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Tytuł:
Electrokinetic and flotation behavior of rutile in the presence of lead ions and aluminium ions
Autorzy:
Cheng, Hongwei
Liu, Changmiao
Guo, Zhenxu
Feng, Ansheng
Wei, Min
Lv, Zihu
Wu, Dongyin
Zhao, Dengkui
Powiązania:
https://bibliotekanauki.pl/articles/110558.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
lead ions
aluminium ions
rutile
flotation
Opis:
The effects of Pb(II) ions and Al(III) ions on the electro kinetic and flotation behavior of rutile were investigated by micro-flotation tests, zeta potential measurements and solution chemistry analysis. Micro-flotation results indicate that the Pb(II) ions can effectively improve the flotation recovery of rutile while the Al(III) ions significantly inhibit the flotation of rutile. Zeta potential measurements reveal that a collector styrene phosphoric acid (SPA) can adsorb on the rutile surface after the addition of Pb(II) ions, but hardly adsorb on the rutile surface after the addition of Al(III) ions. Pb(II) ions adsorb on the rutile surface in the form of Pb(OH)+ and Pb(OH)2(s), and the latter one is the main reason that activates rutile flotation. Al(III) ions adsorb on the rutile surface mainly in the form of Al(OH)3(s), which prevent the direct interaction between the rutile and the collector, resulting in a decrease of rutile flotation recovery.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 2; 458-466
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of instruments of nuclear physics to the calculation of theoretical dose distributions in various organs of the human body for beams used in hadrontherapy
Autorzy:
Maliszewska, W.
Sękowski, P.
Skwira-Chalot, I.
Powiązania:
https://bibliotekanauki.pl/articles/146972.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
carbon ions
hadrontherapy
hydrogen ions
SRIM
Xeloss
Opis:
The area of interests of nuclear physics are studies of reactions, wherein atomic nuclei of projectile collide with target nuclei. An amount of energy lost by projectile nucleus during its passing through the target is a major issue – it is important to know how charged particles interact with matter. It is possible to afford this knowledge by using theoretical programs that calculate energy loss applying the Bethe-Bloch equation. Hadrontherapy, which is a field of still growing interest, is based on the interactions of charged particles with matter. Therefore, there exists a need of creating a simple model that could be used to the calculation of dose distributions in biological matter. Two programs (SRIM, Xeloss), used to the calculation of energy loss by nuclear physicist, have been adapted to determine the dose distributions in analogues of human tissues. Results of the calculations with those programs for beams used in hadrontherapy (e.g. 1H, 12C) will be compared with experimental data available in references.
Źródło:
Nukleonika; 2016, 61, 1; 19-22
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of diaphragms on measurements of ions emitted from dense magnetized plasmas
Autorzy:
Skladnik-Sadowska, E.
Sadowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/146562.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
diagnostic of ions
energy distribution
plasma discharges
separate ions
Opis:
The paper concerns the diagnostics of ions escaping from dense magnetized plasma (DMP) discharges. Particular attention is paid to the basic problem of the separation of such ions from the investigated plasma, under the condition that this process should not disturb the velocity (and energy) distribution functions of the measured ions.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 57-60
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption kinetic, equilibrium and thermodynamic investigations of Zn(II) and Ni(II) ions removal by poly(azomethinethioamide) resin with pendent chlorobenzylidine ring
Autorzy:
Kumar, P. S.
Ethiraj, H.
Venkat, A.
Deepika, N.
Nivedha, S.
Vidhyadevi, T.
Ravikumar, L.
Sivanesan, S.
Powiązania:
https://bibliotekanauki.pl/articles/780002.pdf
Data publikacji:
2015
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
adsorption
models
Ni(II) ions
poly(azomethinethioamide)
Zn(II) ions
Opis:
This paper reports the application of poly(azomethinethioamide) (PATA) resin having the pendent chlorobenzylidine ring for the removal of heavy metal ions such as Zn(II) and Ni(II) ions from the aqueous solutions by adsorption technology. Kinetic, equilibrium and thermodynamic models for Zn(II) and Ni(II) ions adsorption were applied by considering the effect of contact time, initial metal ion concentration and temperature data, respectively. The adsorption influencing parameters for the maximum removal of metal ions were optimized. Adsorption kinetic results followed the pseudo-second order kinetic model based on the correlation coefficient (R2) values and closed approach of experimental and calculated equilibrium adsorption capacity values. The removal mechanism of metal ions by PATA was explained with the Boyd kinetic model, Weber and Morris intraparticle diffusion model and Shrinking Core Model (SCM). Adsorption equilibrium results followed the Freundlich model based on the R2 values and error functions. The maximum monolayer adsorption capacity of PATA for Zn(II) and Ni(II) ions removal were found to be 105.4 mg/g and 97.3 mg/g, respectively. Thermodynamic study showed the adsorption process was feasible, spontaneous, and exothermic in nature.
