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Sample records for zeolite 4a system

  1. Adsorption Cooling System Using Metal-Impregnated Zeolite-4A

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    Somsuk Trisupakitti

    2016-01-01

    Full Text Available The adsorption cooling systems have been developed to replace vapor compression due to their benefits of being environmentally friendly and energy saving. We prepared zeolite-4A and experimental cooling performance test of zeolite-water adsorption system. The adsorption cooling test-rig includes adsorber, evaporator, and condenser which perform in vacuum atmosphere. The maximum and minimum water adsorption capacity of different zeolites and COP were used to assess the performance of the adsorption cooling system. We found that loading zeolite-4A with higher levels of silver and copper increased COP. The Cu6%/zeolite-4A had the highest COP at 0.56 while COP of zeolite-4A alone was 0.38. Calculating the acceleration rate of zeolite-4A when adding 6% of copper would accelerate the COP at 46%.

  2. Hydrogen radiolytic release from zeolite 4A/water systems under γ irradiations

    International Nuclear Information System (INIS)

    Frances, Laëtitia; Grivet, Manuel; Renault, Jean-Philippe; Groetz, Jean-Emmanuel; Ducret, Didier

    2015-01-01

    Although the radiolysis of bulk water is well known, some questions remain in the case of adsorbed or confined water, especially in the case of zeolites 4A, which are used to store tritiated water. An enhancement of the production of hydrogen is described in the literature for higher porous structures, but the phenomenon stays unexplained. We have studied the radiolysis of zeolites 4A containing different quantities of water under 137 Cs gamma radiation. We focused on the influence of the water loading ratio. The enhancement of hydrogen production compared with bulk water radiolysis has been attributed to the energy transfer from the zeolite to the water, and to the influence of the water structure organization in the zeolite. Both were observed separately, with a maximum efficiency for energy transfer at a loading ratio of about 13%, and a maximum impact of structuration of water at a loading ratio of about 4%. - Highlights: • We irradiated samples of zeolites 4A which contained different quantities of water. • We measured the quantity of hydrogen released. • Hydrogen radiolytic yields, present two maxima, for two water loading ratios. • Hydrogen release is enhanced by the strength of the zeolite/water interaction. • Hydrogen release is enhanced by the quantity of water interacting with the zeolite

  3. Synthesis of 4A zeolites from kaolin for obtaining 5A zeolites through ionic exchange for adsorption of arsenic

    International Nuclear Information System (INIS)

    Resmini Melo, Carolina; Gracher Riella, Humberto; Cabral Kuhnen, Nivaldo; Angioletto, Elidio; Melo, Aline Resmini; Bernardin, Adriano Michael; Rocha, Marcio Roberto da; Silva, Luciano da

    2012-01-01

    Highlights: ► We synthesize 4A zeolite from kaolin by hydrothermal reaction with sodium hydroxide. ► The 4A zeolite synthesized underwent ion exchange with calcium ions, with different parameters, to obtain 5A zeolites. ► The best 4A zeolite obtained was used as adsorbent material for arsenic ions. ► The results showed that the 5A zeolite material obtained is a good adsorber of heavy ions. - Abstract: The synthesis of adsorbing zeolite materials requires fine control of the processing variables. There are distinct process variable settings for obtaining specific desired types of zeolites. The intent of this study was to obtain 4A zeolites from kaolin in order to obtain 5A zeolites through ionic exchange with the previously synthesized zeolite. This zeolite 5A was used as an adsorbent for arsenic ions. The results obtained were satisfactory.

  4. Fire Performance of Plywood Treated with Ammonium Polyphosphate and 4A Zeolite

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    Mingzhi Wang

    2014-07-01

    Full Text Available Plywood samples treated with ammonium polyphosphate (APP and 4A zeolite were prepared to investigate the effect of zeolite on wood’s burning behavior using a cone calorimeter under a heat flux of 35 kW/m2. Results showed that APP decreased the heat release rate (HRR, total heat release (THR, and mass loss rate (MLR of treated plywood. However, APP significantly increased the total smoke release (TSR and carbon monoxide (CO yield. The addition of 4A zeolite reduced the HRR, peak HRR, and THR of the plywood treated with only APP. The second HRR peak in a typical plywood curve diminished with the addition of as little as 2% 4A zeolite. The average specific extinction area (ASEA and CO yield decreased significantly with the presence of zeolite in the APP. The ignition time did not change significantly and the TSR increased when zeolite was present. Thus, a suitable amount of 4A zeolite works synergistically with APP in promoting flame retardancy in flame retardant plywood.

  5. Development of spent salt treatment technology by zeolite column system. Performance evaluation of zeolite column

    International Nuclear Information System (INIS)

    Miura, Hidenori; Uozumi, Koichi

    2009-01-01

    At electrorefining process, fission products(FPs) accumulate in molten salt. To avoid influence on heating control by decay heat and enlargement of FP amount in the recovered fuel, FP elements must be removed from the spent salt of the electrorefining process. For the removal of the FPs from the spent salt, we are investigating the availability of zeolite column system. For obtaining the basic data of the column system, such as flow property and ion-exchange performance while high temperature molten salt is passing through the column, and experimental apparatus equipped with fraction collector was developed. By using this apparatus, following results were obtained. 1) We cleared up the flow parameter of column system with zeolite powder, such as flow rate control by argon pressure. 2) Zeolite 4A in the column can absorb cesium that is one of the FP elements in molten salt. From these results, we got perspective on availability of the zeolite column system. (author)

  6. Kinetic analysis of temperature-induced transformation of zeolite 4A to low-carnegieite

    International Nuclear Information System (INIS)

    Kosanovic, C.; Subotic, B.; Ristic, A.

    2004-01-01

    Kinetics of the isothermal amorphization of zeolite 4A and recrystallization of the formed amorphous phase to low-carnegieite at three different temperatures were investigated by powder X-ray diffraction method. Changes in the fractions f A of zeolite 4A, f a of amorphous aluminosilicate and f C of low-carnegieite during heating of zeolite 4A, show that amorphization and recrystallization take place simultaneously. Kinetic analyzes of single processes (amorphization, recrystallization) as well as solution of the population balance of the entire transformation process (simultaneous transformation of zeolite 4A into amorphous aluminosilicate and its recrystallization into low-carnegieite) have shown that: (A) the transformation of zeolite 4A takes place by a random, diffusion-limited agglomeration of the short-range-ordered aluminosilicate subunits formed by thermally induced breaking of Si-O-Si and Si-O-Al bonds between different building units of zeolite framework; and (B) the crystallization of low-carnegieite occurs by homogeneous nucleation of low-carnegieite inside the matrix of amorphous aluminosilicate and diffusion-controlled, one-dimensional growth of the nuclei, thus forming needle-shaped crystals of low-carnegieite

  7. Statistical planning of experiments applied in zeolite 4A synthesis

    International Nuclear Information System (INIS)

    Santos, Armindo; Santos, Liessi Luiz; Oliveira, Maria Lucia M. de; Pinto, Joao Mario Andrade

    1995-01-01

    Zeolite, an aluminum silicate which can be used in high level radioactive waste immobilization is presented. A brief description of various aspects of 4A Zeolite is made emphasizing the fractioned factorial statistic planning results, with two levels without replication, applied in the synthesis of this compound. (author). 7 refs., 3 figs

  8. Effect of the modification of a natural mexican zeolite in the sorption of cadmium and 4-chloro phenol

    International Nuclear Information System (INIS)

    Cortes M, R.

    2007-01-01

    Clinoptilolite type zeolite is a material of relative abundance in Mexico, which possess ion exchange properties and it can be used in the removal of metal ions from polluted waters. The external surface of zeolites can be modified with cationic surfactants. This modification could have a negative effect on the removal of metal ions and provides to the material the capacity to adsorb phenolic compounds. For this reason, it is important to know the capability of the modified material on the sorption of metal ions and phenolic compounds, simultaneously. The aim of this work was to evaluate the effect of the external surface modification with surfactant of a Mexican zeolite over its sorption capacity of cadmium and 4-chloro phenol, in batch and column systems. To accomplish that, a clinoptilolite type zeolitic rock from a deposit located in the state of Sonora, Mexico, was used. It was ground, sieved and characterized with different techniques; and its external surface area was modified with hexadecyltrimethylammonium bromide (HDTMA-Br). A grain size fraction was selected to carry out sorption kinetics and equilibrium experiments, as well as packed column tests with zeolitic material and solutions of cadmium and 4-chloro phenol. There are different models proposed in literature that are used to describe sorption kinetics and equilibrium. In this work, the sorption experimental results were adjusted to some of these models to identify controlling mechanisms on the kinetics and equilibrium of the studied systems. The results showed that the cadmium adsorption on natural and modified zeolite was similar in batch systems. For the case of 4-chloro phenol sorption, it was observed that natural zeolite does not retain this compound, while in modified zeolite the sorption is better than other comparable materials. The results also showed that for the case of cadmium sorption, the mechanism involved was ion exchange; while for sorption of 4-chloro phenol, a partition mechanism

  9. Radiolysis of water confined in zeolites 4A: application to tritiated water storage

    International Nuclear Information System (INIS)

    Frances, Laetitia

    2014-01-01

    Self-radiolysis of tritiated water (HTO) adsorbed in zeolites 4A shows differences compared to free-bulk water radiolysis. We studied the roles of zeolites on that. We took special care with the influence of water loading ratio. We first exposed zeolites to external irradiations, reproducing selectively the dose or the dose rate measured in the case of tritiated water storage. This strategy enables the characterising of the samples after their irradiation since they are not contaminated by tritium. Those experiments revealed the high stability of zeolites 4A. We used a second approach which consisted in studying the precise case of self-radiolysis of tritiated water, in order to obtain radiolytic yields representative of HTO storage. The comparison between the quantities of gas released when zeolites are exposed to the three different sources that we used (electrons accelerated at 10 MeV, γ released by radioactive decay of 137 Cs and β - released by radioactive decay of tritium) revealed the strong influence of the dose rate. Moreover, whatever the irradiation source, zeolites 4A first favour hydrogen release and secondarily oxygen release too. On the contrary, zeolites favour next a recombination between those radiolytic products, with a dependence on their water loading ratio. Several processes are discussed to explain such a phenomena, not noticed during the free-bulk water radiolysis. (author) [fr

  10. Fabrication of 6FDA-durene membrane incorporated with zeolite T and aminosilane grafted zeolite T for CO2/CH4 separation

    Science.gov (United States)

    Jusoh, Norwahyu; Fong Yeong, Yin; Keong Lau, Kok; Shariff, Azmi Mohd

    2017-08-01

    In the present work, zeolite T and aminosilane grafted zeolite T are embedded into 6FDA-durene polyimide phase for the fabrication of mixed matrix membranes (MMMs). FESEM images demonstrated that the improvement of interfacial adhesion between zeolite and polymer phases in MMM loaded with aminosilane grafted zeolite T was not significant as compared to zeolite T/6FDA-durene MMM. From the gas permeation test, CO2/CH4 selectivity up to 26.4 was achieved using MMM containing aminosilane grafted zeolite T, while MMM loaded with ungrafted zeolite T showed CO2/CH4 selectivity of 19.1. In addition, MMM incorporated with aminosilane grafted zeolite T particles successfully lies on Robeson upper bound 2008, which makes it an attractive candidate for CO2/CH4 separation.

  11. Effect of Fe3O4 addition on removal of ammonium by zeolite NaA.

    Science.gov (United States)

    Liu, Haibo; Peng, Shuchuan; Shu, Lin; Chen, Tianhu; Bao, Teng; Frost, Ray L

    2013-01-15

    Magnetic zeolite NaA with different Fe(3)O(4) loadings was prepared by hydrothermal synthesis based on metakaolin and Fe(3)O(4). The effect of added Fe(3)O(4) on the removal of ammonium by zeolite NaA was investigated by varying the Fe(3)O(4) loading, pH, adsorption temperature, initial concentration, adsorption time. Langmuir, Freundlich, and pseudo-second-order modeling were used to describe the nature and mechanism of ammonium ion exchange using both zeolite and magnetic zeolite. Thermodynamic parameters such as change in Gibbs free energy, enthalpy and entropy were calculated. The results show that all the selected factors affect the ammonium ion exchange by zeolite and magnetic zeolite, however, the added Fe(3)O(4) apparently does not affect the ion exchange performance of zeolite to the ammonium ion. Freundlich model provides a better description of the adsorption process than Langmuir model. Moreover, kinetic analysis indicates the exchange of ammonium on the two materials follows a pseudo-second-order model. Thermodynamic analysis makes it clear that the adsorption process of ammonium is spontaneous and exothermic. Regardless of kinetic or thermodynamic analysis, all the results suggest that no considerable effect on the adsorption of the ammonium ion by zeolite is found after the addition of Fe(3)O(4). According to the results, magnetic zeolite NaA can be used for the removal of ammonium due to the good adsorption performance and easy separation method from aqueous solution. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. The annihilation of ortho-positronium in the α and β cavities of the 4A zeolite and those CoZ4A and MnZ4A

    International Nuclear Information System (INIS)

    Cabral P, A.; Garcia S, I.; Jimenez B, J.; Solache R, M.; Bonifacio M, J.; Rodriguez F, C.; Bulbulian, S.

    2002-01-01

    The lifetime of the ortho-positronium in the zeolite 4A, partially dehydrated, changes to three characteristic modes. The first mode could be associated with the water elimination of the small β cavity of this zeolite. At the end of this first dehydration process it is estimated a cavity radius, R = 33.8 nm. The other two types of variation of lifetime of ortho-positronium would be associated with the water elimination of the α great cavity and of the rest of the zeolite. From the zeolite 4A totally dehydrated and of the zeolite 4A exchanged with Co (II) and MN (II), also dehydrated radius are respectively determined for the α great cavity of R = 48.1, 54.5 and 56.5 nm. (Author)

  13. Penggunaan zeolit alam untuk mengurangi kandungan krom dan nh4+ dalam air limbah penyamakan kulit

    Directory of Open Access Journals (Sweden)

    Supraptiningsih Supraptiningsih

    2006-07-01

    Full Text Available Leather tanning waste water contains chemical compounds, such as chromium and NH4+ in high concentration, so if they are thrown away without treatment they will make some problems. The aims of this research is to adsorb the cations in leather tanning waste water i.e chromium and NH4+ used natural zeolite as an adsorbent. Research was done by comparing amount of chromium and NH4+ in effluent waste water treatment unit with amount of chromium and NH4+ after being adsorbed by zeolite in a batch system. The result of this research showed that efficiency difference between using zeolite and waste water treatment unit was significant. The optimal condition to reduce chromium and NH4+ was by using 300 grams per liter waste, zeolite particle size was 50-60 mesh, contact time was 24 hours and pH 8±0,1. In this condition, zeolites could reduce chromium from 3728,56mg/l to 365,39 mg/l or 90,20%, and NH4+ from 3040,02 mg/l menjadi 209,76 mg/l or 93,10%. Waste water treatment unit could reduce chromium 63,55% and NH4+ 56,75%.

  14. Removal of barium and strontium from aqueous solution using zeolite 4A.

    Science.gov (United States)

    Araissi, Manel; Ayed, Imen; Elaloui, Elimame; Moussaoui, Younes

    2016-01-01

    The adsorption efficiency of Sr(2+) and Ba(2+) from aqueous solutions by zeolite 4A was investigated. Adsorption studies were carried out both in single and binary component systems. The single ion equilibrium adsorption data were fitted to three isotherm models: Langmuir, Freundlich and Dubinin-Radushkevich. The Langmuir model represents the equilibrium data better than the Freundlich model in the studied initial metal concentration (0.3-25 mmol L(-1)) in both the single and binary component systems. The obtained RL (separation factor or Langmuir parameter) values were in the range of 0-1 indicating that Sr(2+) and Ba(2+) sorption were favorable. The obtained mean free energy value for adsorption of Ba(2+) and Sr(2+) was 8.45 kJ mol(-1) and 9.12 kJ mol(-1), respectively, indicating that both ions were uptaken through an ion exchange process. The maximum adsorption capacities (Qmax) were 2.25 mmol g(-1) and 2.34 mmol g(-1) for Ba(2+) and Sr(2+) ions, respectively. Also, the study of the competitive sorption of ions in the binary system showed that zeolite 4A preferentially adsorbs cations in the following order: Ba(2+) < Sr(2+).

  15. The fabrication of porous 4A-zeolite-supported Ag nanoparticles catalysts and its catalytic activity for styrene epoxidation

    Directory of Open Access Journals (Sweden)

    Youkui Wu

    Full Text Available Binderless hierarchically porous 4A-zeolite has been successful produced through hydrothermal crystallization, in which silicon-aluminum sol binded to the carbon nanofibers (CNFs, that is to say, where the CNFs powder was coated during the crystallization 4A-zeolite. The mixing of silica-alumina sol and CNFs was only a simple physical mixing process. The samples of micropores-macroporous hierarchical 4A-zeolite (P-4A-zeolite was analyzed by a series of characterization techniques, such as field emission scanning electron microscope (FESEM, transmission electron microscopy (TEM, simultaneous thermal analysis (STA and CO2 adsorption-desorption (BET and BJH, and so on. In addition, the adsorption test of silver nanoparticles was carried out. The characterization results indicated the presence of micropores and the formation of macroporous. At the same time, silver adsorption test proved that the prepared P-4A-zeolite had good adsorption performance and the catalytic performance of Ag/P-4A-zeolite was further investigated through the epoxidation of styrene. Keywords: Carbon nanofibers, Porous 4A-zeolite, Silver nanoparticles, Styrene epoxidation

  16. Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application.

    Science.gov (United States)

    Ma, Dongyang; Wang, Zhendong; Guo, Min; Zhang, Mei; Liu, Jingbo

    2014-11-01

    Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO3/g, comparable to commercially-available zeolite (310 mg CaCO3/g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Dongyang; Wang, Zhendong; Guo, Min [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Mei, E-mail: zhangmei@ustb.edu.cn [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); Liu, Jingbo [The Department of Chemistry, Texas A and M University-Kingsville, Kingsville, TX 78363 (United States); The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2014-11-15

    Highlights: • Concept to convert waste to valuable product is carried out in this study. • An industrially feasible and cost-effective approach was developed and optimized. • Highly crystalline and well-defined zeolite was produced under moderate conditions. • The zeolite derived from the bauxite tailings displayed high ion exchange capacity. • Bauxite tailings have potential application in heavy metal ions adsorbent. - Abstract: Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO{sub 3}/g, comparable to commercially-available zeolite (310 mg CaCO{sub 3}/g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China.

  18. Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application

    International Nuclear Information System (INIS)

    Ma, Dongyang; Wang, Zhendong; Guo, Min; Zhang, Mei; Liu, Jingbo

    2014-01-01

    Highlights: • Concept to convert waste to valuable product is carried out in this study. • An industrially feasible and cost-effective approach was developed and optimized. • Highly crystalline and well-defined zeolite was produced under moderate conditions. • The zeolite derived from the bauxite tailings displayed high ion exchange capacity. • Bauxite tailings have potential application in heavy metal ions adsorbent. - Abstract: Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO 3 /g, comparable to commercially-available zeolite (310 mg CaCO 3 /g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China

  19. Hydrothermal conversion of FAU zeolite into RUT zeolite in TMAOH system

    OpenAIRE

    Jon, Hery; Takahashi, Shoutarou; Sasaki, Hitoshi; Oumi, Yasunori; Sano, Tsuneji

    2008-01-01

    The highly crystalline and pure RUT (RUB-10) zeolite could be obtained from the hydrothermal conversion of FAU zeolite used as a crystalline Si/Al source in tetramethylammonium hydroxide (TMAOH) media. As compared to amorphous silica/Al(OH)3 and amorphous silica/γ-Al2O3 sources, the crystallization rate for the formation of RUT zeolite was clearly faster when FAU zeolite was employed as the Si/Al source. Moreover, it was found that the hydrothermal conversion of FAU zeolite into RUT zeolite d...

  20. Recent advances of pore system construction in zeolite-catalyzed chemical industry processes.

    Science.gov (United States)

    Shi, Jing; Wang, Yangdong; Yang, Weimin; Tang, Yi; Xie, Zaiku

    2015-12-21

    The kaleidoscopic applications of zeolite catalysts (zeo-catalysts) in petrochemical processes has been considered as one of the major accomplishments in recent decades. About twenty types of zeolite have been industrially applied so far, and their versatile porous architectures have contributed their most essential features to affect the catalytic efficiency. This review depicts the evolution of pore models in zeolite catalysts accompanied by the increase in industrial and environmental demands. The indispensable roles of modulating pore models are outlined for zeo-catalysts for the enhancement of their catalytic performances in various industrial processes. The zeolites and related industrial processes discussed range from the uni-modal micropore system of zeolite Y (12-ring micropore, 12-R) in fluid catalytic cracking (FCC), zeolite ZSM-5 (10-R) in xylene isomerization and SAPO-34 (8-R) in olefin production to the multi-modal micropore system of MCM-22 (10-R and 12-R pocket) in aromatic alkylation and the hierarchical pores in FCC and catalytic cracking of C4 olefins. The rational construction of pore models, especially hierarchical features, is highlighted with a careful classification from an industrial perspective accompanied by a detailed analysis of the theoretical mechanisms.

  1. Synthesis of Zeolite NaA from Low Grade (High Impurities) Indonesian Natural Zeolite

    OpenAIRE

    Mustain, Asalil; Wibawa, Gede; Nais, Mukhammad Furoiddun; Falah, Miftakhul

    2014-01-01

    The zeolite NaA has been successfully synthesized from the low grade natural zeolite with high impurities. The synthesis method was started by mixing natural zeolite powder with NH4Cl aqueous solution in the reactor as pretreatment. The use of pretreatment was to reduce the impurities contents in the zeolite. The process was followed by alkaline fusion hydrothermal treatment to modify the framework structure of natural zeolite and reduce the SiO2/Al2O3 ratio. Finally, the synthesized zeolite ...

  2. Modification of zeolite 4A for use as an adsorbent for glyphosate and as an antibacterial agent for water.

    Science.gov (United States)

    Zavareh, Siamak; Farrokhzad, Zahra; Darvishi, Farshad

    2018-07-15

    The aim of this work was to design a low cost adsorbent for efficient and selective removal of glyphosate from water at neutral pH conditions. For this purpose, zeolite 4A, a locally abundant and cheap mineral material, was ion-exchanged with Cu 2+ to produce Cu-zeolite 4A. The FTIR results revealed that the modification has no important effect on chemical structure of zeolite 4A. After modification, highly crystalline zeolite 4A was converted to amorphous Cu-zeolite 4A according to XRD studies. The SEM images showed spherical-like particles with porous surfaces for Cu-zeolite 4A compared to cubic particles with smooth surfaces for zeolite 4A. Adsorption equilibrium data were well fitted with non-linear forms of Langmuir, Freundlich and Temkin isotherms. The maximum adsorption capacity for Cu-zeolite 4A was calculated to be 112.7 mg g -1 based on the Langmuir model. The adsorption of glyphosate by the modified adsorbent had fast kinetics fitted both pseudo-first-order and pseudo-second-order models. A mechanism based on chemical adsorption was proposed for the removal process. The modified adsorbent had a good selectivity to glyphosate over natural waters common cations and anions. It also showed desired regeneration ability as an important feature for practical uses. The potential use of the developed material as antibacterial agent for water disinfection filters was also investigated by MIC method. Relatively strong antibacterial activity was observed for Cu-zeolite 4A against Gram-positive and Gram-negative model bacteria while zeolite 4A had no antibacterial properties. No release of Cu 2+ to aqueous solutions was detected as unique feature of the developed material. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Processing of radioactive waste solution with zeolites, (4)

    International Nuclear Information System (INIS)

    Mimura, Hitoshi; Kanno, Takuji

    1978-01-01

    Volatilization of Cs from Cs type zeolites and calcined zeolites were studied at high temperature. Synthetic zeolites A, X, Y, synthetic mordenite (Zeolon), natural mordenite and clinoptilolite saturated with Cs were used in this study. Volatilized Cs from CsX was largest in quantity and from cs type natural zeolites smallest. Volatilization of Cs was observed at about 800 0 C and increased as the calcining temperature rose. Volatilized Cs from CsA was smallest in synthetic zeolites. CsA recrystallized to nepheline and pollucite with the ratio of about 1 : 1 above 1,000 0 C and it seemed that the volatilization of Cs from pollucite was suppressed with the nepheline phase surrounded them. The rate of volatilization was very fast within the initial 10 min and very slow after 60 min except for CsX. This behavior suggested that the rate was very fast before structural transformation. The mean volatilization rate of Cs in 3 hr from calcined CsX (pollucite) was 1.1 x 10 -4 mg/cm 2 .min and the others were 10 -5 -- 10 -6 mg/cm 2 .min. The amount of volatilized Cs in Ar flow was decreased 20 -- 90% of that in air flow. Volatilized species was identified with Cs 2 O by mass spectrometry. (auth.)

  4. Zeolite-zeolite composite composed of Y zeolite and single-crystal-like ZSM-5 zeolite: Fabricated by a process like “big fish swallowing little one”

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Meng; Li, Peng [Research Centre of Energy Chemical & Catalytic Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Zheng, Jiajun, E-mail: zhengjiajun@tyut.edu.cn [Research Centre of Energy Chemical & Catalytic Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Liu, Yujian [SINOPEC Research Institute of Petroleum Processing, Beijing, 100083 (China); Kong, Qinglan [Research Centre of Energy Chemical & Catalytic Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Tian, Huiping [SINOPEC Research Institute of Petroleum Processing, Beijing, 100083 (China); Li, Ruifeng, E-mail: rfli@tyut.edu.cn [Research Centre of Energy Chemical & Catalytic Technology, Taiyuan University of Technology, Taiyuan 030024 (China)

    2017-06-15

    Zeolite-zeolite composite composed of Y and ZSM-5 zeolite was prepared using depolymerized Y as partial nutrients for the growth of ZSM-5. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), FT-IR, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), N{sub 2} adsorption-desorption measurement and Thermogravimetric analysis (TG). Chemical equilibrium at the solution-crystal interface was changed because of the partially depolymerized Y zeolite, the conditions necessary for the growth of ZSM-5 were therefore obtained. ZSM-5 zeolite crystals nucleated and grew on the interface, and Y zeolite crystals were then gradually swallowed by the growing single-crystal-like ZSM-5. - Graphical abstract: Y zeolite crystals in the hydrothermal system were partially depolymerized and an ambience in favor of the formation of ZSM-5 was formed, and ZSM-5 zeolite crystals nucleated and grew up on the external surfaces of Y zeolite crystals. As a consequence, Y zeolite crystals were swallowed by single-crystal-like ZSM-5. - Highlights: • Zeolite composite is composed by Y zeolite and single-crystal-like ZSM-5. • A composite material formed by a process like “big fish swallowing little one”. • Ratio of two zeolites in the as-synthesized sample can be adjusted.

  5. Isomerisation of c4-c6 aldoses with zeolites

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to isomerization of C4-C6 aldoses to their corresponding C4-C6 ketoses. In particular, the invention concerns isomerization of C4-C6 aldoses over solid zeolite catalysts free of any metals other than aluminum, in the presence of suitable solvent(s) at suitable elevated...... temperatures. C6 and C5 aldose sugars such as glucose and xylose, which are available in large amounts from biomass precursors, are isomerized to fructose and xylulose respectively, in a one or two-step process over inexpensive commercially available zeolite catalysts, containing aluminum as the only metal...

  6. Vitrification of highly-loaded SDS zeolites

    International Nuclear Information System (INIS)

    Siemens, D.H.; Bryan, G.H.; Knowlton, D.E.; Knox, C.A.

    1982-11-01

    Pacific Northwest Laboratory (PNL) is demonstrating a vitrification system designed for immobilization of highly loaded SDS zeolites. The Zeolite Vitrification Demonstration Project (ZVDP) utilizes an in-can melting process. All steps of the process have been demonstrated, from receipt of the liners through characterization of the vitrified product. The system has been tested with both nonradioactive and radioactive zeolite material. Additional high-radioactivity demonstrations are scheduled to begin in FY-83. 5 figures, 4 tables

  7. EFFECT OF GRAIN SIZE AND ACTIVATION TIME OF ZEOLITE TO ADSORPTION AND DESORPTION OF NH4OH AND KCL AS MODEL OF FERTILIZER-ZEOLITE MIX

    Directory of Open Access Journals (Sweden)

    Muhammad Prasantio Bimantio

    2017-10-01

    Full Text Available Zeolites can be used as adsorbent, ion exchange, catalyst, or catalyst carrier. Application of fertilizer use in the zeolite also be one of the interesting topic. Zeolites in a mixture of fertilizer can use to control the release of nutrients. The purpose of this research is to study the effect of grain size and time of the activation of zeolite to adsorption and desorption of NH4OH and KCl as modeling of ZA and KCl fertilizer, to obtain the value of adsorption rate constant (ka and desorption rate constant (kd. This research procedure include: the process of adsorption by adding zeolite with various size and time of activation into a sealed beaker glass and let the adsorption process occurs for 24 hours. After 24 hours, the solution was filtered, the zeolite then put in 100 ml of aquadest into a sealed beaker glass and let the desorption process happened for another 24 hours. Three samples with the largest difference solution concentrations looked for the value of the ka and kd. Zeolite configuration with the largest ka is trialed with fertilizer and compared with the value of ka obtained from modeling. The result for NH4OH adsorbate, -50+60 mesh 2 hours configuration zeolite give the largest ka. For KCl adsorbate, -30+40 mesh 4 hours configuration zeolite give the largest ka. The value between modeling and trials with fertilizers are not much different.

  8. Zeolite studies. Aluminium phosphate zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Haegh, G.S.; Blindheim, U.

    1983-12-01

    Alpo-zeolites (ALPO4-zeolites) have been synthesized by hydrothermal synthesis in an autoclave from alumina, tetralkylammonium hydroxide and phosphorus acid. Catalysis tests with hydrocarbons indicate that the compounds have good olefinisomerization activity and selectivity.

  9. Ultra-small Ag clusters in zeolite A4: Antibacterial and thermochromic applications

    Science.gov (United States)

    Horta-Fraijo, P.; Cortez-Valadez, M.; Flores-Lopez, N. S.; Britto Hurtado, R.; Vargas-Ortiz, R. A.; Perez-Rodriguez, A.; Flores-Acosta, M.

    2018-03-01

    The physical and chemical properties of metal clusters depend on their atomic structure, therefore, it is important to determine the lowest-energy structures of the clusters in order to understand and utilize their properties. In this work, we use the Density Functional Theory (DFT) at the generalized gradient approximation level Becke's three-parameter and the gradient corrected functional of Lee, Yang and Puar (B3LYP) in combination with the basis set LANL2DZ (the effective core potentials and associated double-zeta valence) to determine some of the structural, electronic and vibrational properties of the planar silver clusters (Agn clusters n = 2-24). Additionally, the study reports the experimental synthesis of small silver clusters in synthetic zeolite A4. The synthesis was possible using the ion exchange method with some precursors like silver nitrate (AgNO3) and synthetic zeolite A4. The silver clusters in zeolite powder underwent thermal treatment at 450 °C to release the remaining water or humidity on it. The morphology of the particles was determined by Transmission Electron microscopy. The nanomaterials obtained show thermochromic properties. The structural parameters were correlated theoretically and experimentally.

  10. Performance of zeolite scavenge column in Xe monitoring system

    International Nuclear Information System (INIS)

    Wang Qian; Wang Hongxia; Li Wei; Bian Zhishang

    2010-01-01

    In order to improve the performance of zeolite scavenge column, its ability of removal of humidity and carbon dioxide was studied by both static and dynamic approaches. The experimental results show that various factors, including the column length and diameter, the mass of zeolite, the content of water in air, the temperature rise during adsorption, and the activation effectiveness all effect the performance of zeolite column in scavenging humanity and carbon dioxide. Based on these results and previous experience, an optimized design of the zeolite column is made for use in xenon monitoring system. (authors)

  11. Systems including catalysts in porous zeolite materials within a reactor for use in synthesizing hydrocarbons

    Science.gov (United States)

    Rolllins, Harry W [Idaho Falls, ID; Petkovic, Lucia M [Idaho Falls, ID; Ginosar, Daniel M [Idaho Falls, ID

    2012-07-24

    Catalytic structures include a catalytic material disposed within a zeolite material. The catalytic material may be capable of catalyzing a formation of methanol from carbon monoxide and/or carbon dioxide, and the zeolite material may be capable of catalyzing a formation of hydrocarbon molecules from methanol. The catalytic material may include copper and zinc oxide. The zeolite material may include a first plurality of pores substantially defined by a crystal structure of the zeolite material and a second plurality of pores dispersed throughout the zeolite material. Systems for synthesizing hydrocarbon molecules also include catalytic structures. Methods for synthesizing hydrocarbon molecules include contacting hydrogen and at least one of carbon monoxide and carbon dioxide with such catalytic structures. Catalytic structures are fabricated by forming a zeolite material at least partially around a template structure, removing the template structure, and introducing a catalytic material into the zeolite material.

  12. Na-A4 zeolites as host of PbS nanoparticles

    International Nuclear Information System (INIS)

    Flores A, M.; Perez S, R.; Aceves T, R.; Arizpe C, H.; Sotelo L, M.; Ramirez B, R.

    2006-01-01

    In this work we report the optical and structural properties of composite materials based on the semiconductor PbS enclosed in type A zeolite. The composite materials were obtained by chemical reaction in several steps of the zeolite in alkaline aqueous solutions containing Pb 2+ and S 2- ions successively. Three samples were prepared at temperatures of 40, 50 and 60 C during the chemical reaction with S 2- ions. The obtained materials were studied by x-ray diffraction, scanning and transmission electron microscopy, diffuse reflectance spectroscopy and photoluminescence. The experimental results show the formation of spherical-shaped PbS particles with nano metric size and cubic crystalline structure embedded in the zeolite matrix. The absorption spectra of the samples display a well defined absorption band at about 300 nm due to the PbS nanoparticles in the zeolite matrix. In addition, an absorption peak appears in the absorption spectra at about 400 nm assigned to exciton transitions. (Author)

  13. Hierarchical zeolites: progress on synthesis and characterization of mesoporous zeolite single crystal catalysts

    DEFF Research Database (Denmark)

    Kustova, Marina; Egeblad, Kresten; Christensen, Claus H.

    2007-01-01

    Recently, a new family of crystalline zeolitic materials was reported, the so-called mesoporous zeolite single crystals featuring individual zeolite single crystals with an additional noncrystalline mesopore system interconnected with the usual micropore system of the zeolite, resulting...... measurements. Additionally, the results of diffusion of n-hexadecane in conventional and mesoporous zeolites are presented. Isomerization and cracking of n-hexadecane was chosen as model test reaction for these materials. All results support that mesoporous zeolites are superior catalysts due to improved mass...... transport. Importantly, the mesoporous zeolites show significant improved resistance to poisoning by carbon formation....

  14. Effect of the modification of a natural mexican zeolite in the sorption of cadmium and 4-chloro phenol; Efecto de la modificacion de una zeolita natural mexicana en la sorcion de cadmio y 4-clorofenol

    Energy Technology Data Exchange (ETDEWEB)

    Cortes M, R [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2007-07-01

    Clinoptilolite type zeolite is a material of relative abundance in Mexico, which possess ion exchange properties and it can be used in the removal of metal ions from polluted waters. The external surface of zeolites can be modified with cationic surfactants. This modification could have a negative effect on the removal of metal ions and provides to the material the capacity to adsorb phenolic compounds. For this reason, it is important to know the capability of the modified material on the sorption of metal ions and phenolic compounds, simultaneously. The aim of this work was to evaluate the effect of the external surface modification with surfactant of a Mexican zeolite over its sorption capacity of cadmium and 4-chloro phenol, in batch and column systems. To accomplish that, a clinoptilolite type zeolitic rock from a deposit located in the state of Sonora, Mexico, was used. It was ground, sieved and characterized with different techniques; and its external surface area was modified with hexadecyltrimethylammonium bromide (HDTMA-Br). A grain size fraction was selected to carry out sorption kinetics and equilibrium experiments, as well as packed column tests with zeolitic material and solutions of cadmium and 4-chloro phenol. There are different models proposed in literature that are used to describe sorption kinetics and equilibrium. In this work, the sorption experimental results were adjusted to some of these models to identify controlling mechanisms on the kinetics and equilibrium of the studied systems. The results showed that the cadmium adsorption on natural and modified zeolite was similar in batch systems. For the case of 4-chloro phenol sorption, it was observed that natural zeolite does not retain this compound, while in modified zeolite the sorption is better than other comparable materials. The results also showed that for the case of cadmium sorption, the mechanism involved was ion exchange; while for sorption of 4-chloro phenol, a partition mechanism

  15. The annihilation of ortho-positronium in the {alpha} and {beta} cavities of the 4A zeolite and those CoZ4A and MnZ4A; La aniquilacion del orto-positronio en las cavidades {alpha} y {beta} de la zeolita 4A y en las de CoZ4A y MnZ4A

    Energy Technology Data Exchange (ETDEWEB)

    Cabral P, A.; Garcia S, I.; Jimenez B, J.; Solache R, M.; Bonifacio M, J.; Rodriguez F, C.; Bulbulian, S. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    The lifetime of the ortho-positronium in the zeolite 4A, partially dehydrated, changes to three characteristic modes. The first mode could be associated with the water elimination of the small {beta} cavity of this zeolite. At the end of this first dehydration process it is estimated a cavity radius, R = 33.8 nm. The other two types of variation of lifetime of ortho-positronium would be associated with the water elimination of the {alpha} great cavity and of the rest of the zeolite. From the zeolite 4A totally dehydrated and of the zeolite 4A exchanged with Co (II) and MN (II), also dehydrated radius are respectively determined for the {alpha} great cavity of R = 48.1, 54.5 and 56.5 nm. (Author)

  16. Applicability of Zeolite Based Systems for Ammonia Removal and Recovery From Wastewater.

    Science.gov (United States)

    Das, Pallabi; Prasad, Bably; Singh, Krishna Kant Kumar

    2017-09-01

      Ammonia discharged in industrial effluents bears deleterious effects and necessitates remediation. Integrated systems devoted to recovery of ammonia in a useful form and remediation of the same addresses the challenges of waste management and its utilization. A comparative performance evaluation study was undertaken to access the suitability of different zeolite based systems (commercial zeolites and zeolites synthesized from fly ash) for removal of ammonia followed by its subsequent release. Four main parameters which were studied to evaluate the applicability of such systems for large scale usage are cost-effectiveness, ammonia removal efficiency, performance on regeneration, and ammonia release percentage. The results indicated that synthetic zeolites outperformed zeolites synthesized from fly ash, although the later proved to be more efficient in terms of total cost incurred. Process technology development in this direction will be a trade-of between cost and ammonia removal and release efficiencies.

