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Skuteczność syntetycznych zeolitów w usuwaniu metali ciężkich i substancji organicznych z roztworów wodnych

Medykowska Magdalena

Wiadomości Chemiczne

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2023

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[Z] 77, 1-2

97--117

EN

With constantly increasing ecological needs, it is necessary to look for suitable solutions aimed at purifying the water and soil environment. Synthetic zeolites, i.e. porous, ion-exchangeable, acid- and heat-resistant, sodium and calcium aluminosilicates, may be the answer to this demand. This paper presents the adsorption capabilities of two synthetic zeolites (Na-X, Na-P1) obtained via hydrothermal reaction of aqueous sodium hydroxide and high-carbon fly ash. For this purpose, the experiment was conducted with adsorbates from two groups: heavy metals (Pb(II), Zn(II)) and organic substances (polymer - poly(acrylic acid) (PAA), nonsteroidal anti-inflammatory drug – diclofenac (DCF)). Adsorption was carried out in single and mixed adsorbate systems (metal-metal; metal-organic substance; organic substance-organic substance). The adsorption capacity of the studied zeolites was determined relative to Pb(II), Zn(II) and DCF. Desorption processes were also carried out to illustrate the regeneration abilities of the examined porous materials. In addition, the structure of the electrical double layer was characterized using potentiometric titrations and electrophoretic mobility measurements. The highest adsorbed amounts of heavy metals in single systems are observed for Na-X, i.e. 322.1 mg/g Pb(II) and 332.5 mg/g of Zn(II). In the case of Na-P1 zeolite, these amounts were 332.9 mg/g and 103.6 mg/g for Pb(II) and Zn(II), respectively. In mixed adsorbate systems there is a decrease in heavy metal adsorption, after the addition of both another metal or organic substance. In the first case, the decrease is small - the adsorption of Pb(II) on Na-X drops to 309.36 mg/g. In contrast, in mixed systems in the presence of anionic organic substances, the decrease in the amount of adsorbed ions is much greater. In the presence of DCF, Pb(II) adsorption on Na-X decrease to 98.7 mg/g, whereas on Na-P1 to 99.7 mg/g. The main mechanisms of the adsorption process in such systems are: competition for the adsorbent's active sites and the formation of complexes between adsorbates of opposite ionic character. However, the addition of a heavy metal causes increase of the drug adsorption. In the case of Pb(II) ions, the amount of DCF adsorbed on Na-X increases from 6.68 mg/g to 12.86 mg/g, and a slight decrease is observed on Na-P1. On the other hand, in the presence of PAA, DCF adsorption on Na-X decreases to 5.86 mg/g. Moreover, the synthesized adsorbents can be successfully regenerated with hydrochloric acid (in the single and mixed systems containing heavy metals). The addition of Pb(II)/Zn(II) and PAA causes a decrease in the zeta potential of the examined zeolites, whereas the addition of DCF increases this parameter. In turn, the surface charge density decreases in the presence of each adsorbate. It was proved that both synthetic zeolites can be successfully used in soil and water purification processes in continuously improved procedures.

2

The Impact Evaluation of Zeolitization Parameters on the Properties of Sewage Sludge Ash

Latosińska Jolanta

Journal of Ecological Engineering

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2019

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Vol. 20, nr 10

195--205

EN

The incineration of municipal sewage sludge causes the formation of ash, which needs further utilization. The literature gives only few examples of the chemical sewage sludge ash conversion with the hydrothermal method. The effect of conversion depends on the properties of the raw material and the process parameters. According to the domestic and foreign test results of the conversion of fly ash from coal, the fusion method is more effective. The aim of the paper was to evaluate the impact of chemical sewage sludge ash conversion with the fusion method on the chosen properties of the obtained material. The applied conversion parameters were the ratio of sewage sludge ash:NaOH, the concentration of NaOH, the activation time and temperature as well as the crystallization temperature and time. In some of the samples, the introduction of the fusion caused the formation of the following, e.g. (hydroxy)sodalite, zeolite X and zeolite Y, zeolite P, (hydroxy)cancrinite. The temperature of the thermal treatment of sludge, the ratio of ash:NaOH and the crystallization time were the parameters having a statistically significant impact on the effect of zeolitization and the properties of the obtained material, but the changes of their values had little effect on the tested features of the modified ash. On the basis of the leaching of Cd, Cr and Ni from the samples after the conversion it was proven that a higher temperature of the thermal treatment of sewage sludge was favourable for the formation of permanent structures.

