Temat: jony metali - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Kompozyty chitozanowo-zeolitowe otrzymywane na bazie popiołów lotnych do usuwania metali ciężkich
Chitosan-zeolite composites obtained from fly ashes for heavy metal ions removal
Autorzy:: Kołodyńska, D.
Franus, W.
Powiązania:: https://bibliotekanauki.pl/articles/394320.pdf
Data publikacji:: 2016
Wydawca:: Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:: jony metali ciężkich
zeolity
chitozan
heavy metal ions
zeolites
chitosan
Opis:: Adsorpcja to jedna z najskuteczniejszych metod stosowanych do usuwania substancji toksycznych z roztworów wodnych. Skuteczność tej metody uzależniona jest od doboru i ilości odpowiedniego sorbentu. W ostatnim czasie obserwuje się wzrost zainteresowania usuwaniem szkodliwych i toksycznych związków od wód powierzchniowych i ścieków za pomocą tak zwanych sorbentów naturalnych. Wykazano m.in. dużą skuteczność usuwania fosforanów, jonów metali ciężkich, fluorków, boru ze ścieków za pomocą popiołów lotnych. Ponadto, w wielu pracach opisano wykorzystanie tego typu materiałów w usuwaniu barwników, fenoli, wielopierścieniowych węglowodorów aromatycznych i innych związków organicznych. Popioły lotne powstają w procesie spalania węgla. Roczna produkcja popiołów lotnych utrzymuje się na poziomie 5,5 • 10 8 Mg, przy czym największymi producentami popiołów lotnych są Chiny, USA i Indie. W Polsce w 2013 roku wytworzono 4,5 • 10 6 Mg popiołów lotnych z czego 87% zostało wykorzystane. Stwarza to ogromne problemy środowiskowe. Skład chemiczny i mineralogiczny jak również właściwości popiołów lotnych uzależnione są od pochodzenia, wartości kalorycznej węgla, a także innych parametrów, takich jak zawartość wody, rozmiar ziaren, stopień amorficzności itp. Popioły lotne mogą być stosowane w wielu dziedzinach, między innymi dodawane są do cementu i betonu. Ze względu na obecność mikro- i makroelementów stosuje się je w rolnictwie. Po procesie modyfikacji, m.in. za pomocą wysokiej temperatury, mielenia, działania kwasów czy dodatku chitozanu mogą być stosowane jako efektywne sorbenty substancji szkodliwych i toksycznych z wód i ścieków.
Adsorption is one of the most effective methods used to removal of toxic substances from aqueous solutions. The effectiveness of this method depends on the selection and amounts of the corresponding sorbent. Recently there has been observed growth of interest in removal of harmful and toxic compounds from surface waters and wastewaters by means of so called natural sorbents. Among others good efficiency of removal of phosphates, heavy metal ions fluorides, boron from wastewaters was proved by means of fly ash. Moreover, it is useful in removal of dyes, phenols, polycyclic aromatic hydrocarbons and other organic compounds as discussed in nu- merous papers. Fly ash is formed as a by-product in coal combustion. The yearly fly ash production is estimated to be 5.5 • 10 8 Mg, however, the largest amounts are produced in China, the USA and India. In Poland in 2013 there was created 4.5 • 10 6 Mg of fly ash, of which 87% was subjected to recovery. This enormous amount of industrial wastes can be a serious environmental problem. Chemical and mineralogical compositions as well as physicochemical properties of fly ash depend on geochemical origin and calorific capacity as well as water content, particle size, degree of amorphicity etc. Fly ashes can be used in many fields, among others, they are added to cement and concrete. Due to the presence of micro- and macroelements they are applied in agriculture. After modification using high temperature, grinding, acid activation or chitosan they can be applied as an effective sorbents of different pollutants from waters and wastewaters.