  17. Method of producing zeolite encapsulated nanoparticles

    DEFF Research Database (Denmark)

    2015-01-01

    The invention therefore relates to a method for producing zeolite, zeolite-like or zeotype encapsulated metal nanoparticles, the method comprises the steps of: 1) Adding one or more metal precursors to a silica or alumina source; 2) Reducing the one or more metal precursors to form metal...... nanoparticles on the surface of the silica or alumina source; 3) Passing a gaseous hydrocarbon, alkyl alcohol or alkyl ether over the silica or alumina supported metal nanoparticles to form a carbon template coated zeolite, zeolite-like or zeotype precursor composition; 4a) Adding a structure directing agent...... to the carbon template coated zeolite, zeolite-like or zeotype precursor composition thereby creating a zeolite, zeolite-like or zeotype gel composition; 4b) Crystallising the zeolite, zeolite-like or zeotype gel composition by subjecting said composition to a hydrothermal treatment; 5) Removing the carbon...

  18. Method for producing zeolites and zeotypes

    DEFF Research Database (Denmark)

    2015-01-01

    The invention relates to a method for producing zeolite, zeolite-like or zeotype particles comprising the steps of: 1 ) Adding one or more metal precursors to a silica or alumina source; 2) Reducing the one or more metal precursors to form metal nanoparticles on the surface of the silica or alumina...... source; 3) Passing a gaseous hydrocarbon, alkyl alcohol or alkyl ether over the silica or alumina supported metal nanoparticle to form a carbon template coated zeolite, zeolite-like or zeotype precursor composition; 4a) Adding a structure directing agent to the carbon template coated zeolite, zeolite......-like or zeotype precursor composition thereby creating a zeolite, zeolite-like or zeotype gel composition; 4b) Crystallising the zeolite, zeolite-like or zeotype gel composition by subjecting said composition to a hydrothermal treatment; 5) Removing the carbon template and structure directing agent and isolating...

  19. OBTAINING OF THE MG2+ FORM OF THE ZEOLITE 4A WITH ION EXCHANGE OF MAGNESIUM SALTS

    Directory of Open Access Journals (Sweden)

    Blagica Cekova

    2016-01-01

    Full Text Available Zeolites are sodium alumino silicates which in in their composition contain zeolite water. They have a three-dimensional structure. Spatial structure defined by a strictly defined geometry of pores and cavities. For ionic еchange is used magnesium salt (MgCl2*6H2O whose aqueous solutions were with the following concentrations (MgCl2*6H2O = 2,5; 3.5; 4,5 mol / dm3 , and other parameters of the ion exchange: time t = 20, 30, 40 and temperature of 298 and 330 K. Ionian capacity is calculated as mmgMgO / 1g zeolite.

  20. EXPERIMENTAL DESIGN AND RESPONSE SURFACE MODELING OF PI/PES-ZEOLITE 4A MIXED MATRIX MEMBRANE FOR CO2 SEPARATION

    Directory of Open Access Journals (Sweden)

    T. D. KUSWORO

    2015-09-01

    Full Text Available This paper investigates the effect of preparation of polyimide/polyethersulfone (PI/PES blending-zeolite mixed matrix membrane through the manipulation of membrane production variables such as polymer concentration, blending composition and zeolite loading. Combination of central composite design and response surface methodology were applied to determine the main effect and interaction effects of these variables on membrane separation performance. The quadratic models between each response and the independent parameters were developed and the response surface models were tested with analysis of variance (ANOVA. In this study, PI/ (PES–zeolite 4A mixed matrix membranes were casted using dry/wet phase inversion technique. The separation performance of mixed matrix membrane had been tested using pure gases such as CO2 and CH4. The results showed that zeolite loading was the most significant variable that influenced the CO2/CH4 selectivity among three variables and the experimental results were in good agreement with those predicted by the proposed regression models. The gas separation performance of the membrane was relatively higher as compare to polymeric membrane. Therefore, combination of central composite design and response surface methodology can be used to prepare optimal condition for mixed matrix membrane fabrication. The incorporation of 20 wt% zeolite 4A into 25 wt% of PI/PES matrix had resulted in a high separation performance of membrane material.

  1. ZEOLITIZATION OF SEWAGE SLUDGE ASH WITH A FUSION METHOD

    Directory of Open Access Journals (Sweden)

    Jolanta Latosińska

    2016-11-01

    Full Text Available The study shows the results of zeolitization of municipal sewage sludge ash with the indirect fusion method followed by a hydrothermal method. The zeolitization of sewage sludge ash was conducted at the melting temperature of 550°C and the melting time of 60 minutes, crystallization temperatures of 60°C and 90°C, crystallization time of 6 hours and the SSA:NaOH ratio of 1:1.8; 1:1.4. The research of modified sewage sludge ashes included the observation of changes of ash particles surface and the identification of crystalized phases. The zeolitization of sewage sludge ash at the ratio of SSA:NaOH 1.0:1.4 did not cause the formation of zeolite phases. On the other hand, the zeolitization at the ratio of SSA:NaOH 1.0:1.8 resulted in the formation of desired zeolite phases such as zeolite Y (faujasite and hydroxysodalite. The presented method of sewage sludge ash zeolitization allows to obtain highly usable material. Synthesized zeolites may be used as adsorbents and ion exchangers. They can be potentially used to remove heavy metals as well as ammonia from water and wastewater.

  2. A modeling study of vacuum sorption characteristics of carbon dioxide on 4A zeolite molecular sieves

    Energy Technology Data Exchange (ETDEWEB)

    Prazniak, J.K.; Byers, C.H.

    1987-08-01

    A model is presented to describe the isothermal adsorption of carbon dioxide (CO/sub 2/) and of nitrogen (N/sub 2/) on 4A zeolite molecular sieves under cryogenic conditions. The model is comprised of a fluid-phase mass balance representing the dynamics of gas in the bed and a one-dimensional diffusion equation representing adsorption in the solid. Cubic crystals of 4A zeolite are assumed to be spherical, and the concentration dependence of the diffusivity of the sorbate in both the gas and solid phases is considered. Numerical solution of the parabolic partial differential model equations is accomplished using orthogonal collocation in conjunction with an ordinary differential equation integrator suitable for stiff equations. 34 refs., 18 figs., 5 tabs.

  3. Removal of ammonia nitrogen from leachate of Muribeca municipal solid waste landfill, Pernambuco, Brazil, using natural zeolite as part of a biochemical system.

    Science.gov (United States)

    Lins, Cecilia Maria M S; Alves, Maria Cristina M; Campos, Juacyara C; Silva, Fabrícia Maria S; Jucá, José Fernando T; Lins, Eduardo Antonio M

    2015-01-01

    The inadequate disposal of leachate is one of the key factors in the environmental impact of urban solid waste landfills in Brazil. Among the compounds present in the leachates from Brazilian landfills, ammonia nitrogen is notable for its high concentrations. The purpose of this study was to assess the efficiency of a permeable reactive barrier filled with a natural zeolite, which is part of a biochemical system for the tertiary treatment of the leachate from Muribeca Municipal Solid Waste Landfill in Pernambuco, Brazil, to reduce its ammonia nitrogen concentration. This investigation initially consisted of kinetic studies and batch equilibrium tests on the natural zeolite to construct the sorption isotherms, which showed a high sorption capacity, with an average of 12.4 mg NH4+.L(-1), a value close to the sorption rates found for the aqueous ammonium chloride solution. A permeable reactive barrier consisting of natural zeolite, as simulated by the column test, was efficient in removing the ammonia nitrogen present in the leachate pretreated with calcium hydroxide. Nevertheless, the regenerated zeolite did not satisfactorily maintain the sorption properties of the natural zeolite, and an analysis of their cation-exchange properties showed a reduced capacity of 54 meq per 100 g for the regenerated zeolite compared to 150 meq per 100 g for the natural zeolite.

  4. Evaluation of operating characteristics for a chabazite zeolite system for treatment of process wastewater at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Kent, T.E.; Perona, J.J.; Jennings, H.L.; Lucero, A.J.; Taylor, P.A.

    1998-02-01

    Laboratory and pilot-scale testing were performed for development and design of a chabazite zeolite ion-exchange system to replace existing treatment systems at the Process Waste Treatment Plant (PWTP) at Oak Ridge National Laboratory (ORNL). The process wastewater treatment systems at ORNL need upgrading to improve efficiency, reduce waste generation, and remove greater quantities of contaminants from the wastewater. Previous study indicated that replacement of the existing PWTP systems with an ion-exchange system using chabazite zeolite will satisfy these upgrade objectives. Pilot-scale testing of the zeolite system was performed using a commercially available ion-exchange system to evaluate physical operating characteristics and to validate smaller-scale column test results. Results of this test program indicate that (1) spent zeolite can be sluiced easily and completely from a commercially designed vessel, (2) clarification followed by granular anthracite prefilters is adequate pretreatment for the zeolite system, and (3) the length of the mass transfer zone was comparable with that obtained in smaller-scale column tests. Laboratory studies were performed to determine the loading capacity of the zeolite for selected heavy metals. These test results indicated fairly effective removal of silver, cadmium, copper, mercury, nickel, lead, and zinc from simple water solutions. Heavy-metals data collected during pilot-scale testing of actual wastewater indicated marginal removal of iron, copper, and zinc. Reduced effectiveness for other heavy metals during pilot testing can be attributed to the presence of interfering cations and the relatively short zeolite/wastewater contact time. Flocculating agents (polyelectrolytes) were tested for pretreatment of wastewater prior to the zeolite flow-through column system. Several commercially available polyelectrolytes were effective in flocculation and settling of suspended solids in process wastewater

  5. Synthesis and characterization of Ruthenium (II) amines with the chelating agent 4-4' dithio-pyridine occluded in Na Y zeolite

    International Nuclear Information System (INIS)

    Marques, Clelia Mara de Paula; Franco, Douglas Wagner; Sanches, Rosemary

    1993-01-01

    The aim of this work is to study the chemical behavior of metallic complexes of Ru(II) encapsulated in Na Y zeolites. We chose systems with well known chemical behaviour in solution and which present a great interest, because of the bridging ligand used (4,4-Dithiodipyridine). This ligand is the first example of the great efficiency of the S-S bridge in conducting electrons. In this work we describe the ionic exchange reactions between the Na Y zeolite and the complex ion [Ru (N H 3 ) 5 DTDP] 2+ to obtain [Ru (N H 3 ) 5 DTDP]-Y sample. The [Ru (N H 3 ) 5 ] 2 DTDP)-Y sample is prepared through the reaction between [Ru (N H 3 ) 5 H 2 O] 2+ and [Ru (N H 3 ) 5 DTDP]-Y. These sample were characterized by spectroscopic techniques. (author)

  6. Influence of zeolite structure on the activity and durability of Co-Pd-zeolite catalysts in the reduction of NOx with methane

    International Nuclear Information System (INIS)

    Pieterse, J.A.Z.; Van den Brink, R.W.; Booneveld, S.; De Bruijn, F.A.

    2003-01-01

    Selective catalytic reduction of NO with CH 4 was studied over ZSM-5, MOR, FER and BEA zeolite-based cobalt (Co) and palladium (Pd) catalysts in the presence of oxygen and water. As compared to other catalytic systems reported in literature for CH 4 -SCR in the presence of water, zeolite supported Co-Pd combination catalysts are very active and selective. The most active catalysts, based on MOR and ZSM-5, are characterised by well-dispersed Pd ions in the zeolite that activate methane. Wet ion exchange is a good method to achieve high dispersion of Pd provided that it is carried out in a competitive manner. The presence of cobalt (Co 3 O 4 , Co-oxo ions) boosts SCR activity by oxidising NO to NO 2 . The activity of the zeolite-based Co-Pd combination catalysts decreases with prolonged times on stream. The severity of the deactivation was found to be different for different zeolite topologies. The characterisation and evaluation of freshly calcined catalysts and spent catalysts show two things that occur during reaction: (1) zeolite solvated metal cations disappear in favour of (inactive) metal oxides and presumably larger metal entities, i.e. loss of dispersion; (2) loss of crystallinity affiliated with steam-dealumination and the concomitant formation of extra-framework aluminium (EFAL) in the presence of water. Both phenomena strongly depend on the (reaction) temperature. The deactivation of Co-Pd-zeolite resembles the deactivation of Pd-zeolite. Hence, future research could encompass the stabilisation of Pd (cations) in the zeolite pores by exploring additives other than cobalt. For this, detailed understanding on the siting of Pd in zeolites is important

  7. The Effect of Zeolite on Aggregate Stability Indices

    Directory of Open Access Journals (Sweden)

    F. Sohrab

    2016-02-01

    Full Text Available Introduction: Soil structural stability affects the profitability and sustainability of agricultural systems. Particle size distribution (PSD and aggregate stability are the important characteristics of soil. Aggregate stability has a significant impact on the development of the root system, water and carbon cycle and soil resistance against soil erosion. Soil aggregate stability, defined as the ability of the aggregates to remain intact when subject to a given stress, is an important soil property that affects the movement and storage of water, aeration, erosion, biological activity and growth of crops. Dry soil aggregate stability (Mean Weight Diameter (MWD, Geometric Mean Diameter (GMD and Wet Aggregate Stability (WAS are important indices for evaluating soil aggregate stability.To improve soil physical properties, including modifying aggregate, using various additives (organic, inorganic and chemicals, zeolites are among what has been studied.According to traditional definition, zeolites are hydratealuminosilicates of alkaline and alkaline-earth minerals. Their structure is made up of a framework of[SiO4]−4 and [AlO4]−5 tetrahedron linked to each other's cornersby sharing oxygen atoms. The substitution of Si+4 by Al+3 intetrahedral sites results inmore negative charges and a high cation exchange capacity.Zeolites, as natural cation exchangers, are suitable substitutes to remove toxic cations. Among the natural zeolites,Clinoptilolite seems to be the most efficient ion exchanger and ion-selective material forremoving and stabilizing heavy metals.Due to theexisting insufficient technical information on the effects of using different levels of zeolite on physical properties of different types of soils in Iran, the aim of this research was to assess the effects of two different types of zeolite (Clinoptilolite natural zeolite, Z4, and Synthetic zeolite, A4 on aggregate stability indicesof soil. Materials and Methods: In this study at first

  8. Catalytic transformation of methyl benzenes over zeolite catalysts

    KAUST Repository

    Al-Khattaf, S.

    2011-02-01

    Catalytic transformation of three methyl benzenes (toluene, m-xylene, and 1,2,4-trimethyl benzene) has been investigated over ZSM-5, TNU-9, mordenite and SSZ-33 catalysts in a novel riser simulator at different operating conditions. Catalytic experiments were carried out in the temperature range of 300-400 °C to understand the transformation of these alkyl benzenes over large pore (mordenite and SSZ-33) in contrast to medium-pore (ZSM-5 and TNU-9) zeolite-based catalysts. The effect of reaction conditions on the isomerization to disproportionation product ratio, distribution of trimethylbenzene (TMB) isomers, and p-xylene/o-xylene ratios are reported. The sequence of reactivity of the three alkyl benzenes depends upon the pore structure of zeolites. The zeolite structure controls primarily the diffusion of reactants and products while the acidity of these zeolites is of a secondary importance. In the case of medium pore zeolites, the order of conversion was m-xylene > 1,2,4-TMB > toluene. Over large pore zeolites the order of reactivity was 1,2,4-TMB > m-xylene > toluene for SSZ-33 catalyst, and m-xylene ∼ 1,2,4-TMB > toluene over mordenite. Significant effect of pore size between ZSM-5 and TNU-9 was observed; although TNU-9 is also 3D 10-ring channel system, its slightly larger pores compared with ZSM-5 provide sufficient reaction space to behave like large-pore zeolites in transformation of aromatic hydrocarbons. We have also carried out kinetic studies for these reactions and activation energies for all three reactants over all zeolite catalysts under study have been calculated. © 2011 Elsevier B.V.

  9. ASETILASI PADA FENOL DAN ANISOL MENGGUNAKAN ANHIDRIDA ASAM ASETAT BERKATALIS Zr4+-ZEOLIT BETA

    Directory of Open Access Journals (Sweden)

    DA Retnoningrum

    2015-07-01

    Full Text Available Zeolit beta pada umumnya memiliki keasaman tinggi dan berpotensi aktif sebagai katalis heterogen dalam asilasi Friedel-Crafts senyawa aromatik. Untuk meningkatkan stabilitas dan selektivitasnya, zeolit beta perlu diaktivasi dan dimodifikasi terlebih dahulu dengan mengembankan logam aktif zirkonium dengan metode pertukaran ion. Karakterisasi katalis meliputi analisis kristalinitas katalis dengan XRD, sifat permukaan katalis dengan Surface Area Analyzer dan uji keasaman dengan pengadsorbsi piridin. Dalam penelitian ini, dipelajari aktivitas dan selektivitas katalis Zr4+-zeolit beta dalam reaksi asetilasi fenol dan anisol. Reaksi dilakukan pada berbagai variasi suhu yaitu 100 dan 130C dengan waktu reaksi yaitu pada jam ke 4, 8 dan 12. Hasil asetilasi kemudian dianalisis menggunakan GC, FTIR dan analisis produk menggunakan GC-MS. Asetilasi fenol dengan katalis Zr4+-zeolit beta menghasilkan produk fenil etanoat dengan kadar 95,87% dan selektivitas 100%. Hasil ini didapatkan pada suhu reaksi 130C dan waktu reaksi 8 jam. Asetilasi pada cincin benzena baik pada fenol maupun anisol tidak terjadi, hal ini karena asetilasi pada cincin benzena lebih sukar dibandingkan asetilasi pada gugus OH fenol. Perlu adanya kondisi lain untuk melakukan asetilasi pada cincin benzena. Asetilasi anisol pada waktu reaksi 24 jam dan temperatur 130C didapatkan produk dengan kadar 74%.Beta zeolite generally has a high acidity and potentially active as heterogeneous catalyst in the Friedel-Crafts acylation of aromatic compounds. To improve its stability and selectivity, beta zeolite needs to be activated and modified in advance with zirconium to elicit active metal using ion exchange method. Characterization of catalyst include catalyst’s crystallinity using XRD analysis, the nature of the catalyst surface with the Surface Area Analyzer and the acidity test using pyridine adsorption. In the current study the activity and the selectivity of catalyst Zr4+-beta zeolite

  10. Salt-occluded zeolite waste forms: Crystal structures and transformability

    International Nuclear Information System (INIS)

    Richardson, J.W. Jr.

    1996-01-01

    Neutron diffraction studies of salt-occluded zeolite and zeolite/glass composite samples, simulating nuclear waste forms loaded with fission products, have revealed complex structures, with cations assuming the dual roles of charge compensation and occlusion (cluster formation). These clusters roughly fill the 6--8 angstrom diameter pores of the zeolites. Samples are prepared by equilibrating zeolite-A with complex molten Li, K, Cs, Sr, Ba, Y chloride salts, with compositions representative of anticipated waste systems. Samples prepared using zeolite 4A (which contains exclusively sodium cations) as starting material are observed to transform to sodalite, a denser aluminosilicate framework structure, while those prepared using zeolite 5A (sodium and calcium ions) more readily retain the zeolite-A structure. Because the sodalite framework pores are much smaller than those of zeolite-A, clusters are smaller and more rigorously confined, with a correspondingly lower capacity for waste containment. Details of the sodalite structures resulting from transformation of zeolite-A depend upon the precise composition of the original mixture. The enhanced resistance of salt-occluded zeolites prepared from zeolite 5A to sodalite transformation is thought to be related to differences in the complex chloride clusters present in these zeolite mixtures. Data relating processing conditions to resulting zeolite composition and structure can be used in the selection of processing parameters which lead to optimal waste forms

  11. Electron irradiation of zeolites

    International Nuclear Information System (INIS)

    Wang, S.X.; Wang, L.M.; Ewing, R.C.

    1999-01-01

    Three different zeolites (analcime, natrolite, and zeolite-Y) were irradiated with 200 keV and 400 keV electrons. All zeolites amorphized under a relatively low electron fluence. The transformation from the crystalline-to-amorphous state was continuous and homogeneous. The electron fluences for amorphization of the three zeolites at room temperature were: 7.0 x 10 19 e - /cm 2 (analcime), 1.8 x 10 20 e - /cm 2 (natrolite), and 3.4 x 10 20 e - /cm 2 (zeolite-Y). The different susceptibilities to amorphization are attributed to the different channel sizes in the structures which are the pathways for the release of water molecules and Na + . Natrolite formed bubbles under electron irradiation, even before complete amorphization. Analcime formed bubbles after amorphization. Zeolite-Y did not form bubbles under irradiation. The differences in bubble formation are attributed to the different channel sizes of the three zeolites. The amorphization dose was also measured at different temperatures. An inverse temperature dependence of amorphization dose was observed for all three zeolites: electron dose for amorphization decreased with increasing temperature. This unique temperature effect is attributed to the fact that zeolites are thermally unstable. A semi-empirical model was derived to describe the temperature effect of amorphization in these zeolites

  12. Synthesis and Characterization of Zeolite Na−Y and Its Conversion to the Solid Acid Zeolite H−Y

    DEFF Research Database (Denmark)

    Warner, Terence Edwin; Galsgaard Klokker, Mads; Nielsen, Ulla Gro

    2017-01-01

    Zeolite Y has an iconic crystal structure, but more importantly, the hydrogen modification zeolite H−Y is the classic example of a solid acid which is used extensively as a catalyst in the oil industry. This metastable compound cannot be synthesized directly, which creates an opportunity to discuss...... various preparative strategies with the students, such as the three-stage procedure described here. Stage I concerns the hydrothermal synthesis of zeolite Na−Y, followed by ion-exchange with an ammonium acetate solution to form zeolite NH4−Y, and the latter is subsequently converted to zeolite H......−Y by thermolysis. Stages II and III may instead be performed using commercially available zeolites, Na−Y and NH4−Y, respectively, which shifts the learning objectives to structural characterization of zeolites. The characterization of the product and intermediate materials gives the students a practical insight...

  13. Carbon monoxide hydrogenation over ruthenium zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, P.A.; Nijs, H.H.; Verdonck, J.J.; Uytterhoeven, J.B.

    1978-03-01

    Ru zeolites are active and stable methanation catalysts. Under Fischer--Tropsch conditions they show a narrow product distribution. Further work is needed to assign this to a possible effect exerted by the zeolite cages. When the size of the Ru particles enclosed in the zeolite cages is increased, a lower methanation activity is found and a higher amount of C/sub 2/ and C/sub 3/ products are formed under Fischer--Tropsch conditions. This effect has not been reported until now on other supports. The less acidic zeolites act as promoters of the CO hydrogenation: under methanation conditions the activity is increased; under Fischer--Tropsch conditions, the selectivity is shifted toward higher hydrocarbons. This is explained by the particular zeolite property that electron deficient metal agglomerates seem to be formed on the acidic zeolites. With respect to kinetic behavior, relative activity of different metals, influence of reaction temperature on product distribution, the zeolite behaves in the same way a conventional alumina support. 4 figs., 4 tables.

  14. The Effect of an Ultrasound Radiation on the Synthesis of 4A Zeolite from Fly Ash

    Science.gov (United States)

    Susanto, H.; Imani, N. A. C.; Aslamiyah, N. R.; Istirokhatun, T.; Robbani, M. H.

    2018-05-01

    The use of coal as a fuel source generates a lot of solid waste fly ash. Thus, efforts to reduce or utilize the amount of fly ash are urgently needed. This paper presents zeolite synthesis from fly ash. The fly ash was activated by using NaOH solution prior to fusing process with a weight ratio of 1:2 and mixing with distilled water at a weight ratio of 1:5. Thereafter, the addition of alumina with a concentration of 0.71 %, 1.42 %, 2.12 %, and 2.8 % w/v was performed. The effects of heating and ultrasound radiation on the characteristic of zeolite products were investigated. The results showed that the addition of alumina 2.8 % w/v resulted in the Si/Al ratio of zeolite 4A is ∼1. SEM images demonstrated that the presence of ultrasound wave resulted in crystals structure morphology as also supported by XRD characterization. The average crystal size for the ultrasonic treatment was 42.46 nm.

  15. Fluoride removal from double four-membered ring (D4R) units in As-synthesized Ge-containing zeolites

    KAUST Repository

    Liu, Xiaolong

    2011-11-22

    Fluoride anions can be removed from the framework of as-prepared Ge-containing zeolites ITQ-13 and ITQ-17 without modification of the crystallinity and crystal habit. By contrast to all-silica ITQ-13 for which fluoride could not get out from D4R units, F is completely removed from Ge rich zeolites, even from D4R cages. This has been explained by the relaxing effect of germanium, making F less necessary for the stabilization of the small D4R units. Si/Ge ratios are similar in as-prepared and treated zeolites, indicating that the framework composition is not affected by the removal of anions. The fluoride-free zeolites possess XRD patterns similar to those of the as-made solids but their 29Si NMR spectra are significantly different, revealing the sensitivity of the method to the environment of silicon atoms in the framework. The extent of fluoride that can be removed from D4R units depends not only on the framework Ge content but also on the zeolite topology: for similar contents, F is much more easily eliminated from ITQ-17 than from ITQ-13. © 2011 American Chemical Society.

  16. Adsorption methods for hydrogen isotope storage on zeolitic sieves

    International Nuclear Information System (INIS)

    Cristescu, Ioana; Cristescu, Ion; Vasut, F.; Brad, S.; Lazar, A.

    2001-01-01

    For hydrogen isotope separation, adsorption molecular sieves and active carbon were used. Adsorption process proceeds at liquid nitrogen and liquid hydrogen temperatures. Commercial zeolites have the same proprieties with natural zeolites, but they have a regular pore structure. They also have affinity for molecules of different size with defined shapes. Experimental results obtained at liquid nitrogen temperature (77.4 K) and liquid hydrogen revealed the efficient behaviour of the active carbon and zeolitic sieves for hydrogen isotopes temporary storage. We study adsorption of the synthetic zeolites in a wide range of temperatures and pressures and we used the molecular sieves 4A, 5A and active carbon. The 4A and 5A zeolites have a tridimensional structure with 11.4 A diameter. When the hydration water is eliminated, the material keeps a porous structure. The porous volume represents 45% from the zeolite mass for 4A and 5A sieves. The activation temperature of the zeolite and the carbon is very important for obtaining a high adsorption capacity. If the temperature used for activation is low, the structural water will be not eliminated and the adsorption capacity will be low. The excessive temperature will destroy the porous structure. The adsorption capacity for the hydrogen isotopes was calculated with the relation: A = V ads /m (cm 3 /g). The adsorption capacity and efficiency for the adsorbent materials, are given. Physical adsorption process of the hydrogen isotopes was carried out at liquid nitrogen temperature. The flux gas used in the adsorption system is composed of dry deuterium and protium. This mixture is cooled in liquid nitrogen and then is passed to the adsorbent getter at the same temperature (77.4 K). The gas flux in the adsorbent getter is 5 and 72 l/h (which correspond to 0.008 and 0.134 discharge velocity, respectively). (authors)

  17. Preparation of Ethylene Vinyl Acetate/Zeolite 4A Mixed Matrix Membrane for CO2/N2 Separation

    Directory of Open Access Journals (Sweden)

    Iman Khalilinejad

    2016-07-01

    Full Text Available A great contribution in research activities on carbon dioxide (CO2 separation, as the most important challenge in greenhouse gases control, has been made to develop new polymeric membranes. In this case, mixed matrix membranes (MMMs, comprised of rigid particles dispersed in a continuous polymeric matrix, was proposed as an effective method to improve the separation properties of polymeric membranes. In this research, ethylene vinyl acetate (EVA copolymer and zeolite 4A powders were applied to prepare MMMs using solution casting/solvent evaporation method and CO2/N2 separation performance of the membranes was examined under different feed pressures (3-8 bar and operating temperatures (25-50°C. Morphological and structural characterizations of the membranes were evaluated using scanning electron microscopy (SEM, Fourier transform infrared (FTIR spectroscopy, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, density and solvent-induced swelling measurements. The gas permeability measurements through the constant-volume method showed the permeability of two gases increased in the presence of zeolite 4A nanoparticles in the polymer matrix. Calculation of diffusivity coefficients of gases revealed that improvement in the diffusivity of all gases into membrane matrix was the main reason for permeability enhancement. In addition, the increase in the CO2/N2 ideal selectivity with the presence of zeolite 4A nanoparticles in the polymer matrix was attributed to the increment in CO2/N2 diffusion selectivity. Under optimum condition, with the addition of 10 wt% zeolite 4A nanoparticles into the membrane matrix, the CO2 permeability increased from 20.81 to 35.24 Barrer and its related selectivity increased 20% compared to that of neat EVA membrane. Furthermore, the membrane performances increased upon feed pressure rise, while the selectivity decreased with the increase in temperature.

  18. Characterization Of Cobalt-Exchanged Zeolite A By DRIFT Spectroscopy

    Science.gov (United States)

    Kappers, M. J.; van der Maas, John H.; Chalmers, J. M.; Howard, J.

    1989-12-01

    In-situ DRIFT spectroscopy has been succesfully used for the characterization of Co4Na4-A. Dehydration of the zeolite A appears to involve formation and breakdown of hydration complexes and hydrolysis. The position of cations and hydroxyl groups within the zeolite structure was derived from the adsorption of carbon monoxide and acetonitrile.

  19. Zeolite food supplementation reduces abundance of enterobacteria.

    Science.gov (United States)

    Prasai, Tanka P; Walsh, Kerry B; Bhattarai, Surya P; Midmore, David J; Van, Thi T H; Moore, Robert J; Stanley, Dragana

    2017-01-01

    According to the World Health Organisation, antibiotics are rapidly losing potency in every country of the world. Poultry are currently perceived as a major source of pathogens and antimicrobial resistance. There is an urgent need for new and natural ways to control pathogens in poultry and humans alike. Porous, cation rich, aluminosilicate minerals, zeolites can be used as a feed additive in poultry rations, demonstrating multiple productivity benefits. Next generation sequencing of the 16S rRNA marker gene was used to phylogenetically characterize the fecal microbiota and thus investigate the ability and dose dependency of zeolite in terms of anti-pathogenic effects. A natural zeolite was used as a feed additive in laying hens at 1, 2, and 4% w/w for a 23 week period. At the end of this period cloacal swabs were collected to sample faecal microbial communities. A significant reduction in carriage of bacteria within the phylum Proteobacteria, especially in members of the pathogen-rich family Enterobacteriaceae, was noted across all three concentrations of zeolite. Zeolite supplementation of feed resulted in a reduction in the carriage of a number of poultry pathogens without disturbing beneficial bacteria. This effect was, in some phylotypes, correlated with the zeolite concentration. This result is relevant to zeolite feeding in other animal production systems, and for human pathogenesis. Copyright © 2016 Elsevier GmbH. All rights reserved.

  20. Cure kinetics and mechanical interfacial characteristics of zeolite/DGEBA composites

    International Nuclear Information System (INIS)

    Park, Soo Jin; Kim, Young Mi; Shin, Jae Sup

    2003-01-01

    In this work, the zeolite/diglycidylether of bisphenol A(DGEBA) systems were investigated in terms of the cure kinetics and mechanical interfacial properties of the composites. The 4, 4-Diamino Diphenyl Methane(DDM) was used as a curing agent for epoxy. Two types of zeolite(PZ) were prepared with 15 and 35 wt% KOH treatments(15-BZ and 35-BZ, respectively) for 24 h, and their surface characteristics were studied by X-ray Photoelectron Spectroscopy (XPS) and X-Ray Diffraction (XRD). Cure kinetics of the composites were examined in the context of Differential Scanning Calorimetry(DSC), and mechanical interfacial properties were investigated in critical stress intensity factor(K IC ) and critical strain energy release rate(G IC ). In the results of XPS and XRD, sodium ion(Na) of zeolite was exchanged for potassium ion(K), resulting from the treatment of KOH. Also, Si 2p /A1 2p composition ratios of the treated zeolite were increased, which could be attributed to the weakening of A1-O bond in framework. Cure activation energy(E a ) of 15-BZ composites was decreased, whereas K IC and G IC were increased, compared with those of the pure zeolite/DGEBA composites. It was probably accounted that the acidity of zeolite was increased by surface treatments and the cure reaction between zeolite and epoxy was influenced on the increased acidity of zeolite

  1. Zeolite ZSM-57

    International Nuclear Information System (INIS)

    Valyocsik, E.W.; Page, N.M.; Chu, C.T.W.

    1989-01-01

    This patent describes a synthetic porous crystalline zeolite having a molar ratio of XO 2 ; Y 2 O 3 of at least 4. Wherein X represents silicon and/or germanium and Y represents aluminum, boron, chromium, iron and/or gallium. The porous crystalline zeolite having at least the X-ray diffraction lines as set forth in the text

  2. Avaliação da liberação de NH4NO3 ocluido em zeólita 4A a partir de soluções salinas Assessment of release of NH4NO3 occluded zeolite 4A in solutions from salinas

    Directory of Open Access Journals (Sweden)

    Jardel Cavalcante Rolim de Almeida Andrade

    2010-01-01

    Full Text Available The zeolite 4A was used to evaluate the thermo kinetics parameters of NH4+ and NO3- ions occluded in its structure. The Osawa method for activation energy calculation was used to evaluate its thermal stability, and the results shown that the ion species interact differently depending on the zeolite pores, which determines the controlled release by its structure.

  3. Methane emissions abatement by multi-ion-exchanged zeolite A prepared from both commercial-grade zeolite and coal fly ash.

    Science.gov (United States)

    Hui, K S; Chao, C Y H

    2008-10-01

    The performance of multimetal-(Cu, Cr, Zn, Ni, and Co)-ion-exchanged zeolite A prepared from both a commercial-grade sample and one produced from coal fly ash in methane emissions abatement was evaluated in this study. The ion-exchange process was used to load the metal ions in zeolite A samples. The methane conversion efficiency by the samples was studied under various parameters including the amount of metal loading (7.3-19.4 wt%), reaction temperature (25-500 degrees C), space velocity (8400-41 900 h(-1)), and methane concentration (0.5-3.2 vol %). At 500 degrees C, the original commercial-grade zeolite A catalyzed 3% of the methane only, whereas the addition of different percentages of metals in the sample enhanced the methane conversion efficiency by 40-85%. Greater methane conversion was observed by increasing the percentage of metals added to the zeolite even though the BET surface area of the zeolite consequently decreased. Higher percentage methane conversion over the multi-ion-exchanged samples was observed at lower space velocities indicating the importance of the mass diffusion of reactants and products in the zeolite. Compared to the multi-ion-exchanged zeolite A prepared from the commercial-grade zeolite, the one produced from coal fly ash demonstrated similar performances in methane emissions abatement, showing the potential use of this low cost recycled material in gaseous pollutant treatment.

  4. The potential of Saudi Arabian natural zeolites in energy recovery technologies

    International Nuclear Information System (INIS)

    Nizami, A.S.; Ouda, O.K.M.; Rehan, M.; El-Maghraby, A.M.O.; Gardy, J.; Hassanpour, A.; Kumar, S.; Ismail, I.M.I.