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Porównanie fizykochemicznych właściwości zeolitów syntetycznych typu 4A i NaY : model sorpcji metanu na zeolitach

Wrzosek-Jakubowska J., Gworek B.

Przemysł Chemiczny

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2016

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T. 95, nr 3

594--598

PL

Przeprowadzono badania sit molekularnych NaY i 4A (syntetycznych glinokrzemianów o regularnej mikroporowatej strukturze) obejmujące identyfikację materiału pod względem mineralogicznym i określenie jego podstawowych właściwości fizykochemicznych. Zaproponowano prawdopodobny mechanizm adsorpcji metanu na kryształach zeolitów, wykorzystując program do modelowania molekularnego Material Studio 7.0. Stwierdzono, że zarówno powierzchnia wewnętrzna, objętość wszystkich porów i mikroporów, jak i całkowite stężenie centrów kwasowych na powierzchni zeolitu typu NaY są większe niż w przypadku zeolitu typu 4A.

EN

Two synthetic zeolites NaY and 4A were studied for pore topog. and structure, elementary compn., sp. surface and acidity. Their ability for MeH adsorption was estd. by numerical modeling. The NaY zeolite showed faujasite structure and much higher MeH adsorption capacity than the 4A zeolite of Linde structure.

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Synteza zeolitów do adsorpcji acetonu

Warzybok M.

Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture

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2016

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z. 63, nr 2/I

359--371

PL

Celem prowadzonych badań było uzyskanie efektywnych adsorbentów do usuwania acetonu z gazów odlotowych. Wybrano zeolit typu Y ze względu na jego wysoką termo stabilność umożliwiającą desorpcję zaadsorbowanego acetonu w temperaturach dochodzących do 1000°C. Proces syntezy składał się z czterech etapów: (1) aktywacji termicznej surowego materiału, (2) starzenia mieszanin reakcyjnych w temperaturze otoczenia, (3) krystalizacji (wysokotemperaturowego ogrzewania składników) oraz (4) przemywania i suszenia produktu. Jako substraty wykorzystano naturalne materiały ilaste – bentonit (B), haloizyt (H) oraz kaolin (K). Aby zapewnić odpowiedni stosunek molowy Na2O:SiO2:Al2O3:H2O do syntezy zastosowano również krzemionkę (SiO2) oraz roztwory chlorku (NaCl) oraz wodorotlenku sodu (NaOH). Podczas badań optymalizowano: temperaturę aktywacji, czas starzenia oraz czas i temperaturę etapu krystalizacji. Wpływ optymalizowanych parametrów na właściwości otrzymanych adsorbentów oceniano na podstawie: masy uzyskanego produktu, straty po prażeniu (LOI [%]), stężenia jonów Na+ w przesączach poreakcyjnych (CNa [mg/l]) oraz pojemności adsorpcyjnej względem acetonu (qe[mg/g]). Optymalna temperatura aktywacji wyjściowych materiałów ilastych wynosi 600°C. Podnoszenie temperatury aktywacji o kolejne 100°C skutkowało pogarszaniem właściwości adsorbentów. Wydłużenie czasu starzenia i krystalizacji, jak również podwyższenie temperatury etapu krystalizacji poprawia właściwości adsorpcyjne otrzymanych zeolitów. Optymalny czas etapu krystalizacji zależy od rodzaju materiału wyjściowego użytego do syntezy, temperatury aktywacji oraz czasu starzenia. Wydłużenie czasu starzenia mieszanin reakcyjnych pozwala na skrócenie czasu krystalizacji.