Źródło:
Polish Journal of Chemical Technology; 2015, 17, 3; 100-109
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on different behavior and mechanism of Ca(II) and Fe(III) adsorption on spodumene surface
Autorzy:
Yu, F.
Wang, Y.
Wang, J.
Xie, Z.
Powiązania:
https://bibliotekanauki.pl/articles/110230.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
spodumene surface
calcium ions
iron ions
adsorption mechanism
DFT calculation
Opis:
Behavior and mechanism of Ca2+ and Fe3+ adsorption on spodumene surface were investigated by micro flotation tests, zeta potential measurements, and density functional theory (DFT) calculation methods. The micro flotation tests showed that Ca2+ and Fe3+ activated the flotation of spodumene remarkably. However, the effect of Fe3+ was more significant than that of Ca2+. Additionally, Fe3+ significantly changed the zeta potential of spodumene while Ca2+ showed a little change. Meanwhile, the calculated adsorption energy of Fe3+ on spodumene surface was much greater than that of Ca2+ indicating that Fe3+ is more apt to be adsorbed on spodumene surface than Ca2+. The value of bond population in Ca-O illustrated that the bond of Ca-O consists of partial covalent proportion and some ionic component. On the contrary, the bond of Fe-O showed a relatively strong covalent property. The partial density of states (PDOS) of free Ca/Fe and the reacted O atom on spodumene (110) surface before and after the adsorption showed that Fe 3d orbital and O 2p orbital formed hybridization. The density of states (DOS) near the Fermi level of spodumene surface after adsorption with Fe3+ was much stronger than that with Ca2+.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 535-550
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of process water effect on the activation of sphalerite during differential flotation of Pb-Cu-Zn
Autorzy:
Gutiérrez Pérez, Victor Hugo
Olvera Vázquez, Seydy Lizbeth
Santos Madrid, Rocio
Regino Piña, Rafael
Cruz Ramírez, Alejandro
Rivera Salinas, Jorge Enrique
Alaniz Hernández, Daniel Israel
Powiązania:
https://bibliotekanauki.pl/articles/2146897.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sphalerite activation
process water
differential flotation
copper ions
lead ions
Opis:
This work was aimed to analyze the effect of concentration of Cu.2+ and Pb.2+ ions in flotation process water with sphalerite activation, the analysis was performed at Cozamin Mining flotation circuit. This analysis demonstrated that (i) it was possible to determine the relationship between Sodium Cyanide and Ammonium Bisulfite used as depressants and Cu.2+ and Pb.2+ contents in the process water. (ii) It also proved the relationship between lead and iron content in the head with the Pb.2+ ions in process water. According to the data gathered and analysis performed, (iii) it was also determined that it was possible to reuse process water as long as the use of Ammonium Bisulfite was reduced and recommended replacing the use of Sodium Cyanide with Zinc Sulfate (ZnSO4) as a depressant of Sphalerite. Additionally, the concentration of Cu.2+ and Pb.2+ ions in the water should be controlled in a range of 10 to 20 ppm and 0.10 to 0.20 ppm, respectively.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 3; art. no. 146906
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the nature of silver ions in complex media
Autorzy:
Loza, K.
Diendorf, J.
Sengstock, C.
Koller, M.
Epple, M.