    2016-01-01

    Energy consumption in KSA (kingdom of Saudi Arabia) is growing rapidly due to economic development with raised levels of population, urbanization and living standards. Fossil fuels are currently solely used to meet the energy requirements. The KSA government have planned to double its energy generating capacity (upto 120 GW (gigawatts)) by 2032. About half of the electricity capacity of this targeted energy will come from renewable resources such as nuclear, wind, solar, WTE (waste-to-energy) etc. Natural zeolites are found abundantly in KSA at Jabal Shamah occurrence near Jeddah city, whose characteristics have never been investigated in energy related applications. This research aims to study the physical and chemical characteristics of natural zeolite in KSA and to review its potential utilization in selected WTE technologies and solar energy. The standard zeolite group of alumina–silicate minerals were found with the presence of other elements such as Na, Mg and K etc. A highly crystalline structure and thermal stability of natural zeolites together with unique ion exchange, adsorption properties, high surface area and porosity make them suitable in energy applications such as WTE and solar energy as an additive or catalyst. A simple solid–gas absorption system for storing solar energy in natural zeolites will be a cheap alternative method for KSA. In AD (anaerobic digestion), the dual characteristics of natural zeolite like Mordenite will increase the CH_4 production of OFMSW (organic fraction of municipal solid waste). Further investigations are recommended to study the technical, economical, and environmental feasibility of natural zeolite utilization in WTE technologies in KSA. - Highlights: • A highly crystalline structure is found in natural zeolites. • Natural zeolites will store solar energy in solid–gas absorption system. • The composites of natural zeolites will produce more liquid fuel like gasoline. • The natural zeolite will increase

  5. Effect of natural Bayah zeolite particle size reduction to physico-chemical properties and absortion against potassium permanganate (KMnO4)

    Science.gov (United States)

    Widayanti, Siti Mariana; Syamsu, Khaswar; Warsiki, Endang; Yuliani, Sri

    2016-02-01

    Recently, researches on nanotechnology have been developed very rapid, as well as the utilization of nano-zeolites. Nano-sized material has several advantages which are expanding absorptive surfaces so it will enhance the material absorption and shorten the absorption time. Zeolite as a KMnO4 binder, has been widely recognized for its ability to extend the shelf life of vegetables and fruits. This study was conducted to determine zeolites physico-chemical characters from different particle size and the effect on KMnO4 absorption. Potassium permanganate (KMnO4) is a strong oxidizer for reducing the quantity of ethylene in storage process of fresh horticultural products. The treatment consisted of (1) different length of milling time (10, 20, 30, 40, and 60 minutes) and (2) the duration of chemical activation with 1 N KOH solution. Physical and chemical characters of zeolite were analyzed using BET, PSA, XRD and SEM. The research design was randomized design. The result implied that milling time was significantly affecting the zeolite particle size, material surface area, and the size of pore diameter and volume. Milling treatment for 40 minutes produced higher zeolite surface area and pore volume than other treatments. While the duration of chemical activation using 1 N KOH solution gives different effect on zeolite absorption to KMnO4 solution. Milling time for 60 minutes and activated for 48 hours has higher initial adsorption than other treatments.

  6. Methylcellulose-Directed Synthesis of Nanocrystalline Zeolite NaA with High CO₂ Uptake.

    Science.gov (United States)

    Shakarova, Dilshod; Ojuva, Arto; Bergström, Lennart; Akhtar, Farid

    2014-07-28

    Zeolite NaA nanocrystals with a narrow particle size distribution were prepared by template-free hydrothermal synthesis in thermo-reversible methylcellulose gels. The effects of the amount of methylcellulose, crystallization time and hydrothermal treatment temperature on the crystallinity and particle size distribution of the zeolite NaA nanocrystals were investigated. We found that the thermogelation of methylcellulose in the alkaline Na₂O-SiO₂-Al₂O₃-H₂O system played an important role in controlling the particle size. The synthesized zeolite nanocrystals are highly crystalline, as demonstrated by X-ray diffraction (XRD), and scanning electron microscopy (SEM) shows that the nanocrystals can also display a well-defined facetted morphology. Gas adsorption studies on the synthesized nanocrystalline zeolite NaA showed that nanocrystals with a size of 100 nm displayed a high CO₂ uptake capacity (4.9 mmol/g at 293 K at 100 kPa) and a relatively rapid uptake rate compared to commercially available, micron-sized particles. Low-cost nanosized zeolite adsorbents with a high and rapid uptake are important for large scale gas separation processes, e.g., carbon capture from flue gas.

  7. Removal of cesium and strontium from low active waste solutions by zeolites

    International Nuclear Information System (INIS)

    Jain, Savita; Ramaswamy, M.; Theyyunni, T.K.

    1994-01-01

    Ion exchange, crystallographic and thermal characteristics of sodium, cesium and strontium forms of locally available synthetic zeolites have been investigated. X-ray and differential thermal analyses have confirmed that the synthetic materials AR1 and 4A belonged to the mordenite and A type families of zeolites respectively. Equilibrium uptake of cesium and strontium ions by sodium forms of zeolite was studied as a function of time, pH and sodium concentration. It was found that the rate of sorption by AR1 was higher than that by 4A. In regard to pH, distribution of nuclides on zeolites was found to pass through maxima at a pH value of around 9. Sodium ion interfered with the sorption of cesium and strontium by zeolites. However, at sodium concentration ≤ 0.01 M, distribution coefficient values for these nuclides were sufficiently high to merit consideration of these zeolites for low level waste treatment. Lab-scale column runs using 5 ml beds of materials showed that the zeolites AR1 and 4A were very effective in removing cesium and strontium nuclides respectively from large volumes (a decontamination factor of 50 for a throughput of 6000 bed volumes) of actual low level waste solutions. Thus, the zeolite system has a potential future for large scale application in the treatment of low level wastes. (author). 6 refs., 5 figs., 6 tabs

  8. Zeolite function studied by neutron diffraction

    International Nuclear Information System (INIS)

    Newsam, J.M.

    1988-01-01

    Some recent figures relating to industrial uses of zeolites are summarized. Recent advances in the application of neutron diffraction to zeolite science are overviewed, with particular emphasis on powder diffraction (PND) results. Single crystal neutron diffraction studies of some 17 hydrated natural and synthetic zeolites have now appeared and they provide a consistent picture of zeolite-water interactions. Complete PND studies of hydrated synthetic ABW- and SOD-framework zeolites have also been reported. Other PND studies have explored the structural consequences of non-framework cation exchange, of framework modification by dealumination, and of framework cation substitution. Relatively simple zeolite-hydrocarbon sorbate complexes that have been studied include benzene in zeolite Y, and benzene and pyridine in zeolite L. Areas that are well poised for further development include further extensions to lower symmetry systems, the use of PND data for zeolite structure solution, studies at elevated temperatures and pressures, and further studies of zeolite sorbate complexes. (author) 68 refs., 7 figs

  9. The role of zeolite in the Fischer–Tropsch synthesis over cobalt–zeolite catalysts

    International Nuclear Information System (INIS)

    Sineva, L V; Mordkovich, V Z; Asalieva, E Yu

    2015-01-01

    The review deals with the specifics of the Fischer–Tropsch synthesis for the one-stage syncrude production from CO and H 2 in the presence of cobalt–zeolite catalytic systems. Different types of bifunctional catalysts (hybrid, composite) combining a Fischer–Tropsch catalyst and zeolite are reviewed. Special attention focuses on the mechanisms of transformations of hydrocarbons produced in the Fischer–Tropsch process on zeolite acid sites under the synthesis conditions. The bibliography includes 142 references

  10. Selective methane chlorination to methyl chloride by zeolite Y-based catalysts

    Science.gov (United States)

    Joo, Hyeonho; Kim, Daeho; Lim, Kwang Soo; Choi, Yong Nam; Na, Kyungsu

    2018-03-01

    The CH4 chlorination over Y zeolites was investigated to produce CH3Cl in a high yield. Three different catalytic systems based on Y zeolite were tested for enhancement of CH4 conversion and CH3Cl selectivity: (i) HY zeolites in H+-form having various Si/Al ratios, (ii) Pt/HY zeolites supporting Pt metal nanoparticles, (iii) Pt/NaY zeolites in Na+-form supporting Pt metal nanoparticles. The reaction was carried out using the gas mixture of CH4 and Cl2 with the respective flow rates of 15 and 10 mL min-1 at 300-350 °C using a fixed-bed reactor under a continuous gas flow condition (gas hourly space velocity = 3000 mL g-1 h-1). Above the reaction temperature of 300 °C, the CH4 chlorination is spontaneous even in the absence of catalyst, achieving 23.6% of CH4 conversion with 73.4% of CH3Cl selectivity. Under sufficient supplement of thermal energy, Cl2 molecules can be dissociated to two chlorine radicals, which triggered the C-H bond activation of CH4 molecule and thereby various chlorinated methane products (i.e., CH3Cl, CH2Cl2, CHCl3, CCl4) could be produced. When the catalysts were used under the same reaction condition, enhancement in the CH4 conversion was observed. The Pt-free HY zeolite series with varied Si/Al ratios gave around 27% of CH4 conversion, but there was a slight decrease in CH3Cl selectivity with about 64%. Despite the difference in acidity of HY zeolites having different Si/Al ratios, no prominent effect of the Si/Al ratios on the catalytic performance was observed. This suggests that the catalytic contribution of HY zeolites under the present reaction condition is not strong enough to overcome the spontaneous CH4 chlorination. When the Pt/HY zeolite catalysts were used, the CH4 conversion reached further up to 30% but the CH3Cl selectivity decreased to 60%. Such an enhancement of CH4 conversion could be attributed to the strong catalytic activity of HY and Pt/HY zeolite catalysts. However, both catalysts induced the radical cleavage of Cl2

  11. Impact of steel slag on the ammonium adsorption by zeolite and a new configuration of zeolite-steel slag substrate for constructed wetlands.

    Science.gov (United States)

    Shi, Pengbo; Jiang, Yingbo; Zhu, Hongtao; Sun, Dezhi

    2017-07-01

    The CaO dissolution from slag, as well as the effects of influencing parameters (i.e. pH and Ca 2+ concentration) on the ammonium adsorption onto zeolite, was systematically studied in this paper. Modeling results of Ca 2+ and OH - release from slag indicated that pseudo-second-order reaction had a better fitness than pseudo-first-order reaction. Changing pH value from 7 to 12 resulted in a drastic reduction of the ammonium adsorption capacity on zeolite, from the peak adsorption capacity at pH 7. High Ca 2+ concentration in solution also inhibited the adsorption of ammonium onto zeolite. There are two proposed mechanisms for steel slag inhibiting the ammonium adsorption capacity of zeolite. On the one hand, OH - released from steel slag can react with ammonium ions to produce the molecular form of ammonia (NH 3 ·H 2 O), which would cause the dissociation of NH 4 + from zeolite. On the other hand, Ca 2+ could replace the NH 4 + ions to adhere onto the surface of zeolite. An innovative substrate filling configuration with zeolite placed upstream of the steel slag was then proposed to eliminate the disadvantageous effects of steel slag. Experimental results showed that this novel filling configuration was superior to two other filling configurations in terms of ammonium removal.

  12. Zeolite - a possible substitute of silica gel in spectrophotometric determination of uranium?

    International Nuclear Information System (INIS)

    Foeldesova, M; Dillinger, P.

    2006-01-01

    Zeolites sorption abilities differ from the ones of the silica gel, which is normally used for uranium determination by spectrophotometric method. The difference is obvious mainly in the case of zeolites chemically modified with 1 or 2 mol/L NaOH solution. Absorbances measured using these zeolites on an radioactive water samples were 4 to 4.2 times bigger than the ones with silica gel. This avoids a use of one universal calibration curve for experimental data evaluation. Within delivered experimental data only a calibration curve for silica gel was provided. Its application to zeolites caused substantial misinterpretation of the results. Calculational construction of individual calibration curves made at this work shaw, that zeolites have a potential to replace the silica gel. This possibility is necessary to confirm by more experiments. Better sorption abilities of the modified zeolites would be utilized to reduce the lower limit for uranium determination by spectrophotometric method. (authors)

  13. Design and fabrication of zeolite macro- and micromembranes

    Science.gov (United States)

    Chau, Lik Hang Joseph

    2001-07-01

    The chemical nature of the support surface influences zeolite nucleation, crystal growth and elm adhesion. It had been demonstrated that chemical modification of support surface can significantly alter the zeolite film and has a good potential for large-scale applications for zeolite membrane production. The incorporation of titanium and vanadium metal ions into the structural framework of MFI zeolite imparts the material with catalytic properties. The effects of silica and metal (i.e., Ti and V) content, template concentration and temperature on the zeolite membrane growth and morphology were investigated. Single-gas permeation experiments were conducted for noble gases (He and Ar), inorganic gases (H2, N2, SF6) and hydrocarbons (methane, n-C4, i-C4) to determine the separation performance of these membranes. Using a new fabrication method based on microelectronic fabrication and zeolite thin film technologies, complex microchannel geometry and network (supported zeolite films. The zeolite micropatterns were stable even after repeated thermal cycling between 303 K and 873 K for prolonged periods of time. This work also demonstrates that zeolites (i.e., Sil-1, ZSM-5 and TS-1) can be employed as catalyst, membrane or structural materials in miniature chemical devices. Traditional semiconductor fabrication technology was employed in micromachining the device architecture. Four strategies for the manufacture of zeolite catalytic microreactors were discussed: zeolite powder coating, uniform zeolite film growth, localized zeolite growth, and etching of zeolite-silicon composite film growth inhibitors. Silicalite-1 was also prepared as free-standing membrane for zeolite membrane microseparators.

  14. Spin probes of chemistry in zeolites

    International Nuclear Information System (INIS)

    Werst, D.W.; Trifunac, A.D.

    1997-09-01

    Electron spin resonance (EPR) studies in zeolites are reviewed in which radiolysis was used to ionize the zeolite lattice, create reactive intermediates, spin label reaction products and to provide a window onto chemistry and transport of adsorbates and matrix control of chemistry. The review examines reactions of radical cations and the influence of the geometry constraints inside the zeolite, explores how zeolite model systems can be used to learn about energy and charge transfer in solids and illustrates the use of radiolysis and EPR for in situ spectroscopic studies of solid-acid catalysis. The various spin probes created inside the zeolite pores report on properties of the zeolites as well as shed light on radiolytic processes

  15. Magnetic zeolites a and p synthesized from kaolin: synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Bessa, R.A.; Oliveira, C.P.; Nascimento, R.F.; Bohn, F.; Loiola, A.R. [Universidade Federal do Ceara (UFCE), CE (Brazil)

    2016-07-01

    Full text: Zeolites are hydrated aluminosilicates of open chain, formed by silica and alumina tetrahedral structures linked by common oxygen atoms, generating interconnected pores and cages with molecular dimensions and well defined sizes that limit matter transference between internal surface and application medium. They can be found naturally or synthesized using different aluminum and silicon sources that may modify the produced zeolite. Their industrial application has grown enormously over the last century. However, a big issue that still remains is the difficulty in retrieving zeolite powders when used in aqueous media. This work reports the use of kaolin as an alternative raw material for zeolite syntheses by means of hydrothermal route and subsequent preparation of magnetic composites through magnetite impregnation. The syntheses of two different zeolites were carried out by mixing appropriate amounts of metakaolin (kaolin previously calcined at 600 deg C for 2 h), sodium metasilicate and sodium hydroxide solution, aged for 18 h and heated at 100 °C for 4-48 h. After these processes, the final materials were washed several times with distilled water, filtered and dried at 80 deg C for 12 h. Magnetic composites were prepared by impregnating the zeolites with of Fe3O4 nanoparticles (NP) synthesized by the partial oxidation and precipitation of Fe2+ ions. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, FTIR spectroscopy and magnetization measurements. The results of XRD and FTIR provide evidence of the success in the synthesis of both zeolites A and P as well as Fe3O4. Subsequently, composites were formed by mixtures of zeolite A + NP and zeolite P + NP. The existence of secondary crystalline phases was also confirmed. However, it did not interfered significantly in the results as these phases appear as minor amounts and are most likely residues from the clay used as the main silica and alumina sources. Scanning

  16. Silver zeolite antimicrobial activity in aluminium heating, ventilation and air conditioning system ducts.

    Science.gov (United States)

    Rizzetto, R; Mansi, A; Panatto, D; Rizzitelli, E; Tinteri, C; Sasso, T; Gasparini, R; Crovari, P

    2008-03-01

    Air pollution in confined environments is a serious health problem, in that most people spend long periods indoors (in homes, offices, classrooms etc.). Some people (children, the elderly, heart disease patients, asthmatic or allergic subjects) are at greater risk because of their conditions of frailty. The growing use of air-conditioning systems in many public and private buildings aggravates this health risk, especially when these systems are not correctly installed or regularly serviced. The aim of our study was to verify the capacity of Ag+ ions to stop the growth of bacteria and moulds inside the ducts of Heating, Ventilation and Air Conditioning system ducts (HVAC) systems when these ducts were lined with active Ag+ ions zeolite-coated panels. A Y-shaped HVAC model with two branches was used; one branch was made of traditional galvanized iron, as was the whole system, while the other was lined with active Ag+ zeolite-coated polyurethane panels. During the test, samples of dust present inside both ducts were collected and seeded in liquid and solid media to detect bacteria and moulds. The presence of bacteria was also sought in the air emerging from the outlets of both ducts. Tests made on samples of particulate collected from the two different ducts revealed a lower total bacterial load in the samples collected from the Ag+ zeolite-coated duct than in the samples from the traditional Zn galvanized duct. In addition, the values of bacterial load found in the air emerging from the Ag+ ions zeolite-lined duct were 5 times lower than those found in the air from the traditional galvanized iron duct. The utilization of Ag+ zeolite-coated panels in air-conditioning systems could improve the quality of the emerging air in comparison with traditional installations in galvanized iron. This innovation could prove particularly advantageous in the event of accidents during the installation of air-conditioning systems or of contaminated aerosols coming from outside.

  17. The Use of Zeolit and Activated Carbon on Packing System of Corydoras aenus

    Directory of Open Access Journals (Sweden)

    E. Supriyono

    2007-07-01

    Full Text Available Problem frequently found by Indonesian exporter in sending ornamental fish including Corydoras aenus to overseas is the low survival rate that caused by decrease in water quality during transportation.  Suitable and efficient packing technology is very needed to send live fish for long time transportation.  Two third of packing plastic volume was filled by oxygen, and Corydoras aenus 20 fish/pack.  Packing plastic was placed into styrofoam and ice was added to maintain at low temperature.  Zeolit and activated carbon was cover up by cloth and then placed into the pack.  Dosage treatment of zeolit and activated carbon was 20 gram zeolit, 15 gram zeolit and 5 gram activated carbon, 10 gram zeolit and 10 gram activated carbon, 5 gram zeolit and 15 gram activated carbon, 20 gram activated carbon, and no added zeolit and no activated carbon as control.  Fish condition was observed every 6 hours, while water quality measurement was performed every 24 hours for 120 hours.  The results of study showed that adding 20 gram zeolit without activated carbon in closed packing system of Corydoras aenus in 20oC could maintained in lower concentration of total nitrogen ammonia and unionized ammonia (NH3, reached of 7.83±0.13 mg/l and 0.046±0.003 mg/l, respectively.  The level of total nitrogen ammonia and unionized ammonia were relatively lower compared to mix of zeolit and activated carbon, and only activated carbon.  Survival rate of fish by this treatment was 100%, higher than other treatment (85-95%. Keywords: zeolit, activated carbon, packing, Corydoras   ABSTRAK Permasalahan yang sering dihadapi oleh para eksportir Indonesia dalam pengiriman ikan hias termasuk Corydoras aenus ke luar negeri adalah rendahnya survival rate diantaranya disebabkan oleh kualitas air yang memburuk selama pengangkutan. Teknologi pengepakan yang tepat dan efisien sangat dibutuhkan dalam rangka pengiriman ikan hidup untuk tempat tujuan yang membutuhkan waktu lama

  18. Hydrothermally grown zeolite crystals

    International Nuclear Information System (INIS)

    Durrani, S.K.; Qureshi, A.H.; Hussain, M.A.; Qazi, N.K.

    2009-01-01

    The aluminium-deficient and ferrosilicate zeolite-type materials were synthesized by hydrothermal process at 150-170 degree C for various periods of time from the mixtures containing colloidal reactive silica, sodium aluminate, sodium hydroxide, iron nitrate and organic templates. Organic polycation templates were used as zeolite crystal shape modifiers to enhance relative growth rates. The template was almost completely removed from the zeolite specimens by calcination at 550 degree C for 8h in air. Simultaneous thermogravimetric (TG) and differential thermal analysis (DTA) was performed to study the removal of water molecules and the amount of organic template cations occluded inside the crystal pore of zeolite framework. The 12-13% weight loss in the range of (140-560 degree C) was associated with removal of the (C/sub 3/H/sub 7/)/sub 4/ N+ cation and water molecules. X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) techniques were employed to study the structure, morphology and surface features of hydrothermally grown aluminium-deficient and ferrosilicate zeolite-type crystals. In order to elucidate the mode of zeolite crystallization the crystallinity and unit cell parameters of the materials were determined by XRD, which are the function of Al and Fe contents of zeolites. (author)

  19. Energetics of sodium-calcium exchanged zeolite A.

    Science.gov (United States)

    Sun, H; Wu, D; Guo, X; Shen, B; Navrotsky, A

    2015-05-07

    A series of calcium-exchanged zeolite A samples with different degrees of exchange were prepared. They were characterized by powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC). High temperature oxide melt drop solution calorimetry measured the formation enthalpies of hydrated zeolites CaNa-A from constituent oxides. The water content is a linear function of the degree of exchange, ranging from 20.54% for Na-A to 23.77% for 97.9% CaNa-A. The enthalpies of formation (from oxides) at 25 °C are -74.50 ± 1.21 kJ mol(-1) TO2 for hydrated zeolite Na-A and -30.79 ± 1.64 kJ mol(-1) TO2 for hydrated zeolite 97.9% CaNa-A. Dehydration enthalpies obtained from differential scanning calorimetry are 32.0 kJ mol(-1) H2O for hydrated zeolite Na-A and 20.5 kJ mol(-1) H2O for hydrated zeolite 97.9% CaNa-A. Enthalpies of formation of Ca-exchanged zeolites A are less exothermic than for zeolite Na-A. A linear relationship between the formation enthalpy and the extent of calcium substitution was observed. The energetic effect of Ca-exchange on zeolite A is discussed with an emphasis on the complex interactions between the zeolite framework, cations, and water.

  20. [NH4+-N removal stability of zeolite media packed multistage-biofilm system for coke-plant wastewater treatment].

    Science.gov (United States)

    Zhao, Wen-Tao; Huang, Xia; He, Miao; Zhang, Peng-Yi; Zuo, Chen-Yan

    2009-02-15

    The practical ammonia stripping effectiveness of coke-plant wastewater treatment may vary widely, and high NH4+-N shock loading will lead to the fluctuation of residual NH4+-N concentration of biological effluent. A zeolite media packed multistage-biofilm system (ZMBS) was used for coke-plant wastewater treatment for enhancing the NH4+-N treatment ability of the bio-system to shock loading, as well as achieving high COD removal efficiency. Treatment performance during steady-state and shock loading and transformation of organic pollutants in the system were investigated systematically. The experiment results indicated that when the system was operated at NH4+-N loading 0.21 kg/(m3 x d) and COD loading NH4+-N and COD concentrations were (2.2 +/- 1.2) mg/L, (228 +/- 60) mg/L with average removal efficiencies of (99.1 +/- 0.5)% and (86.0 +/- 2.6)%. During the twice NH4+-N shock loadings [0.03 kg/(m3 x d) and 0.06 kg/(m3 x d)], ZMBS showed a strong resisting ability with average removal efficiencies of 99.0% and 92.9% higher than those of a compared system's 96.8% and 89.3%. By monitoring the change of water quality along the length of the ZMBS's cells, two function zones for different pollutant removal were found to exist, named as decarbonization/nitrification (C/N) zone and nitrification (N) zone, and the NH4+-N removal rate in N zone was 2-8 times as that in C/N zone. TOC concentrations of organic matters with relative molecular weight 1 x 10(4), were 227.6, 104.8 and 35.0 mg/L in raw wastewater, and 31.2, 22.9 and 31.5 mg/L in the effluent, respectively. Organic matters with relative molecular weight 1x 10(3) were the main remained substances in the effluent.

  1. Removal of pyridine and quinoline by bio-zeolite composed of mixed degrading bacteria and modified zeolite

    International Nuclear Information System (INIS)

    Bai Yaohui; Sun Qinghua; Xing Rui; Wen Donghui; Tang Xiaoyan

    2010-01-01

    In the process of the biodegradation of pyridine and quinoline, ammonium is often generated because of the transformation of N from pyridine and quinoline. Zeolite has been proven to be an effective sorbent for the removal of the ammonium. The natural zeolite can be modified to be the macroporous carrier in the biological wastewater treatment process. In this study, a specific bio-zeolite composed of mixed bacteria (a pyridine-degrading bacterium and a quinoline-degrading bacterium) and modified zeolite was used for biodegradation and adsorption in two types of wastewater: sterile synthetic and coking wastewater. The experimental results indicated that pyridine and quinoline could be degraded simultaneously by the mixed bacteria. Furthermore, NH 4 + -N transformed from pyridine and quinoline could be removed by the modified zeolite. In addition, the bacterial community structures of the coking wastewater and the bio-zeolite were monitored by the amplicon length heterogeneity polymerase-chain reaction (LH-PCR) technique. Both LH-PCR results and scanning electron microscope (SEM) observations indicated that the microorganisms, including BW001 and BW003, could be easily attached on the surface of the modified zeolite and that the bio-zeolite could be used in the treatment of wastewater containing pyridine and/or quinoline.

  2. Synthesis of zeolites 'type A' for adsorption of CO2

    International Nuclear Information System (INIS)

    Vieira, L.O.; Madeira, A.C.; Merlini, A.; Melo, C.R.; Mendes, E.; Santos, M.G.S.; Angioletto, E.

    2012-01-01

    The separation of gases is a very expensive step in the chemical industry and unquestionable relevance. In this work it was found the effectiveness of using zeolites of type A in the separation of CO 2 in a gas mixture containing 25% CO 2 , 4% O 2 and 71% N 2 concentrations similar to exhaust gases from combustion processes. To this end, was synthesized using zeolites type A commercial kaolin and mounted to an adsorption column to test the efficiency of zeolites in the adsorption of CO 2 . The synthesized zeolites showed surface area of 66.22m 2 /g. The CO 2 concentration was determined by gas chromatography with TCD detector. Adjusting the data to the Langmuir model, there was obtained the kinetics of adsorption. From these, we found the ability of zeolite to adsorb CO 2 used in the column of 0.461285mg/g. The results of adsorption proved promising and showed maximum adsorption of 78.4% at a time of 10 seconds. (author)

  3. NATO Advanced Research Workshop on Physicochemical Properties of Zeolitic Systems and Their Low Dimensionality

    CERN Document Server

    Derouane, Eric; Hölderich, Wolfgang

    1990-01-01

    Low dimensionality is a multifarious concept which applies to very diversified materials. Thus, examples of low-dimensional systems are structures with one or several layers, single lines or patterns of lines, and small clusters isolated or dispersed in solid systems. Such low­ dimensional features can be produced in a wide variety of materials systems with a broad spectrum of scientific and practical interests. These features, in turn, induce specific properties and, particularly, specific transport properties. In the case of zeolites, low dimensionality appears in the network of small-diameter pores of molecular size, extending in one, two or three di­ mensions, that these solids exhibit as a characteristic feature and which explains the term of "molecular sieves" currently used to name these ma­ terials. Indeed, a large number of industrial processes for separation of gases and liquids, and for catalysis are based upon the use of this low­ dimensional feature in zeolites. For instance, zeolites constit...

  4. INTERKALASI XILENOL ORANGE PADA ZEOLIT ALAM LAMPUNG SEBAGAI ELEKTRODA ZEOLIT TERMODIFIKASI

    Directory of Open Access Journals (Sweden)

    Fitriyah Fitriyah

    2016-07-01

    Full Text Available Zeolit terbagi menjadi zeolit alam dan zeolit sintesis, kapasitas adsorpsi zeolit alam umumnya lebih rendah daripada zeolit sintesis, sehingga untuk meningkatkan kapasitas adsorpsinya, karakter permukaan zeolit alam perlu diubah dengan melakukan proses modifikasi permukaan melalui berbagai metode, salah satunya dengan metode interkalasi. Tujuan penelitian ini yaitu menginterkalasi zat warna xilenol orange ke dalam zeolit alam Lampung dan mengaplikasikannya sebagai elektroda zeolit termodifikasi. Melalui proses interkalasi diharapkan dapat meningkatkan kegunaan dan nilai tambah dari zeolit. Data hasil penelitian menunjukkan bahwa xilenol orange (XO dapat diinterkalasikan ke dalam zeolit, hal ini dapat dilihat dari pita spektrum FTIR yang memiliki serapan pada bilangan gelombang 1383 cm-1, yaitu menunjukkan serapan dari S=O simetris dan asimetris pada gugus –SO3H,hal ini diduga karena XO memiliki gugus SO3 sehingga menyebabkan adanya serangan pada proton zeolit. Berdasarkan penelitian dapat disarikan bahwa xilanol orange dapat terinterkalasi pada zeolit alam Lampung dan dapat dimanfaatkan sebagai elektroda pendeteksi logam.

  5. Processing of radioactive waste solution with zeolites. I. Thermal transformation of Na, Cs and Sr type zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, T; Mimura, H; Kitamura, T [Tohoku Univ., Sendai (Japan). Research Inst. of Mineral Dressing and Metallurgy

    1976-08-01

    Thermal transformation of Na, Cs and Sr type zeolites were studied by means of differential thermal analysis (DTA), thermogravimetric analysis (TGA) and X-ray powder diffraction. Synthetic zeolites A, X and Y, synthetic mordenite (Zeolon) and natural mordenite were used in this study. Na type zeolites of A and X recrystallized to Nepheline (NaAlSiO/sub 4/) above 1,000/sup 0/C, but the structures of zeolite Y and mordenite collapsed above about 900/sup 0/C and did not recrystallize until 1,200/sup 0/C. Cs type zeolites of A and X recrystallized to pollucite (CsAlSi/sub 2/O/sub 6/) above 1,000/sup 0/C and Cs type of zeolite Y recrystallized to it above 1,100/sup 0/C, but the structure of mordenite collapsed above 1,000/sup 0/C and did not recrystallize until 1,200/sup 0/C. On Sr type zeolites, zeolite A and X recrystallized to strontium aluminosilicate (SrAl/sub 2/Si/sub 2/O/sub 8/) above 1,100/sup 0/C and zeolite Y recrystallized to it above 1,200/sup 0/C, but the structure of mordenite collapsed above 1,000/sup 0/C. The results described above were supported by microscopic observation and the measurement of density. If this solidifications by calcination of zeolites are further studied, new informations concerning the fixation of Cs and Sr will be obtained.

  6. Immobilization of krypton-85 in zeolite 5A

    International Nuclear Information System (INIS)

    Christensen, A.B.; Del Debbio, J.A.; Knecht, D.A.; Tanner, J.E.; Cossel, S.C.

    1983-01-01

    This paper describes the technical feasibility and presents a summary of a preconceptual design and cost estimate for a process to immobilize krypton-85 by sintering in zeolite 5A at 700 0 C and 100 MPa for 2 to 4 h. Krypton loading of 30 to 60 m 3 at STP per m 3 solid can be achieved. The initial water concentration in zeolite 5A has a catalytic effect on the sintering rate and must be kept at about 1 wt% by heating prior to the encapsulation run. High initial water loadings and/or encapsulation times longer than 4 h must be avoided because the sintered zeolite 5A recrystallizes to an anorthite-type feldspar and releases the trapped krypton. Data are presented to show how the process conditions affect krypton encapsulation in zeolie 5A and how to assure the quality of the product. By adding a powdered glass frit to the commercial zeolite 5A 2 mm beads, a solid mass is formed during encapsulation, which can be further compacted using standard hot isotatic pressing techniques at 33 MPa and 600 0 C to form a fused glassy matrix enclosing the amorphous zeolite. A process for encapsulating the annual krypton-85 production at a commercial 2000 metric ton of heavy metal spent fuel reprocessing plant is developed. A hot isostatic press (HIP) with an isolated work zone of 8 or 16 L capacity is required to operate for 600 or 300 cycles per year, respectively. Existing HIP technology uses work zones from 1 to 3500 L capacity at similar production rates. A combined encapsulation/compaction cycle is proposed as an option to most effectively immobilize the krypton and the zeolite. A preconceptual design and cost estimate is given for a commercial-scale Kr encapsulation facility. The facility is designed to withstand a worst case rupture of the HIP. The maximum lease is estimated to result in an off-site dose well below accident protective action guidance levels

  7. Templating mesoporous zeolites

    DEFF Research Database (Denmark)

    Egeblad, Kresten; Christensen, Christina Hviid; Kustova, Marina

    2008-01-01

    The application of templating methods to produce zeolite materials with hierarchical bi- or trimodal pore size distributions is reviewed with emphasis on mesoporous materials. Hierarchical zeolite materials are categorized into three distinctly different types of materials: hierarchical zeolite...... crystals, nanosized zeolite crystals, and supported zeolite crystals. For the pure zeolite materials in the first two categories, the additional meso- or macroporosity can be classified as being either intracrystalline or intercrystalline, whereas for supported zeolite materials, the additional porosity...... originates almost exclusively from the support material. The methods for introducing mesopores into zeolite materials are discussed and categorized. In general, mesopores can be templated in zeolite materials by use of solid templating, supramolecular templating, or indirect templating...

  8. Use of Natural Zeolite to Upgrade Activated Sludge Process

    Directory of Open Access Journals (Sweden)

    Hanife Büyükgüngör

    2003-01-01

    Full Text Available The objective of this study was to achieve better efficiency of phosphorus removal in an enhanced biological phosphorus removal process by upgrading the system with different amounts of natural zeolite addition. The system performance for synthetic wastewater containing different carbon sources applied at different initial concentrations of phosphorus, as well as for municipal wastewater, was investigated. Natural zeolite addition in the aerobic phase of the anaerobic/aerobic bioaugmented activated sludge system contributed to a significant improvement of phosphorus removal in systems with synthetic wastewater and fresh municipal wastewater. Improvement of phosphorus removal with regard to the control reactors was higher with the addition of 15 than with 5 g/L of natural zeolite. In reactors with natural zeolite addition with regard to the control reactors significantly decreased chemical oxygen demand, ammonium and nitrate, while higher increment and better-activated sludge settling were achieved, without changes in the pH-values of the medium. It was shown that the natural zeolite particles are suitable support material for the phosphate-accumulating bacteria Acinetobacter calcoaceticus (DSM 1532, which were adsorbed on the particle surface, resulting in increased biological activity of the system. The process of phosphorus removal in a system with bioaugmented activated sludge and natural zeolite addition consisted of: metabolic activity of activated sludge, phosphorus uptake by phosphate-accumulating bacteria adsorbed on the natural zeolite particles and suspended in solution, and phosphorus adsorption on the natural zeolite particles.

  9. Nonionic emulsion-mediated synthesis of zeolite beta

    Indian Academy of Sciences (India)

    Zeolite beta synthesis was first carried out in a newly developed emulsion system containing nonionic polyoxyethylated alkylphenol surfactant, which showed interesting non-conventional features. Compared to the conventional hydrothermal synthesis of zeolite beta, the reported nonionic emulsion system showed a faster ...

  10. UKURAN PARTIKEL DAN KONFORMASI KRISTAL ZEOLIT-A HASIL SINTESIS DENGAN PENAMBAHAN TETRAPROPILAMMONIUM HIDROKSIDA (TPAOH

    Directory of Open Access Journals (Sweden)

    Nurul - Widiastuti

    2014-12-01

    Full Text Available Abstract PARTICLE SIZE AND CRYSTAL CONFORMATION OF SYNTHESIZED ZEOLITE-A WITH TETRAPROPYLAMMONIUM HYDROXIDE (TPAOH ADDITION. The aims of this research is to study the effect of tetrapropylammonium hydroxide (TPAOH concentration in the synthesis of zeolite A to its physical characteristics such as crystallinity, crystal conformation and average crystal size. The zeolite A was synthesized with composition 3.165 Na2O : 1.000 Al2O3 : 1.926 SiO2 : 128 H2O : x TPAOH where x was 0; 0.0385; 0.0577; 0.0770; 0.1540 and 4.1602. The zeolite was crystalized under hydrothermal condition in a stainless steel autoclave at 100°C for 5 hours. The resulting crystal was washed with distilled water until pH 8 and then dried in an oven at 80oC for 24 hours. FT-IR and XRD analysis results show that the synthesized zeolite A at x = 4.1602 has the lowest crystallinity. It is estimated due to the mass of TPAOH was four times higger than the mass of zeolite framework components (Si and Al. SEM and PSD (Particle Size Distribution analysis results show that TPAOH concentration affected the crystal conformation and the average size of zeolite A particles. The formation of chained crystal conformation was caused by the electrostatic interactions between TPA+ and negatively charge of zeolite framework. In addition, the particel size of the synthesized zeolite A at x = 0.1540 was 2.024 µm which was smaller than the particel size of the synthesized zeolite A without TPAOH, which was 3.534 µm. Keywords: average size of particles; crystal conformation; TPAOH; zeolite A Abstrak Penelitian ini bertujuan untuk mempelajari pengaruh konsentrasi TPAOH (Tetrapropilamonium hidroksida dalam sintesis zeolit A terhadap sifat fisikanya yang meliputi kekristalan, konformasi kristal dan ukuran rata-rata kristal yang terbentuk. Pada penelitian   ini   zeolit A   disintesis    dengan komposisi 3,165 Na2O : 1 Al2O3 : 1,926 SiO2 :128 H2O: x TPAOH. Konsentrasi TPAOH divariasikan dengan

  11. Catalytic Fast Pyrolysis of Cellulose Using Nano Zeolite and Zeolite/Matrix Catalysts in a GC/Micro-Pyrolyzer.

    Science.gov (United States)

    Lee, Kyong-Hwan

    2016-05-01

    Cellulose, as a model compound of biomass, was catalyzed over zeolite (HY,.HZSM-5) and zeolite/matrix (HY/Clay, HM/Clay) in a GC/micro-pyrolyzer at 500 degrees C, to produce the valuable products. The catalysts used were pure zeolite and zeolite/matrix including 20 wt% matrix content, which were prepared into different particle sizes (average size; 0.1 mm, 1.6 mm) to study the effect of the particle size of the catalyst for the distribution of product yields. Catalytic pyrolysis had much more volatile products as light components and less content of sugars than pyrolysis only. This phenomenon was strongly influenced by the particle size of the catalyst in catalytic fast pyrolysis. Also, in zeolite and zeolite/matrix catalysts the zeolite type gave the dominant impact on the distribution of product yields.