Źródło:: Zeszyty Naukowe Instytutu Gospodarki Surowcami Mineralnymi i Energią PAN; 2016, 95; 145-155
2080-0819
Pojawia się w:: Zeszyty Naukowe Instytutu Gospodarki Surowcami Mineralnymi i Energią PAN
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Metalotioneiny i motywy policysteinylowe : oddziaływanie z jonami metali
Metallothioneins and polythiol motifs : interactions with metal ions
Autorzy:: Krzywoszyńska, K.
Kozłowski, H.
Powiązania:: https://bibliotekanauki.pl/articles/171939.pdf
Data publikacji:: 2018
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: metalotioneiny
motywy policysteinylowe
jony metali
metallothioneins
polythiol motifs
metal ions
Opis:: Many of biochemical paths and processes require some metal ions to occur. There are also known the negative effects of the presence of metal ions in the organism. The both sides of metal ions interactions on the living organism require specific regulations and cannot be left without supervision and control of the organism itself. One of the strategy to keep the control on metal ions are cystein-rich proteins that play crucial role in detoxication of metal ions that are dangerous for human organism as well as they help to maintain homeostasis of essential metal ions. Matallothioneins are one of the well known, but still not fully understood, cysteine- rich proteins. They are small proteins but may contain up to 30% of cysteine residues in the sequence, and what makes them very special from chemical point of view - all of the thiols present there are reduced [1]. This property makes these proteins very tempting for coordination of various metal ions. The most efficient binding to metallothionein is observed for the ions belonging to a Group 11 and 12. Cu⁺, Zn2⁺ and Cd2⁺ represent these metal ions [2]. Besides of the lack of disulfide bridges, metallothioneins show also the absence or low amount of aromatic amino acid residues in the sequence [1]. Studies of the metallothioneins and their isoforms among different organisms show that the position of cysteine residues is very conservative [3]. Considering this aspect of metallothionein structure, some specific motifs of cysteine residues arrangement can be found in the sequence of these proteins. Most of the common polythiol motifs are CXC, CXXC, CXXXC, CC – where C is a cysteine residue and X is random α-amino acid residue (other than cysteine) [3–5]. The influence of the cysteine residues organization on the specificity of metal ions binding was intensively studied. The differences observed for specificity of metal ions binding by metallothioneins and selected polythiol motifs are reviewed in this paper – with strong emphasis on the effect of the cysteine residues topography.
Źródło:: Wiadomości Chemiczne; 2018, 72, 7-8; 383-395
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Mechanizm sorpcji jonów metali w hydrożelu chitozanowym - badania kalorymetryczne
Mechanism of metal ion soprtion in chitosan hydrogel - calorimetric studies
Autorzy:: Zarzycki, R.
Modrzejewska, Z.
Kierzkowska-Pawlak, H.
Sujka, W.
Powiązania:: https://bibliotekanauki.pl/articles/127430.pdf
Data publikacji:: 2009
Wydawca:: Towarzystwo Chemii i Inżynierii Ekologicznej
Tematy:: chitozan
adsorpcja
jony metali
ciepło reakcji
chitosan
adsorption
metal ions
heat reaction
Opis:: Przedstawiono kalorymetryczne badania hydrożelu chitozanowego dotyczące mechanizmu sorpcji Cu(II), Ag(I) i Ca(II). Wyznaczono ciepła reakcji sorpcji tych jonów. Proces ten prowadzono dla maksymalnego stężenia danego jonu. Z pomiarów efektu cieplnego wynika, iż dla jonów Cu(II) i Ag(I) proces sorpcji ma charakter chemiczny (chemisorpcja). Efekt cieplny jest rzędu kilkudziesięciu kJ/mol. Natomiast jony Ca(II), które korzystnie wpływają na organizm ludzki, nie wykazują tego efektu.
