0.1-0.9 µm and 55% of particles with sizes from 0.9 to 5 µm.

Synthesis of citrates of selected lanthanides (Er, Ho and Lu)

80%

Janusz W. , Pikus S. , Skwarek E. , Olszewska E.

Physicochemical Problems of Mineral Processing

2020

tom Vol. 56, iss. 6

225--234

Holmium, erbium and lutetium citrates can be synthesized by transforming freshly precipitated holmium, erbium and lutetium hydroxides in the citric acid solution under the hydrothermal conditions (above 100 ℃) after 3 days of reaction. In this paper in order to determine the synthesis conditions, the hydroxide and citrate stability areas of selected lanthanides were compared. The studies of the structure of the obtained holmium citrate, erbium and lutetium samples showed that these compounds crystallize in a monoclinic system. The crystallite sizes determined by the HalderWagner method were 67.8 ± 8.0nm, 103.7 ± 4.5nm and 68.1 ± 4.2nm, respectively for the holmium citrate, erbium citrate and lutetium citrate samples. The shifts of the hydroxyl and carboxyl groups of citric acid in the FTIR spectrum indicate the interactions of both groups with holmium, erbium and lutetium cations. Then the obtained samples were subjected to the analysis of composition, and their particle size distribution was determined.

The effect of hydrothermal modification of titanium phosphate on the adsorption affinity towards cadmium ions

70%

Janusz W. , Khalameida S. , Skwarek E. , Sydorchuk V. , Charmas B.

2019

tom Vol. 55, iss. 6

1568--1576

The effect of hydrothermal treatment of the gel or xerogel oftitanium phosphate (TiP) sample on the surface properties was studied usingthe EDS and FTIR ATR methods. The results show that the hydrothermal treatment of initial titanium phosphate decreases the amount of physically adsorbed water but increases the surface concentration of phosphate groups. Supplementary measurements of electrokinetic properties of modified and hydrothermally modified titanium phosphate samples confirmed an increase of the concentration of acidic groups on theTiP surface. The adsorption affinity of titanium phosphate towards cadmium ions was discussed. It was found that at a low initial concentration of cadmium ions adsorption affinity increases as a resultof hydrothermal treatment of TiP gel.