  12. Zeolite Y: Synthesis, Modification, and Properties—A Case Revisited

    Directory of Open Access Journals (Sweden)

    Wolfgang Lutz

    2014-01-01

    Full Text Available Y zeolites dealuminated by steaming were introduced as fluid-cracking catalysts in the year 1970. Extensive research has been done to develop suitable dealumination techniques, to investigate crystal structure, and to characterize catalytic behaviour. However, the origin of the secondary pore system formed in the zeolite structure during dealumination process remained completely obscure over a period of four decades. Open questions concerned also the existence of extraframework siliceous admixture in addition to extraframework aluminium species which can dramatically change the catalytic properties of these zeolites. This paper gives a review on the synthesis of DAY materials and provides some answers to several open questions.

  13. Optimization for zeolite regeneration and nitrogen removal performance of a hypochlorite-chloride regenerant.

    Science.gov (United States)

    Zhang, Wei; Zhou, Zhen; An, Ying; Du, Silu; Ruan, Danian; Zhao, Chengyue; Ren, Ning; Tian, Xiaoce

    2017-07-01

    Simultaneous zeolites regeneration and nitrogen removal were investigated by using a mixed solution of NaClO and NaCl (NaClO-NaCl solution), and effects of the regenerant on ammonium removal performance and textural properties of zeolites were analyzed by long-term adsorption and regeneration operations. Mixed NaClO-NaCl solution removed more NH 4 + exchanged on zeolites and converted more of them to nitrogen than using NaClO or NaCl solution alone. Response surface methodological analysis indicated that molar ratio of hypochlorite and nitrogen (ClO - /N), NaCl concentration and pH value all had significant effects on zeolites regeneration and NH 4 + conversion to nitrogen, and the optimum condition was obtained at ClO - /N of 1.75, NaCl concentration of 20 g/L and pH of 10.0. Zeolites regenerated by mixed NaClO-NaCl solution showed higher ammonium adsorption rate and lower capacity than unused zeolites. Zeolites and the regeneration solution were both effective even after 20 cycles of use. Composition and morphological analysis revealed that the main mineral species and surface morphology of zeolites before and after NaClO-NaCl regeneration were unchanged. Textural analysis indicated that NaClO-NaCl regeneration leads to an increased surface area of zeolites, especially the microporosity. The results indicated that NaClO-NaCl regeneration is an attractive method to achieve sustainable removal of nitrogen from wastewater through zeolite. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Synthesis of novel perfluoroalkylglucosides on zeolite and non-zeolite catalysts.

    Science.gov (United States)

    Nowicki, Janusz; Mokrzycki, Łukasz; Sulikowski, Bogdan

    2015-04-08

    Perfluoroalkylglucosides comprise a very important class of fluorine-containing surfactants. These compounds can be synthesized by using the Fisher reaction, starting directly from glucose and the required perfluoroalcohols. We wish to report on the use of zeolite catalysts of different structure and composition for the synthesis of perfluoroalkylglucosides when using glucose and 1-octafluoropentanol as substrates. Zeolites of different pore architecture have been chosen (ZSM-5, ZSM-12, MCM-22 and Beta). Zeolites were characterized by XRD, nitrogen sorption, scanning electron microscopy (SEM) and solid-state 27Al MAS NMR spectroscopy. The activity of the zeolite catalysts in the glycosidation reaction was studied in a batch reactor at 100 °C below atmospheric pressure. The performance of zeolites was compared to other catalysts, an ion-exchange resin (Purolite) and a montmorillonite-type layered aluminosilicate. The catalytic performance of zeolite Beta was the highest among the zeolites studied and the results were comparable to those obtained over Purolite and montmorillonite type catalysts.

  15. Characterization of Zeolite in Zeolite-Geopolymer Hybrid Bulk Materials Derived from Kaolinitic Clays

    Directory of Open Access Journals (Sweden)

    Hayami Takeda

    2013-05-01

    Full Text Available Zeolite-geopolymer hybrid materials have been formed when kaolin was used as a starting material. Their characteristics are of interest because they can have a wide pore size distribution with micro- and meso-pores due to the zeolite and geopolymer, respectively. In this study, Zeolite-geopolymer hybrid bulk materials were fabricated using four kinds of kaolinitic clays (a halloysite and three kinds of kaolinite. The kaolinitic clays were first calcined at 700 °C for 3 h to transform into the amorphous aluminosilicate phases. Alkali-activation treatment of the metakaolin yielded bulk materials with different amounts and types of zeolite and different compressive strength. This study investigated the effects of the initial kaolinitic clays on the amount and types of zeolite in the resultant geopolymers as well as the strength of the bulk materials. The kaolinitic clays and their metakaolin were characterized by XRD analysis, chemical composition, crystallite size, 29Si and 27Al MAS NMR analysis, and specific surface area measurements. The correlation between the amount of zeolite formed and the compressive strength of the resultant hybrid bulk materials, previously reported by other researchers was not positively observed. In the studied systems, the effects of Si/Al and crystalline size were observed. When the atomic ratio of Si/Al in the starting kaolinitic clays increased, the compressive strength of the hybrid bulk materials increased. The crystallite size of the zeolite in the hybrid bulk materials increased with decreasing compressive strength of the hybrid bulk materials.

  16. Three Mile Island zeolite vitirification demonstration program

    International Nuclear Information System (INIS)

    Siemens, D.H.; Knowlton, D.E.; Shupe, M.W.

    1981-06-01

    The cleanup of the high-activity-level water at Three Mile Island (TMI) provides an opportunity to further develop waste management technology. Approximately 790,000 gallons of high-activity-level water at TMI's Unit-2 Nuclear Power Station will be decontaminated at the site using the submerged demineralizer system (SDS). In the SDS process, the cesium and strontium in the water are sorbed onto zeolite that is contained within metal liners. The Department of Energy has asked the Pacific Northwest Laboratory (PNL) to take a portion of the zeolite from the SDS process and demonstrate, on a production scale, that this zeolite can be vitrified using the in-can melting process. This paper is a brief overview of the TMI zeolite vitrification program. The first section discusses the formulation of a glass suitable for immobilizing SDS zeolite. The following section describes a feed system that was developed to feed zeolite to the in-can melter. It also describes the in-can melting process and the government owned facilities in which the demonstrations will take place. Finally, the schedule for completing the program activities is outlined

  17. ADSORPTION MALACHITE GREEN ON NATURAL ZEOLITE

    OpenAIRE

    Eko Ariyanto

    2012-01-01

    A natural zeolite was employed as adsorbent for reducing of malachite green from aqueous solution. A batch system was applied to study the adsorption of malachite green in single system on natural zeolite. The adsorption studies indicate that malachite green in single component system follows the second-order kinetics and the adsorption is diffusion process with two stages for malachite green. Malachite green adsorption isotherm follows the Langmuir model.

  18. Molecular simulation of water removal from simple gases with zeolite NaA.

    Science.gov (United States)

    Csányi, Eva; Ható, Zoltán; Kristóf, Tamás

    2012-06-01

    Water vapor removal from some simple gases using zeolite NaA was studied by molecular simulation. The equilibrium adsorption properties of H(2)O, CO, H(2), CH(4) and their mixtures in dehydrated zeolite NaA were computed by grand canonical Monte Carlo simulations. The simulations employed Lennard-Jones + Coulomb type effective pair potential models, which are suitable for the reproduction of thermodynamic properties of pure substances. Based on the comparison of the simulation results with experimental data for single-component adsorption at different temperatures and pressures, a modified interaction potential model for the zeolite is proposed. In the adsorption simulations with mixtures presented here, zeolite exhibits extremely high selectivity of water to the investigated weakly polar/non-polar gases demonstrating the excellent dehydration ability of zeolite NaA in engineering applications.

  19. Zeolite synthesis from the pyrrolidine containing system and their catalytic properties in the methanol conversion reaction

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Kunio; Kiyozumi, Yoshimichi; Shin, Shigemitsu; Ogawa, Kiyoshi; Yamazaki, Yasuyoshi; Watanabe, Hideo

    1987-12-18

    Systhesis of zeolite from a system containing cheaper pyrrolidine as a crystallization regulator than quaternary ammonium ion was carried out and the methanol conversion reaction was studied over the systhesized zeolite to get C/sub 2/ and C/sub 3/ olefins. Hydrous gels were prepared by adding and agitating pyrrolidine, water glass and sulfuric acid to aluminum sulfate solution; and aluminum nitrate, colloidal silica and pyrrolidine to NaOH solution. Five zeolite, that is, ZSM-5, ZSM-35, ZSM-39, ZSM-48 and KZ-1 were synthesized by changing gel components. X-ray powder diffraction, BET specific surface areas, micropore diameters, micropore volumes, oxygen contents by scanning electron photomicrographs and infra-red spectra were examined. The organic base in hydrous gels influenced greatly on the zeolite composition and structure. The ZSM-5 zeolite exhibited the superior performance as to a high selectivity of light olefins over the target of development. (12 figs, 1 tab, 20 refs)

  20. Zeolite-templated carbon replica: a Grand Canonical Monte-Carlo simulation study

    International Nuclear Information System (INIS)

    Thomas Roussel; Roland J M Pellenq; Christophe Bichara; Roger Gadiou; Antoine Didion; Cathie Vix Guterl; Fabrice Gaslain; Julien Parmentier; Valentin Valtchev; Joel Patarin

    2005-01-01

    Microporous carbon materials are interesting for several applications such as hydrogen storage, catalysis or electrical double layer capacitors. The development of the negative templating method to obtain carbon replicas from ordered templates, has lead to the synthesis of several new materials which have interesting textural properties, attractive for energy storage. Among the possible templates, zeolites can be used to obtain highly microporous carbon materials. Nevertheless, the phenomena involved in the replica synthesis are not fully understood, and the relationships between the structure of the template, the carbon precursor and the resulting carbon material need to be investigated. Experimental results for carbon zeolite-templated nano-structures can be found in a series of papers; see for instance ref. [1] in which Wang et al describe a route to ultra-small Single Wall Carbon Nano-tubes (SWNTs) using the porosity of zeolite AlPO 4 -5. After matrix removal, the resulting structure is a free-standing bundle of 4 Angstroms large nano-tubes. However, it is highly desirable to obtain an ordered porous carbon structure that forms a real 3D network to be used for instance in gas storage applications. Carbon replica of faujasite and EMT zeolites can have these properties since these zeolites have a 3D porous network made of 10 Angstroms cages connected to each other through 7 Angstroms large windows. The first step of this study was to generate a theoretical carbon replica structure of various zeolites (faujasite, EMT, AlPO 4 -5, silicalite). For this purpose, we used the Grand Canonical Monte-Carlo (GCMC) technique in which the carbon-carbon interactions were described within the frame of a newly developed Tight Binding approach and the carbon-zeolite interactions assumed to be characteristic of physi-sorption. The intrinsic stability of the subsequent carbon nano-structures was then investigated after mimicking the removal of the inorganic phase by switching

  1. Improving the osteointegration of Ti6Al4V by zeolite MFI coating

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yong [Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi' an, Shaanxi 710032 (China); Jiao, Yilai [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, Liaoning 110016 (China); Li, Xiaokang [Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi' an, Shaanxi 710032 (China); Guo, Zheng, E-mail: guozheng@fmmu.edu.cn [Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi' an, Shaanxi 710032 (China)

    2015-05-01

    Osteointegration is crucial for success in orthopedic implantation. In recent decades, there have been numerous studies aiming to modify titanium alloys, which are the most widely used materials in orthopedics. Zeolites are solid aluminosilicates whose application in the biomedical field has recently been explored. To this end, MFI zeolites have been developed as titanium alloy coatings and tested in vitro. Nevertheless, the effect of the MFI coating of biomaterials in vivo has not yet been addressed. The aim of the present work is to evaluate the effects of MFI-coated Ti6Al4V implants in vitro and in vivo. After surface modification, the surface was investigated using field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). No difference was observed regarding the proliferation of MC3T3-E1 cells on the Ti6Al4V (Ti) and MFI-coated Ti6Al4V (M−Ti) (p > 0.05). However, the attachment of MC3T3-E1 cells was found to be better in the M−Ti group. Additionally, ALP staining and activity assays and quantitative real-time RT-PCR indicated that MC3T3-E1 cells grown on the M−Ti displayed high levels of osteogenic differentiation markers. Moreover, Van-Gieson staining of histological sections demonstrated that the MFI coating on Ti6Al4V scaffolds significantly enhanced osteointegration and promoted bone regeneration after implantation in rabbit femoral condylar defects at 4 and 12 weeks. Therefore, this study provides a method for modifying Ti6Al4V to achieve improved osteointegration and osteogenesis. - Highlights: • Osteointegration is a crucial factor for orthopedic implants. • We coated MFI zeolite on Ti6Al4V substrates and investigated the effects in vitro and in vivo. • The MFI coating displayed good biocompatibility and promoted osteogenic differentiation in vitro. • The MFI coating promoted osteointegration and osteogenesis peri-implant in vivo.

  2. A bioscaffolding strategy for hierarchical zeolites with a nanotube-trimodal network.

    Science.gov (United States)

    Li, Guannan; Huang, Haibo; Yu, Bowen; Wang, Yun; Tao, Jiawei; Wei, Yingxu; Li, Shougui; Liu, Zhongmin; Xu, Yan; Xu, Ruren

    2016-02-01

    Hierarchical zeolite monoliths with multimodal porosity are of paramount importance as they open up new horizons for advanced applications. So far, hierarchical zeolites based on nanotube scaffolds have never been reported. Inspired by the organization of biominerals, we have developed a novel precursor scaffolding-solid phase crystallization strategy for hierarchical zeolites with a unique nanotube scaffolding architecture and nanotube-trimodal network, where biomolecular self-assembly (BSA) provides a scaffolding blueprint. By vapor-treating Sil-1 seeded precursor scaffolds, zeolite MFI nanotube scaffolds are self-generated, during which evolution phenomena such as segmented voids and solid bridges are observed, in agreement with the Kirkendall effect in a solid-phase crystallization system. The nanotube walls are made of intergrown single crystals rendering good mechanical stability. The inner diameter of the nanotube is tunable between 30 and 90 nm by varying the thickness of the precursor layers. Macropores enclosed by cross-linked nanotubes can be modulated by the choice of BSA. Narrow mesopores are formed by intergrown nanocrystals. Hierarchical ZSM-5 monoliths with nanotube (90 nm), micropore (0.55 nm), mesopore (2 nm) and macropore (700 nm) exhibit superior catalytic performance in the methanol-to-hydrocarbon (MTH) conversion compared to conventional ZSM-5. BSA remains intact after crystallization, allowing a higher level of organization and functionalization of the zeolite nanotube scaffolds. The current work may afford a versatile strategy for hierarchical zeolite monoliths with nanotube scaffolding architectures and a nanotube-multimodal network leading to self-supporting and active zeolite catalysts, and for applications beyond.

  3. The addition of salt in the water media containing zeolite and active charcoal on closed system transportation of gourami fish fry Osphronemus goramy Lac.

    Directory of Open Access Journals (Sweden)

    Kukuh Nirmala

    2013-11-01

    Full Text Available Transportation of fish fry with high density in closed system will reduce levels of O2, increasing CO2 and NH3, will also elevate the fish stress so that increase fish mortality. To reduce the effects of increased CO2 and NH3 can be applied by using zeolite and activated charcoal, while to reduce the fish stress is through the addition of salt. This study aims to determine the dose of salt added into the water containing zeolite and activated charcoal in a closed transportation system with a high fry density for 72 hours. The study was conducted two stages, namely the preliminary study and the primary study. The preliminary study involved the observation of the survival rate of fish fry during fasting, oxygen consumption rate of fish fry, the rate of total ammonia nitrogen (TAN excretion of fish fry, and the adsorption capacity of TAN by zeolite and activated charcoal. In the primary study, fry transport simulations was carried out for 72 hours in the laboratory. Gourami fry (body length of 4 cm and body weight of 1.7 g with the fry density of 50 fish/L were placed in the packing bag which has been filled with zeolite as much as 20 g/L and activated charcoal as much as 10 g/L. The study used a completely randomized design with five treatments and two replications: A: blank (without zeolite, activated charcoal, and salt, B: control (20 g/L zeolite+10 g/L activated charcoal, C: 20 g/L zeolite+10 g/L activated charcoal and 1 g/L salt, D: 20 g/L zeolite+10 g/L activated charcoal and 3 g/L of salt, and E: 20 g/ L zeolite+10 g/L activated charcoal and 5 g/L salt. The results of preliminary study showed that the survival rate of fish fry was 100% and active swimming for five days without food, the level of oxygen consumption as much as 1340.28 mgO2, produce NH3 as much as 22.64 mg/L, while zeolite and activated charcoal adsorbs >50% of TAN in time of 120 seconds. In the primary study, the survival rate of fish fry during the 72-hour transportation for

  4. Supported Zeolite Beta Layers via an Organic Template-Free Preparation Route

    Directory of Open Access Journals (Sweden)

    Stephanie Reuss

    2018-01-01

    Full Text Available Layers of high silica zeolites, synthesized with an organic structure directing agent (OSDA and grown onto porous support structures, frequently suffer from the thermal stress during the removal of OSDA via the calcination process. The different thermal expansion coefficients of the zeolite and the support material, especially when stainless steel is used as a support, causes enormous tension resulting in defect formation in the zeolite layer. However, the calcination is an easy procedure to decompose the OSDA in the pore system of the zeolite. Recently, methods to synthesize zeolite beta without the use of an organic structure directing agent have been described. In the present study, a seed-directed synthesis is used to prepare OSDA-free zeolite beta layers on stainless steel supports via an in situ preparation route. For the application as membrane, a porous stainless steel support has been chosen. The beta/stainless steel composites are characterized by X-ray diffraction (XRD and scanning electron microscopy (SEM. To prove its possible application as a membrane, the beta/stainless steel composites were also tested by single gas permeances of H2, He, CO2, N2, and CH4.

  5. ADSORPTION MALACHITE GREEN ON NATURAL ZEOLITE

    Directory of Open Access Journals (Sweden)

    Eko Ariyanto

    2012-02-01

    Full Text Available A natural zeolite was employed as adsorbent for reducing of malachite green from aqueous solution. A batch system was applied to study the adsorption of malachite green in single system on natural zeolite. The adsorption studies indicate that malachite green in single component system follows the second-order kinetics and the adsorption is diffusion process with two stages for malachite green. Malachite green adsorption isotherm follows the Langmuir model.

  6. Zeolite Nanoparticles for Selective Sorption of Plasma Proteins.

    Science.gov (United States)

    Rahimi, M; Ng, E-P; Bakhtiari, K; Vinciguerra, M; Ali Ahmad, H; Awala, H; Mintova, S; Daghighi, M; Bakhshandeh Rostami, F; de Vries, M; Motazacker, M M; Peppelenbosch, M P; Mahmoudi, M; Rezaee, F

    2015-11-30

    The affinity of zeolite nanoparticles (diameter of 8-12 nm) possessing high surface area and high pore volume towards human plasma proteins has been investigated. The protein composition (corona) of zeolite nanoparticles has been shown to be more dependent on the plasma protein concentrations and the type of zeolites than zeolite nanoparticles concentration. The number of proteins present in the corona of zeolite nanoparticles at 100% plasma (in vivo state) is less than with 10% plasma exposure. This could be due to a competition between the proteins to occupy the corona of the zeolite nanoparticles. Moreover, a high selective adsorption for apolipoprotein C-III (APOC-III) and fibrinogen on the zeolite nanoparticles at high plasma concentration (100%) was observed. While the zeolite nanoparticles exposed to low plasma concentration (10%) exhibited a high selective adsorption for immunoglobulin gamma (i.e. IGHG1, IGHG2 and IGHG4) proteins. The zeolite nanoparticles can potentially be used for selectively capture of APOC-III in order to reduce the activation of lipoprotein lipase inhibition during hypertriglyceridemia treatment. The zeolite nanoparticles can be adapted to hemophilic patients (hemophilia A (F-VIII deficient) and hemophilia B (F-IX deficient)) with a risk of bleeding, and thus might be potentially used in combination with the existing therapy.

  7. Mesoporous zeolite single crystal catalysts: Diffusion and catalysis in hierarchical zeolites

    DEFF Research Database (Denmark)

    Christensen, Christina Hviid; Johannsen, Kim; Toernqvist, Eric

    2007-01-01

    During the last years, several new routes to produce zeolites with controlled mesoporosity have appeared. Moreover, an improved catalytic performance of the resulting mesoporous zeolites over conventional zeolites has been demonstrated in several reactions. In most cases, the mesoporous zeolites...... exhibit higher catalytic activity, but in some cases also improved selectivity and longer catalyst lifetime has been reported. The beneficial effects of introducing mesopores into the zeolites has in most instances been attributed to improved mass transport to and from the active sites located...... in the zeolite micropores. Here, we briefly discuss the most important ways of introducing mesopores into zeolites and, for the first time, we show experimentally that the presence of mesopores dramatically increases the rate of diffusion in zeolite catalysts. This is done by studying the elution of iso...

  8. Catalytic Oxidation by Transition Metal Ions in Zeolites.

    Science.gov (United States)

    1984-09-28

    exotic schemes were developed. It was previously demonstrated that MoCI5 may be reacted with a HYu (here Yu denotes a steam-stabilized or...34ultrastable" zeolite) to form a MoYu zeolite and HC1 which is removed from the system.1 In this study, MoYu zeolites have been prepared by reacting HYu with Mo

  9. Hydrogenation of hexene over platinum on alumina vs. platinum in a Na-Y zeolite

    International Nuclear Information System (INIS)

    Miner, R.S. Jr.; Ione, K.G.; Namba, S.; Turkevich, J.

    1978-01-01

    In order to study the efficacy of zeolites as supports, several platinum H--Y zeolites were prepared by ion exchanging an H--Y zeolite with Pt(NH 3 ) 4 Cl 2 and reducing these products with hydrazine hydrate (A, B, C). Another preparation was made by adsorbing 32-A platinum sol on the zeolite crystallites (D). These catalysts were studied for hydrogenation and isomerization of hexene-1, ethylene hydrogenation, hydrogen chemisorption, and poison titration. They were compared with monodisperse Pt (32 A diameter) on alumina. A marked difference was found between the behavior of hexene-1 with the platinum-in-zeolite and with the platinum-on-alumina

  10. UTILIZATION OF ACTIVATED ZEOLITE AS MOLECULAR SIEVE IN CHROMATOGRAPHIC COLUMN FOR SEPARATION OF COAL TAR COMPOUNDS

    Directory of Open Access Journals (Sweden)

    Dwi Retno Nurotul Wahidiyah

    2010-06-01

    Full Text Available Application of activated zeolite (ZAA as molecular sieve to separate compounds of coal tar from vaccum fractional distillation, have been done. The size of zeolite was 10-20 mesh and used as solid phase in column chromatography with length of 30 cm. The first step of the research was coal pyrolisis and the product (tar was distillated by fractional column and vaccum system at reduced pressure 44 cmHg and maximum temperature at 200 oC. The distillate from this procedure was flowed to the column chromatography of zeolite (ZAA. The compound absorbed by zeolite was eluted with varying solvents, i.e: CCl4, acetone and ethanol. Each fraction was then analyzed by gas chromatography. The results showed, zeolite have a capability to separate the compounds of tar and it tends to absorb medium hydrocarbon. The nonpolar eluent [CCl4] gives the better result in eluting tar compound than polar (ethanol or medium polar eluents (acetone.   Keywords: zeolite, coal tar, column chromatography

  11. Reduction volume of radioactive wastes using natural zeolite

    International Nuclear Information System (INIS)

    Endro Kismolo; Nurimaniwathy; Vemi Ridantami

    2013-01-01

    The aim of this experience was to know of the characteristics of zeolite as the sorbent for reduction volume of liquid waste with the Pb contaminant contain. The experiment was done by sorption method a batch performed by using zeolite from Gedangsari Gunung Kidul with the grain size (-60+80) mesh, (-80+100) mesh dan (-100+120) mesh which was activated by (NH 4 ) CI and NH 4 N0 3 1.0 M. Weight of sorbent was added was variated from 5.0 to 40.0 %, and variation of silica sand to added from 0.5 to 2.5 % of weight sorbent. Stirring speed was varied from 30 to 180 rpm and the stirring time of 10 to 120 minutes, and filtrates from filtering process to analyzed by Absorption Analysis Spectrophotometry utilities. From the experience can be achieved of data that the best sorption to obtained at the condition of zeolite on (-80+100) mesh, sorbent added of 25 %, stirring speed of 120 rpm, time of stirring of 90 minutes, and the setting time of 120 minutes. At this condition to obtained sorption efficiency are 64.162 % for natural zeolite, 7.034 % for zeolite be activated with NH 4 N0 3 and 77.414 % for zeolite be activated with NH 4 Cl 1.0 M. (author)

  12. The hybrid methylene blue-zeolite system: a higher efficient photo catalyst for photo inactivation of pathogenic microorganisms

    International Nuclear Information System (INIS)

    Smolinska, M.; Cik, G.; Sersen, F.; Caplovicova, M.; Takacova, A.; Kopani, M.

    2015-01-01

    The composite system can be prepared by incorporation of methylene blue into the channels of zeolite and by adsorption on the surface of the crystals. The composite photo sensitizer effectively absorbs the red light (kmax = 648 nm) and upon illumination with light-emitting diode at a fluence rate of 1.02 mW cm-2 generates effectively reactive singlet oxygen in aqueous solution, which was proved by EPR spectroscopy. To test efficiency for inactivation of pathogenic microorganisms, we measured photo killing of bacteria Escherichia coli and Staphylococcus aureus and yeasts Candida albicans. We found out that after the microorganisms have been adsorbed at the surface of such modified zeolite, the photo generated singlet oxygen quickly penetrates their cell walls, bringing about their effective photo inactivation. The growth inhibition reached almost 50 % at 200 and 400 mg modified zeolite in 1 ml of medium in E. coli and C. albicans, respectively. On the other hand, the growth inhibition of S. aureus reached 50 % at far smaller amount of photo catalyst (30 lg per 1 ml of medium). These results demonstrate differences in sensitivities of bacteria and yeast growth. The comparison revealed that concentration required for IC50 was in case of C. albicans several orders of magnitude lower for a zeolite-immobilized dye than it was for a freely dissolved dye. In S. aureus, this concentration was even lower by four orders of magnitude. Thus, our work suggested a new possibility to exploitation of zeolite and methylene blue in the protection of biologically contaminated environment, and in photodynamic therapy.

  13. Catalase-like activity studies of the manganese(II) adsorbed zeolites

    Science.gov (United States)

    Ćiçek, Ekrem; Dede, Bülent

    2013-12-01

    Preparation of manganese(II) adsorbed on zeolite 3A, 4A, 5A. AW-300, ammonium Y zeolite, organophilic, molecular sieve and catalase-like enzyme activity of manganese(II) adsorbed zeolites are reported herein. Firstly zeolites are activated at 873 K for two hours before contact manganese(II) ions. In order to observe amount of adsorption, filtration process applied for the solution. The pure zeolites and manganese(II) adsorbed zeolites were analysed by FT-IR. As a result according to the FT-IR spectra, the incorporation of manganese(II) cation into the zeolite structure causes changes in the spectra. These changes are expected particularly in the pseudolattice bands connected with the presence of alumino and silicooxygen tetrahedral rings in the zeolite structure. Furthermore, the catalytic activities of the Mn(II) adsorbed zeolites for the disproportionation of hydrogen peroxide were investigated in the presence of imidazole. The Mn(II) adsorbed zeolites display efficiency in the disproportion reactions of hydrogen peroxide, producing water and dioxygen in catalase-like activity.

  14. Environmental application of modified natural zeolites

    International Nuclear Information System (INIS)

    Nikashina, V.A.; Myasoedov, B.F.

    1998-01-01

    The following techniques were used for the chemical modification of the natural zeolites: (1) treatment of natural zeolites with organic substances. Examples of applications of these sorbents to the decontamination and disinfection of solutions of different composition and surface waters are presented. (2) Treatment of the natural zeolites with a inorganic substances. (2.1) The clinoptilolite-rich tuffs were treated with a hot suspensions of freshly precipitated magnetite. This leads to the preparation of sorbents possessing magnetic properties. The radionuclides and heavy metals recovery from soils and silts was investigated using different soil and ferromagnetic zeolite weights ratios and contact times. Different soils and sorbent of varying capacities were used for these investigations. As example, the recovery 137 Cs and 85 Sr from soils of different nature is presented. (2.2) Treatment of natural zeolites with Fe-containing solutions of Fe-containing natural waters. The filtration of these solutions through clinoptilolite-rich tuffs makes leads to preparation of materials possessing high selectivity to PO 4 3- ions. The properties of these sorbents can be utilized for the PO 4 3+ decontamination of waters (e.g. waste waters) and for the subsequent use of these materials in agriculture as fertilizers.(author)

  15. Magnetic zeolite NaA: synthesis, characterization based on metakaolin and its application for the removal of Cu2+, Pb2+.

    Science.gov (United States)

    Liu, Haibo; Peng, Shuchuan; Shu, Lin; Chen, Tianhu; Bao, Teng; Frost, Ray L

    2013-06-01

    The optimum parameters for synthesis of zeolite NaA based on metakaolin were investigated according to results of cation exchange capacity and static water adsorption of all synthesis products and selected X-ray diffraction (XRD). Magnetic zeolite NaA was synthesized by adding Fe3O4 in the precursor of zeolite. Zeolite NaA and magnetic zeolite NaA were characterized with scanning electron microscopy (SEM) and XRD. Magnetic zeolite NaA with different Fe3O4 loadings was prepared and used for removal of heavy metals (Cu(2+), Pb(2+)). The results show the optimum parameters for synthesis zeolite NaA are SiO2/Al2O3=2.3, Na2O/SiO2=1.4, H2O/Na2O=50, crystallization time 8h, crystallization temperature 95 °C. The addition of Fe3O4 makes the NaA zeolite with good magnetic susceptibility and good magnetic stability regardless of the Fe3O4 loading, confirming the considerable separation efficiency. Additionally, Fe3O4 loading had a little effect on removal of heavy metal by magnetic zeolite, however, the adsorption capacity still reaches 2.3 mmol g(-1) for Cu(2+), Pb(2+) with a removal efficiency of over 95% in spite of 4.7% Fe3O4 loading. This indicates magnetic zeolite can be used to remove metal heavy at least Cu(2+), Pb(2+) from water with metallic contaminants and can be separated easily after a magnetic process. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. The high temperature synthesis of CsAlSiO 4-ANA, a new polymorph in the system Cs 2OAl 2O 3SiO 2. I. The end member of ANA type of zeolite framework

    Science.gov (United States)

    Dimitrijevic, R.; Dondur, V.; Petranovic, N.

    1991-12-01

    High temperature phase transformations of Cs + exchanged zeolites were investigated. Above 1000°C, CsX, CsY (FAU), and Cs, ZK-4 (LTA) frameworks recrystallized in a pollucite phase. A Cs + loaded mordenite recrystallized at 1300°C in the orthorhombic CsAlSi 5O 12 phase. A Cs + exchanged zeolite A at 960°C recrystallized in a mixture of two polymorphic CsAlSiO 4 phases having different (Al,Si)O 4 frameworks. The unstable orthorhombic CsAlSiO 4ABW phase has a topotactic transition at 1150°C into an ordered low CsAlSiO 4-ANA framework. Further calcination produces, at 1200°C, transformation of the low CsAlSiO 4-ANA phase to the more stable high CsAlSiO 4-ANA polymorph having cubic ( a 0 = 13.6595 (5) Å) symmetry and an ordered SiAl distribution. The crystal structure of high CsAlSiO 4ANA, a new polymorph in the system Cs 2OAl 2O 3SiO 2, was determined using X-ray Rietveld analyses and 29Si MAS NMR spectroscopy.

  17. Oxidative regeneration of toluene-saturated natural zeolite by gaseous ozone: The influence of zeolite chemical surface characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Alejandro, Serguei [Laboratorio de Tecnologías Limpias (F. Ingeniería), Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción (Chile); Núcleo de Energías Renovables (F. Ingeniería), Universidad Católica de Temuco, Rudecindo Ortega 02950, Temuco (Chile); Valdés, Héctor, E-mail: hvaldes@ucsc.cl [Laboratorio de Tecnologías Limpias (F. Ingeniería), Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción (Chile); Manéro, Marie-Hélène [Université de Toulouse (France); INPT, UPS (France); Laboratoire de Génie Chimique, 4, Allée Emile Monso, F–31030 Toulouse (France); CNRS (France); Laboratoire de Génie Chimique, F–31030 Toulouse (France); Zaror, Claudio A. [Departamento de Ingeniería Química (F. Ingeniería), Universidad de Concepción, Concepción, Correo 3, Casilla 160–C (Chile)

    2014-06-01

    Highlights: • Surface acidity of modified natural zeolite is related to its chemical reactivity. • Brønsted acid sites are associated to toluene adsorption. • Lewis acid sites could decompose ozone generating surface active oxygen species. • Infrared spectra evidence active atomic oxygen and oxidation by-product formation. • 2NH4Z1 sample shows the highest reactivity toward adsorbed toluene. - Abstract: In this study, the effect of zeolite chemical surface characteristics on the oxidative regeneration of toluene saturated-zeolite samples is investigated. A Chilean natural zeolite (53% clinoptilolite, 40% mordenite and 7% quartz) was chemically modified by acid treatment with hydrochloric acid and by ion-exchange with ammonium sulphate. Thermal pre-treatments at 623 and 823 K were applied and six zeolite samples with different chemical surface characteristics were generated. Chemical modification of natural zeolite followed by thermal out-gassing allows distinguishing the role of acidic surface sites on the regeneration of exhausted zeolites. An increase in Brønsted acid sites on zeolite surface is observed as a result of ammonium-exchange treatment followed by thermal treatment at 623 K, thus increasing the adsorption capacity toward toluene. High ozone consumption could be associated to a high content of Lewis acid sites, since these could decompose ozone into atomic active oxygen species. Then, surface oxidation reactions could take part among adsorbed toluene at Brønsted acid sites and surface atomic oxygen species, reducing the amount of adsorbed toluene after the regenerative oxidation with ozone. Experimental results show that the presence of adsorbed oxidation by-products has a negative impact on the recovery of zeolite adsorption capacity.

  18. Oxidative regeneration of toluene-saturated natural zeolite by gaseous ozone: The influence of zeolite chemical surface characteristics

    International Nuclear Information System (INIS)

    Alejandro, Serguei; Valdés, Héctor; Manéro, Marie-Hélène; Zaror, Claudio A.

    2014-01-01

    Highlights: • Surface acidity of modified natural zeolite is related to its chemical reactivity. • Brønsted acid sites are associated to toluene adsorption. • Lewis acid sites could decompose ozone generating surface active oxygen species. • Infrared spectra evidence active atomic oxygen and oxidation by-product formation. • 2NH4Z1 sample shows the highest reactivity toward adsorbed toluene. - Abstract: In this study, the effect of zeolite chemical surface characteristics on the oxidative regeneration of toluene saturated-zeolite samples is investigated. A Chilean natural zeolite (53% clinoptilolite, 40% mordenite and 7% quartz) was chemically modified by acid treatment with hydrochloric acid and by ion-exchange with ammonium sulphate. Thermal pre-treatments at 623 and 823 K were applied and six zeolite samples with different chemical surface characteristics were generated. Chemical modification of natural zeolite followed by thermal out-gassing allows distinguishing the role of acidic surface sites on the regeneration of exhausted zeolites. An increase in Brønsted acid sites on zeolite surface is observed as a result of ammonium-exchange treatment followed by thermal treatment at 623 K, thus increasing the adsorption capacity toward toluene. High ozone consumption could be associated to a high content of Lewis acid sites, since these could decompose ozone into atomic active oxygen species. Then, surface oxidation reactions could take part among adsorbed toluene at Brønsted acid sites and surface atomic oxygen species, reducing the amount of adsorbed toluene after the regenerative oxidation with ozone. Experimental results show that the presence of adsorbed oxidation by-products has a negative impact on the recovery of zeolite adsorption capacity

  19. Comparing gas separation performance between all known zeolites and their zeolitic imidazolate framework counterparts.