Powiązania:
https://bibliotekanauki.pl/articles/286036.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
silver ions
biocides
biomaterials
Opis:
Antimicrobial biocides are commonly used to present the growth of bacteria on surfaces and within materials. They are typically added in small quantities to many applications to prevent bacterial growth on the treated object. Silver is increasingly used in many applications due to the aim to replace organic chemical agents by inorganic additives. Examples of applications are bacteriostatic water filters for household use or swimming pool algaecides and numerous devices, ranging from consumer commodities like mobile phones, refrigerators, and clothes to medical devices like catheters, implant surfaces, and plasters. To meet the diversity of application types, many different forms of silver compounds have been developed to serve this market. In particular, there is little information on the types of transformations that silver nanoparticles will undoubtedly undergo in real, complex environments during long-term aging, and the impact of these transformations on their distribution in the environment, bioavailability, and toxicity potential. The biocidal action results from the interaction of silver ions with bacteria. The most potent compounds for a high silver release are soluble silver salts like silver nitrate or silver acetate. These are fully water soluble with a high silver ion release rate. Therefore they are often used as control in cell experiments to elucidate the biological effect of silver nanoparticles. However, in the case of free silver nanoparticles the interactions can be more complex and catalytic reactions on the particle surface which depend on the size and shape of the nanoparticles can render the system very complex. If AgNO3 is used as control, it is tacitly assumed, that the free silver ion concentration is the same as that in the added AgNO3. This obviously cannot be true because of the presence of a whole set of proteins, biomolecules and inorganic ions like Cl- and H2PO4- in the biological medium. These will react with the silver ions in one or the other way. We report on experiments on the behaviour of silver ions in biologically relevant concentrations in different media, from physiological salt solution over phosphate-buffered saline solution to cell culture media. For dissolution and immersion experiments PVP-coated silver nanoparticles were synthesized by reduction with glucose in the presence of PVP. The final silver concentration in all dispersions was determined by atomic absorption spectroscopy. The dissolution of silver nanoparticles was followed in long-term experiments out of a dialysis tube which was permeable only for silver ions. In case of immersion experiments, the nanoparticles and all precipitates were isolated by ultracentrifugation, redispersed in pure water and again subjected to ultracentrifugation. The particles were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray powder diffraction. The dissolution requires the presence of dissolved oxygen. If no oxygen is present, only a very small fraction of silver is dissolved, possibly by traces of oxygen in the experimental setup. An oxidizing agent like H2O2 clearly enhances the dissolution. The presence of NaCl, either in pure form or as PBS, strongly slows down the dissolution, probably due to silver chloride formation. Cysteine has a clearly inhibiting effect with almost no dissolution of the silver nanoparticles whereas glucose has a decelerating effect but leads to a similar final dissolved fraction. This suggests that cysteine adsorbs onto the silver nanoparticle surface with its thiol group and prevents the oxidation. In contrast, glucose slows down the dissolution, but clearly did not prevent the oxidation on a longer time scale. We have extended the studies by mixing silver nanoparticle dispersions with different media of increasingly biological nature. The solutions/dispersions were stirred for equilibration and then subjected to ultracentrifugation. All precipitates and nanoparticles were isolated by this way and then analyzed. The results show that both initially present silver ions and released silver ions are mainly precipitated as AgCl if chloride is present. Only in the absence of chloride, glucose is able to reduce Ag+ to Ag0. The initially present silver nanoparticles were recovered in all cases. Silver phosphate was not observed in any case, probably due to the moderate pH (around 7) at which phosphate is mostly protonated to hydrogen phosphate and dihydrogen phosphate. We can conclude that released silver ions precipitate mostly as AgCl in biological media, and that most cell culture studies where silver ions are used as control are in fact studying the effect of colloidal silver chloride on the cells. To prove this assumption, human mesenchymal stem cells (hMSC) were cultured in the presence of silver chloride nanoparticles (diameter 120 nm), and the viability of the cells was analyzed by fluorescence microscopy. In general, we clearly observed that pure silver nanoparticles have lower toxicity to hMSC compared to silver chloride nanoparticles with a comparable total silver dose. Silver acetate in the biological medium had a comparable toxicity to hMSC compared to silver chloride nanoparticles with the same total silver dose.
Źródło:
Engineering of Biomaterials; 2014, 17, no. 128-129; 80
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biosorption Capacity of Activated Sludge Sand Bed for Removal of Copper from Treated Wastewater
Autorzy:
Trybułowski, Łukasz
Rogowska, Weronika
Zakrzewski, Jakub
Powiązania:
https://bibliotekanauki.pl/articles/2027810.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
copper ions
biosorption
wastewater
Opis:
In this paper, the biosorption capacity of activated sludge sand bed was investigated for copper removal from wastewater. A sand bed consisting of three layers was used for the study: (1) filter gravel with a diameter of 2 to 3 mm, (2) a biological part inoculated with 200 ml of flocculent activated sludge with a dry weight of 5 kg/$m^3$, (3) filter sand with a grain diameter of about 3 mm. The filter was fed with model wastewater prepared with sodium acetate, potassium nitrate, ammonium chloride, and potassium dihydrogen phosphate I and II basic. The source of Cu ions in the wastewater was $CuSO_4$. The model wastewater used in this study was collected every 24 hours. The experiment was terminated when the concentration of Cu in the treated wastewater sample was equal to that in the treated wastewater. Such a phenomenon was indicative of the depletion of the sorption capacity of the tested bed, which was observed after 26 days. The concentration of copper in raw and effluent from the bed was studied using atomic absorption spectroscopy (ASA) in samples mineralized in nitric acid ($HNO_3$) with the addition of perhydrol ($H_2O_2$). Two equilibrium models, Langmuir and Freudlich, were analyzed to study the absorption isotherms.