EN

The aim of the research was to study the synthesis of zeolites for adsorbing acetone. The synthesis process consisted of four stages: (1) thermal activation of the raw material; (2) aging of the reaction mixtures at the ambient temperature; (3) crystallization (at high temperatures); and (4) washing and drying the products. As substrates of the synthesis (silica and aluminium sources) three natural clay materials were used – bentonite (B), halloysite (H) and koalin (K). During the synthesis we also used silica (SiO2), sodium chloride and sodium hydroxide. During the examinations, the following parameters of the process were optimized: the temperature of the thermal activation of the raw material; the time of aging the reagents; and the time and the temperature of the crystallization stage. The influence of these optimized parameters on properties of the received adsorbents was assessed based on the following values: growth of the product mass; loss of ignition (LOI [%]); content of Na+ cations in the filtrate (CNa [mg/l]); and the adsorption capacity for acetone (qe [mg/g]). Based on the achieved results, we can state, that the optimal temperature for the thermal activation of used clay materials is 600°C. As expected extending the time and increasing the temperature of the crystallization stage influenced the improvement of the properties of the adsorbents. Depending on the initial material, as well as the temperature of the activation and the time of aging, the optimum time for the crystallization stage was different.

5

Sorption of selected organic compounds on organo-zeolites

Szala B., Turek P., Bajda T., Czerwiński J., Franus W.

Geology, Geophysics and Environment

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2012

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Vol. 38, no. 4

539--540

EN

Zeolites are microporous, aluminosilicate minerals that are characterized by cage-like structures, high surface areas, and high cation-exchange capacities. They are widely used as commercial adsorbents: in industry for water purification; as catalysts, for the preparation of advanced materials and in nuclear reprocessing. Zeolites are used to extract nitrogen from the air in order to increase oxygen content for both industrial and medical purposes and they are also used in agriculture. Natural zeolites form where volcanic rocks and ash layers react with alkaline groundwater. Currently, the world's annual production of natural zeolite is about 3 million tonnes. Demand for zeolites is extremely high, with their usage continually on the increase. Unfortunately, natural zeolites contain an admixture which reduces the purity of their composition. Furthermore, natural zeolites' properties (CEC, charge, size of cavities etc.) make it difficult to implement them in specific chemical processes - further perpetuating the demand for synthetic zeolites. Sorption of apolar substances on zeolites is low because the process takes place only on the outer surface of the crystallites. To increase the chemical affinity of the zeolite's surface to the apolar organic compounds, organic ions from quaternary ammonium salts such as hexadecyltrimethylammonium bromide (HDTMA) and dodecyltrimethylammonium chloride (DDTMA), replaced the natural cations on their exchangeable positions. HDTMA and DDTMA have a strong affinity for the zeolite's surface and replace positively charged inorganic counter-ions and neutralize the negative surface charge of the zeolite. The aim of the study was to determine the effectiveness of sorption for organically modified zeolites produced from fly ash for benzene, toluene, ethylbenzene, xylene, phenol, aniline, naphthalene, gasoline, phenan-threne, anthracene and pyrene. Material used in this study was an X-type zeolite prepared from coal fly ash. As a result of alkaline reaction of fly ash with NaOH, experimental cases bring zeolitic materials that are rich in a Na-X phase. The synthesis was performed by pouring 400 mL of an aqueous solution of NaOH onto 20 g of fly ash. This process was carried out for 24 hours at 75°C. After a series of reactions, the material was washed twice with distilled water to remove the excess NaOH solution. The result of this process was to ultimately obtain a product containing 60% zeolite . HDTMA and DDTMA were adsorbed on a synthetic zeolite in amounts of 1.0 and 2.0 of the external cation exchange capacity (ECEC) in quantities of 24.4 mmol and 48.8 mmol per 100 g of zeolite respectively. In order to select the optimal conditions for modification, the test was performed with different ratios of the solid product (zeolite) to the solution (aqueous solution of ammonium salts). Ratios used were: 1:10, 1:20, 1:30, 1:40, with modification temperature: room temperature, 40°C, 60°C and 80°C. On Surfactant-Modified Zeolite (SMZ) sorption of apolar compounds was performed. 200 mg of the organo-zeolite was placed in a tube and 10 cm aqueous of benzene, toluene, ethylben-zene, xylene, phenol, aniline, naphthalene, gasoline, phenanthrene, anthracene and pyrene was added. After modification with the HDTMA and DDTMA surfactans, the zeolite used in this work shows a significant ability to remove organic contamination from aqueous solution. As a result of this, the maximum sorption capacity of organo-zeolites and zeolites in terms of these compounds was ultimately determined. Synthetic zeolites exhibit very good sorption properties and HDTMA proved to be a better surface modifier than DDTMA. Sorption efficiencies of apolar compounds were observed at greater than 80% for all compounds in solutions. The results of this research can be used in environmental protection as well as for further study on the properties of SMZ and their potential industrial applications.