In the present research, studies were performed to determine the character of adsorption of Ca(II), Cu(II), Ag(I) ions in chitosan. The studies were carried out for chitosan hydrogel. The character of sorption was determined on the basis of calorimetric studies. The heat of reaction was measured during the sorption of individual ions. The process of adsorption was carried out for a maximum ion concentration. It follows from the measurement of the heat of sorption for Cu(II) and Ag(I) ions that the sorption process has a chemical character, which is shown by a measurable thermal effect of the order of dozens kJ/mol. It is interesting that Ca(II) ions which have an advantageous influence on living organisms, do not reveal this effect.
Źródło:: Proceedings of ECOpole; 2009, 3, 1; 221-227
1898-617X
2084-4557
Pojawia się w:: Proceedings of ECOpole
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Biosorbenty stosowane w usuwaniu jonów metali ciężkich z zanieczyszczonego
Biosorbents for heavy metal-contaminated environment
Autorzy:: Zabochnicka-Świątek, M.
Powiązania:: https://bibliotekanauki.pl/articles/1208156.pdf
Data publikacji:: 2013
Wydawca:: Stowarzyszenie Inżynierów i Techników Przemysłu Chemicznego. Zakład Wydawniczy CHEMPRESS-SITPChem
Tematy:: biosorbent
biosorpcja
bioakumulacja
jony metali ciężkich
biosorbents
biosorption
bioaccumulation
heavy metal ions
Opis:: Omówiono możliwości wykorzystania wybranych biosorbentów do usuwania jonów metali ciężkich z zanieczyszczonego środowiska. Zaprezentowano najważniejsze biologiczne materiały stosowane w procesach biosorpcji i bioakumulacji oraz sposoby ich modyfikacji. Dokonano przeglądu możliwości praktycznego zastosowania wybranych biosorbentów.
The application of selected biosorbents for heavy metal-contaminated environment was discussed. The most important biological materials for biosorption and bioaccumulation processes and modification methods of biomass were presented. Practical application of selected biosorbents was discussed.
Źródło:: Chemik; 2013, 67, 10; 971-978
0009-2886
Pojawia się w:: Chemik
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Regulacja aktywności katalitycznej rybozymów HDV oraz deoksyrybozymów za pomocą antybiotyków i jonów metali
Regulation of the catalytic activity of HDV ribozymes and deoxyribozymes with antibiotics and metal ions
Autorzy:: Wrzesinski, J.
Ciesiołka, J.
Powiązania:: https://bibliotekanauki.pl/articles/171740.pdf
Data publikacji:: 2018
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: antybiotyki
rybozymy HDV
deoksyrybozymy
jony metali
antibiotics
HDV ribozymes
deoxyribozymes
metal ions
Opis:: This review article describes the results of a 15-year cooperation between the Department of RNA Biochemistry at the Institute of Bioorganic Chemistry, Polish Academy of Sciences in Poznań and the Medical Chemistry Team of the Faculty of Chemistry at the University of Wrocław, headed by Professor Małgorzata Jeżowska- -Bojczuk. A wide spectrum of antibiotics and other low molecular compounds and their complexes with Cu²⁺ ions have been tested as potential inhibitors of the HDV ribozyme catalytic reaction. Unexpectedly, it has been found that a number of compounds, depending on the conditions, exhibit inhibitory or stimulatory properties, i.e. they act as modulators of the RNA catalysis process. It was found that the effect of stimulation / inhibition of the catalytic activity of the HDV ribozyme is closely related to the degree of protonation of the antibiotics under study in given conditions. Their ability to inhibit catalysis also increases after binding the Cu²⁺ cation. In an environment with a higher pH, antibiotics usually stimulate the cleavage reaction, as at least some of their nitrogen centers are allowed to participate in the catalysis reaction, as proton acceptors / donors or a catalytic metal ion coordination site. During the study of one of the antibiotics, bacitracin, it was also observed that it exhibits nucleolytic properties with RNA and DNA molecules. The discovery of the hydrolytic properties of bacitracin extended the potential use of this antibiotic in antiviral therapy with the aim to destroy undesired nucleic acids in the cell. To search for DNAzymes catalyzing RNA hydrolysis, the in vitro selection method was used. In the selection experiment aimed at obtaining DNAzymes active in the presence of Cd²⁺ ions, variants belonging to the family of DNAzymes 8–17 previously described in the literature were obtained. Analysis of their properties showed that not only Cd²⁺ but also Zn²⁺ and Mn²⁺ ions support catalysis, therefore the site of catalytic metal ion coordination is not highly specific. The DNAzymes obtained in the second selection experiment showed an optimum of catalytic activity in the pH range of 4.0–4.5 and were inactive at a pH higher than 5.0. Interestingly, they do not require the presence of any divalent metal ions as cofactors in the catalysis reaction. The obtained results broaden the repertoire of DNAzymes which operate under non-physiological conditions and bring new information on the possible mechanisms of reactions catalyzed by nucleic acids.