    Science.gov (United States)

    Gómez-Álvarez, Paula; Hamad, Said; Haranczyk, Maciej; Ruiz-Salvador, A Rabdel; Calero, Sofia

    2016-01-07

    To find optimal porous materials for adsorption-based separations is a challenging task due to the extremely large number of possible pore topologies and compositions. New porous material classes such as Metal Organic Frameworks (MOFs) are emerging, and hope to replace traditionally used materials such as zeolites. Computational screening offers relatively fast searching for candidate structures as well as side-by-side comparisons between material families. This work is pioneering at examining the families comprised by the experimentally known zeolites and their respective Zeolitic Imidazolate Framework (ZIF) counterparts in the context of a number of environmental and industrial separations involving carbon dioxide, nitrogen, methane, oxygen, and argon. Additionally, unlike related published work, here all the targeted structures have been previously relaxed through energy minimization. On the first level of characterization, we considered a detailed pore characterization, identifying 24 zeolites as promising candidates for gas separation based on adsorbate sizes. The second level involved interatomic potential-based calculations to assess the adsorption performance of the materials. We found no correlation in the values of heat of adsorption between zeolites and ZIFs sharing the same topology. A number of structures were identified as potential experimental targets for CO2/N2, and CO2/CH4 affinity-based separations.

  20. Synthesis of cubic Y zeolite using a pulsed microwave heating system

    Directory of Open Access Journals (Sweden)

    Araújo L.R.G. de

    1999-01-01

    Full Text Available Cubic Y zeolite were successfully synthesized using microwave heating for 18 - 25 min, whereas 10 - 50 h are required by hydrothermal heating technique depending upon the lattice Si/Al ratio. To this end, we used a commercial microwave oven modified in order to provide pulsed microwave pumping on the synthesis mixtures. The obtained samples were analyzed by X-ray diffraction, BET surface area and infrared spectroscopy measurements. As a result, we verify that Y zeolite samples obtained from hydrogels containing low aluminum contents, present a good degree of crystallinity and then can be suitable for using in adsorption and catalysis experiments.

  1. Directing factors affecting the synthesis of a MFI-type zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Vinaches, P.; Pergher, S.B.C. [Universidade Federal de Rio Grande do Norte (UFRN), RN (Brazil); Lopes, C.W. [Institute of Chemical Technology, Mumbai (India); Gomez-Hortiguela, L. [Instituto de Catalisis y Petroleoquimica, Madrid (Spain); Finger, P.H.; Silva, B.A. da; Dallago, R.M.; Mignoni, M.L. [Universidade Regional Integrada do Alto Uruguai e das Missoes (URI), Erechim, RS (Brazil)

    2016-07-01

    Full text: Zeolites are crystalline tectosilicates constituted by (TO4) tetrahedra connected through the oxygens of their vertices. The importance of these materials is that their properties differ, due to their variable compositions and structures, leading to the possibility of applying them into different industries, for example, as catalyst in petroleum industry or sensors in quality control. One of the big questions in this area is about the understanding of the chemistry that directs to one or another type of zeolite. Another important question is the search of new zeolitic structures for new applications. One approach to answer both is the study of the structure-directing agents, which are inorganic or organic molecules used in the synthesis of zeolites. New and already-used molecules have been studied within different synthesis conditions and different techniques, as characterization or computational studies. And several attempts of rationalization were and, still, will be performed. In this research, an imidazolium-based compound was studied in hydrothermal zeolite synthesis as organic structure-directing agent (OSDA). The products were obtained with Si/Al or Si/(Al+Zn) compositions, proved by ICP data. X-ray diffractograms showed two different zeolitic types: MFI and TON. It was observed that when Zn was present in the synthesis gel, pure MFI phases were able to appear. But in his absence, the products were all mixtures of MFI and TON zeolites. It was also possible to distinguish both phases by SEM micrographs, as MFI had brick-like shape and TON appeared as needles. The obtained zeolites were stable until 900°C minimum, as tested by a TG/DTG/DSC experiment. To prove that the chosen OSDA directed these structures, a CHN analysis was performed, resulting in integrity of the molecules inside the zeolitic pores and cavities. Finally, a rationale about the location and conformation of the OSDA was needed to understand these experimental results. So, it was

  2. Directing factors affecting the synthesis of a MFI-type zeolite

    International Nuclear Information System (INIS)

    Vinaches, P.; Pergher, S.B.C.; Lopes, C.W.; Gomez-Hortiguela, L.; Finger, P.H.; Silva, B.A. da; Dallago, R.M.; Mignoni, M.L.

    2016-01-01

    Full text: Zeolites are crystalline tectosilicates constituted by (TO4) tetrahedra connected through the oxygens of their vertices. The importance of these materials is that their properties differ, due to their variable compositions and structures, leading to the possibility of applying them into different industries, for example, as catalyst in petroleum industry or sensors in quality control. One of the big questions in this area is about the understanding of the chemistry that directs to one or another type of zeolite. Another important question is the search of new zeolitic structures for new applications. One approach to answer both is the study of the structure-directing agents, which are inorganic or organic molecules used in the synthesis of zeolites. New and already-used molecules have been studied within different synthesis conditions and different techniques, as characterization or computational studies. And several attempts of rationalization were and, still, will be performed. In this research, an imidazolium-based compound was studied in hydrothermal zeolite synthesis as organic structure-directing agent (OSDA). The products were obtained with Si/Al or Si/(Al+Zn) compositions, proved by ICP data. X-ray diffractograms showed two different zeolitic types: MFI and TON. It was observed that when Zn was present in the synthesis gel, pure MFI phases were able to appear. But in his absence, the products were all mixtures of MFI and TON zeolites. It was also possible to distinguish both phases by SEM micrographs, as MFI had brick-like shape and TON appeared as needles. The obtained zeolites were stable until 900°C minimum, as tested by a TG/DTG/DSC experiment. To prove that the chosen OSDA directed these structures, a CHN analysis was performed, resulting in integrity of the molecules inside the zeolitic pores and cavities. Finally, a rationale about the location and conformation of the OSDA was needed to understand these experimental results. So, it was

  3. Zeolite from Cikancra Tasikmalaya, West Java: a review of its properties

    International Nuclear Information System (INIS)

    Estiaty, Lenny Marilyn; Prijatama, Herry; Zulkarnain, Iskandar; Kurnia, Dewi F.; Nurlela, Iis; Goto, Yoshiaki; Szuciya

    2002-01-01

    Samples from natural zeolite deposit in Cikancra village, Tasikmalaya, West Java were investigated for its main properties. Chemical composition was analyzed by X-ray Fluorescence (XRF) and Atomic Absorption Spectrometry (AAS) methods. Mineralogical analyses were carried out using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) methods. Furthermore, continuous flow method was applied for cation exchange capacity (CEC) determination and TG-DTA (thermal gravimetry - differential thermal analysis) was carried out to see the thermal behaviour of the zeolite. Analysis results showed that the chemical composition was dominated by silica and alumina, while other elements like sodium, iron, potassium and titanium were present in lesser amounts. The sellite type was identified as mordenite and depopulation. SEM photographs indicated crystals of mordenite in fibrous or needle forms and platy clinoptilolite. Zeolite Cikancra was also found to have a relatively high exchange capacity with a CEC value of 143.58 meq/100 g. Thermal analysis revealed that water vapor was released from zeolite at temperature of 80.5 to 148 oC with a weight loss of 9.4%. Furthermore, crystal water was released at 481.8 oC , which was indicated with a weight loss of 4.3%. Based on those determined properties, Zeolite Cikancra has the ability to be used for wastewater treatment, agriculture or animal nutrient applications, drying and odorless

  4. Synthesis of Zeolite Materials for Noble Gas Separation

    International Nuclear Information System (INIS)

    Achey, R.; Rivera, O.; Wellons, M.; Hunter, D.

    2017-01-01

    Microporous zeolite adsorbent materials are widely used as a medium for separating gases. Adsorbent gas separation systems can run at ambient temperature and require minimal pressure to flow the input gas stream across the adsorbent bed. This allows for low energy consumption relative to other types of separation systems. Specific zeolites also have a high capacity and selectivity for the gases of interest, leading to compact and efficient separation systems. These characteristics are particularly advantageous for the application of signatures detection for non-proliferation, which often requires portable systems with low power draw. Savannah River National Laboratory currently is the leader in using zeolites for noble gas sampling for non-proliferation detection platforms. However, there is a constant customer need for improved sampling capabilities. Development of improved zeolite materials will lead to improved sampling technology. Microwave-assisted and conventional hydrothermal synthesis have been used to make a variety of zeolites tailored for noble gas separation. Materials characterization data collected in this project has been used to help guide the synthesis of improved zeolite materials. Candidate materials have been down-selected based on highest available surface area, maximum overall capacity for gas adsorption and highest selectivity. The creation of improved adsorbent materials initiated in this project will lead to development of more compact, efficient and effective noble gas collectors and concentrators. The work performed in this project will be used as a foundation for funding proposals for further material development as well as possible industrial applications.

  5. Synthesis of Zeolite Materials for Noble Gas Separation

    Energy Technology Data Exchange (ETDEWEB)

    Achey, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Rivera, O. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wellons, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hunter, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-10-02

    Microporous zeolite adsorbent materials are widely used as a medium for separating gases. Adsorbent gas separation systems can run at ambient temperature and require minimal pressure to flow the input gas stream across the adsorbent bed. This allows for low energy consumption relative to other types of separation systems. Specific zeolites also have a high capacity and selectivity for the gases of interest, leading to compact and efficient separation systems. These characteristics are particularly advantageous for the application of signatures detection for non-proliferation, which often requires portable systems with low power draw. Savannah River National Laboratory currently is the leader in using zeolites for noble gas sampling for non-proliferation detection platforms. However, there is a constant customer need for improved sampling capabilities. Development of improved zeolite materials will lead to improved sampling technology. Microwave-assisted and conventional hydrothermal synthesis have been used to make a variety of zeolites tailored for noble gas separation. Materials characterization data collected in this project has been used to help guide the synthesis of improved zeolite materials. Candidate materials have been down-selected based on highest available surface area, maximum overall capacity for gas adsorption and highest selectivity. The creation of improved adsorbent materials initiated in this project will lead to development of more compact, efficient and effective noble gas collectors and concentrators. The work performed in this project will be used as a foundation for funding proposals for further material development as well as possible industrial applications.

  6. Comparing charcoal and zeolite reflection filters for volatile anaesthetics: A laboratory evaluation.

    Science.gov (United States)

    Sturesson, Louise W; Frennström, Jan O; Ilardi, Marcella; Reinstrup, Peter

    2015-08-01

    A modified heat-moisture exchanger that incorporates a reflecting filter for use with partial rebreathing of exhaled volatile anaesthetics has been commercially available since the 1990 s. The main advantages of the device are efficient delivery of inhaled sedation to intensive care patients and reduced anaesthetic consumption during anaesthesia. However, elevated arterial CO2 values have been observed with an anaesthetic conserving device compared with a conventional heat and moisture exchanger, despite compensation for larger apparatus dead space. The objective of this study is to thoroughly explore the properties of two reflecting materials (charcoal and zeolites). A controlled, prospective, observational laboratory study. Lund University Hospital, Sweden, from December 2011 to December 2012. None. Three filters, with identical volumes, were compared using different volatile anaesthetics at different conditions of temperature and moisture. The filtering materials were charcoal or zeolite. Glass spheres were used as an inert control. Consumption of volatile anaesthetics using different reflecting materials in filters at different conditions regarding temperature and moisture. CO2 reflection by the filtering materials: glass spheres, charcoal or zeolite. Isoflurane consumption in an open system was 60.8 g h(-1). The isoflurane consumption in dry, warm air was 39.8 g h(-1) with glass spheres. Changing to charcoal and zeolite had a profound effect on isoflurane consumption, 11.8 and 10.7 g h(-1), respectively. Heating and humidifying the air as well as the addition of N2O created only minor changes in consumption. The percentage of isoflurane conserved by the charcoal filter was independent of the isoflurane concentration (0.5 to 4.5%). Reflection of sevoflurane, desflurane and halothane by the charcoal filter was similar to reflection of isoflurane. Both charcoal and zeolite filters had CO2 reflecting properties and end-tidal CO2 increased by 3 to 3.7% compared

  7. Antimicrobial properties of zeolite-X and zeolite-A ion-exchanged with silver, copper, and zinc against a broad range of microorganisms.

    Science.gov (United States)

    Demirci, Selami; Ustaoğlu, Zeynep; Yılmazer, Gonca Altın; Sahin, Fikrettin; Baç, Nurcan

    2014-02-01

    Zeolites are nanoporous alumina silicates composed of silicon, aluminum, and oxygen in a framework with cations, water within pores. Their cation contents can be exchanged with monovalent or divalent ions. In the present study, the antimicrobial (antibacterial, anticandidal, and antifungal) properties of zeolite type X and A, with different Al/Si ratio, ion exchanged with Ag(+), Zn(2+), and Cu(2+) ions were investigated individually. The study presents the synthesis and manufacture of four different zeolite types characterized by scanning electron microscopy and X-ray diffraction. The ion loading capacity of the zeolites was examined and compared with the antimicrobial characteristics against a broad range of microorganisms including bacteria, yeast, and mold. It was observed that Ag(+) ion-loaded zeolites exhibited more antibacterial activity with respect to other metal ion-embedded zeolite samples. The results clearly support that various synthetic zeolites can be ion exchanged with Ag(+), Zn(2+), and Cu(2+) ions to acquire antimicrobial properties or ion-releasing characteristics to provide prolonged or stronger activity. The current study suggested that zeolite formulations could be combined with various materials used in manufacturing medical devices, surfaces, textiles, or household items where antimicrobial properties are required.

  8. Application of positron annihilation to the characterization of zeolites

    International Nuclear Information System (INIS)

    Nakanishi, H.; Ujihira, Y.

    1982-01-01

    Positron annihilation lifetime and Doppler-broadening measurements were carried out for synthetic zeolite 13X, SK-40, NH 4 -X, and NH 4 -Y by varying the evacuation temperature in order to study the character of the zeolite cages. Four components of the positron annihilation, derived from the lifetime spectra, were interpreted from the results of the authors' measurements and other studies on zeolites. The o-Ps lifetimes in the cages became longer as the desorption of water molecules proceeded. It was found that some active groups in zeolites interacted with o-Ps and reduced the o-Ps lifetime after all the water molecules had detected. Bronsted acid in the zeolite acted not only as an oxidizer but also as an inhibitor of Ps formation. An attempt was made to estimate the amount of Bronsted acids by the positron lifetime technique. The longest lifetime of 50 ns indicates o-Ps annihilation in a pore with 60 A free diameter, which seems to exist irregularly in the faujasite zeolites. It was found that o-Ps was oxidized in this large cavity

  9. Preparation of zeolite-A/chitosan hybrid composites and their bioactivities and antimicrobial activities

    International Nuclear Information System (INIS)

    Yu, Liang; Gong, Jie; Zeng, Changfeng; Zhang, Lixiong

    2013-01-01

    Zeolite-A/chitosan hybrid composites with zeolite contents of 20–55 wt.% were prepared by in situ transformation of silica/chitosan mixtures in a sodium aluminate alkaline solution through impregnation–gelation–hydrothermal synthesis. The products were characterized by X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mercury penetration porosimetry. Their in vitro bioactivities were examined using as-synthesized and Ca 2+ -exchanged hybrid composites in simulated body fluid (SBF) for hydroxyapatite (HAP) growth. Their antimicrobial activities for Escherichia coli (E. coli) in trypticase soy broth (TSB) were evaluated using Ag + -exchanged hybrid composites. The zeolite-A/chitosan hybrid composites could be prepared as various shapes, including cylinders, plates and thin films. They possessed macropores with pore sizes ranging from 100 to 300 μm and showed compressive mechanical strength as high as 3.2 MPa when the zeolite content was 35 wt.%. Fast growth on the Ca 2+ -exchanged hybrid composites was observed with the highest weight gain of 51.4% in 30 days. The 35 wt.% Ag + -exchanged hybrid composite showed the highest antimicrobial activity, which could reduce the 9 × 10 6 CFU mL −1 E. coli concentration to zero within 4 h of incubation time with the Ag + -exchanged hybrid composite amount of 0.4 g L −1 . The bioactivity and antimicrobial activity could be combined by ion-exchanging the composites first with Ca 2+ and then with Ag + . These zeolite-A/chitosan hybrid composites have potential applications on tissue engineering and antimicrobial food packaging. - Graphical abstract: Zeolite A/chitosan hybrid composites were prepared by in situ transformation of precursors in the chitosan matrix, which possess macroporous structures and exhibit superior bioactivity and antimicrobial activity and potential biomedical application. Highlights: • Zeolite A

  10. Preparation of zeolite-A/chitosan hybrid composites and their bioactivities and antimicrobial activities

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Liang; Gong, Jie [State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009 (China); Zeng, Changfeng [College of Mechanic and Power Engineering, Nanjing University of Technology, Nanjing 210009 (China); Zhang, Lixiong, E-mail: lixiongzhang@yahoo.com [State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009 (China)

    2013-10-15

    Zeolite-A/chitosan hybrid composites with zeolite contents of 20–55 wt.% were prepared by in situ transformation of silica/chitosan mixtures in a sodium aluminate alkaline solution through impregnation–gelation–hydrothermal synthesis. The products were characterized by X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mercury penetration porosimetry. Their in vitro bioactivities were examined using as-synthesized and Ca{sup 2+}-exchanged hybrid composites in simulated body fluid (SBF) for hydroxyapatite (HAP) growth. Their antimicrobial activities for Escherichia coli (E. coli) in trypticase soy broth (TSB) were evaluated using Ag{sup +}-exchanged hybrid composites. The zeolite-A/chitosan hybrid composites could be prepared as various shapes, including cylinders, plates and thin films. They possessed macropores with pore sizes ranging from 100 to 300 μm and showed compressive mechanical strength as high as 3.2 MPa when the zeolite content was 35 wt.%. Fast growth on the Ca{sup 2+}-exchanged hybrid composites was observed with the highest weight gain of 51.4% in 30 days. The 35 wt.% Ag{sup +}-exchanged hybrid composite showed the highest antimicrobial activity, which could reduce the 9 × 10{sup 6} CFU mL{sup −1}E. coli concentration to zero within 4 h of incubation time with the Ag{sup +}-exchanged hybrid composite amount of 0.4 g L{sup −1}. The bioactivity and antimicrobial activity could be combined by ion-exchanging the composites first with Ca{sup 2+} and then with Ag{sup +}. These zeolite-A/chitosan hybrid composites have potential applications on tissue engineering and antimicrobial food packaging. - Graphical abstract: Zeolite A/chitosan hybrid composites were prepared by in situ transformation of precursors in the chitosan matrix, which possess macroporous structures and exhibit superior bioactivity and antimicrobial activity and potential biomedical

  11. LiCa{sub 4}Si{sub 4}N{sub 8}F and LiSr{sub 4}Si{sub 4}N{sub 8}F. Nitridosilicate fluorides with a BCT-zeolite-type network structure

    Energy Technology Data Exchange (ETDEWEB)

    Horky, Katrin; Schnick, Wolfgang [Department of Chemistry, Inorganic Solid-State, Chemistry, University of Munich (LMU), Butenandtstrasse 5-13, 81377, Munich (Germany)

    2017-02-17

    LiCa{sub 4}Si{sub 4}N{sub 8}F and LiSr{sub 4}Si{sub 4}N{sub 8}F were synthesized from Si{sub 3}N{sub 4}, LiNH{sub 2}, CaH{sub 2}/SrH{sub 2}, and LiF through a metathesis reaction in a radiofrequency furnace. The crystal structures of both compounds were solved and refined on the basis of single-crystal X-ray diffraction data [LiCa{sub 4}Si{sub 4}N{sub 8}F: P2{sub 1}/c (no. 14), a = 10.5108(3), b = 9.0217(3), c = 10.3574(3) Aa, β = 117.0152(10) , R{sub 1} = 0.0422, wR{sub 2} = 0.0724, Z = 4; LiSr{sub 4}Si{sub 4}N{sub 8}F: P4nc (no. 104), a = 9.3118(4), b = 9.3118(4), c = 5.5216(2) Aa, R{sub 1} = 0.0160, wR{sub 2} = 0.0388, Z = 2]. The silicate substructure of both compounds is built up of vertex-sharing SiN{sub 4} tetrahedra, thereby forming a structure analogous to the BCT zeolite with Ca{sup 2+}/Sr{sup 2+}, Li{sup +}, and F{sup -} ions filling the voids. The crystal structure of LiSr{sub 4}Si{sub 4}N{sub 8}F is homeotypic with that of Li{sub 2}Sr{sub 4}Si{sub 4}N{sub 8}O as it exhibits the same zeolite-type [SiN{sub 2}]{sup 2-} framework, but incorporates LiF instead of Li{sub 2}O. In contrast to the respective Sr compound, LiCa{sub 4}Si{sub 4}N{sub 8}F shows a distortion of the BCT-zeolite-type network as well as an additional site for F. Both F sites in LiCa{sub 4}Si{sub 4}N{sub 8}F exhibit different coordination spheres to LiSr{sub 4}Si{sub 4}N{sub 8}F. The title compounds are the first reported lithium alkaline-earth nitridosilicates containing fluorine. The crystal structures were confirmed by lattice-energy calculations (MAPLE), energy-dispersive X-ray spectroscopy (EDX) measurements, and powder X-ray diffraction. IR spectra confirmed the absence of N-H bonds. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. A general method to incorporate metal nanoparticles in zeolites and zeotypes

    DEFF Research Database (Denmark)

    2015-01-01

    Disclosed herein is a method for producing a zeolite, zeolite-like or zeotype structure with selective formation of metal, metal oxide or metal sulphide nanoparticles and/or clusters inside the zeolite, zeolite-like or zeotype structure.......Disclosed herein is a method for producing a zeolite, zeolite-like or zeotype structure with selective formation of metal, metal oxide or metal sulphide nanoparticles and/or clusters inside the zeolite, zeolite-like or zeotype structure....

  13. Ammonium removal from high-strength aqueous solutions by Australian zeolite

    DEFF Research Database (Denmark)

    Wijesinghe, D. Thushari N; Dassanayake, Kithsiri B.; Sommer, Sven G.

    2016-01-01

    Removal of ammonium nitrogen (NH4 +-N) particularly from sources which are highly rich in nitrogen is important for addressing environmental pollution. Zeolites, aluminosilicate minerals, are commonly used as commercial adsorbents and ion-exchange medium in number of commercial applications due...... to its high adsorption capacity of ammonium (NH4 +). However, detailed investigations on NH4 + adsorption and ion exchange capacities of Australian natural zeolites are rare, particularly under higher NH4 + concentrations in the medium. Therefore, this study was conducted to determine NH4 + adsorption...... characteristics of Australian natural zeolites at high NH4 + concentrations with and without other chemical compounds in an aqueous solution. Results showed that initial NH4 + concentration, temperature, reaction time, and pH of the solution had significant effects on NH4 + adsorption capacity of zeolite...

  14. Zeolites: promising candidates for drug delivery systems (DDSs)

    OpenAIRE

    Vilaça, Natália; Amorim, Ricardo; Baltazar, Fátima; Fonseca, António Manuel; Neves, Isabel C.

    2012-01-01

    [Excerpt] The aim of controlled drug delivery systems (DDSs) is to administer the necessary amount of drug safely and effectively to specific sites in the human body and to regulate the temporal drug profile for maximum therapeutic benefits.[1] Zeolites are crystalline aluminosilicates solids with very regular microporous structures and they have been recently considered for medical use due to their biological properties and stability in biological environments.[1,2] The large variety in ...

  15. Zeolite-templated carbon replica: a grand canonical Monte-Carlo simulation study

    International Nuclear Information System (INIS)

    Roussel, Th.; Pellenq, R.J.M.; Bichara, Ch.; Gadiou, R.; Didion, A.; Vix-Guterl, C.; Gaslain, F.; Parmentier, J.; Valtchev, V.; Patarin, J.

    2005-01-01

    Microporous carbon materials are interesting for several applications such as hydrogen storage, catalysis or electrical double layer capacitors. The development of the negative templating method to obtain carbon replicas from ordered templates, has lead to the synthesis of several new materials which have interesting textural properties, attractive for energy storage. Among the possible templates, zeolites can be used to obtain highly microporous carbon materials. Nevertheless, the phenomena involved in the replica synthesis are not fully understood, and the relationships between the structure of the template, the carbon precursor and the resulting carbon material need to be investigated. Experimental results for carbon zeolite-templated nano-structures can be found in a series of papers; see for instance ref. [1] in which Wang et al describe a route to ultra-small Single Wall Carbon Nano-tubes (SWNTs) using the porosity of zeolite AlPO 4 -5. After matrix removal, the resulting structure is a free-standing bundle of 4 Angstroms large nano-tubes. However, it is highly desirable to obtain an ordered porous carbon structure that forms a real 3D network to be used for instance in gas storage applications. Carbon replica of faujasite and EMT zeolites can have these properties since these zeolites have a 3D porous network made of 10 Angstroms cages connected to each other through 7 Angstroms large windows. The first step of this study was to generate a theoretical carbon replica structure of various zeolites (faujasite, EMT, AlPO 4 -5, silicalite). For this purpose, we used the Grand Canonical Monte-Carlo (GCMC) technique in which the carbon-carbon interactions were described within the frame of a newly developed Tight Binding approach and the carbon-zeolite interactions assumed to be characteristic of physisorption. The intrinsic stability of the subsequent carbon nano-structures was then investigated after mimicking the removal of the inorganic phase by switching

  16. Characterisation of poly(methacrylates) formed inside zeolites by gamma irradiation

    International Nuclear Information System (INIS)

    Kwiatkowski, J.; Whittaker, A.K.

    1996-01-01

    Full text: Inclusion polymerisation was first developed in the second half of the 50's as an alternative to Ziegler-Natta co-ordination polymerisation to obtain highly stereo-regular polymers. Inclusion polymerisation was performed in organic clathrates such as thio-urea channels. However the channels are only stable when formed around the monomer. This means there is a specific concentration of monomer, namely saturation, for which the host/channel system can exist. There is also a limited number of monomers which are suitable for use with a given clathrate and the channel dimension is not usually a variable parameter for a given monomer/clathrate system. One exception is Tris(o-phenolenedioxy)cycotriphosphazene. Initiation of the monomer can be easily achieved by high energy irradiation and many of the polymers obtained show considerable chemical and steric regularity. For example poly (2,3 -dimethylbutadiene) obtained by polymerisation in a thio-urea inclusion compound has only the 1,4 trans structure and is highly crystalline. The restriction on the number of clathrate and monomer systems has lead us to investigate the use of zeolites as hosts for inclusion compounds. Zeolites exist independently of any included guest compound. They are aluminosilicate compounds whose structures form molecular-dimension channels and belong to a class of materials known as molecular sieves. Channel structures can be in 1,2 or 3 dimensions. The structural aluminium in the zeolite creates a negative charge on the lattice which is balanced by cations. In this study we have diffused methyl and ethyl methacrylate into Na-ZSM5, Beta, Y and Mordenite zeolites. The samples where irradiated under vacuum and then extracted. The structures of the exrtracted polymer have been characterized by GPC, NMR and DSC The results will be correlated as a function of the channel size of the zeolite and compared to the bulk system

  17. Absorption behavior of iodine from molten salt mixture to zeolite

    International Nuclear Information System (INIS)

    Sugihara, Kei; Terai, Takayuki; Suzuki, Akihiro; Uozumi, Koichi; Tsukada, Takeshi; Koyama, Tadafumi

    2011-01-01

    Behavior of zeolite to absorb anion fission product (FP) elements in molten LiCl-KCl eutectic salt was studied using iodine. At first, zeolite-A was selected as the suitable type of zeolite among zeolite-A (powder), zeolite-X (powder and granule), and zeolite-Y (powder) through experiments to heat the zeolite together with LiCl-KCl-KI salt, respectively. As the next step, similar experiments to immerse zeolite-A in molten LiCl-KCl-KI salt containing various concentrations of iodine were performed. The affinity of iodine to zeolite was evaluated using the separation factor (SF) value, which is defined as [I/(I+Cl) mol ratio in zeolite after immersion]/[I/(I+Cl) mol ratio in salt after immersion]. Since the SF values ranged between 4.3 and 9.1, stronger affinity of iodine than chlorine to zeolite-A was revealed. Finally, influence of co-existing cation FPs was studied by similar absorption experiments in LiCl-KCl-KI salt containing CsCl, SrCl 2 , or NdCl 3 . The SF values were less than those obtained in the LiCl-KCl-KI salt and this can be ascribed to the sharing of inner space of zeolite cage among absorbed cations and anions. (author)

  18. Multicomponent liquid ion exchange with chabazite zeolites

    International Nuclear Information System (INIS)

    Robinson, S.M.; Arnold, W.D. Jr.; Byers, C.W.

    1993-10-01

    In spite of the increasing commercial use of zeolites for binary and multicomponent sorption, the understanding of the basic mass-transfer processes associated with multicomponent zeolite ion-exchange systems is quite limited. This study was undertaken to evaluate Na-Ca-Mg-Cs-Sr ion exchange from an aqueous solution using a chabazite zeolite. Mass-transfer coefficients and equilibrium equations were determined from experimental batch-reactor data for single and multicomponent systems. The Langmuir isotherm was used to represent the equilibrium relationship for binary systems, and a modified Dubinin-Polyani model was used for the multicomponent systems. The experimental data indicate that diffusion through the microporous zeolite crystals is the primary diffusional resistance. Macropore diffusion also significantly contributes to the mass-transfer resistance. Various mass-transfer models were compared to the experimental data to determine mass-transfer coefficients. Effective diffusivities were obtained which accurately predicted experimental data using a variety of models. Only the model which accounts for micropore and macropore diffusion occurring in series accurately predicted multicomponent data using single-component diffusivities. Liquid and surface diffusion both contribute to macropore diffusion. Surface and micropore diffusivities were determined to be concentration dependent

  19. AKTIVASI ZEOLIT ALAM SEBAGAI ADSORBEN PADA ALAT PENGERING BERSUHU RENDAH

    Directory of Open Access Journals (Sweden)

    Laeli Kurniasari

    2012-04-01

    Full Text Available ACTIVATION OF NATURAL ZEOLITE AS AN ADSORBENT FOR LOW TEMPERATURE DRYING SYSTEM. Drying is one process which is used in many industries, especially in food product. The process usually still has low energy efficiency and can make food deterioration because of the usage of high temperature. One alternative in drying technology is the use of zeolite as a water vapor adsorbent. This kind of drying method make it possible to operate in lower temperature, hence it will be suitable for heat sensitive product. Natural zeolit can be one promising adsorbent since it is spreadly abundant in Indonesia. Natural zeolite must be activated first before used, in order to get zeolite with high adsorption capacity. Activation process in natural zeolite will change the Si/Al ratio, polarity, and affinity of zeolite toward water vapor and also increase the porosity. Activation of natural zeolite can be done with two methods, chemical activation use NaOH and physical activation use heat. In the activation using NaOH, natural zeolite is immersed with NaOH solution 0.5-2N in 2 hour with temperature range 60-900C. The process is continued with the drying of zeolite in oven with 1100C for 4 hours. While in heat treatment, zeolit is heated into 200-5000C in furnace for 2-5 hours. SEM analysis is used to compare the change in zeolite morphology before and after each treatment, while to know the adsorption capacity of zeolite, the analyses were done in many temperature and relative humidity. Result gives the best condition in NaOH activation is NaOH 1N and temperature 700C, with water vapor loading is 0.171 gr/gr adsorbent. In heat treatment, the best condition is 3000C and 3 hours with loading 0.137 gr water vapor/gr adsorbent.  Pengeringan merupakan salah satu proses yang banyak digunakan pada produk pangan. Proses ini umumnya menyebabkan kerusakan pada bahan pangan, disamping masih rendahnya efisiensi energi. Salah satu alternatif pada proses pengeringan yaitu

  20. Removal of cesium radioisotopes from solutions using granulated zeolites

    International Nuclear Information System (INIS)

    Bronic, J.; Subotic, B.

    1991-01-01

    The influence of type of zeolite and the flow rate of solution through the column on the removal efficiency of radioactive cesium ions from solution has been investigated. The analysis of the change in the concentration of cesium ions in the solutions and distribution of cesium ions in the column fillings (granulated zeolites), after passing the solutions through the columns filled with various granulated zeolites (zeolite 4A, zeolite 13X, synthetic mordenite) was performed. On the basis of the results of this study, the conditions for the most efficient removal of cesium ions from solutions have been discussed. (author) 35 refs.; 9 figs.; 1 tab

  1. Zeolites and clays behavior in presence of radioactive solutions

    International Nuclear Information System (INIS)

    Carrera Garcia, L.M.

    1991-01-01

    Natural aluminosilicates have found application as selective ion exchangers for radioactive cations, present in liquid wastes arising from nuclear facilities. Among severals cations and complex mixtures of them, Co is a common constituent of liquid radioactive wastes. Two types of zeolites (Y zeolite, and natural mexican erionite), and two types of clays (natural bentonite, and Al-expanded bentonite (Al-B) were used. Previous to the experiments, the zeolites and the natural bentonite were stabilized to their respective Na + form using 5N NaCl solution. 2Na + → 60 Co 2+ ion exchange kinetics in zeolites and clays was followed by gamma spectrometry using a NaCl-Co(NO 3 ) 2 isonormal solution (0.1N) labeled with 60 Co-Co(NO 3 ) 2 (100 μ Ci). Before and after experiments, the structural changes in the cristallinity of aluminosilicates were determined by X-ray diffraction. XRD analyzes show that the cristallinity of the aluminosilicates was not affected by ion exchange. After Co exchange the cell parameters were determined in all samples. The efficiency of zeolites, natual clays and expanded clays to remove cobalt ions from solutions depends on the ion echange capacity of the material. Results for long contacts time, 18 days, show that Co is more effectively removed by Y zeolite ( 4.07 wt %), followed by erionite (3.09 wt %), then bentonite ( 2.36 wt %) and finally expanded bentonite ( 0.70 wt %). In Y zeolite an unusual fast soportion uptake of 4.51 % wt Co was observed followed by a desorption process to 4.07 %. This effect is due to the different hydration degree of zeolites during the contact time between the zeolite and the 60 Co solution. In erionite the exchange is lower than in Y-zeolite, frist because the Si/Al ratio is higher for erionite than for Y-zeolite and second because K ions in erionite cannot be exchanged during the stabilization of erionite in 5N NaCl solution. The low exchange in expanded bentonite was expected because its cation exchange

  2. Immobilization of krypton-85 in zeolite 5A and porous glass

    International Nuclear Information System (INIS)

    Christensen, A.B.; DelDebbio, J.A.; Knecht, D.A.; Tanner, J.E.; Cossel, S.C.

    1981-12-01

    This report demonstrates the technical and economic feasibility for immobilizing krypton-85 by high pressure/high temperature encapsulation in zeolite 5A or thirsty Vyco porous glass. Data are presented to show how process conditions affect the encapsulation and how to compact the zeolite beads with glass frit or other additives to form a fused mass with low dispersibility potential. Krypton specific loadings of 30 and 50 m 3 STP gas per m 3 solid are readily achieved at 100 MPa in porous glass at 900 0 C and zeolite 5A at 700 0 C. Krypton is encapsulated by a sintering process where the porous glass and zeolite 5A voids are sealed. With zeolite 5A, the initial water concentration has a catalytic effect on the sintering, resulting in a transition from crystalline zeolite 5A to an amorphous aluminosilicate. Krypton leakage experiments are used to predict leakage rates from glass or zeolite of less than 0.03% and 0.3% for 10-y storage at 300 and 400 0 C, respectively. Heating the loaded zeolite at 600 to 700 0 C for 4 h removes 0.1% of the total krypton which is loosely held and reduces the subsequent leakage rates at 300 to 400 0 C. Zeolite 5A is chosen as the preferred material to immobilize krypton-85. A preconceptual design and cost estimate is given for a facility to encapsulate 110% of the krypton production of a 2000 metric ton of heavy metal per year reprocessing plant, or 230 m 3 of gas containing 19 MCi of krypton-85. A hot isostatic press (HIP) with an isolated work zone of 8 or 16 L capacity is required to operate for 600 or 300 cycles per year, respectively. Existing HIP technology uses work zones from 1 to 3500 L capacity at similar production rates. A preliminary safety evaluation shows that an incredible worst case accident could be contained and the maximum off-site dose would be well below accident protective action guidance levels

  3. Elimination of Escherichia coli and Salmonella in Clam by Using Zeolite in a Station of Depuration.

    Science.gov (United States)

    Gdoura, Morsi; Sellami, Hanen; Khannous, Lamia; Ketata, Najib; Neila, Idriss Ben; Traore, Al Ibrahim; Chekir, Zouhair; Gdoura, Radhouane

    2017-09-01

      The application of natural zeolite for water and wastewater treatment has been carried out and is still a promising technique in environmental cleaning processes. Natural zeolite can be used to improve the purification process of clams (Ruditapes decussatus). Thus, our study aimed at improving the clam purification system in order to reduce Escherichia coli and eliminate Salmonella in samples artificially contaminated with this bacterium using a natural zeolite to replace the biological filter. The results showed that zeolite used in a depuration system improved the clam purification process. Moreover, natural zeolite exhibited high performance in the adsorption of bacteria and allowed to reduce the Escherichia coli abundance in 24 h, thus ensuring purified clams conformity with the ISO 16649-3 standard. These results indicate the beneficial effects of using zeolite in the adsorption of bacteria and the reduction in the abundance of Escherichia coli and set the Salmonella from marine organisms.

  4. Extreme Flexibility in a Zeolitic Imidazolate Framework

    DEFF Research Database (Denmark)

    Wharmby, M.T.; Henke, S.; Bennett, T.D.

    2015-01-01

    Desolvated zeolitic imidazolate framework ZIF-4(Zn) undergoes a discontinuous porous to dense phase transition on cooling through 140 K, with a 23% contraction in unit cell volume. The structure of the non-porous, low temperature phase was determined from synchrotron X-ray powder diffraction data...