Źródło:
Journal of Ecological Engineering; 2022, 23, 2; 61-69
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Superconducting Cyclotron as a primary accelerator for exotic beam facilities
Autorzy:
Maggiore, M.
Rifuggiato, D.
Calabretta, L.
Powiązania:
https://bibliotekanauki.pl/articles/146203.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
cyclotron
ions
medical
superconducting
Opis:
A four sector compact superconducting cyclotron for light ion beams with a maximum energy of 250 MeV/amu has been studied. This cyclotron is mainly designed to accelerate H2 + ions to be extracted by stripping. Ions like C, O or Ne can also be accelerated and extracted by stripping. Extraction by stripping allows to overcome many problems, especially if a certain beam intensity is requested. The preliminary design model of the magnet circuit has been accomplished with the 3D electromagnetic code OPERA [4]. The design of the main coils and of the cryostat has been investigated, too. The features of beam dynamics of this cyclotron, including extraction trajectories, will be presented. Several fields of application have been envisaged for this cyclotron, namely nuclear physics, therapy treatment, interdisciplinary research and radioisotope production using low or medium intensity beams.
Źródło:
Nukleonika; 2003, 48,suppl.2; 165-167
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Various ionic substitutions in hydroxyapatites - physicochemical studies
Autorzy:
Kolmas, J.
Laskus, A.
Szurkowska, K.
Pajor, K.
Pajchel, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/285828.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
hydroxyapatite
ions
physicochemical analysis
Źródło:
Engineering of Biomaterials; 2018, 21, 148; 45
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmentally and Economically Feasibility Manufacturing Process of Potassium Nitrate for Small Scale Industries: A Review
Autorzy:
Joshi, C. S.
Shukla, M. R.
Patel, K.
Joshi, J. S.
Sahu, O.
Powiązania:
https://bibliotekanauki.pl/articles/411997.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Chemical
discharge
ions
Salts
Waste
Opis:
Potassium Nitrate (PN) is of the basic need of chemical industry. With increase of demand in different production section of fertilizer, pharmaceutical, explosive, food industry etc, potassium nitrate the production becoming non economical to industry. The operating conditions and parameters are the main factors, which responsible for maximised the profits. The main aim of this study is to compared the production potassium nitrate in profitable as well as environmentally suitability way. From the literature different manufacturing process has been summarized for concluding this study.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2015, 41; 88-99
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of polymer inclusion membranes doped with 1-hexyl-4-methylimidazole for pertraction of zinc(II) and other transition metal ions
Autorzy:
Ulewicz, M.
Radzyminska-Lenarcik, E.
Powiązania:
https://bibliotekanauki.pl/articles/110567.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
polymer inclusion membrane
PIM
metal ions separation
zinc(II)
transition metal ions
imidazole derivatives
Opis:
Transport of Zn(II) from unary aqueous chloride solutions and from solutions which contain mixtures of Cd(II), Co(II) and Ni(II) ions in source phases (cMe = 0.001 mol/dm3, pH = 6.0) across polymer inclusion membranes (PIMs) doped with 1-hexyl-4-methylimidazole as ion carrier was studied. The use of 1-hexyl-4-methylimidazole enables the separation of 98.5% Zn(II) from a unary solution and 96.9% from a quaternary solution of Zn(II)-Cd(II)-Co(II)-Ni(II) after running the process for 24 hours. Using that ion carrier, the metals are transported in the following order: Zn(II) > Cd(II) > Ni(II) > Co(II), and the selectivity coefficients of Zn(II)/Cd(II), Zn(II)/Ni(II), and Zn(II)/Co(II) are 12.9, 23.4 and 40.8, respectively. Findings of atomic force microscopy (AFM) examinations as well as thermograms of a polymer inclusion membrane containing 1-hexyl-4-methylimidazole are also presented. A membrane with 1.0 mol/dm3 of carrier has a porosity of 15.8%, and roughness of 6.6 nm. The membranes remain thermally stable at temperatures up to 200oC. The findings were compared with earlier-reported results for 1-hexylimidazole.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 2; 447-460
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Germanate glasses co-doped with Ce3+/Ln3+ (Ln = Pr, Tb, Dy) for white light emitting diodes
Autorzy:
Górny, Agata
Sołtys, Marta
Pisarska, Joanna
Pisarski, Wojciech A.