Źródło:: Wiadomości Chemiczne; 2018, 72, 7-8; 397-415
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Removal of zinc, cadmium and nickel from mining waste leachate using walnut shells
Autorzy:: Ayala, Julia
Fernandez, Begona
Powiązania:: https://bibliotekanauki.pl/articles/208277.pdf
Data publikacji:: 2019
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: metal ions
adsorption
biosorption
adsorbent
kinetics
copper
jony metali
adsorpcja
biosorpcja
kinetyka
miedź
Opis:: The removal of heavy metals from aqueous solutions using walnut shells was investigated. The effects of pH, contact time, initial metal concentration, adsorbent concentration, and co-ions were studied in synthetic solutions. Metal uptake was found to be dependent on the initial pH of the solution; the removal rate increased upon increasing pH, showing the highest affinity at pH 5–7. The amount of metal removed improved with increasing initial concentration. Increasing adsorbent dosage enhanced removal efficiency, but reduced the amount absorbed per unit mass of walnut shells. The presence of co-ions suppressed the uptake of heavy metals, divalent ions having a more negative effect than monovalentions. The adsorption of Zn, Cd and Ni onto walnut shells was found to fit Langmuir and Freundlich isotherms. The results obtained in the tests with mining waste leachate showed the potential use of walnut shells for the removal of heavy metals.
Źródło:: Environment Protection Engineering; 2019, 45, 2; 141-158
0324-8828
Pojawia się w:: Environment Protection Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Polihistydylowe sekwencje z motywem His-tag – ich rola i biologiczne znaczenie oddziaływania z jonami metali
Polyhistidine sequences with His-tag motif – their role and biological significance of interaction with metal ions
Autorzy:: Wątły, J.
Kozłowski, H.
Powiązania:: https://bibliotekanauki.pl/articles/172145.pdf
Data publikacji:: 2016
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: histydyna
His-tag
jony metali
białka
histidine
His-tag motif
metal ions
proteins
Opis:: His-tags are specific sequences containing six to nine subsequent histydyl residues and they are used commercially in immobilized metal affinity chromatography (IMAC) as molecular ‘anchors’ that bind to a metal ion (usually nickel), immobilized by chelation with nitrilotriacetic acid (NTA) bound to a solid support [37, 38]. Consecutive histidines are the common denominator for both His-tags used in molecular biology and for quite remote biological phenomena – more than 2000 histidine- rich proteins (HRPs) are found in microorganisms including 60% and 82% of archaeal and bacterial species, respectively and their roles are not well characterized [73]. The physicochemical properties of histidine make it a versatile amino acid that influences protein conformation and enzymatic activity [15]. Many natural proteins with a His-tag domain are assigned to different functions, for example: most bacterial proteins, containing this motif are probably involved in the homeostasis of nickel ions [68, 76], while others, e.g. newly isolated peptides from the venom of the snake genus Atheris contain poly-histidyl-poly-glycyl sequences (pHpG) can act on the cardiovascular system by inhibiting snake venom metalloproteinases and affect its function by acting on specific receptors [58, 62]. His-rich motifs have been found also e.g. in Zn²⁺ transporters, prion proteins, His-rich glycoproteins, transcription factors or numerous copper-binding proteins [56, 67, 84]. Binding mode and the thermodynamic properties of the system depends on the specific metal ion and the histidine sequence. Despite the wide application of the His-tag for purification of proteins, little is known about the properties of metalbinding to such tag domain. Recent experimental and theoretical studies have shown that metal ions, e.g. Cu²⁺ can bind to various sets of imidazoles depending on the number of histidine residues that are located in His-rich sequences. The occurrence of polymorphic binding states and the formation of an α-helical structure induced by metal ion coordination suggest that proteins with a His-tag domain may serve as the dynamic site able to ‘move’ metal ions along the tag sequence [99, 100]. This might explain the frequent occurrence of such sequences in bacterial Ni²⁺ chaperones, which transfer the metal ion between different proteins.