  5. Studi Hubungan Struktur Mikro dan Keaktifan Zeolit Alam Akibat Proses Pengasaman

    Directory of Open Access Journals (Sweden)

    Made Cuaca Vahindra Suriawan

    2012-11-01

    Full Text Available Natural zeolite is known as metal pollutant adsorbent in industrial waste treatment. As initial study for utilization ofnatural zeolite from Indonesia for metal pollutants adsorbent in liquid waste, then the physical properties should berecognized first. Activation is the first step in order to the natural zeolite able to adsorb the metal pollutants in the waste.One method to activate is by applying acid solution such as sulfuric acid (H2SO4 to activate the natural zeolite. The purposeof this research is to observe the change on microstructure of natural zeolite obtained from the mining at Tasikmalaya, WestJava, Indonesia due to chemical activated, to be compared to one without chemical activation. The variation of concentrationof H2SO4 namely: 2 4 , 6, 8, and 10 % , with 30 minutes soaking time , in a room temperatur. The microstructure then isobserved by using optical microscope following standard for ceramography. The change in microstructure then is analyzedand studied to be related with the ability of natural zeolite in adsorb the metal pollutant. The level activity of the zeolite canbe recognized by measuring its porosity.

  6. Zeolite Vitrification Demonstration Program nonradioactive-process operations summary

    International Nuclear Information System (INIS)

    Bryan, G.H.; Knox, C.A.; Goles, R.G.; Ethridge, L.J.; Siemens, D.H.

    1982-09-01

    The Submerged Demineralizer System is a process developed to decontaminate high-activity level water at Three Mile Island by sorbing the activity (primarily Cs and Sr) onto beds of zeolite. Pacific Northwest Laboratory's Zeolite Vitrification Demonstration Program has the responsibility of demonstrating the full-scale vitrification of this zeolite material. The first phase of this program has been to develop a glass formulation and demonstrate the vitrification process with the use of nonradioactive materials. During this phase, four full-scale nonradioactive demonstration runs were completed. The same zeolite mixture being used in the SDS system was loaded with nonradioactive isotopes of Cs and Sr, dried, blended with glass-forming chemicals and fed to a canister in an in-can melter furnace. During each run, the gaseous effluents were sampled. After each run, glass samples were removed and analyzed

  7. Removal of excess nutrients by Australian zeolite during anaerobic digestion of swine manure.

    Science.gov (United States)

    Wijesinghe, D Thushari N; Dassanayake, Kithsiri B; Scales, Peter; Sommer, Sven G; Chen, Deli

    2018-03-21

    The objective of this study was to investigate the feasibility of using natural and NaCl-treated Australian zeolites to simultaneously remove excess nutrients from anaerobically digested swine manure. Ion adsorption and desorption properties of Australian zeolite during the anaerobic digestion of swine manure were investigated. Two experiments were conducted: the first was an adsorption experiment with multi-component solutions that corresponded with the ionic composition of swine manure digestates. The second experiment determined the effects of zeolite dose rates during anaerobic digestion of swine manure on the removal of N, P and K from solution. Adsorption isotherms confirmed selectivity for K + over NH 4 + by Australian natural and sodium zeolites. Therefore, NH 4 + removal was considerably reduced when there was simultaneous K + uptake. Natural zeolite desorbed more Ca 2+ during K + and NH 4 + adsorption than sodium zeolite. The ion exchange reaction was independent of the presence of P. P removal was very dependent on the pH of the medium. Natural Australian zeolite was shown to be a potential sorbent for the removal of NH 4 + , K + and P during the anaerobic digestion of swine manure. However, the application of high concentrations of zeolite at higher pH values (> 7.5) might not be appropriate for anaerobic digestion, because zeolite desorbed more Ca 2+ ions into the solution at the higher doses of zeolite and then availability of P for microbial growth might be reduced as a result of PO 4 3- precipitation with Ca 2+ at the higher pH.

  8. Polyphosphates substitution for zeolite to in detergents

    International Nuclear Information System (INIS)

    Restrepo V, Gloria M.; Ocampo G, Aquiles; Saldarriaga M, Carlos

    1996-01-01

    The detergents, as well as the cleaning products, contain active ingredients that are good to increase their efficiency and some of them, as the sodium Tripoli-phosphate (TPF), they have turned out to be noxious for the environment. The zeolites use in the formulation of detergents has grown substantially since they fulfill the same function of the TPF and they have been recommended ecologically as substitutes from these when not being polluting. The objective of this work is to obtain a zeolite with appropriate characteristics for its use in the formulation of detergents, reproducing those of the zeolites used industrially. The zeolite synthesis is studied 4A starting from hydro-gels of different composition, varying the operation conditions and using two raw materials: (sodium meta-silicate, commercial degree and metallic aluminum) and clay type kaolin like silica source and aluminum It is looked for to get a product of beveled cubic morphology, or spherical, with glass size between 1 and 3 microns and that it possesses good capacity of conical exchange. Since the capacity and speed of ionic exchange is influenced by the particle size, time of contact and temperature, experimentation conditions settle down to measure the exchange of ions calcium and magnesium in watery solutions that they simulate the real situation of a laundry process in the country. This way the ability of the zeolite 4A obtained to diminish the concentration of these ions in the laundry waters is evaluated and its possibilities like component in the formulation of detergents non-phosphatates. Of the synthesized zeolites, the best in agreement is chosen with chemical properties as ionic and physical exchange capacity as crystalline, particle size and color, to prepare a detergent in which the polyphosphates is substituted partial and totally for the synthesized zeolite

  9. Structure modification of natural zeolite for waste removal application

    Science.gov (United States)

    Widayatno, W. B.

    2018-03-01

    Tremendous industrialization in the last century has led to the generation of huge amount of waste. One of the recent hot research topics is utilizing any advance materials and methods for waste removal. Natural zeolite as an inexpensive porous material with a high abundance holds a key for efficient waste removal owing to its high surface area. However, the microporous structure of natural zeolite hinders the adsorption of waste with a bigger molecular size. In addition, the recovery of natural zeolite after waste adsorption into its pores should also be considered for continuous utilization of this material. In this study, the porosity of natural zeolite from Tasikmalaya, Indonesia, was hydrothermally-modified in a Teflon-lined autoclave filled with certain pore directing agent such as distilled water, KOH, and NH4OH to obtain hierarchical pore structure. After proper drying process, the as-treated natural zeolite is impregnated with iron cation and heat-treated at specified temperature to get Fe-embedded zeolite structure. XRD observation is carried out to ensure the formation of magnetic phase within the zeolite pores. The analysis results show the formation of maghemite phase (γ-Fe2O3) within the zeolite pore structure.

  10. Synthesis of zeolite-zeolite (mfi-fau) composite catalysts for the isomerization of n-hexane

    International Nuclear Information System (INIS)

    Ghouri, A.S; Usman, M.R.

    2017-01-01

    In this research work, the aim is to produce a relatively novel zeolite-zeolite (MFI-FAU) composite catalyst having better potential of catalyzing isomerization of lighter hydrocarbons such as light naphtha, n-pentane, n-hexane, n-heptane and mixture thereof. A series of zeolite-zeolite (MFI-FAU) composite catalysts have been synthesized by incorporating previous practices and techniques. The catalytic performance of as-synthesized zeolite-zeolite (MFI-FAU) composite catalysts have been investigated by isomerizing 95% pure n-hexane in conventional fixed bed flow micro-reactor at temperature 200-240 ºC under atmospheric pressure. In order to explore chemical and physical features of zeolite-zeolite (MFI-FAU) composite catalysts, they are examined and characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectrometry (EDX), N2 adsorption-desorption measurements (BET, BJH, t-plot measurements) and Fourier transform infrared (FTIR) spectroscopy equipped with attenuated total reflectance (ATR) arrangements. (author)

  11. Hydrogen Selective Exfoliated Zeolite Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Tsapatsis, Michael [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Daoutidis, Prodromos [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Elyassi, Bahman [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Lima, Fernando [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Iyer, Aparna [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Agrawal, Kumar [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Sabnis, Sanket [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science

    2015-04-06

    The objective of this project was to develop and evaluate an innovative membrane technology at process conditions that would be representative of Integrated Gasification Combined Cycle (IGCC) advanced power generation with pre-combustion capture of carbon dioxide (CO2). This research focused on hydrogen (H2)-selective zeolite membranes that could be utilized to separate conditioned syngas into H2-rich and CO2-rich components. Both experiments and process design and optimization calculations were performed to evaluate the concept of ultra-thin membranes made from zeolites nanosheets. In this work, efforts in the laboratory were made to tackle two fundamental challenges in application of zeolite membranes in harsh industrial environments, namely, membrane thickness and membrane stability. Conventional zeolite membranes have thicknesses in the micron range, limiting their performance. In this research, we developed a method for fabrication of ultimately thin zeolite membranes based on zeolite nanosheets. A range of layered zeolites (MWW, RWR, NSI structure types) suitable for hydrogen separation was successfully exfoliated to their constituent nanosheets. Further, membranes were made from one of these zeolites, MWW, to demonstrate the potential of this group of materials. Moreover, long-term steam stability of these zeolites (up to 6 months) was investigated in high concentrations of steam (35 mol% and 95 mole%), high pressure (10 barg), and high temperatures (350 °C and 600 °C) relevant to conditions of water-gas-shift and steam methane reforming reactions. It was found that certain nanosheets are stable, and that stability depends on the concentration of structural defects. Additionally, models that represent a water-gas-shift (WGS) membrane reactor equipped with the zeolite membrane were developed for systems studies. These studies had the aim of analyzing the effect of the membrane reactor integration into IGCC plants

  12. Hydrothermal preparation of zeolite Li-A and ion exchange properties of Cs and Sr in salt waste

    International Nuclear Information System (INIS)

    Lee, S. H.; Kim, J. G.; Lee, J. H.; Kim, J. H.

    2005-01-01

    An advanced spent fuel management process that were based on Li reduction of the oxide spent fuel to a metallic form will generate a LiCl waste. Zeolite A has been reported as a promising immobilization medium for waste salt with CsCl and SrCl 2 . However, Sodium is accumulated as an ionic form (Na + -ion) in molten salt during ion exchange step between Na + -ion in zeolite A and Li + -ion in the molten salt. Therefore, zeolite Na-A need to be replaced by the Li-type zeolite for recycling the salt waste by removing the Cs and Sr ions. In this study, the hydrothermal preparation of zeolite Li-A was performed in 350ml pressure vessel by P. Norby method. The preparation characteristics of zeolite Li-A was investigated. And the ion exchange properties of Cs and Sr in molten LiCl salt were investigated under the condition of 923K using zeolite 4A and prepared zeolite Li-A

  13. Small-angle x-ray scattering from the early growth stages of zeolite A

    International Nuclear Information System (INIS)

    Singh, P.; White, J.

    1999-01-01

    Full text: The work presented here with the use of SAXS (Small-Angle X-ray Scattering) is in attempt to identify a different paradigm to the organic template induced crystallization of zeolites, in particular zeolite 'A'. The reactions have been followed by small angle X-ray scattering from the time of first mixing of the constituents until the final separation of zeolite A crystals. The processes happening during the growth are expected to follow successive transformation of intermediate metastable phases until the formation of thermodynamically most stable phase and scattering signatures from these developments may be useful for extracting interesting information about the processes in situ. The scattering functions from a synthesis system of zeolite 'A' at the initial and final stage of reaction are presented.The different growth processes of zeolite 'A' from different silicate and aluminium sources are found. The differences are attributed to different rate limiting steps in the syntheses

  14. Design and characterization of chitosan/zeolite composite films — Effect of zeolite type and zeolite dose on the film properties

    International Nuclear Information System (INIS)

    Barbosa, Gustavo P.; Debone, Henrique S.; Severino, Patrícia; Souto, Eliana B.; Silva, Classius F. da

    2016-01-01

    Chitosan films can be used as wound dressings for the treatment of chronic wounds and severe burns. The antimicrobial properties of these films may be enhanced by the addition of silver. Despite the antimicrobial activity of silver, several studies have reported the cytotoxicity as a factor limiting its biomedical applications. This problem may, however, be circumvented by the provision of sustained release of silver. Silver zeolites can be used as drug delivery platforms to extend the release of silver. The objective of this study was to evaluate the addition of clinoptilolite and A-type zeolites in chitosan films. Sodium zeolites were initially subjected to ion-exchange in a batch reactor. Films were prepared by casting technique using a 2% w/w chitosan solution and two zeolite doses (0.1 or 0.2% w/w). Films were characterized by thermal analysis, color analysis, scanning electron microscopy, X-ray diffraction, and water vapor permeation. The results showed that films present potential for application as dressing. The water vapor permeability is one of the main properties in wound dressings, the best results were obtained for A-type zeolite/chitosan films, which presented a brief reduction of this property in relation to zeolite-free chitosan film. On the other hand, the films containing clinoptilolite showed lower water vapor permeation, which may be also explained by the best distribution of the particles into the polymer which also promoted greater thermal resistance. - Highlights: • Zeolite/chitosan composite films were prepared by casting technique. • Micrographs showed slight difference according to the content and A-type zeolite. • The barrier properties of the films were suitable to the dressing application. • Film characterization suggested that zeolites interacted with the chitosan chain.

  15. Design and characterization of chitosan/zeolite composite films — Effect of zeolite type and zeolite dose on the film properties

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Gustavo P.; Debone, Henrique S. [Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema (Brazil); Severino, Patrícia [Universidade Tiradentes, Instituto de Tecnologia e Pesquisa, Aracaju (Brazil); Souto, Eliana B. [Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra (FFUC), Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra (Portugal); Center for Neuroscience and Cell Biology & Institute for Biomedical Imaging and Life Sciences (CNC-IBILI), University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra (Portugal); Silva, Classius F. da, E-mail: cfsilva@unifesp.br [Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema (Brazil)

    2016-03-01

    Chitosan films can be used as wound dressings for the treatment of chronic wounds and severe burns. The antimicrobial properties of these films may be enhanced by the addition of silver. Despite the antimicrobial activity of silver, several studies have reported the cytotoxicity as a factor limiting its biomedical applications. This problem may, however, be circumvented by the provision of sustained release of silver. Silver zeolites can be used as drug delivery platforms to extend the release of silver. The objective of this study was to evaluate the addition of clinoptilolite and A-type zeolites in chitosan films. Sodium zeolites were initially subjected to ion-exchange in a batch reactor. Films were prepared by casting technique using a 2% w/w chitosan solution and two zeolite doses (0.1 or 0.2% w/w). Films were characterized by thermal analysis, color analysis, scanning electron microscopy, X-ray diffraction, and water vapor permeation. The results showed that films present potential for application as dressing. The water vapor permeability is one of the main properties in wound dressings, the best results were obtained for A-type zeolite/chitosan films, which presented a brief reduction of this property in relation to zeolite-free chitosan film. On the other hand, the films containing clinoptilolite showed lower water vapor permeation, which may be also explained by the best distribution of the particles into the polymer which also promoted greater thermal resistance. - Highlights: • Zeolite/chitosan composite films were prepared by casting technique. • Micrographs showed slight difference according to the content and A-type zeolite. • The barrier properties of the films were suitable to the dressing application. • Film characterization suggested that zeolites interacted with the chitosan chain.

  16. Surfactant-modified zeolites as permeable barriers to organic and inorganic groundwater contaminants

    International Nuclear Information System (INIS)

    Bowman, R.S.; Sullivan, E.J.

    1995-01-01

    We have shown in laboratory experiments that natural zeolites treated with hexadecyltrimethylammonium (HDTMA) are effective sorbents for nonpolar organics, inorganic cations, and inorganic anions. Due to their low cost (∼$0.75/kg) and granular nature, HDTMA-zeolites appear ideal candidates for reactive, permeable subsurface barriers. The HDTMA-zeolites are stable over a wide range of pH (3-13), ionic strength (1 M Cs + or Ca 2+ ), and in organic solvents. Surfactant-modified zeolites sorb nonpolar organics (benzene, toluene, xylene, chlorinated aliphatics) via a partitioning mechanism, inorganic cations (Pb 2+ ) via ion exchange and surface complexation, and inorganic anions (CrO 4 2- , SeO 4 2- , SO 4 2- ) via surface precipitation.The goal of this work is to demonstrate the use of surfactant-modified zeolite as a permeable barrier to ground water contaminants

  17. Effect of Australian zeolite on methane production and ammonium removal during anaerobic digestion of swine manure

    DEFF Research Database (Denmark)

    Wijesinghe, D. Thushari N.; Dassanayake, Kithsiri B.; Scales, Peter J.

    2018-01-01

    acidogenesis due to the high N contents of swine manure considerably reduce CH4 yield. The reduction of N during anaerobic digestion by the addition of zeolite improves CH4 production and reduces potential environmental threats associated with ammonia (NH3) emissions from anaerobic digestion of swine manure....... The main objective of this study was to determine the optimum Australian zeolite dose that produces maximum NH4 + recovery at optimum CH4 production. In laboratory experiments, swine manure was treated with natural and sodium zeolites at 0, 10, 40, 70, 100 mg/L and digested anaerobically for 60 days....... Natural zeolite at a dose of 40 g/L resulted in the largest increase (29%) in total CH4 yield from swine manure compared to the nil zeolite treatments. The lag phase of digestion was decreased with increasing zeolite doses up to 100 g/L. Natural and sodium zeolites at a dose of 100 g/L reduced NH4 + by 50...

  18. Aluminum-rich mesoporous MFI - type zeolite single crystals

    DEFF Research Database (Denmark)

    Kustova, Marina; Kustov, Arkadii; Christensen, Christina Hviid

    2005-01-01

    Zeolitcs are crystalline materials, which are widely used as solid acid catalysts and supports in many industrial processes. Recently, mesoporous MFI-type zeolite single crystals were synthesized by use of carbon particles as a mesopore template and sodium aluminate as the aluminum Source....... With this technique, only zeolites with relatively low Al contents were reported (Si/Al ratio about 100). In this work, the preparation of aluminum-rich mesoporous MFI-type zeolite single crystals (Si/Al similar to 16-50) using aluminum isopropoxide as the aluminum Source is reported for the first time. All samples...... are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature programmed desorption (NH3-TPD), and N-2 adsorption measurements. The obtained zeolites combine the high crystallinity and the characteristic micropores of zeolites with an intracrystalline mesopore system...

  19. Computer simulation of molecular sorption in zeolites

    International Nuclear Information System (INIS)

    Calmiano, Mark Daniel

    2001-01-01

    The work presented in this thesis encompasses the computer simulation of molecular sorption. In Chapter 1 we outline the aims and objectives of this work. Chapter 2 follows in which an introduction to sorption in zeolites is presented, with discussion of structure and properties of the main zeolites studied. Chapter 2 concludes with a description of the principles and theories of adsorption. In Chapter 3 we describe the methodology behind the work carried out in this thesis. In Chapter 4 we present our first computational study, that of the sorption of krypton in silicalite. We describe work carried out to investigate low energy sorption sites of krypton in silicalite where we observe krypton to preferentially sorb into straight and sinusoidal channels over channel intersections. We simulate single step type I adsorption isotherms and use molecular dynamics to study the diffusion of krypton and obtain division coefficients and the activation energy. We compare our results to previous experimental and computational studies where we show our work to be in good agreement. In Chapter 5 we present a systematic study of the sorption of oxygen and nitrogen in five lithium substituted zeolites using a transferable interatomic potential that we have developed from ab initio calculations. We show increased loading of nitrogen compared to oxygen in all five zeolites studied as expected and simulate adsorption isotherms, which we compare to experimental and simulated data in the literature. In Chapter 6 we present work on the sorption of ferrocene in the zeolite NaY. We show that a simulated, low energy sorption site for ferrocene is correctly located by comparing to X-ray powder diffraction results for this same system. The thesis concludes with some overall conclusions and discussion of opportunities for future work. (author)

  20. Nanocellulose-Zeolite Composite Films for Odor Elimination.

    Science.gov (United States)

    Keshavarzi, Neda; Mashayekhy Rad, Farshid; Mace, Amber; Ansari, Farhan; Akhtar, Farid; Nilsson, Ulrika; Berglund, Lars; Bergström, Lennart

    2015-07-08

    Free standing and strong odor-removing composite films of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite adsorbents have been colloidally processed. Thermogravimetric desorption analysis (TGA) and infrared spectroscopy combined with computational simulations showed that commercially available silicalite-1 and ZSM-5 have a high affinity and uptake of volatile odors like ethanethiol and propanethiol, also in the presence of water. The simulations showed that propanethiol has a higher affinity, up to 16%, to the two zeolites compared with ethanethiol. Highly flexible and strong free-standing zeolite-CNF films with an adsorbent loading of 89 w/w% have been produced by Ca-induced gelation and vacuum filtration. The CNF-network controls the strength of the composite films and 100 μm thick zeolite-CNF films with a CNF content of less than 10 vol % displayed a tensile strength approaching 10 MPa. Headspace solid phase microextraction (SPME) coupled to gas chromatography-mass spectroscopy (GC/MS) analysis showed that the CNF-zeolite films can eliminate the volatile thiol-based odors to concentrations below the detection ability of the human olfactory system. Odor removing zeolite-cellulose nanofibril films could enable improved transport and storage of fruits and vegetables rich in odors, for example, onion and the tasty but foul-smelling South-East Asian Durian fruit.

  1. New ion-exchanged zeolite derivatives: antifungal and antimycotoxin properties against Aspergillus flavus and aflatoxin B1

    Science.gov (United States)

    Savi, Geovana D.; Cardoso, Willian A.; Furtado, Bianca G.; Bortolotto, Tiago; Da Agostin, Luciana O. V.; Nones, Janaína; Torres Zanoni, Elton; Montedo, Oscar R. K.; Angioletto, Elidio

    2017-08-01

    Zeolites are microporous crystalline hydrated aluminosilicates with absorbent and catalytic properties. This material can be used in many applications in stored-pest management such as: pesticide and fertilizer carriers, animal feed additives, mycotoxin binders and food packaging materials. Herein, four 4A zeolite forms were prepared by ion-exchange and their antifungal effect against Aspergillus flavus was highlighted. Additionally, the antimycotoxin activity and the aflatoxin B1 (AFB1) adsorption capacity of these zeolites as well as their toxic effects on Artemia sp. were investigated. The ion-exchanged zeolites with Li+ and Cu2+ showed the best antifungal activity against A. flavus, including effects on conidia germination and hyphae morphological alterations. Regarding to antimycotoxin activity, all zeolite samples efficiently inhibited the AFB1 production by A. flavus. However, the ion-exchanged zeolites exhibited better results than the 4A zeolite. On the other hand, the AFB1 adsorption capacity was only observed by the 4A zeolite and zeolite-Li+. Lastly, our data showed that all zeolites samples used at effective concentrations for antifungal and antimycotoxin assays (2 mg ml-1) showed no toxic effects towards Artemia sp. Results suggest that some these ion-exchanged zeolites have great potential as an effective fungicide and antimycotoxin agent for agricultural and food safety applications.

  2. Introduction to chemistry of crystalline zeolites and its applications

    International Nuclear Information System (INIS)

    Lobo Cabezas, Raul Francisco

    2006-01-01

    Establishes the zeolites as the most important group of solid acids and its relation to the contemporaneous chemical industry. It describes that zeolites are used in the following applications: refineries, chemicals/petrochemicals, environmental chemistry, separation of gas, adsorbent ia and ionic exchange in water purification in mineral processes, medicine and agricultural industry. Zeolites are defined as crystalline aluminium silicates with a compound structure of interconnected tetrahedrons. It mentions the key components in zeolites structure. It focuses that structural basic unity of the zeolite is the tetrahedron and compound structural unities are: cells and columns. Besides, it describes that pore system defines a lot of all its properties; but chemical composition affects them. Composition and properties of zeolites are established: adsorption, molecular sieves, acidity, selectivity, transition state in the hydrocarbon's chemistry. It concludes that the newer application of zeolite is in oxidations: Titanium-Silicate-1; production of propylene's oxide using peroxide of hydrogen as oxidizing. The catalysis is an active area of research, and the most popular areas are related to chemicals and the environment [es

  3. Methanation of CO2 over Zeolite-Encapsulated Nickel Nanoparticles

    DEFF Research Database (Denmark)

    Goodarzi, Farnoosh; Kang, Liqun; Wang, Feng Ryan

    2018-01-01

    in an increased metal dispersion and, consequently, a high catalytic activity for CO2 methanation. With a gas hourly space velocity of 60000 ml/g catalyst h-1 and H2/CO2=4, the zeolite-encapsulated Ni nanoparticles result in 60% conversion at 450°C, which corresponds to a site-time yield of around 304 mol CH4/mol......Efficient methanation of CO2 relies on the development of more selective and stable heterogeneous catalysts. Here we present a simple and effective method to encapsulate Ni nanoparticles in zeolite silicalite-1. In this method, the zeolite is modified by selective desilication, which creates intra...

  4. Uranium,Radium and Iron Absorption from Liquid Waste Uranium Ore Processing by Zeolite

    International Nuclear Information System (INIS)

    Wismawati, T; Sorot sudiro, A; Herjati, T

    1998-01-01

    The aim of this work is to determine zeolites sorption capacity and the distribution coefficient of uranium, radium, and iron in zeolite-liquid waste system. Mineralogical composition of zeolite used in the experiment has been determine by examining the thin sections of zeolite grains under a microscope. Zeolite has ben activated by the dilute sulfuric acid or sodium hydroxide solution. The results show that the use of 0.25 N sodium hydroxide solution could be optimizing the zeolite for uranium and iron ions sorption and that of 0.1 N sulfuric acid solution is for radium sorption. The re-activation process has been carried out in three hours. Under such a condition, the sorption efficiency of zeolite to those ions have been known to be 45.85% for uranium, 96.63 % for iron and 87.80 % for radium. The distribution coefficients of uranium, radium and iron ion in zeolite-liquid waste system have been calculated 0.85, 7.02, and 28.65 ml/g respectively

  5. Natural zeolite reactivity towards ozone: The role of compensating cations

    International Nuclear Information System (INIS)

    Valdés, Héctor; Alejandro, Serguei; Zaror, Claudio A.

    2012-01-01

    Highlights: ► Chemical and thermal treatment enhances catalytic activity of natural zeolite. ► Modified natural zeolite exhibits high stability after thermal treatment. ► Reducing the compensating cation content leads to an increase on ozone abatement. ► Surface active atomic oxygen was detected using the DRIFT technique. ► The highest reactivity toward ozone was performed by NH4Z3 zeolite sample. - Abstract: Among indoor pollutants, ozone is recognised to pose a threat to human health. Recently, low cost natural zeolites have been applied as alternative materials for ozone abatement. In this work, the effect of compensating cation content of natural zeolite on ozone removal is studied. A Chilean natural zeolite is used here as starting material. The amount of compensating cations in the zeolite framework was modified by ion exchange using an ammonium sulphate solution (0.1 mol L −1 ). Characterisation of natural and modified zeolites were performed by X-ray powder diffraction (XRD), nitrogen adsorption at 77 K, elemental analysis, X-ray fluorescence (XRF), thermogravimetric analysis coupled with mass spectroscopy (TGA-MS), and temperature-programmed desorption of ammonia (NH 3 -TPD). Ozone adsorption and/or decomposition on natural and modified zeolites were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Results show that the zeolite compensating cation content affects ozone interaction with zeolite active sites. Ammonium ion-exchange treatments followed by thermal out-gassing at 823 K, reduces ozone diffusion resistance inside the zeolite framework, increasing ozone abatement on zeolite surface active sites. Weak and strong Lewis acid sites of zeolite surface are identified here as the main active sites responsible of ozone removal.

  6. Removal of Cu(II) from leachate using natural zeolite as a landfill liner material.

    Science.gov (United States)

    Turan, N Gamze; Ergun, Osman Nuri

    2009-08-15

    All hazardous waste disposal facilities require composite liner systems to act as a barrier against migration of contaminated leachate into the subsurface environment. Removal of copper(II) from leachate was studied using natural zeolite. A serial of laboratory systems on bentonite added natural zeolite was conducted and copper flotation waste was used as hazardous waste. The adsorption capacities and sorption efficiencies were determined. The sorption efficiencies increased with increasing natural zeolite ratio. The pseudo-first-order, the pseudo-second-order, Elovich and the intra-particle diffusion kinetic models were used to describe the kinetic data to estimate the rate constants. The second-order model best described adsorption kinetic data. The results indicated that natural zeolite showed excellent adsorptive characteristics for the removal of copper(II) from leachate and could be used as very good liner materials due to its high uptake capacity and the abundance in availability.

  7. Removal of Cu(II) from leachate using natural zeolite as a landfill liner material

    International Nuclear Information System (INIS)

    Turan, N. Gamze; Ergun, Osman Nuri

    2009-01-01

    All hazardous waste disposal facilities require composite liner systems to act as a barrier against migration of contaminated leachate into the subsurface environment. Removal of copper(II) from leachate was studied using natural zeolite. A serial of laboratory systems on bentonite added natural zeolite was conducted and copper flotation waste was used as hazardous waste. The adsorption capacities and sorption efficiencies were determined. The sorption efficiencies increased with increasing natural zeolite ratio. The pseudo-first-order, the pseudo-second-order, Elovich and the intra-particle diffusion kinetic models were used to describe the kinetic data to estimate the rate constants. The second-order model best described adsorption kinetic data. The results indicated that natural zeolite showed excellent adsorptive characteristics for the removal of copper(II) from leachate and could be used as very good liner materials due to its high uptake capacity and the abundance in availability.

  8. Effect of cation nature of zeolite on carbon replicas and their electrochemical capacitance

    International Nuclear Information System (INIS)

    Zhou, Jin; Li, Wen; Zhang, Zhongshen; Wu, Xiaozhong; Xing, Wei; Zhuo, Shuping

    2013-01-01

    Graphical abstract: Cation nature of zeolite influences the porosity, surface chemical properties of carbon replicas of zeolite, resulting in different electrochemical capacitance. Highlights: ► The porosity of carbon replica strongly depends on zeolite's effective pore size. ► The surface chemical properties influence by the cation nature of zeolite. ► The N-doping introduces large pseudo-capacitance. ► The HYC800 carbon showed a high capacitance of up to 312 F g −1 in 1 M H 2 SO 4 . ► The prepared carbons show good durability of galvanostatic cycle. -- Abstract: N-doped carbon replicas of zeolite Y are prepared, and the effect of cation nature of zeolite (H + or Na + ) on the carbon replicas is studied. The morphology, structure and surface properties of the carbon materials are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N 2 adsorption, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The pore regularity, pore parameter and surface chemical properties of the carbons may strongly depend on the cation nature of the zeolite Y. The carbon replicas of zeolite HY (H-form of zeolite Y) possesses higher pore regularity and much larger surface area than those of zeolite NaY (Na-form of zeolite Y), while the latter carbons seem to possess higher carbonization degrees. Electrochemical measurements show a large faradaic capacitance related to the N- or O-containing groups for the prepared carbons. Owing to the large specific surface area, high pore regularity and heteroatom-doping, the HYC800 sample derived from zeolite HY presents very high gravimetric capacitance, up to 312.4 F g −1 in H 2 SO 4 electrolyte, and this carbon can operate at 1.2 V with good retention ratio in the range of 0.25 to 10 A g −1

  9. Selective adsorption of thiophene and 1-benzothiophene on metal-ion-exchanged zeolites in organic medium.

    Science.gov (United States)

    Xue, Mei; Chitrakar, Ramesh; Sakane, Kohji; Hirotsu, Takahiro; Ooi, Kenta; Yoshimura, Yuji; Feng, Qi; Sumida, Naoto

    2005-05-15

    Adsorption of the organic sulfur compounds thiophene (TP) and 1-benzothiophene (1-BTP) in an organic model solution of hydrodesulfurizated gasoline (heptane with 1 wt% toluene and 0.156 mM (5 ppmw as sulfur) TP or 1-BTP) was studied by a batch method at 80 degrees C using metal-ion-exchanged Y-zeolites. Although NaY-zeolite or its acid-treated material rarely adsorbed the organic sulfur compounds, NaY-zeolites exchanged with Ag+, Cu2+, and Ce3+ ions and NH(4)Y-zeolites exchanged with Ce3+ ions showed markedly high adsorptive capacities for TP and 1-BTP. The sulfur uptake increased in the order CuY-zeolite(Na)(Na) for both the organic sulfur compounds. The adsorption isotherms for TP and 1-BTP followed the Langmuir's relationship and the saturation capacities by CeY-zeolite(Na) were calculated as 0.022 and 0.033 mmol/g, respectively. The mole ratios of TP/Ce and 1-BTP/Ce were 0.031 and 0.047, respectively. CeY-zeolite(NH4) which was prepared from NH4Y-zeolite showed less uptake of TP and 1-BTP than CeY-zeolite(Na), probably due to its lower cerium content.

  10. Process for producing zeolite adsorbent and process for treating radioactive liquid waste with the zeolite adsorbent

    International Nuclear Information System (INIS)

    Motojima, K.; Kawamura, F.

    1984-01-01

    Zeolite is contacted with an aqueous solution containing at least one of copper, nickel, cobalt, manganese and zinc salts, preferably copper and nickel salts, particularly preferably copper salt, in such a form as sulfate, nitrate, or chloride, thereby adsorbing the metal on the zeolite in its pores by ion exchange, then the zeolite is treated with a water-soluble ferrocyanide compound, for example, potassium ferrocyanide, thereby forming metal ferrocyanide on the zeolite in its pores. Then, the zeolite is subjected to ageing treatment, thereby producing a zeolite adsorbent impregnated with metal ferrocyanide in the pores of zeolite. The adsorbent can selectively recover cesium with a high percent cesium removal from a radioactive liquid waste containing at least radioactive cesium, for example, a radioactive liquid waste containing cesium and such coexisting ions as sodium, magnesium, calcium and carbonate ions at the same time at a high concentration. The zeolite adsorbent has a stable adsorbability for a prolonged time

  11. Ion exchange and hydrolysis reactions in zeolites

    International Nuclear Information System (INIS)

    Harjula, Risto.

    1993-09-01

    Among other uses, zeolites are efficient cation exchangers for aquatic pollution control. At present they they are mainly used in nuclear waste effluent treatment and in detergency. In the thesis, several ion exchange equilibria, important in these main fields of zeolite applications, were studied, with special emphasis on the formulation and calculation of the equilibria. The main interest was the development of thermodynamic formulations for the calculation of zeolite ion exchange equilibria in solutions of low or very low (trace) ion concentration, which are relevant for the removal of trace pollutants, such as radionuclides, from waste waters. Two groups of zeolite-cation systems were studied. First, binary Ca 2+ /Na + exchange in zeolites X and Y, which are of interest for detergency applications. Second, binary Cs + /Na + and Cs + /K + exchanges, and ternary Cs + /Na + /K + exchange in mordenite, which are important in nuclear waste effluent treatment. The thesis is based on five previous publications by author. (100 refs., 7 figs.)

  12. Synthesis and characterization of Al-TON zeolite using a dialkylimizadolium as structure-directing agent

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Christian Wittee; Pergher, Sibele Berenice Castella, E-mail: chriswittee@gmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Villarroel-Rocha, Jhonny [Laboratorio de Solidos Porosos, Instituto de Fisica Aplicada, Universidad Nacional de San Luis, Chacabuco, San Luis (Argentina); Silva, Bernardo Araldi Da; Mignoni, Marcelo Luis [Universidade Regional Integrada, Erechim, RS (Brazil)

    2016-11-15

    In this work, the synthesis of zeolites using 1-butyl-3-methylimidazolium chloride [C{sub 4}MI]Cl as a structure-directing agent was investigated. The organic cation shows effectiveness and selectivity for the syntheses of TON zeolites under different reaction conditions compared to the traditional structure directing agent, 1,8-diaminooctane. The 1-butyl-3-methylimidazolium cation lead to highly crystalline materials and its role as OSDA in our synthesis conditions has been confirmed by characterization techniques. ICP-OES confirms the presence of Al in the samples and {sup 27}Al MAS NMR analysis indicated that aluminum atoms were incorporated in tetrahedral coordination. Scanning electron microscopy indicated that changing the crystallization condition (static or stirring), zeolites with different crystal size were obtained, which consequently affects the textural properties of the zeolites. Moreover, varying some synthesis parameters MFI zeolite can also be obtained. (author)

  13. Towards a methanol economy: Zeolite catalyzed production of synthetic fuels

    DEFF Research Database (Denmark)

    Mentzel, Uffe Vie

    The main focus of this thesis is zeolite catalyzed conversion of oxygenates to hydrocarbon fuels and chemicals. Furthermore, conversion of ethane to higher hydrocarbons has also been studied. After a brief introduction to the concept of “the methanol economy” in the first chapter, the second...... a commercial H-ZSM-5 zeolite impregnated with gallium and/or molybdenum is described. The object was to investigate if the presence of methanol in the feed could enhance the conversion of ethane, but in all cases the opposite is observed; the presence of methanol actually suppresses the conversion of ethane...... various zeolite catalysts is studied in Chapter 4. When 2-propanol or 1-butanol is converted over H-ZSM-5, the total conversion capacities of the catalyst are more than 25 times higher than for conversion of methanol and ethanol. Furthermore, for conversion of C3+ alcohols, the selectivity shifts during...