Powiązania:
https://bibliotekanauki.pl/articles/173993.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
glasses
rare earth ions
white luminescence
Opis:
Glasses doped with lanthanides ions may be good white light emitters due to their interesting physical and spectroscopic properties. In this paper, the optical spectroscopy of rare earths doped glasses with a special emphasis on application as white LED were presented. The luminescent glass materials containing Ln3+ (Ln = Pr, Tb, Dy) and Ce3+ ions were obtained. The glasses samples were prepared by a traditional melt-quenching technique. The optical properties of glasses containing various concentrations of rare earth ions were analyzed. It was observed that luminescence bands corresponding to characteristic transitions of Ln3+ and cerium ions are present on spectra measured under direct excitation of Ce3+. Therefore, it indicates that the energy transfer process between Ce3+ /Pr3+, Ce3+ /Tb3+, Ce3+ / Dy3+ ions in glasses occurs. Some parameters such as correlated color temperature (CCT) and chromaticity coordinates (CIE) that characterize white LEDs were analyzed and discussed in detail.
Źródło:
Optica Applicata; 2019, 49, 3; 383-391
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza struktury chemicznej hydroksyapatytu wzbogaconego jonami Mn 2+ wygrzewanego w wysokiej temperaturze
Structural characterization of thermally processed hydroxyapatite enriched in Mn2+ ions
Autorzy:
Kolmas, J.
Jabłoński, M.
Ślósarczyk, A.
Kołodziejski, W.
Powiązania:
https://bibliotekanauki.pl/articles/286145.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
hydroksyapatyty
biokompatybilność
apatyt
hydroxyapatite
biocompatibility
ions
Opis:
Syntetyczne hydroksyapatyty (HAs), ze względu na wysoką biokompatybilność z ludzkimi tkankami zmineralizowanymi, są szeroko stosowane jako biomateriały w ortopedii oraz stomatologii. Struktura hydroksyapatytu Ca10(PO4)6(OH)2 pozwala na szereg jonowych podstawień, które mogą zachodzić zarówno w pozycji kationów wapnia jak i ortofosforanów oraz strukturalnych grup hydroksylowych. Wprowadzenie dodatkowych jonów do struktury hydroksyapatytu może wpływać na jego właściwości biologiczne i fizykochemiczne. Mangan jest śladowym pierwiastkiem wchodzącym w skład biologicznego apatytu (mineralnego składnika kości oraz zębów). Odgrywa on kluczową rolę w powstawaniu matrycy organicznej. Dodatkowo indukuje integryny, grupę receptorów umożliwiających adhezję komórek. Ostatnio przeprowadzone badania potwierdziły, że hydroksyapatyt wzbogacony jonami manganu Mn2+ wykazuje łatwiejszą osteointegrację niż czysty hydroksyapatyt, dlatego też może być z powodzeniem stosowany jako pokrycie implantów metalicznych. W powyższej pracy wykorzystano standardową metodę mokrą do syntezy hydroksyapatytów zawierających niewielkie ilości jonów Mn2+. Otrzymane próbki wygrzewano następnie w dwóch różnych temperaturach: 800 oraz 1250°C. Głównym celem tej pracy było zbadanie wpływu procesu termicznego na strukturę chemiczną hydroksyapatytuwzbogaconego jonami manganowymi. Do badań fizykochemicznych wykorzystano: proszkową dyfraktometrię rentgenowską (PXRD), mikroskopię elektronową (SEM oraz TEM), spektroskopię w podczerwieni (FT-IR) oraz spektroskopię magnetycznego rezonansu jądrowego w ciele stałym (ssNMR). Wprowadzenie jonów Mn2+ do struktury hydroksyapatytu zostało potwierdzone dzięki zastosowaniu metod PXRD oraz ssNMR. Wykazano także, że obecność manganu ułatwia termiczny rozkład hydroksyapatytu do oksyhydroksyapatytu. Próbki wygrzewane w wyższej temperaturze (1250°) okazały się niehomogeniczne. Zawierały, oprócz fazy hydroksyapatytu, dodatkowe fazy krystaliczne: oksyhydroksyapatyt, oksyapatyt, dziewięciotlenek dwufosforu i czterowapnia (TTCP) oraz α-ortofosforan wapnia (αTCP). Użyte metody fizykochemiczne pozwoliły stwierdzić, że w próbkach kalcynowanych (wygrzewanych w temperaturze 800°C) jony manganowe zajmują przede wszystkim pozycje wapnia Ca(I) w komórce elementarnej hydroksyapatytu. Podczas wygrzewania w wyższej temperaturze dochodzi do częściowego przemieszczenia jonów manganu w pozycje Ca(II).