Źródło:: Wiadomości Chemiczne; 2016, 70, 11-12; 1-24
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Kompleksy jonów metali d- i f-elektronowych z N-tlenkiem pirydyny i związkami pochodnymi : badania spektroskopowe
Complexes of d- and f-metal ions with pyridine N-oxide and its derivatives: spectroscopic studies
Autorzy:: Hnatejko, Z.
Powiązania:: https://bibliotekanauki.pl/articles/171812.pdf
Data publikacji:: 2011
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: kompleksy jonów metali
jony metali
N-tlenki pirydyny
spektroskopia
complexes
metal ions
pyridine N-oxides
spectroscopy
Opis:: This article reviews results of studies, collected in the literature, related to complexation abilities of pyridine N-oxides, including forms and properties of dand f-metal ion complexes with this group of ligands. In this paper the synthetic pathways of the ligands, based on an oxidation of the corresponding heterocyclic compounds are presented (Scheme 3) [2, 4, 5]. Substituted pyridine N-oxides form an interesting group of compounds, which have found numerous applications [296-299, 314-318]. They have been used in catalysis, crystal engineering, synthesis of coordination polymers, as well as drugs and components in pharmaceutical chemistry [300-309]. Some of them are useful in destroying of microorganisms and the HIV virus [277, 278, 303-307]. Moreover, they are important compounds in the thermal and photochemical oxidation processes [296-299]. The complexes of metal ions with the N-oxide ligands can be formed by binding an oxygen atom of the N›O group, and/or by binding the substituents present in the aromatic ring, e.g. oxygen atoms of carboxylic groups. The complexes can be obtained in monomeric [64, 159], dimeric [58] or polymeric forms [60, 153, 175]. The formation of polymeric forms is more effective when the distance between the positions of COOH and N›O groups in the aromatic ring increases [168]. Complexes of Ln3+ ions and particularly of Eu3+ with pyridine N-oxides are good luminescent materials, better than their heterocyclic counterparts [180, 211]. The emission intensity of europium ions in these systems depends on the efficiency of the LMCT (ligand-metal charge transfer) and LMET (ligand-metal energy transfer) transitions, as well as on electron-donor properties of the substituents present in the pyridine N-oxide ring [37, 132, 155]. A special role in the complexation of Ln3+ ions plays cryptands, which can encapsulate the metal ion. This process protects the metal ion from a penetration of its first coordination sphere by solvent molecules or counterions [245, 246]. The complexes of europium(III) with macromonocyclic, macrobicyclic and acyclic ligands, equipped with photoactive units such as pyridine N-oxide, 2,2'-bipyridine-N,N'-dioxide or 3,3'-biisoquinoline-2,2'-dioxide in solutions, solid states, and incorporated in a silicate matrices by sol-gel method, gained a lot of attention [247-274].