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Wykorzystanie popiołów lotnych klasy F do produkcji materiału zeolitowego na skalę półtechniczną

Franus W., Wdowin M.

Polityka Energetyczna

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2011

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T. 14, z. 2

79-91

PL

W artykule przedstawiono charakterystykę popiołów lotnych klasy F z trzech zakładów energetycznych w Polsce: Elektrowni Kozienice S.A., Elektrowni Rybnik S.A. i Elektrowni Stalowa Wola, jako potencjalnych dostawców surowców odpadowych do produkcji zeolitów syntetycznych. Analizowane popioły lotne poddano analizie składu mineralnego (XRD, SEM), chemicznego (XRF, CEC (Cation Exchange Capacity) - pojemność jonowymienna) oraz badaniom teksturalnym (powierzchnia właściwa BET, struktura porów). Zeolity z opisywanych popiołów pierwotnie otrzymywano na skalę laboratoryjną metodą syntezy hydrotermalnej popiołu lotnego z ługiem sodowym. Z uwagi na pozytywne wyniki prowadzonych reakcji syntezy oraz otrzymanie wysokiej czystości materiału zeolitowego typu X, podjęto próbę przełożenia procesu na skalę półtechniczną. W tym celu zaprojektowano i wykonano prototyp w pełni zautomatyzowanej linii technologicznej na potrzeby prowadzenia procesu syntezy. Scharakteryzowano również otrzymany w opisanym procesie materiał zeolitowy, a następnie dokonano porównania parametrów technologicznych (powierzchnia właoeciwa BET, CEC) popiołów lotnych z otrzymanym materiałem zeolitowym. Badania wykazały, że produkowany materiał zeolitowy charakteryzuje się 20-krotnie wyższą powierzchnią właściwą BET w stosunku do popiołów lotnych (średnio 14 m2/g) oraz nawet 25-krotnie wyższą wartością CEC (do 252 meq/100 g) w stosunku do materiału wyjściowego, przez co stanowi bardzo dobrej jakości sorbent mineralny. W pracy dokonano również charakterystyki ekonomicznej proponowanego rozwiązania technologicznego.

EN

In the article characteristics of F class fly ash as a potential waste materials to production of synthetic zeolites were performed. The research materials have constituted fly ashes come from three Polish power plants: Elektrownia Kozienice S.A., Elektrownia Rybnik S.A., Elektrownia Stalowa Wola S.A. On selected waste materials basic mineralogical (XRD, SEM), chemical (XRF, CEC) and textural (the BET surface area) analysis were conducted. Previous, synthetic zeolites were obtained at laboratory scale during hydrothermal synthesis of fly ash with soda lye. Because of positive results of conducted synthesis reactions and obtaining high purity zeolitic materials type X, an attempt of conducting this process on semi-technical scale were taken up. For this purpose a prototype full automated technological line to conducting of synthesis process were developed. Obtained at this process zeolitic materials were characterized. Next, the technical parameters (the BET surface area, CEC) of fly ash and obtained zeolitic materials were compared. Results have shown that produced zeolitic materials have about 20 fold higher BET surface area than fly ash (average 14 m2/g) and even 25 fold higher CEC values (up to 252 meq/100g) in comparison to initial materials (fly ash), what makes them very good quality sorbents. Also a detailed economic analysis of proposed technological line was performed.

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Zeolity syntetyczne

Sarbak Z.

LAB Laboratoria, Aparatura, Badania

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2006

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R. 11, nr 6

17-20

8

Zeolity syntetyczne

Sarbak Z.

LAB Laboratoria, Aparatura, Badania

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2006

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R. 11, nr 5

12-16