Synthetic hydroxyapatites (HAs), due to their high compatibility with human mineralized tissues are widely used in implant materials for orthopaedic and dental applications. Hydroxyapatite structure Ca10(PO4)6(OH)2 is tolerant to several ionic substitutions. They can occur in HA for calcium cations, for orthophosphates and structural hydroxyl ions. The incorporation of additional ions into the apatite crystals may change their biological or physicochemical properties. Manganese appears in biological apatite (bone and teeth) and plays a key role in the development of organic matrix. It also induces integrins, receptors mediating cellular interactions with extracellular matrix and cell surface ligands. Manganese-doped HA exhibits better osseointegration than pure HA, thus it may be used as a coating of metallic implants. In this paper, hydroxyapatites enriched in small amounts of manganese ions Mn2+ were synthesized by standard wet method. The obtained samples were heated at two different temperatures: 800 and 1250ºC. The main aim of this study was to determine the influence of thermal processing of hydroxyapatite enriched in Mn2+ ions on its chemical structure. For profound physicochemical studies powder X-ray diffractometry (PXRD), electron microscopy (SEM and TEM), infrared spectroscopy (FT-IR) and solid-state nuclear magnetic resonance (ssNMR) were applied. The incorporation of manganese ions was confirmed using PXRD and ssNMR methods. It was found that the presence of manganese facilitates hydroxyapatite dehydration and decomposition to oxyhydroxyapatite. The samples heated at 1250ºC are not homogenous and contain, apart from hydroxyapatite other crystalline phases: oxyhydroxyapatite, oxyapatite, tetracalcium phosphate (TTCP) and α-tricalcium phosphate (αTCP). In the calcined sample (heated at 800ºC), manganese ions preferentially occupy the Ca(I) position in the hydroxyapatite crystallographic unit cell. During heat treatment at the higher temperature, some Mn2+ ions move to the Ca(II) position.
Źródło:
Engineering of Biomaterials; 2014, 17, no. 128-129; 10-11
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reduction of chromium(VI) ions from aqueous solutions by using the solvent impregnated resin
Autorzy:
Wójcik, G.
Hubicki, Z.
Powiązania:
https://bibliotekanauki.pl/articles/115625.pdf
Data publikacji:
2011
Wydawca:
Fundacja na Rzecz Młodych Naukowców
Tematy:
sorption of chromium(VI) ions
reduction
Opis:
The solvent impregnated resins enables effective recovery of microquantities of chromium(VI) ions from wastewaters. The solvent impregnated resin (SIR) Amberlite XAD 7 HP as polymer matrix has been prepared by the wet-impregnation technique. Aliquat 336 was employed as the extractant and acetone as the solvents for impregnation. Sorption of chromium(VI) was investigated in the batch process . Sorption of chromium(VI) was studied in the pH range from 1.5 to 7. It was stated that sorption of chromium(VI) ions depends on acidity of solution. The values of recovery factors of chromium(VI) are higher at low pH than in neutral solution. The speciation of chromium was investigated in the studied pH range. Reduction of chromium(VI) to chromium(III) under acidic conditions was observed. Chromium was determined by using the spectrophotometric and atomic absorption spectroscopy methods. Both methods permit to observe changing of valence of chromium(III) and (VI) oxidation states. The prepared SIR is a new sorbent used for recovery of chromium ions from wastewaters.
Źródło:
Challenges of Modern Technology; 2011, 2, 3; 41-43
2082-2863
2353-4419
Pojawia się w:
Challenges of Modern Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 250

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