  14. Evaluation of synthetic zeolite as engineering passive permeable reactive barrier

    International Nuclear Information System (INIS)

    Ibrahim, O.A.A.

    2011-01-01

    models were used to describe the pollutant transport within the permeable reactive barrier. Based on the obtained results, the following can be concluded: 1. Synthetic zeolite X proposed as a reactive barrier material was successfully prepared and completely characterized using XRD, FTIR, EDX, and SEM techniques. 2. Sorption studies indicated the feasibility of using the prepared zeolite X as a reactive barrier material due to its high capacity, chemical stability and selectivity for the concerned heavy metals (Zn 2+ and Cd 2+ ions). 3. Transport properties of both zinc and cadmium ions through zeolite X packed column have been determined. The hydrodynamic dispersion coefficients needed for describe the migration of Zn 2+ and Cd 2+ ions were determined. 4. Retardation coefficients using linear and nonlinear isotherm models were utilized to determine the capability of the synthesized zeolite X to impede the movement of zinc and cadmium ions carried by the fluid. 5. Transport of contaminants in groundwater systems, which is based on the integration of advection dispersion equation using specific boundary conditions, provides a number of analytical solutions. Some of these solutions have been derived for one dimensional pulse contaminant input or a continuous input.

  15. Natural zeolite reactivity towards ozone: The role of compensating cations

    Energy Technology Data Exchange (ETDEWEB)

    Valdes, Hector, E-mail: hvaldes@ucsc.cl [Laboratorio de Tecnologias Limpias (F. Ingenieria), Universidad Catolica de la Santisima Concepcion, Alonso de Ribera 2850, Concepcion (Chile); Alejandro, Serguei; Zaror, Claudio A. [Departamento de Ingenieria Quimica (F. Ingenieria), Universidad de Concepcion, Concepcion (Chile)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Chemical and thermal treatment enhances catalytic activity of natural zeolite. Black-Right-Pointing-Pointer Modified natural zeolite exhibits high stability after thermal treatment. Black-Right-Pointing-Pointer Reducing the compensating cation content leads to an increase on ozone abatement. Black-Right-Pointing-Pointer Surface active atomic oxygen was detected using the DRIFT technique. Black-Right-Pointing-Pointer The highest reactivity toward ozone was performed by NH4Z3 zeolite sample. - Abstract: Among indoor pollutants, ozone is recognised to pose a threat to human health. Recently, low cost natural zeolites have been applied as alternative materials for ozone abatement. In this work, the effect of compensating cation content of natural zeolite on ozone removal is studied. A Chilean natural zeolite is used here as starting material. The amount of compensating cations in the zeolite framework was modified by ion exchange using an ammonium sulphate solution (0.1 mol L{sup -1}). Characterisation of natural and modified zeolites were performed by X-ray powder diffraction (XRD), nitrogen adsorption at 77 K, elemental analysis, X-ray fluorescence (XRF), thermogravimetric analysis coupled with mass spectroscopy (TGA-MS), and temperature-programmed desorption of ammonia (NH{sub 3}-TPD). Ozone adsorption and/or decomposition on natural and modified zeolites were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Results show that the zeolite compensating cation content affects ozone interaction with zeolite active sites. Ammonium ion-exchange treatments followed by thermal out-gassing at 823 K, reduces ozone diffusion resistance inside the zeolite framework, increasing ozone abatement on zeolite surface active sites. Weak and strong Lewis acid sites of zeolite surface are identified here as the main active sites responsible of ozone removal.

  16. High-throughput preparation and testing of ion-exchanged zeolites

    International Nuclear Information System (INIS)

    Janssen, K.P.F.; Paul, J.S.; Sels, B.F.; Jacobs, P.A.

    2007-01-01

    A high-throughput research platform was developed for the preparation and subsequent catalytic liquid-phase screening of ion-exchanged zeolites, for instance with regard to their use as heterogeneous catalysts. In this system aqueous solutions and other liquid as well as solid reagents are employed as starting materials and 24 samples are prepared on a library plate with a 4 x 6 layout. Volumetric dispensing of metal precursor solutions, weighing of zeolite and subsequent mixing/washing cycles of the starting materials and distributing reaction mixtures to the library plate are automatically performed by liquid and solid handlers controlled by a single common and easy-to-use programming software interface. The thus prepared materials are automatically contacted with reagent solutions, heated, stirred and sampled continuously using a modified liquid handling. The high-throughput platform is highly promising in enhancing synthesis of catalysts and their screening. In this paper the preparation of lanthanum-exchanged NaY zeolites (LaNaY) on the platform is reported, along with their use as catalyst for the conversion of renewables

  17. ADSORPSI POLUTAN ION DIKROMAT MENGGUNAKAN ZEOLIT ALAM TERMODIFIKASI AMINA (Adsorption of Dichromate Ions Pollutant Using Ammine Modified-Natural Zeolites

    Directory of Open Access Journals (Sweden)

    Eko Sri Kunarti

    2015-11-01

    24,66 kJ/mol. ABSTRACT Chromium (VI is a heavy metal pollutant that is harmful to health and the environment, therefore Cr(VI ions in aqueous solution removal is important to overcome the environmental pollution. Adsorption process is one of simple techniques that can be used to take metal ions. Adsorption study of dichromate ions as a wastewater model of Cr(VI has been conducted in this research by using ammine modified natural zeolite as adsorbents. The research was initiated by preparation of adsorbent of ammine-modified natural zeolites. The preparation was started by washing the natural zeolite (Z using distilled water and refluxing by 3M hydrochloric acid. Refluxed zeolites (ZA were modified by a quaternary ammonium salt, N-cethyl-N,N,N-trimethylammonium bromide (CTAB, and a primary amine, propylamine (PA. The natural zeolite (Z, acid activated zeolite (ZA and amine-modified zeolites were then applied for adsorption of dichromate ions. Characterization of zeolite samples was performed by infrared spectroscopy and X-ray diffraction methods to confirm the crystal structure, and atomic absorption spectroscopy method to analyze the adsorbed dichromate ions. Results showed that all zeolite samples contain clinoptilolite, mordernite and quartz minerals. The zeolite structure was not changed by heat and chemical treatments. Modification of zeolites enhanced the adsorption efficiency of natural zeolites. The dichromate ions were better adsorbed on ammine modified-zeolites compared to that of unmodified-zeolite with adsorption ability of CTAB modified zeolite (CTAB-Z was greater than that of propylammine modified zeolite (PA-Z. The adsorption of dichromate on zeolite samples was achieved in the order of CTAB-Z > PA-Z > ZA > Z, with the adsorption efficiency was about 1.96; 1.74; 0.90 and 0.48 mg/g, respectively. The dichromate ions adsorption by CTAB modified zeolite is chemical adsorption (chemisorption with the adsorption energy of 24.66 kJ/mol.

  18. Stability of krypton fixed in zeolite-3A and -5A

    International Nuclear Information System (INIS)

    Matsuoka, Shingo; Nakamura, Hirone; Tamura, Takaaki; Takano, Takemi; Ito, Yasuo; Sugawara, Ichiro.

    1986-01-01

    The fixation operation was carried out at 450 ∼ 650 deg C, 1,000 atm for 24 h. The amount of fixed Kr was measured using thermal neutron activation analysis. For zeolite-3A the amount of Kr fixed decreased from 20 to 5 w/o as the fixation temperature rose. In the case of zeolite-5A, Kr fixation was observed at 550 deg C and above, and the amount increased to 15 w/o as the temperature rose to 650 deg C. The diffusion coefficient of Kr in the zeolite was determined from the result of heating tests. The value obtained was substituted in a diffusion equation, enabling us to predict the Kr release behavior at any temperature in a dry atmosphere. Both the samples of zeolite-3A fixed below 525 deg C and of zeolite-5A below 625 deg C showed an intensive Kr release in water that would not be expected from the release behavior under dry conditions. However, such unexpected release was not observed in either sample fixed above these respective temperatures. This could be accounted for by the fact that zeolite cations move easily when zeolite is moisturized. (author)

  19. A database of new zeolite-like materials.

    Science.gov (United States)

    Pophale, Ramdas; Cheeseman, Phillip A; Deem, Michael W

    2011-07-21

    We here describe a database of computationally predicted zeolite-like materials. These crystals were discovered by a Monte Carlo search for zeolite-like materials. Positions of Si atoms as well as unit cell, space group, density, and number of crystallographically unique atoms were explored in the construction of this database. The database contains over 2.6 M unique structures. Roughly 15% of these are within +30 kJ mol(-1) Si of α-quartz, the band in which most of the known zeolites lie. These structures have topological, geometrical, and diffraction characteristics that are similar to those of known zeolites. The database is the result of refinement by two interatomic potentials that both satisfy the Pauli exclusion principle. The database has been deposited in the publicly available PCOD database and in www.hypotheticalzeolites.net/database/deem/. This journal is © the Owner Societies 2011

  20. Rapid synthesis of beta zeolites

    Science.gov (United States)

    Fan, Wei; Chang, Chun -Chih; Dornath, Paul; Wang, Zhuopeng

    2015-08-18

    The invention provides methods for rapidly synthesizing heteroatom containing zeolites including Sn-Beta, Si-Beta, Ti-Beta, Zr-Beta and Fe-Beta. The methods for synthesizing heteroatom zeolites include using well-crystalline zeolite crystals as seeds and using a fluoride-free, caustic medium in a seeded dry-gel conversion method. The Beta zeolite catalysts made by the methods of the invention catalyze both isomerization and dehydration reactions.

  1. Densification of salt-occluded zeolite a powders to a leach-resistant monolith

    International Nuclear Information System (INIS)

    Lewis, M.A.; Fischer, D.F.; Murhpy, C.D.

    1993-01-01

    Pyrochemical processing of spent fuel from the Integral Fast Reactor (IFR) yields a salt waste of LiCl-KCl that contains approximately 6 wt% fission products, primarily as CsCl and SrCl 2 . Past work has shown that zeolite A will preferentially sorb cesium and strontium and will encapsulate the salt waste in a leach-resistant, radiation-resistant aluminosilicate matrix. However, a method is sill needed to convert the salt-occluded zeolite powders into a form suitable for geologic disposal. We are thus investigating a method that forms bonded zeolite by hot pressing a mixture of glass frit and salt-occluded zeolite powders at 990 K (717 degree C) and 28 MPa. The leach resistance of the bonded zeolite was measured in static leach tests run for 28 days in 363 K (90 degree C) deionized water. Normalized release rates of all elements in the bonded zeolite were low, 2 d. Thus, the bonded zeolite may be a suitable waste form for IFR salt waste

  2. Synthesis and characterization of zeolite from coal fly ash

    Science.gov (United States)

    Liu, Yong; Luo, Qiong; Wang, Guodong; Li, Xianlong; Na, Ping

    2018-05-01

    Fly ash (FA) from coal-based thermal power plant was used to synthesize zeolite in NaOH solution with hydrothermal method in this work. Firstly, the effects of calcination and acid treatment on the removal of impurities in fly ash were studied. Then based on the pretreated FA, the effects of alkali concentration, reaction temperature and Si/Al ratio on the synthesis of zeolite were studied in detail. The mineralogy, morphology, thermal behavior, infrared spectrum and specific surface for the synthetic sample were investigated. The results indicated that calcination at 750 °C for 1.5 h can basically remove unburned carbon from FA, and 4 M hydrochloric acid treatment of calcined FA at 90 °C for 2 h will reduce the quality of about 34.3%wt, which are mainly iron, calcium and sulfur elements. The concentration of NaOH, reaction temperature and Si/Al ratio have important effect on the synthesis of zeolite. In this study, 0.5 M NaOH cannot obtain any zeolite. High temperature is beneficial to zeolite synthesis from FA, but easily lead to a variety of zeolites. The synthetic sample contains three kinds of zeolites such as zeolite P, sodalite and zeolite X, when the reaction conditions are 2 M NaOH and 120 °C for 24 h. In this research, quartz always exists in the synthetic sample, but will reduce with the increase of temperature. The synthetic zeolite has the specific surface area of about 42 m2 g‑1 and better thermal stability.

  3. CO2–CH4 permeation in high zeolite 4A loading mixed matrix membranes

    KAUST Repository

    Adams, Ryan T.; Lee, Jong Suk; Bae, Tae-Hyun; Ward, Jason K.; Johnson, J.R.; Jones, Christopher W.; Nair, Sankar; Koros, William J.

    2011-01-01

    Mixed matrix membranes (MMMs) with low particle loadings have been shown to improve the properties of pure polymers for many gas separations. Comparatively few reports have been made for high particle loading (≥50vol.%) MMMs. In this work, CO2-CH4 feeds were used to study the potential of 50vol.% zeolite 4A-poly(vinyl acetate) (PVAc) MMMs for natural gas separations. A low CO2 partial pressure mixed feed probed MMM performance below the plasticization pressure of PVAc and a high CO2 partial pressure mixed feed probed MMM performance at industrially relevant conditions above the plasticization pressure.Under both mixed feed conditions at 35°C, substantial improvements in overall separation performance were observed. At low CO2 partial pressures, CO2 permeability roughly doubled with a nearly 50% increase in selectivity versus pure PVAc under the same conditions. For the high CO2 partial pressure feed, CO2 permeability remained effectively unchanged with a 63% increase in selectivity versus pure PVAc. Surprisingly, the performance of these PVAc based MMMs approached the properties of current " upper bound" polymers. Overall, this work shows that significantly improved performance MMMs can be made with traditional techniques from a low cost, low performance polymer without costly adhesion promoters. © 2010.

  4. CO2–CH4 permeation in high zeolite 4A loading mixed matrix membranes

    KAUST Repository

    Adams, Ryan T.

    2011-02-01

    Mixed matrix membranes (MMMs) with low particle loadings have been shown to improve the properties of pure polymers for many gas separations. Comparatively few reports have been made for high particle loading (≥50vol.%) MMMs. In this work, CO2-CH4 feeds were used to study the potential of 50vol.% zeolite 4A-poly(vinyl acetate) (PVAc) MMMs for natural gas separations. A low CO2 partial pressure mixed feed probed MMM performance below the plasticization pressure of PVAc and a high CO2 partial pressure mixed feed probed MMM performance at industrially relevant conditions above the plasticization pressure.Under both mixed feed conditions at 35°C, substantial improvements in overall separation performance were observed. At low CO2 partial pressures, CO2 permeability roughly doubled with a nearly 50% increase in selectivity versus pure PVAc under the same conditions. For the high CO2 partial pressure feed, CO2 permeability remained effectively unchanged with a 63% increase in selectivity versus pure PVAc. Surprisingly, the performance of these PVAc based MMMs approached the properties of current " upper bound" polymers. Overall, this work shows that significantly improved performance MMMs can be made with traditional techniques from a low cost, low performance polymer without costly adhesion promoters. © 2010.

  5. CaE-T zeolite - a new effective adsorber for vacuum technique

    International Nuclear Information System (INIS)

    Skvazyvaev, V.E.; Khvoshchev, S.S.; Zhdanov, S.P.

    1975-01-01

    Adsorption of air at low pressures on type E zeolites was studied as a function of their composition and dehydration regime. It was shown that zeolite CaE-T has a greatly increased sorption capacity for air at low pressures and that this is more than 3 times that of industrial zeolites currently used in vacuum technology. Mass-spectrometer studies were made of the gas phase over zeolites type E and A after adsorption of air at pressures from 10 -8 to 10 -5 mm Hg at liquid nitrogen temperatures under conditions approximating equilibrium. It was shown that zeolite CaE-T has a high adsorption capacity for Ar, O 2 , and H 2 . Adsorption of H 2 and Ar by zeolites of different structural types at low pressures was studied. It was shown that zeolite CaE-T has a significantly higher adsorption capacity for hydrogen and argon than all industrial zeolites

  6. Biogas cleaning and upgrading with natural zeolites from tuffs.

    Science.gov (United States)

    Paolini, Valerio; Petracchini, Francesco; Guerriero, Ettore; Bencini, Alessandro; Drigo, Serena

    2016-01-01

    CO2 adsorption on synthetic zeolites has become a consolidated approach for biogas upgrading to biomethane. As an alternative to synthetic zeolites, tuff waste from building industry was investigated in this study: indeed, this material is available at a low price and contains a high fraction of natural zeolites. A selective adsorption of CO2 and H2S towards CH4 was confirmed, allowing to obtain a high-purity biomethane (CO2 biogas samples were used, and no significant effects due to biogas impurities (e.g. humidity, dust, moisture, etc.) were observed. Thermal and vacuum regenerations were also optimized and confirmed to be possible, without significant variations in efficiency. Hence, natural zeolites from tuffs may successfully be used in a pressure/vacuum swing adsorption process.

  7. Superconducting characteristics of 4-Å carbon nanotube-zeolite composite

    KAUST Repository

    Lortz, Rolf W.

    2009-04-15

    We have fabricated nanocomposites consisting of 4-A carbon nanotubes embedded in the 0.7-nm pores of aluminophosphate- five (AFI) zeolite that display a superconducting specific heat transition at 15 K. MicroRaman spectra of the samples show strong and spatially uniform radial breathing mode (RBM) signals at 510 cm-1 and 550 cm-1, characteristic of the (4,2) and (5,0) nanotubes, respectively. The specific heat transition is suppressed at >2T, with a temperature dependence characteristic of finite-size effects. Comparison with theory shows the behavior to be consistent with that of a type II BCS superconductor, characterized by a coherence length of 14 ± 2 nm and a magnetic penetration length of 1.5 ± 0.7 μm. Four probe and differential resistance measurements have also indicated a superconducting transition initiating at 15 K, but the magnetoresistance data indicate the superconducting network to be inhomogeneous, with a component being susceptible to magnetic fields below 3 T and other parts capable of withstanding a magnetic field of 5Tor beyond.

  8. Cr(VI) retention and transport through Fe(III)-coated natural zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Du, Gaoxiang [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Li, Zhaohui, E-mail: li@uwp.edu [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Liao, Libing [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Hanson, Renee; Leick, Samantha; Hoeppner, Nicole [Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Jiang, Wei-Teh [Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

    2012-06-30

    Graphical abstract: Breakthrough curves of Cr(VI) from columns packed with raw zeolite (a) and Fe(III)-zeolite (b). The solid line in (b) is the HYDRUS-1D fit to the observed data with adsorption term only, while the dashed line in (b) includes a reduction term in the HYDRUS-1D fit. Highlights: Black-Right-Pointing-Pointer Zeolite modified with Fe(III) could be used for adsorption and retention of Cr(VI). Black-Right-Pointing-Pointer The Fe present on zeolite was in an amorphous Fe(OH){sub 3} form. Black-Right-Pointing-Pointer A Cr(VI) adsorption capacity of 82 mg/kg was found on Fe(III)-zeolite. Black-Right-Pointing-Pointer A Cr(VI) retardation factor of 3 or 5 was determined from column and batch studies. - Abstract: Cr(VI) is a group A chemical based on the weight of evidence of carcinogenicity. Its transport and retention in soils and groundwater have been studied extensively. Zeolite is a major component in deposits originated from volcanic ash and tuff after alteration. In this study, zeolite aggregates with the particle size of 1.4-2.4 mm were preloaded with Fe(III). The influence of present Fe(III) on Cr(VI) retention by and transport through zeolite was studied under batch and column experiments. The added Fe(III) resulted in an enhanced Cr(VI) retention by the zeolite with a capacity of 82 mg/kg. The Cr(VI) adsorption on Fe(III)-zeolite followed a pseudo-second order kinetically and the Freundlich adsorption isotherm thermodynamically. Fitting the column experimental data to HYDRUS-1D resulted in a retardation factor of 3 in comparison to 5 calculated from batch tests at an initial Cr(VI) concentration of 3 mg/L. The results from this study showed that enhanced adsorption and retention of Cr(VI) may happen in soils derived from volcanic ash and tuff that contains significant amounts of zeolite with extensive Fe(III) coating.

  9. Probing Zeolite Crystal Architecture and Structural Imperfections using Differently Sized Fluorescent Organic Probe Molecules.

    Science.gov (United States)

    Hendriks, Frank C; Schmidt, Joel E; Rombouts, Jeroen A; Lammertsma, Koop; Bruijnincx, Pieter C A; Weckhuysen, Bert M

    2017-05-05

    A micro-spectroscopic method has been developed to probe the accessibility of zeolite crystals using a series of fluorescent 4-(4-diethylaminostyryl)-1-methylpyridinium iodide (DAMPI) probes of increasing molecular size. Staining large zeolite crystals with MFI (ZSM-5) topology and subsequent mapping of the resulting fluorescence using confocal fluorescence microscopy reveal differences in structural integrity: the 90° intergrowth sections of MFI crystals are prone to develop structural imperfections, which act as entrance routes for the probes into the zeolite crystal. Polarization-dependent measurements provide evidence for the probe molecule's alignment within the MFI zeolite pore system. The developed method was extended to BEA (Beta) crystals, showing that the previously observed hourglass pattern is a general feature of BEA crystals with this morphology. Furthermore, the probes can accurately identify at which crystal faces of BEA straight or sinusoidal pores open to the surface. The results show this method can spatially resolve the architecture-dependent internal pore structure of microporous materials, which is difficult to assess using other characterization techniques such as X-ray diffraction. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  10. ZEOLITE PERFORMANCE AS AN ANION EXCHANGER FOR ARSENIC SEQUESTRATION IN WATER

    Science.gov (United States)

    Zeolites are well known for their use in ion exchange and acid catalysis reactions. The use of zeolites in anion or ligand exchange reactions is less studied. The NH4+ form of zeolite Y (NY6, Faujasite) has been tested in this work to evaluate its performance for arsenic removal...

  11. Preparation of zeolite-A/chitosan hybrid composites and their bioactivities and antimicrobial activities.

    Science.gov (United States)

    Yu, Liang; Gong, Jie; Zeng, Changfeng; Zhang, Lixiong

    2013-10-01

    Zeolite-A/chitosan hybrid composites with zeolite contents of 20-55 wt.% were prepared by in situ transformation of silica/chitosan mixtures in a sodium aluminate alkaline solution through impregnation-gelation-hydrothermal synthesis. The products were characterized by X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mercury penetration porosimetry. Their in vitro bioactivities were examined using as-synthesized and Ca(2+)-exchanged hybrid composites in simulated body fluid (SBF) for hydroxyapatite (HAP) growth. Their antimicrobial activities for Escherichia coli (E. coli) in trypticase soy broth (TSB) were evaluated using Ag(+)-exchanged hybrid composites. The zeolite-A/chitosan hybrid composites could be prepared as various shapes, including cylinders, plates and thin films. They possessed macropores with pore sizes ranging from 100 to 300 μm and showed compressive mechanical strength as high as 3.2 MPa when the zeolite content was 35 wt.%. Fast growth on the Ca(2+)-exchanged hybrid composites was observed with the highest weight gain of 51.4% in 30 days. The 35 wt.% Ag(+)-exchanged hybrid composite showed the highest antimicrobial activity, which could reduce the 9×10(6) CFU mL(-1)E. coli concentration to zero within 4h of incubation time with the Ag(+)-exchanged hybrid composite amount of 0.4 g L(-1). The bioactivity and antimicrobial activity could be combined by ion-exchanging the composites first with Ca(2+) and then with Ag(+). These zeolite-A/chitosan hybrid composites have potential applications on tissue engineering and antimicrobial food packaging. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Design and characterization of chitosan/zeolite composite films--Effect of zeolite type and zeolite dose on the film properties.

    Science.gov (United States)

    Barbosa, Gustavo P; Debone, Henrique S; Severino, Patrícia; Souto, Eliana B; da Silva, Classius F

    2016-03-01

    Chitosan films can be used as wound dressings for the treatment of chronic wounds and severe burns. The antimicrobial properties of these films may be enhanced by the addition of silver. Despite the antimicrobial activity of silver, several studies have reported the cytotoxicity as a factor limiting its biomedical applications. This problem may, however, be circumvented by the provision of sustained release of silver. Silver zeolites can be used as drug delivery platforms to extend the release of silver. The objective of this study was to evaluate the addition of clinoptilolite and A-type zeolites in chitosan films. Sodium zeolites were initially subjected to ion-exchange in a batch reactor. Films were prepared by casting technique using a 2% w/w chitosan solution and two zeolite doses (0.1 or 0.2% w/w). Films were characterized by thermal analysis, color analysis, scanning electron microscopy, X-ray diffraction, and water vapor permeation. The results showed that films present potential for application as dressing. The water vapor permeability is one of the main properties in wound dressings, the best results were obtained for A-type zeolite/chitosan films, which presented a brief reduction of this property in relation to zeolite-free chitosan film. On the other hand, the films containing clinoptilolite showed lower water vapor permeation, which may be also explained by the best distribution of the particles into the polymer which also promoted greater thermal resistance.

  13. Modifikasi Zeolit Dengan Tembaga (Cu) Dan Uji Sifat Katalitiknya Pada Reaksi Esterifikasi

    OpenAIRE

    Arjek, Orien Claudia Handayani; Fatimah, Is

    2017-01-01

    Zeolite modification with Cu has been conducted. Material modification is done by impregnating Cu through a zeolite powder reflux process with CuSO4.5H2O solution so that theoretical Cu concentration is 5% followed by oxidation and reduction of solids. Material characterization was performed by x-ray diffraction analysis (XRD), Fourier Transform Infra-Red (FTIR) and acidity testing of Cu/Zeolite catalyst.The results showed that the crystallinity level of Cu/Zeolite did not change significantl...

  14. Effects of Zeolite (Clinoptelolite on Performance Characteristics of

    Directory of Open Access Journals (Sweden)

    A Hassan Abadim

    2011-12-01

    Full Text Available A 70-days experiment was conducted to investigate the effects of natural zeolite (clinoptelolite on the performance of commercial laying hens. 288 Hy-Line W36 strain laying hens (50 weeks old were allotted to 6 dietary treatments including basal diet as control and basal diet supplemented with 1, 2, 3, 4 and 5% zeolite that were fed ad -libitum throughout the experiment. Experimental diets for the 6 treatments were prepared to be iso-caloric and iso-nitrogenous. A completely randomized design with six treatments, eight replicates of six birds per replicate was used at this experiment. Daily feed intake (DFI, feed conversion ratio (FCR, egg production, egg weight, egg white quality, eggshell quality (thickness and percentage and body weight changes were measured during the experiment. Results of this experiment showed that DFI, FCR, egg production and egg abnormality were not significantly (P>0.05 affected by zeolite supplementation. Zeolite supplementation significantly increased egg weight, eggshell thickness and live body weight gain of the hens. Dietary zeolite significantly decreased haugh unit of the eggs. In conclusion, natural zeolite significantly improved egg weight and eggshell quality, decreased haugh unit and live weight gain, and had no significant effects on other parameters.

  15. Nanodispersed Suspensions of Zeolite Catalysts for Converting Dimethyl Ether into Olefins

    Science.gov (United States)

    Kolesnichenko, N. V.; Yashina, O. V.; Ezhova, N. N.; Bondarenko, G. N.; Khadzhiev, S. N.

    2018-01-01

    Nanodispersed suspensions that are effective in DME conversion and stable in the reaction zone in a three-phase system (slurry reactor) are obtained from MFI zeolite commercial samples (TsVM, IK-17-1, and CBV) in liquid media via ultrasonic treatment (UST). It is found that the dispersion medium, in which ultrasound affects zeolite commercial sample, has a large influence on particle size in the suspension. UST in the aqueous medium produces zeolite nanoparticles smaller than 50 nm, while larger particles of MFI zeolite samples form in silicone or hydrocarbon oils. Spectral and adsorption data show that when zeolites undergo UST in an aqueous medium, the acid sites are redistributed on the zeolite surface and the specific surface area of the mesopores increases. Preliminary UST in aqueous media of zeolite commercial samples (TsVM, IK-17-1, and CBV) affects the catalytic properties of MFI zeolite nanodispersed suspensions. The selectivity of samples when paraffins and olefins form is largely due to superacid sites consisting of OH groups of hydroxonium ion H3O+.

  16. Síntese de zeólita tipo NaA a partir de caulim para obtenção de zeólita 5A através de troca iônica Synthesis of NaA zeolites from kaolin for obtaining 5A zeolites through ion exchange

    Directory of Open Access Journals (Sweden)

    C. R. Melo

    2010-12-01

    Full Text Available A síntese de zeólitas com o intuito de utilizá-las posteriormente como materiais adsorventes exige rigoroso controle das variáveis de processamento. Para cada tipo diferente de zeólita, existem variáveis de processo distintas para obtenção do tipo específico desejado. Neste trabalho os objetivos foram obter zeólita NaA partindo de caulim, para posteriormente obter zeólita 5A por meio de troca iônica com esta zeólita anteriormente sintetizada. Estas zeólitas, por sua vez, podem ser usadas como adsorventes altamente seletivos para adsorver, por exemplo, metais pesados de efluentes industriais. Os resultados obtidos foram satisfatórios, a metodologia utilizada mostrou-se eficiente. A partir do metacaulim comercial utilizado, obteve-se com sucesso zeólita tipo NaA, e por meio de trocas iônicas obteve-se zeólita 5A. A porcentagem de sódio trocada na zeólita final foi 61,4%.Zeolites synthesis as adsorbing materials requires accurate control of the variables. There are distinct process variables for obtaining specific desired types depending on each different kind of zeolite to be synthesized. This paper was aimed at obtaining NaA zeolites from kaolin in order to obtain zeolites A afterwards through ionic exchange with the previously synthesized zeolite. These zeolites can then be used as highly selective adsorbents to adsorb, for instance, heavy metals in industrial effluents. The results obtained were satisfactory, the methodology was efficient. From the commercial metakaolin used NaA zeolite was obtained successfully, and through ionic exchanges 5A zeolite was obtained. The exchangeable sodium percentage in the final zeolite was 61.4%.

  17. Removal of yellow 5 by a zeolitic material conditioned with iron

    International Nuclear Information System (INIS)

    Alcantara C, A.

    2010-01-01

    The waste waters are at the present time a serious problem because are contaminated by diverse industrial wastes among which are azo dyes used to dye a lot of products, and although there are various methods for the removal of these colorants do not are effective sufficiently, so that diverse techniques more sophisticated have been proposed, such as the elimination by sorption processes. Zeolites are materials found in various regions of Mexico and due to have a good sorption capacity are used to remove metals. In this paper a zeolitic material of the Chihuahua State was conditioned with FeCl 3 and used for remove yellow 5 (tartrazine) in aqueous solutions, also the sorption capacity of modified zeolite with FeCl 3 was examined for the azo dy yellow 5 in aqueous solutions. The sorption kinetics results was adapted to the pseudo second order model, indicating that the process is chemisorption, the sorption isotherms at different temperatures were adjusted to the Langmuir-Freundlich model, which usually it is adapt to systems with heterogeneous adsorbents. On the other hand, the ph value of the aqueous solutions does not affect on the sorption of this dye by the zeolitic material. (Author)

  18. A survey on radon reduction efficiency of zeolite and bentonite in a chamber with artificially elevated radon concentration

    International Nuclear Information System (INIS)

    Mortazavi, S.M.J.

    2007-01-01

    Complete text of publication follows. Objective: Zeolite which is made of a special crystalline structure is a naturally occurring mineral group and can be used in radioactive waste management for site remediation /decontamination. There are a wide variety of naturally occurring and synthetic zeolites, each with a unique structure. The cations in zeolite are highly mobile and can be exchanged for other cationic species. On the other hand, bentonite forms from weathering of volcanic ash. This material may be used as an engineering barrier to enclose nuclear waste. In this study, radon reducing properties of zeolite and bentonite have been investigated. Methods: Using radioactive lantern mantle, a radon prone area with radon levels reaching the EPA's action level (200 Bq/m 3 ) was designed. Two sets of identical chambers (cylindrical chambers, diameter 10 cm, height 16 cm) were used in this study. No zeolite/bentonite was used in the 1 st set of the chambers. A thin layer of either zeolite or bentonite powder was applied to the base of the first set of chambers. An unburned radioactive lantern mantle (activity 800 Bq) was placed in all chambers (both sets) to artificially increase the radon level inside the chamber and simulate the condition of a radon prone area. Radon level monitoring was performed by using a PRASSI portable radon gas survey meter. Results: After placing the cap on its place, the radon levels inside the 1 st set of the chambers were 871.9, 770.3, 769.2 and 635.7 Bq/m 3 after 15, 30, 45 and 60 minutes respectively. Zeolite significantly decreased the radon concentration inside the chambers and radon levels were 367.9, 435.4, 399.0 and 435.4 Bq/m 3 after 15, 30, 45 and 60 minutes. The observed reduction in the radon level was statistically significant. As the radon concentrations in identical chambers with Bentonite were 550.7, 526.5, 536.2 and 479.8 Bq/m 3 after 15, 30, 45 and 60 minutes respectively, it is evident that zeolite is more efficient in

  19. Immobilization technology for krypton in amorphous zeolite

    International Nuclear Information System (INIS)

    Takusagawa, Atsushi; Ishiyama, Keiichi

    1989-01-01

    Radioactive krypton recovered from the offgas of a reprocessing plant requires long-term storage on the order of 100 years. Immobilization technology for krypton into amorphous zeolite 5A is considered one of the best methods for long-term storage. In this report, conditions for immobilization treatment and stability of amorphous zeolite 5A loaded krypton against heat, radiation and water are discussed, and a treatment system using this technology is described. (author)

  20. Removal of paraquat solution onto zeolite material

    Science.gov (United States)

    Sirival, Rujikarn; Patdhanagul, Nopbhasinthu; Preecharram, Sutthidech; Photharin, Somkuan

    2018-04-01

    The purpose of this research was to study the adsorption of paraquat herbicides onto zeolite Y materials by the batch method. Three adsorbents material: Zeolite-3, Zeolite-10, and Zeolite-100 were Si/Al ratio at 3.58, 8.57 and 154.37, respectively. The factors for adsorption of paraquat as follows, adsorption time, initial concentrations of paraquat, pH and adsorption isotherm were investigated. The results showed that zeolite-10 had higher adsorption capacity than zeolite-3 and zeolite-100. The appropriate conditions for adsorption were 24 h., Zeolite 0.1 g., Initial paraquat concentration 100 ppm at pH 6. The adsorption isotherm was found to correspond with Langmuir Isotherm and the maximum paraquat adsorption is 26.38 mg/g for zeolite-10, 21.41 mg/g and 9.60 mg/g for zeolite-3 and zeolite-100, respectively. The characterization of zeolite material with XRD, XRF and BET. Furthermore, the zeolite materials applied to remove other organic and inorganic wastewater.

  1. Fly ash from a Mexican mineral coal. II. Source of W zeolite and its effectiveness in arsenic (V) adsorption

    International Nuclear Information System (INIS)

    Medina, Adriana; Gamero, Procoro; Almanza, Jose Manuel; Vargas, Alfredo; Montoya, Ascencion; Vargas, Gregorio; Izquierdo, Maria

    2010-01-01

    Coal-fired plants in Coahuila (Mexico) produce highly reactive fly ash (MFA), which is used in a one-step process as a raw material in producing zeolite. We explored two routes in the synthesis of zeolite: (a) direct MFA zeolitization, which resulted in the formation of W zeolite with KOH and analcime with NaOH and (b) a MFA fusion route, which resulted in the formation of zeolite W or chabazite with KOH and zeolite X or P with NaOH. No residual crystalline phases were present. When LiOH was employed, ABW zeolite with quartz and mullite were obtained. For both zeolitization routes, the nature of the alkali (KOH, NaOH, LiOH), the alkali/MFA ratio (0.23-1.46), and the crystallization temperature and time (90-175 o C; 8-24 h) were evaluated. Additionally, the effect of temperature and time on MFA fusion was studied. W zeolite was obtained by both zeolitization methods. The direct route is preferred because it is a straightforward method using soft reaction conditions that results in a high yield of low cost zeolites with large crystal agglomerates. It was demonstrated that aluminum modified W zeolite has the ability to remove 99% of the arsenic (V) from an aqueous solution of Na 2 HAsO 4 .7H 2 O originally containing 740 ppb.

  2. Fly ash from a Mexican mineral coal. II. Source of W zeolite and its effectiveness in arsenic (V) adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Medina, Adriana [CINVESTAV IPN-Unidad Saltillo, Carretera Saltillo-Monterrey Km 13.5, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Gamero, Procoro, E-mail: pgamerom@hotmail.com [CINVESTAV IPN-Unidad Saltillo, Carretera Saltillo-Monterrey Km 13.5, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Almanza, Jose Manuel [CINVESTAV IPN-Unidad Saltillo, Carretera Saltillo-Monterrey Km 13.5, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Vargas, Alfredo; Montoya, Ascencion [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, G.A. Madero, C.P. 07730, Distrito Federal (Mexico); Vargas, Gregorio [CINVESTAV IPN-Unidad Saltillo, Carretera Saltillo-Monterrey Km 13.5, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Izquierdo, Maria [Instituto de Ciencias de la Tierra ' Jaume Almera' , CSIC, C/Luis Sole Sabaris, s/n 08028 Barcelona (Spain)

    2010-09-15

    Coal-fired plants in Coahuila (Mexico) produce highly reactive fly ash (MFA), which is used in a one-step process as a raw material in producing zeolite. We explored two routes in the synthesis of zeolite: (a) direct MFA zeolitization, which resulted in the formation of W zeolite with KOH and analcime with NaOH and (b) a MFA fusion route, which resulted in the formation of zeolite W or chabazite with KOH and zeolite X or P with NaOH. No residual crystalline phases were present. When LiOH was employed, ABW zeolite with quartz and mullite were obtained. For both zeolitization routes, the nature of the alkali (KOH, NaOH, LiOH), the alkali/MFA ratio (0.23-1.46), and the crystallization temperature and time (90-175 {sup o}C; 8-24 h) were evaluated. Additionally, the effect of temperature and time on MFA fusion was studied. W zeolite was obtained by both zeolitization methods. The direct route is preferred because it is a straightforward method using soft reaction conditions that results in a high yield of low cost zeolites with large crystal agglomerates. It was demonstrated that aluminum modified W zeolite has the ability to remove 99% of the arsenic (V) from an aqueous solution of Na{sub 2}HAsO{sub 4}.7H{sub 2}O originally containing 740 ppb.