Źródło:: Wiadomości Chemiczne; 2011, 65, 5-6; 461-501
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Transport jonów kobaltu-60, strontu-85, cezu-137, chromu-51 przez polimeryczne membrany inkluzyjne
Autorzy:: Pellowski, Witalis.
Kozłowski, Cezary A.
Walkowiak, Władysław.
Powiązania:: Biuletyn Wojskowy Instytut Chemii i Radiometrii, 1999, nr 1, s. 137-148
Data publikacji:: 1999
Tematy:: Środowisko człowieka skażenia likwidacja metody materiały konferencyjne
Jony metali transport badanie materiały konferencyjne
Opis:: Rys.; Bibliogr.; Streszcz.
Dostawca treści:: Bibliografia CBW

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Skocz do pozycji: 10.

Tytuł:: Application of genetic algorithms to determine heavy metal ions sorption dynamics on clinoptilolite bed
Autorzy:: Tomczak, E. T.
Kamiński, W. L.
Powiązania:: https://bibliotekanauki.pl/articles/185117.pdf
Data publikacji:: 2012
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: algorytm genetyczny
jony metali ciężkich
klinoptylolit
heavy metal ions
clinoptilolite
sorption dynamics
genetic algorithm
Opis:: In the last decade a growing interest was observed in low-cost adsorbents for heavy metal ions. Clinoptilolite is a mineral sorbent extracted in Poland that is used to remove heavy metal ions from diluted solutions. The experiments in this study were carried out in a laboratory column for multicomponent water solutions of heavy metal ions, i.e. Cu(II), Zn(II) and Ni(II). A mathematical model to calculate the metals' concentration of water solution at the column outlet and the concentration of adsorbed substances in the adsorbent was proposed. It enables determination of breakthrough curves for different process conditions and column dimensions. The model of process dynamics in the column took into account the specificity of sorption described by the Elovich equation (for chemical sorption and ion exchange). Identification of the column dynamics consisted in finding model coefficients [beta], KE and Deff and comparing the calculated values with experimental data. Searching for coefficients which identify the column operation can involve the use of optimisation methods to find the area of feasible solutions in order to obtain a global extremum. For that purpose our own procedure of genetic algorithm is applied in the study.
Źródło:: Chemical and Process Engineering; 2012, 33, 1; 103-116
0208-6425
2300-1925
Pojawia się w:: Chemical and Process Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Sorption from Multicomponent Solutions on Freeze-Dried Chitosan
Sorpcja z roztworów wieloskładnikowych na chitozanie suszonym sublimacyjnie
Autorzy:: Tomczak, E.
Szczerbowska, D.
Powiązania:: https://bibliotekanauki.pl/articles/389247.pdf
Data publikacji:: 2010
Wydawca:: Towarzystwo Chemii i Inżynierii Ekologicznej
Tematy:: chitozan
liofilizacja
równowaga sorpcyjna
jony metali ciężkich
chitosan
lyophilization
sorption equilibrium
heavy metal ions
Opis:: The process of adsorption in time-variable conditions in a column packed with lyophilized chitosan beads modified with polyvinyl alcohol (CH-PYA), ethylenediaminetetraacetic acid (CH-PYA-EDTA) or 3-chloropropionic acid (CH-PYA-3CPA) was analyzed. Experiments were carried out in a column filled with freeze-dried chitosan beads of diameter fi = 2.5 mm and fed with water ternary solutions of Cu(II), Ni(II) and Zn(II). Sorption efficiency of single ions was analyzed. Additionally, the influence of initial concentration and flow rate was determined. A pseudo-second order equation was used in the description of ion sorption. Sorption equilibrium on freeze-dried chitosan beads with PVA at 25 °C in static conditions was determined. Freundlich equation was recommended in this case.
Badano proces adsorpcji prowadzony w warunkach zmiennych w czasie na złożu z lofilizowanych kulek chitozanowych modyfikowanych alkoholem poliwinylowym (PVA) z dodatkiem kwasu etyleno-diaaminotetraoctowego (EDTA) lub kwasu 3-chloropropionowego (3CPA). Proces ten prowadzono w kolumnie wypełnionej kulkami o średnicy ok. fi = 2,5 mm dla mieszaniny jonów w roztworach wodnych: miedzi(H) (CuSO4 o 5H2O), niklu(II) (NiSO4 o 6H20) oraz cynku(II) (ZnSO4 o 7H2O). Analizowano kinetykę sorpcji pojedynczych jonów występujących w roztworze trójskładnikowym. Dodatkowo określano wpływ stężenia początkowego i objętościowego natężenia przepływu. Do opisu badanego procesu zastosowano równanie pseudodrugiego rzędu. Określono równowagę sorpcyjną dla liofilizowanego chitozanu z PVA w 25 °C w warunkach statycznych. W tym przypadku zastosowano równanie Freundlicha.
Źródło:: Ecological Chemistry and Engineering. A; 2010, 17, 2-3; 313-321
1898-6188
2084-4530
Pojawia się w:: Ecological Chemistry and Engineering. A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Search for the possibility of utilizing the differences in complex-forming capacities of alkylimidazoles for selective extraction of some metal ions from aqueous solutions
Autorzy:: Radzymińska-Lenarcik, E.
Powiązania:: https://bibliotekanauki.pl/articles/778263.pdf
Data publikacji:: 2008
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:: ekstrakcja selektywna
alkiloimidazol
jony metali przejściowych
selective extraction
alkyl imidazole derivatives
transition metals ions
Opis:: Alkyl substituents in position 1 of the imidazole ring distinctly affect the hydrophobic properties of the molecule and strengthen its basicity. Hence, 1-alkylimidazoles have been used as extractants of a number of metal ions. Again, a methyl substituent in position 2 of the imidazole ring raises by an order of magnitude the basicity. At the same time, the substituent impedes the formation of the 2-alkylimidazole complexes with metal ions due to the steric effect. By the substitution of alkyl groups in position 1 or 2 of the imidazole ring it is possible to program the extraction properties of extractants and to control the selectivity of extraction.
Źródło:: Polish Journal of Chemical Technology; 2008, 10, 1; 73-78
1509-8117
1899-4741
Pojawia się w:: Polish Journal of Chemical Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: Właściwości koordynacyjne wybranych cyklicznych hormonów peptydowych oraz ich pochodnych
Coordination properties of selected cyclic peptide hormones and their analogues
Autorzy:: Witak, Weronika
Marciniak, Aleksandra
Powiązania:: https://bibliotekanauki.pl/articles/1409943.pdf
Data publikacji:: 2021
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: hormony peptydowe
peptydy
wiązanie disulfidowe
jony metali
peptide hormones
cyclic peptides
disulfide bridge
metal ions
Opis:: Hormones are a heterogeneous, significant compounds, responsible for proper functioning of living organisms, produced by specialized cells, tissues and glands. Theirs main role is signals transmission to target tissues, responsible for the right working of the whole organism. Dysfunctions of the hormones homeostasis balance lead to disease states [1-3]. Recently, scientists have paid attention to role of the metal ions in the proper synthesis of these compounds and functioning of human body [4]. More and more scientific works explain the complicated roles of metals as beneficial factors that stimulate the conformation of peptides. Metal ions are responsible for biological properties and influence of hormones binding to appropriate receptors, but also adverse factors [4,5]. The search for an answer to the question about the metal - hormone relationship has led to the development of a new, interdisciplinary studies: metalloendocrinology, linking inorganic chemistry with endocrinology [4]. In this work, we present the literature data that relate to metal - peptide hormone interactions. We focused on cyclic hormones with a disulfide bridge and their analogues. In our review we have focused on selected natural cyclic peptide hormones: oxytocin, vasopressin, somatostatin, hepcidin and amylin. The studies on the coordination abilities showed that transition metal ions, such as copper(II), zinc(II) or nickel(II), form stable complexes with described peptides. Metal ions actively participate in many phenomena. They have played role in the formation of amylin aggregates in patients with type 2 diabetes [6]. The high ability to copper(II) by hepcidin may have an effect on its homeostasis [7]. Stable complexes of oxytocin and vasopressin facilitate binding with appropriate receptors for these peptides [8].
Źródło:: Wiadomości Chemiczne; 2021, 75, 5-6; 799-821
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: Application of modified maize hull for removal of Cu(II) ions from aqueous solutions
Autorzy:: Ghasemi, S. M.
Mohseni-Bandpei, A.
Ghaderpoori, M.
Fakhri, Y.
Keramati, H.
Taghavi, M.
Moradi, B.
Karimyan, K.
Powiązania:: https://bibliotekanauki.pl/articles/208248.pdf
Data publikacji:: 2017
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: heavy metal ions
waste water
Cu(II)
ions
adsorption
biomass
jony metali ciężkich
ścieki
biomasa
adsorpcja
Opis:: Discharge of industrial waste containing heavy metals to the environment is a main concern because of their toxicity to many life forms. Adsorption process is one of the conventional methods in order to adsorb heavy metals from wastewater effluents. Therefore, the removal of Cu(II) from aquatic solutions using modified maize hull was investigated. All experiments were performed in batch conditions. The residual Cu(II) concentration was measured by AAS. Upon increasing the adsorbent dosage, pH, and contact time and decreasing Cu(II) concentration, the removal efficiency of Cu(II) ions increased. In optimum conditions, 50% of copper was removed by modified maize hull. The experimental data were best fitted by the Langmuir type 2 model and the adsorption kinetic model followed a pseudo-second order type 1 model. It seems that the use of the modified maize hull to remove Cu(II) ions is very suitable, low-cost, and efficient.
Źródło:: Environment Protection Engineering; 2017, 43, 4; 93-103
0324-8828
Pojawia się w:: Environment Protection Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:: Attachment of 2,2-bipyridine onto a silica gel for application as a sequestering agent for copper, cadmium and lead ions from an aqueous medium
Autorzy:: Souza, E. J.
Cristante, V. M.
Padilha, P. M.
Jorge, S. M. A.
Martines, M. A. U.
Silva, R. I. V.
Carmo, D. R.
Castro, G. R.
Powiązania:: https://bibliotekanauki.pl/articles/779827.pdf
Data publikacji:: 2011
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:: 2,2-bipirydyna
żel krzemionkowy
adsorpcja
jony metali
2,2'-bipyridine
silica gel
adsorption
metal ions
Opis:: A method was developed to attach 2,2-bipyridine (BP) onto a silica gel surface by a two-step reaction. The fi rst step consisted of a reaction between the matrix and a silylating agent, 3-chloropropyltrimethoxysilane. In the second step of the reaction, a ligand molecule was attached onto Si-CPTS, yielding the product Si-BP. The modified material contained 0.431±0.01 mmol of 2,2-bipyridine per gram of modified silica, as confirmed by FT-IR spectra of the proposed structure. The surface modification was characterized by the BET technique, which revealed a decrease in the surface area from 614 to 450 m2 g-1. The series of adsorption isotherms for the metal ions were adjusted to fit a modified Langmuir equation. The maximum number of moles of copper, cadmium and lead ions adsorbed was 0.64, 0.53, and 0.54 mmol g-1, respectively. The surface saturation was calculated as ¢ fraction and the values obtained, Cu(II) =1.160, Cd(II) = 1.044 and Pb(II) = 0.997, suggest a type 1:1 metal-ligand complex.
Źródło:: Polish Journal of Chemical Technology; 2011, 13, 4; 28-33
1509-8117
1899-4741
Pojawia się w:: Polish Journal of Chemical Technology
Dostawca treści:: Biblioteka Nauki

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