  3. Thermal Analysis of Lampung Zeolite as Ion Cesium Replacement

    International Nuclear Information System (INIS)

    Aslina-Br-Ginting; Dian-Anggraini; Arif-Nugroho

    2007-01-01

    Zeolite have the cation can move freely and as exchangeable partly or totally with other cations. Therefore, it can serve the purpose of ion exchanger very selectively to ion cesium which is present in fuel waste. In this research analysis of pore surface area, radius pore, and adsorption have been done. After the characters of Lampung zeolite is known and then analysis of cation exchange capacity (CEC) toward ion 137 Cs is conducted, analysis of Lampung zeolite adsorption to ion 137 Cs in waste of fissile product and in research waste is subsequently done. Result of analysis show Lampung zeolite has surface area of 10,0478 m 2 , specific surface area of 47,0841 m 2 /g, pore radius of 19,3020 o A and adsorption of 24,500 cc/g. For application as a ion exchange, Lampung zeolite can adsorb ion 137 Cs reaching maximum at concentration of CsCl 0,5 N with the contact time 1 day and the optimum KTK value is 0,8360 m eq/g. While Lampung zeolite is able to adsorb 86,4 % ion Cs in waste of fission product. (author)

  4. Preparation of highly ordered cubic NaA zeolite from halloysite mineral for adsorption of ammonium ions

    International Nuclear Information System (INIS)

    Zhao Yafei; Zhang Bing; Zhang Xiang; Wang Jinhua; Liu Jindun; Chen Rongfeng

    2010-01-01

    Well-ordered cubic NaA zeolite was first synthesized using natural halloysite mineral with nanotubular structure as source material by hydro-thermal method. SEM and HRTEM images indicate that the synthesized NaA zeolite is cubic-shaped crystal with planar surface, well-defined edges and symmetrical and uniform pore channels. The adsorption behavior of ammonium ions (NH 4 + ) from aqueous solution onto NaA zeolite was investigated as a function of parameters such as equilibrium time, pH, initial NH 4 + concentration, temperature and competitive cations. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. A maximum adsorption capacity of 44.3 mg g -1 of NH 4 + was achieved. The regeneration and reusable ability of this adsorbent was evaluated, and the results indicated that the recovered adsorbent could be used again for NH 4 + removal with nearly constant adsorption capacity. Thermodynamic parameters such as change in free energy (ΔG 0 ), enthalpy (ΔH 0 ) and entropy (ΔS 0 ) were also determined, which indicated that the adsorption was a spontaneous and exothermic process at ambient conditions. Compared with other adsorbents, the as-synthesized NaA zeolite displays a faster adsorption rate and higher adsorption capacity, which implies potential application for removing NH 4 + pollutants from wastewaters.

  5. Study of the Cd (II) removal in the presence of methyl orange with a natural zeolite conditioned with iron nanoparticles

    International Nuclear Information System (INIS)

    Xingu C, E. G.

    2015-01-01

    This work presents a study on the removal of cadmium and/or methyl-orange dye in aqueous solution, using natural zeolite clinoptilolite, as sodium homo-ionized and impregnated with iron nanoparticles. Iron nanoparticles were synthesized in the presence of the zeolite by chemical reduction. The evaluation of the removal ability was performed in a monocomponent (cadmium or methyl-orange dye) system by varying the contact time and its initial concentration. Removal capacity in a bi-component (cadmium and methyl orange) system was also studied while varying their concentrations. The characterization of the zeolites, before and after the sorption process, was carried out using several analytical techniques. The characteristics of zeolite clinoptilolite and iron particles were observed by scanning electron microscopy. The iron particles showed diameter sizes between 60 and 200 nm, localized on the surface of the zeolite. By IR spectroscopy no structural changes were detected for any of the treatments made to the zeolitic materials. By X-ray diffraction the clinoptilolite crystalline phase was mainly identified, however, it failed to detect any phase of iron in the zeolite impregnated with iron nanoparticles. Moessbauer spectroscopy indeed detected the impregnated iron phase as iron borides. The homo-ionized and iron nanoparticles impregnated zeolite showed no change in the specific surface area, or the isoelectric point, their values were 22.3 m"2/g and ph 9.8, respectively. However, whereas the active site density for the homo-ionized zeolite was 2.87 sites/nm"2, for iron nanoparticles impregnated zeolite was 20.32 sites/nm"2. As a result of the analysis of the isotherms of cadmium, the maximum sorption capacity of the homo-ionized zeolite was 35.03 mg/g and for the iron nanoparticles impregnated zeolite was 36.43 mg/g. These maximum sorption capacities represent up to 85% of removed cadmium from concentrations of 50 to 600 mg/L. For the removal of methyl orange dye

  6. Environmental applications of natural zeolitic materials based on their ion-exchange properties

    International Nuclear Information System (INIS)

    Colella, C.

    1998-01-01

    Natural zeolites, such as clinoptilolite, chabazite, phillipsite and mordenite, exhibit good selectivities for some water pollutants, e.g., Cs + , NH 4 + and Pb 2+ . Zeolite-rich tuffs may be therefore utilized for removing the above and other cations from wastewaters before discharge. Continuous processes with fixed beds are usually employed for water purification, such as those in service in the U.S.A for ammonium removal from municipal sewage. Direct action of the ion exchanger is needed when the pollutant must be removed from soil and trapped in the zeolite framework. Discontinuous processes (addition of zeolite to the waste solution) are also possible, provided the polluted zeolitic sludge is stabilized-solidified in a cement matrix matrix before disposal. Removal of radionuclides from nuclear power plant waters with natural zeolites is discussed

  7. An integrated remediation system using synthetic and natural zeolites for treatment of wastewater and contaminated sediments

    International Nuclear Information System (INIS)

    Rios Reyes, Carlos; Appasamy, Danen; Clive, Roberts

    2011-01-01

    The major sources of water pollution can be classified as municipal, industrial, and agricultural. Different types of polluted aqueous effluents and sediments may be produced, which contain relatively high levels of heavy metals. During the 1990s, the large-scale development of constructed wetlands around the world drew much attention from public and environmental groups. The present study looks at the use of an integrated remediation system using zeolites for the treatment of wastewater and sediments. Zeolites have been widely studied in the past 10 years due to their attractive properties such as molecular-sieving, high cation exchange capacities, and their affinity for heavy metals. Coal industry by-products-based zeolites (faujasite type) have been tested as an effective and low-cost novel alternative for wastewater treatment, particularly their removing of heavy metals. On the other hand, a preliminary laboratory-scale experiment was conducted on the use of natural zeolites (clinoptilolite type) for the retention of heavy metals from canal sediments. Experimental work revealed promising results, which could be replicated on a bigger scale. Although this has been developed for canal sediments, the remediation strategy can be adapted to different waterways such as rivers. The development of the proposed remediation system in a specific experimental site as the major part of an innovation park can provide great benefits to a population living near contaminated effluents. It provides not only opportunities for the mitigation of environmental impact, improving water quality and landscape amenity, but also allows for several recreational opportunities

  8. SYNTHESIS AND CHARACTERIZATION OF POLYIMIDE-ZEOLITE MIXED MATRIX MEMBRANE

    Directory of Open Access Journals (Sweden)

    Budiyono Budiyono

    2012-02-01

    Full Text Available Biogas has become an attractive alternative energy source due to the limitation of energy from fossil. In this study, a new type of mixed matrix membrane (MMM consisting of polyimide-zeolite was synthesized and characterized for biogas purification. The MMM consists of medium concentration of polymer (20% wt polyimide, 80% N-Methyl-2-pyrrolidone (NMP and 25% zeolite 4A in total solid were prepared by a dry/wet phase inversion technique.  The fabricated MMM was characterized using SEM, DSC, TGA and gas permeation. Post treatment coating procedure was also conducted. The research showed that surface coating by 3% silicone rubber toward MMM PI 20% gave the significant effect to improve membrane selectivity. The ideal selectivity for CO2/CH4 separation increased from 0.99 for before coating to 7.9 after coating for PI-Zeolite MMM, respectively. The results suggest that PI-Zeolite MMM with good post treatment procedure will increase the membrane selectivity and permeability with more saver polymer requirement as well as energy saving due to low energy for mixing.

  9. Na-noparticles of activated natural zeolite on textiles for protection and therapy

    Directory of Open Access Journals (Sweden)

    Ivančica Kovaček

    2009-10-01

    Full Text Available Activated natural zeolite clinoptilolite is microporous hydrated aluminosilicates crystals with well-defined structures containing AlO4 and SiO4 tetrahedral linked through the common oxygen atoms. It is to point out that zeolites act as strong adsorbents and ion-exchangers but having many other useful properties. Due to its cationexchange ability, zeolites have catalytic properties and, for that, multiple uses in medicine and industry, agriculture, water purification and detergents. Zeolites are nontoxic substance, excellent for UVR and microbes protection, for proteins and small molecules such as glucose adsorption. In this paper its positive effect on the metabolism of living organisms and its anticancerogenic, antiviral, antimetastatic and antioxidant effect. The activity of natural zeolite as natural immunostimulator was presented as well as its help in healing wounds. Therefore, the present paper is an attempt to modify cotton (by mercerization and polyester (by alkaline hydrolysis fabrics for summer clothing with addition of natural zeolite nanoparticles for achieving UV and antibacterial protective textiles

  10. for zeolite coating

    Directory of Open Access Journals (Sweden)

    Carlos Renato Rambo

    2006-01-01

    Full Text Available Biotemplating is the processing of microcellular ceramics by reproduction of natural morphologies, where the microstructural features of the biotemplate are maintained in the biomorphic ceramic. Different biotemplates with distinct pore anatomies were used to produce biomorphic supports for the zeolite coating: wood, cardboard, sea-sponge and sisal. The biomorphic ceramics were produced by distinguished processing routes: Al-gas infiltration-reaction, liquid-metal infiltration, dip-coating and sol-gel synthesis, in order to produce nitrides, carbides and oxides, depending on the processing conditions. The zeolite coating was performed by hydrothermal growth of MFI-type (Silicalite-1 and ZSM-5 zeolite crystals onto the internal pore walls of the biomorphic templates. The final biomorphic ceramic-zeolite composites were physically characterized, evaluated in terms of their gas adsorption capabilities and correlated to their microstructure and specific pore anatomy. The combination of the properties of the biomorphic ceramics with the adsorption properties of zeolites results in materials with distinct properties as potential candidates for adsorption and catalytic applications due to their characteristic porosity, molecular sieving capabilities and high thermo-mechanical strength.

  11. An Extra-Large-Pore Zeolite with 24×8×8-Ring Channels Using a Structure-Directing Agent Derived from Traditional Chinese Medicine.

    Science.gov (United States)

    Zhang, Chuanqi; Kapaca, Elina; Li, Jiyang; Liu, Yunling; Yi, Xianfeng; Zheng, Anmin; Zou, Xiaodong; Jiang, Jiuxing; Yu, Jihong

    2018-03-12

    Extra-large-pore zeolites have attracted much interest because of their important applications because for processing larger molecules. Although great progress has been made in academic science and industry, it is challenging to synthesize these materials. A new extra-large-pore zeolite SYSU-3 (Sun Yat-sen University no. 3) has been synthesized by using a novel sophoridine derivative as an organic structure-directing agent (OSDA). The framework structure was solved and refined using continuous rotation electron diffraction (cRED) data from nanosized crystals. SYSU-3 exhibits a new zeolite framework topology, which has the first 24×8×8-ring extra-large-pore system and a framework density (FD) as low as 11.4 T/1000 Å 3 . The unique skeleton of the OSDA plays an essential role in the formation of the distinctive zeolite structure. This work provides a new perspective for developing new zeolitic materials by using alkaloids as cost-effective OSDAs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Positron spectroscopy studies of zeolites

    Science.gov (United States)

    Hung, Ku-Jung

    The lineshapes of two-dimensional angular correlation of electron-positron annihilation radiation (2D-ACAR) in alumina and several zeolites were measured as a function of internal surface areas. In all cases, the lineshape parameter S from 2D-ACAR spectra were found to vary proportionally with internal surface area. In order to investigate the Bronsted acidity in NaHY zeolite, the lineshape parameter evaluation from 2D-ACAR measurements for varied acidity in NaHY zeolites by ion-exchange and thermal desorption were presented. The result from this investigation has demonstrated that the Bronsted acidity in NaHY zeolite was found to vary linearly with the lineshape parameter of the angular correlation spectrum of the sample. The lineshapes of 2D-ACAR spectra were determined for different base adsorbed HY-zeolite samples under a temperature controlled heating system in order to investigate, in-situ, the acid strength and number of Bronsted acid sites in the sample. Results have shown that the lineshape parameter of the angular correlation spectrum of the sample increases with the strength of adsorbed base and decreases with the number of Bronsted acid sites in the sample. This indicated that the lineshape parameter is sensitive to all of the strengths and concentrations of Bronsted acid sites in the HY-zeolite samples. The result from this study has also demonstrated that the large size base, pyridine, would reduce the possibility of positronium formation in the sample by filling the cage to eliminate the internal surface areas where the positroniums are likely to form. However, the small size base, ammonia, did not show any effect on the internal surface areas. Owing to the fact that this technique monitors only the Bronsted acid sites that situate on the surface which relates to the catalytic activity, there is little ambiguity about the location of the source of information obtained. The findings presented in this dissertation point out the fact that such lineshape

  13. Thermal behavior of natural zeolites

    International Nuclear Information System (INIS)

    Bish, D.L.

    1993-01-01

    Thermal behavior of natural zeolites impacts their application and identification and varies significantly from zeolite to zeolite. Zeolites evolve H 2 0 upon heating, but recent data show that distinct ''types'' of water (e.g., loosely bound or tightly bound zeolitic water) do not exist. Rather water is bound primarily to extra-framework cations with a continuum of energies, giving rise to pseudocontinuous loss of water accompanied by a dynamic interaction between remaining H 2 0 molecules and extra-framework cations. These interactions in the channels of zeolites give rise to dehydration dependent on the extra-framework cation, in addition to temperature and water vapor pressure. The dehydration reaction and the extra-framework cation also affect the thermal expansion/contraction. Most zeolites undergo dehydration-induced contractions that may be anisotropic, although minor thermal expansion can be seen with some zeolites. Such contractions can be partially or completely irreversible if they involve modifications of the tetrahedral framework and/or if rehydration is sluggish. Thermally induced structural modifications are also driven initially by dehydration and the concomitant contraction and migration of extra-framework cations. Contraction is accommodated by rotations of structural units and tetrahedral cation-oxygen linkages may break. Thermal reactions that involve breaking of tetrahedral cation-oxygen bonds markedly irreversible and may be kinetically limited, producing large differences between short- and long-term heating

  14. Specific equilibrium behavior of hydrogen isotopes adsorbed onto synthetic zeolite A-type governed by lithium cations

    International Nuclear Information System (INIS)

    Takashima, Shoji; Kotoh, Kenji

    2013-01-01

    Highlights: • Isotherms for H 2 and D 2 adsorbed onto SZ-LiA at 77.4 K are shown. • The adsorption isotherms exhibit specific deviation in the range lower than 10 Pa. • SZ-LiA indicates the power of several 100-times at 0.1 Pa, compared with SZ-NaA. • Experimental isotherms are described empirically by a dual-site Langmuir equation. • The isotope effect on adsorption isotherms appears in the Langmuir constants. -- Abstract: Since synthetic zeolites (SZs) are powerfully adsorptive for hydrogen isotopes at cryogenic temperatures such as liquefied nitrogen, adsorption processes using these have been considered applicable to such as recovery of tritium from the lithium blanket of DT fusion reactor system. Onto these zeolites the adsorptions isotherms for hydrogen isotopes onto SZ-NaA, SZ-CaA and SZ-NaX at 77.4 K were already clarified experimentally and analytically. These isotherms exhibit similar profiles of Langmuir type. In this work, adsorption isotherms were examined for H 2 and D 2 on SZ-LiA at 77.4 K. SZ-LiA was made from SZ-NaA by exchanging its sodium ions for lithium ones, provided by TOSOH Corp. The experimental results demonstrate the specific equilibrium behavior of hydrogen isotopes adsorbed on SZ-LiA, deviating from isothermal profiles on SZ-CaA and SZ-NaX. SZ-LiA show the isothermal profiles of adsorption for H 2 and D 2 similar to on the conventional zeolites in the range from around 1 kPa to the atmospheric pressure, but exhibit a plateau around 1 mol/kg between 0.1 Pa and 100 Pa, while other zeolites show linearly profiling isotherms. This deviation indicates the adsorptive power of SZ-LiA remarkably greater than that of the others

  15. Molecular interactions of alcohols with zeolite BEA and MOR frameworks.

    Science.gov (United States)

    Stückenschneider, Kai; Merz, Juliane; Schembecker, Gerhard

    2013-12-01

    Zeolites can adsorb small organic molecules such as alcohols from a fermentation broth. Also in the zeolite-catalyzed conversion of alcohols to biofuels, biochemicals, or gasoline, adsorption is the first step. Several studies have investigated the adsorption of alcohols in different zeolites experimentally, but computational investigations in this field have mostly been restricted to zeolite MFI. In this study, the adsorption of C1-C4 alcohols in BEA and MOR was investigated using density functional theory (DFT). Calculated adsorption geometries and the corresponding energies of the designed cluster models were comparable to periodic calculations, and the adsorption energies were in the same range as the corresponding computational and experimental values reported in the literature for zeolite MFI. Thus, BEA and MOR may be good adsorption materials for alcohols in the field of downstream processing and catalysis. Aside from the DFT calculations, adsorption isotherms were determined experimentally in this study from aqueous solutions. For BEA, the adsorption of significant amounts of alcohol from aqueous solution was observed experimentally. In contrast, MOR was loaded with only a very small amount of alcohol. Although differences were found between the affinities obtained from gas-phase DFT calculations and those observed experimentally in aqueous solution, the computational data presented here represent molecular level information on the geometries and energies of C1-C4 alcohols adsorbed in zeolites BEA and MOR. This knowledge should prove very useful in the design of zeolite materials intended for use in adsorption and catalytic processes, as it allows adsorption behavior to be predicted via judiciously designed computational models.

  16. Distribution of metal and adsorbed guest species in zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Chmelka, B.F.

    1989-12-01

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes {sup 129}Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of {sup 129}Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, {sup 129}Xe NMR is insensitive to fine structural details at room temperature.

  17. Distribution of metal and adsorbed guest species in zeolites

    International Nuclear Information System (INIS)

    Chmelka, B.F.

    1989-12-01

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes 129 Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of 129 Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, 129 Xe NMR is insensitive to fine structural details at room temperature

  18. Separation of cesium and strontium with zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, T; Hashimoto, H [Tohoku Univ., Sendai (Japan). Research Inst. of Mineral Dressing and Metallurgy

    1976-06-01

    The basic studies of separation of cesium and strontium were made with specimens of zeolite, which are synthetic zeolites A, X and Y; synthetic mordenite; natural mordenite; and clinoptilolite. Ammonium chloride was used as eluent, because it was considered to be a most appropriate eluent in alkaline chlorides. Cesium was easily eluted from the zeolites A and X by ammonium chloride solution, but it was difficult to elute from the synthetic mordenite, natural mordenite and clinoptilolite by ammonium chloride solution, but it was difficult to elute from the zeolites A and X. The zeolite Y is the only one zeolite among these zeolites from which both of cesium and strontium were easily eluted by ammonium chloride solution. Strontium could be separated from cesium with zeolites by formation of Sr-EDTA chelate at pH above 11. In this process, cesium was only exchanged in zeolite column, but strontium flow out from it.

  19. Separation of cesium and strontium with zeolites

    International Nuclear Information System (INIS)

    Kanno, Takuji; Hashimoto, Hiroyuki

    1976-01-01

    The basic studies of separation of cesium and strontium were made with specimens of zeolite, which are synthetic zeolites A, X and Y; synthetic mordenite; natural mordenite; and clinoptilolite. Ammonium chloride was used as eluent, because it was considered to be a most appropriate eluent in alkaline chlorides. Cesium was easily eluted from the zeolites A and X by ammonium chloride solution, but it was difficult to elute from the synthetic mordenite, natural mordenite and clinoptilolite by ammonium chloride solution, but it was difficult to elute from the zeolites A and X. The zeolite Y is the only one zeolite among these zeolites from which both of cesium and strontium were easily eluted by ammonium chloride solution. Strontium could be separated from cesium with zeolites by formation of Sr-EDTA chelate at pH above 11. In this process, cesium was only exchanged in zeolite column, but strontium flow out from it. (auth.)

  20. Unexpected Molecular Sieving Properties of Zeolitic Imidazolate Framework-8

    KAUST Repository

    Zhang, Chen; Lively, Ryan P.; Zhang, Ke; Johnson, Justin R.; Karvan, Oguz; Koros, William J.

    2012-01-01

    We studied molecular sieving properties of zeolitic imidazolate framework-8 (ZIF-8) by estimating the thermodynamically corrected diffusivities of probe molecules at 35 °C. From helium (2.6 Å) to iso-C 4H 10 (5.0 Å), the corrected diffusivity drops 14 orders of magnitude. Our results further suggest that the effective aperture size of ZIF-8 for molecular sieving is in the range of 4.0 to 4.2 Å, which is significantly larger than the XRD-derived value (3.4 Å) and between the well-known aperture size of zeolite 4A (3.8 Å) and 5A (4.3 Å). Interestingly, because of aperture flexibility, the studied C 4 hydrocarbon molecules that are larger than this effective aperture size still adsorb in the micropores of ZIF-8 with kinetic selectivities for iso-C 4H 8/iso-C 4H 10 of 180 and n-C 4H 10/iso-C 4H 10 of 2.5 × 10 6. These unexpected molecular sieving properties open up new opportunities for ZIF materials for separations that cannot be economically achieved by traditional microporous adsorbents such as synthetic zeolites. © 2012 American Chemical Society.

  1. Unexpected Molecular Sieving Properties of Zeolitic Imidazolate Framework-8

    KAUST Repository

    Zhang, Chen

    2012-08-16

    We studied molecular sieving properties of zeolitic imidazolate framework-8 (ZIF-8) by estimating the thermodynamically corrected diffusivities of probe molecules at 35 °C. From helium (2.6 Å) to iso-C 4H 10 (5.0 Å), the corrected diffusivity drops 14 orders of magnitude. Our results further suggest that the effective aperture size of ZIF-8 for molecular sieving is in the range of 4.0 to 4.2 Å, which is significantly larger than the XRD-derived value (3.4 Å) and between the well-known aperture size of zeolite 4A (3.8 Å) and 5A (4.3 Å). Interestingly, because of aperture flexibility, the studied C 4 hydrocarbon molecules that are larger than this effective aperture size still adsorb in the micropores of ZIF-8 with kinetic selectivities for iso-C 4H 8/iso-C 4H 10 of 180 and n-C 4H 10/iso-C 4H 10 of 2.5 × 10 6. These unexpected molecular sieving properties open up new opportunities for ZIF materials for separations that cannot be economically achieved by traditional microporous adsorbents such as synthetic zeolites. © 2012 American Chemical Society.

  2. Radiochemical and thermal studies of the copper(II)-exchanged form of synthetic zeolite linde sieve A

    International Nuclear Information System (INIS)

    Banerjee, S.P.

    1978-01-01

    Synthetic zeolite Linde Sieve A displays a double ion-sieve action. Only small cations can penetrate the single 6-rings into the beta cages. The radiochemical and thermal studies of copper(II)-exchanges form of 4A shows evidence of hydrated copper(II) ions in the zeolite structure. (author)

  3. Synthesis and Structure Determination of Large-Pore Zeolite SCM-14.

    Science.gov (United States)

    Luo, Yi; Smeets, Stef; Peng, Fei; Etman, Ahmed S; Wang, Zhendong; Sun, Junliang; Yang, Weimin

    2017-11-27

    SCM-14 (Sinopec Composite Material No. 14), a new stable germanosilicate zeolite with a 12×8×8-ring channel system, was synthesized using commercially available 4-pyrrolidinopyridine as organic structure-directing agents (OSDAs) in fluoride medium. The framework structure of SCM-14 was determined using rotation electron diffraction (RED), and refined against synchrotron X-ray powder diffraction (SXPD) data for both as-made and calcined materials. The framework structure of SCM-14 is closely related to that of three known zeolites: mordenite (MOR), GUS-1 (GON), and IM-16 (UOS). SCM-14 has the same projection as that of mordenite and GUS-1 when viewed along the 12-ring channels, and possesses two more straight 8-ring channels running perpendicular to the 12-ring channels. The structure of SCM-14 can be constructed by either the same layers as that of GUS-1 or the same columns as that of IM-16. Based on their structural relationship, three topologically reasonable hypothetical zeolites were predicted. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Characterization and antibacterial activity of silver exchanged regenerated NaY zeolite from surfactant-modified NaY zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik, E-mail: niknizam@fbb.utm.my

    2016-02-01

    The antibacterial activity of regenerated NaY zeolite (thermal treatment from cetyltrimethyl ammonium bromide (CTAB)-modified NaY zeolite and pretreatment with Na ions) loaded with silver ions were examined using the broth dilution minimum inhibitory concentration (MIC) method against Escherichia coli (E. coli ATCC 11229) and Staphylococcus aureus (S. aureus ATCC 6538). X-ray diffraction (XRD), attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and chemical elemental analyses were used to characterize the regenerated NaY and AgY zeolites. The XRD patterns indicated that the calcination and addition of silver ions on regenerated NaY zeolite did not affect the structure of the regenerated NaY zeolite as the characteristic peaks of the NaY zeolite were retained, and no new peaks were observed. The regenerated AgY zeolite showed good antibacterial activity against both bacteria strains in distilled water, and the antibacterial activity of the samples increased with increasing Ag loaded on the regenerated AgY zeolite; the regenerated AgY zeolite was more effective against E. coli than S. aureus. However, the antibacterial activity of the regenerated AgY was not effective in saline solution for both bacteria. The study showed that CTAB-modified NaY zeolite materials could be regenerated to NaY zeolite using thermal treatment (550 °C, 5 h) and this material has excellent performance as an antibacterial agent after silver ions loading. - Highlights: • Thermal treatment was used to regenerate surfactant modified zeolite. • The regenerated NaY zeolite formed was added with different silver loadings. • Regenerated AgY zeolite was tested for antibacterial activity on E. coli and S. aureus. • The antibacterial activity increased with increased of the amount of silver loadings. • The zeolite structure did not change with thermal and modification

  5. Characterization and antibacterial activity of silver exchanged regenerated NaY zeolite from surfactant-modified NaY zeolite

    International Nuclear Information System (INIS)

    Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik

    2016-01-01

    The antibacterial activity of regenerated NaY zeolite (thermal treatment from cetyltrimethyl ammonium bromide (CTAB)-modified NaY zeolite and pretreatment with Na ions) loaded with silver ions were examined using the broth dilution minimum inhibitory concentration (MIC) method against Escherichia coli (E. coli ATCC 11229) and Staphylococcus aureus (S. aureus ATCC 6538). X-ray diffraction (XRD), attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and chemical elemental analyses were used to characterize the regenerated NaY and AgY zeolites. The XRD patterns indicated that the calcination and addition of silver ions on regenerated NaY zeolite did not affect the structure of the regenerated NaY zeolite as the characteristic peaks of the NaY zeolite were retained, and no new peaks were observed. The regenerated AgY zeolite showed good antibacterial activity against both bacteria strains in distilled water, and the antibacterial activity of the samples increased with increasing Ag loaded on the regenerated AgY zeolite; the regenerated AgY zeolite was more effective against E. coli than S. aureus. However, the antibacterial activity of the regenerated AgY was not effective in saline solution for both bacteria. The study showed that CTAB-modified NaY zeolite materials could be regenerated to NaY zeolite using thermal treatment (550 °C, 5 h) and this material has excellent performance as an antibacterial agent after silver ions loading. - Highlights: • Thermal treatment was used to regenerate surfactant modified zeolite. • The regenerated NaY zeolite formed was added with different silver loadings. • Regenerated AgY zeolite was tested for antibacterial activity on E. coli and S. aureus. • The antibacterial activity increased with increased of the amount of silver loadings. • The zeolite structure did not change with thermal and modification

  6. Catalytic conversion of ethanol on H-Y zeolite

    Directory of Open Access Journals (Sweden)

    Čegar Nedeljko

    2005-01-01

    Full Text Available The catalytic activity of the H-form of synthetic zeolite NaY was examined in this study. The catalytic activity was determined according to the rate of ethanol conversion in a gas phase in the static system. In the conversion of ethanol on synthetic NaY zeolite at 585, 595, and 610 K, on which the reaction develops at an optimal rate, ethene and diethyl ether are evolved in approximately the same quantity. After transforming the NaY zeolite into the H-form, its catalytic activity was extremely increases so, the reaction develops at a significantly lower temperature with a very large increase in the reaction rate. The distribution of the products also changes, so that at lower temperatures diethyl ether is elvolved in most cases, and the development of ethene is favored at higher ones, and after a certain period of time there is almost complete conversion of ethanol into ethene. The increase in catalytic activity, as well as the change of selectivity of conversion of ethanol on the H-form of zeolite, is the result of removing Na+ cations in the NaY zeolite, so that more acidic catalyst is obtained which contains a number of acidic catalytically active centers, as well as a more powerful one compared to the original NaY zeolite.

  7. Cupric natural zeolites as microbic ides

    International Nuclear Information System (INIS)

    Contreras A, D.; Olguin G, M. T.; Alcantara D, D.; Burrola A, C.

    2009-01-01

    The Escherichia coli and the Candida albicans are considered contamination indicators for what these organisms reflect the water quality. The natural zeolites by their characteristics and properties, they could incorporate to a waters treatment system, as ion exchange, adsorbents and/or microbiocid agents, representing an alternative method of low cost. Inside this investigation work was found that depending on the microorganism type, it varies the quantity of cupric zeolite that is required to carry out the water disinfection, being great for the case of yeasts than the bacteria s. In addition to that marked differences are presented in the required time to reach this process. The characterization of the natural zeolite material, sodium and cupric, was realized by means of scanning electron microscopy, determining the elementary composition (Energy Dispersive Spectroscopy) of each one of them, and by X-ray diffraction. (Author)

  8. Synthesis of type A zeolite from calcinated kaolin

    International Nuclear Information System (INIS)

    Rodrigues, E.C.; Neves, R.F.; Souza, J.A.S.; Moraes, C.G.; Macedo, E.N.

    2011-01-01

    The mineral production has caused great concern in environmental and industrial scenario due to the effects caused to the environment. The industries of processing kaolin for paper are important economically for the state of Para, but produce huge quantities of tailings, which depend on large areas to be stocked. This material is rich in silico-aluminates can be recycled and used as raw material for other industries. The objective is to synthesize zeolite A at different temperatures of calcination and synthesis. The starting materials and synthesis of zeolite A have been identified and characterized through analysis of X-ray diffraction (DRX) and scanning electron microscopy (MEV). The synthesis process of zeolite A, using as source of silica and the aluminum metakaolin, which was calcined at temperatures of 700 ° C and 800 ° C for 2 hours of landing in a burning furnace type muffle. Observed in relation to the calcination of kaolin as the main phase, the metakaolin. This is just a removal of water from its structure, so we opted for the lower temperature, less energy consumption. The synthesis process of zeolite A, produced good results for the formation of zeolites type A, which were characterized with high purities. (author)

  9. Detergent zeolite filtration plant

    OpenAIRE

    Stanković Mirjana S.; Pezo Lato L.

    2003-01-01

    The IGPC Engineering Department designed basic projects for detergent zeolite filtration plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant with a capacity of 75,000 t/y was manufactured, at "Zeolite Mira", Mira (VE), Italy, in 1997, for increasing detergent zeolite production, from 50,000 to 100,000 t/y. The main goal was to increase the detergent zeoli...

  10. Synthesis and characterization of various zeolites and study of dynamic adsorption of dimethyl methyl phosphate over them

    International Nuclear Information System (INIS)

    Khanday, Waheed Ahmad; Majid, Sheikh Abdul; Chandra Shekar, S.; Tomar, Radha

    2013-01-01

    Graphical abstract: Thermal desorption pattern of DMMP over various zeolites (a) 1st desorption and (b) 2nd desorption. - Highlights: • Synthesis of Zeolite-A, MCM-22, Zeolite-X and Erionite by hydrothermal method. • Zeolites were characterized by using XRD, FTIR, BET, NH 3 -TPD, SEM and EDS techniques. • Dynamic adsorption of DMMP on zeolites was carried out using TPD plus chemisorption system. • Thermal desorption of DMMP on zeolites was carried using the same system. - Abstract: Zeolite-A, MCM-22, Zeolite-X and Erionite were synthesized successfully under hydrothermal conditions and were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Brunauer–Emmett–Teller (BET) surface area analysis and thermal programmed desorption (TPD). Dynamic adsorption of dimethyl methyl phosphate (DMMP) was carried out on these zeolites. Zeolite-X having high surface area among all four zeolites shows highest adsorption capacity followed by Erionite and MCM-22 where as Zeolite-A shows the least. For all zeolites adsorption was found to be high initially and it then decreases with increase in injected volume. Then desorption pattern was analyzed which shows two types of peaks, sharp peak representing desorption of physisorbed DMMP and a broad peak representing desorption of strongly chemisorbed DMMP

  11. Effect of different glasses in glass bonded zeolite

    International Nuclear Information System (INIS)

    Lewis, M.A.; Ackerman, J.P.; Verma, S.

    1995-01-01

    A mineral waste form has been developed for chloride waste salt generated during the pyrochemical treatment of spent nuclear fuel. The waste form consists of salt-occluded zeolite powders bound within a glass matrix. The zeolite contains the salt and immobilizes the fission products. The zeolite powders are hot pressed to form a mechanically stable, durable glass bonded zeolite. Further development of glass bonded zeolite as a waste form requires an understanding of the interaction between the glass and the zeolite. Properties of the glass that enhance binding and durability of the glass bonded zeolite need to be identified. Three types of glass, boroaluminosilicate, soda-lime silicate, and high silica glasses, have a range of properties and are now being investigated. Each glass was hot pressed by itself and with an equal amount of zeolite. MCC-1 leach tests were run on both. Soda-lime silicate and high silica glasses did not give a durable glass bonded zeolite. Boroaluminosilicate glasses rich in alkaline earths did bind the zeolite and gave a durable glass bonded zeolite. Scanning electron micrographs suggest that the boroaluminosilicate glasses wetted the zeolite powders better than the other glasses. Development of the glass bonded zeolite as a waste form for chloride waste salt is continuing

  12. Photo-catalysis water splitting by platinum-loaded zeolite A

    Science.gov (United States)

    Cheng, Jing; Gao, Changda; Jing, Ming; Lu, Jian; Lin, Hui; Han, Zhaoxia; Ni, Zhengji; Zhang, Dawei

    2018-05-01

    Under the λ≥420 nm visible light illumination, the Pt4+ ions exchanged LTA zeolite powders without further heat-treatment presented H2 evolution at a rate of 5 μl/(15 mg·h) via photocatalysis water splitting. It was shown that the efficiency of H2 generation by the Pt4+ exchanged LTA zeolite powders without further heat-treatment was higher than the counterpart of the samples with heat treatment. In addition, the samples with lower Pt loading concentration showed higher H2 evolution rate than those of higher Pt loading did. The higher H2 evolution efficiency can be attributed to the effective isolation of water molecules and Pt at the atomic or the few atom ‘cluster’ scale by LTA zeolite’s periodical porous structure, which ensures a more efficient electron transfer efficiency for H2 evolution. However, after extra heat treatment, the Pt atoms reduced from Pt4+ in LTA zeolite’s cavities may tend to migrate to the surface and then form nano-particles, which led to the lower H2 evolution efficiency.

  13. Bacterial inactivation in water by means of a combined process of pulsed dielectric barrier discharge and silver-modified natural zeolite

    International Nuclear Information System (INIS)

    Rodríguez-Méndez, B G; López-Callejas, R; Olguín, M T; Valencia-Alvarado, R; Peña-Eguiluz, R; Mercado-Cabrera, A; Alcántara-Díaz, D; Muñoz-Castro, A E; Hernández-Arias, A N; De la Piedad-Beneitez, A

    2014-01-01

    We propose a novel combined system of pulsed dielectric barrier discharges (PDBDs) and silver-modified natural zeolite (Ag–zeolite) in liquid in bubbles. The system was tested with the Escherichia coli bacteria immersed in water. In order to evaluate the efficiency of the system in bacterial inactivation a microbiological analysis was carried out; 9.82-ln of bacterial reduction was obtained using the combined system, whereas 0.43-ln of bacterial reduction was obtained using Ag–zeolite alone, and 6.26-ln with PDBD. The elapsed time was 10 minutes for the three treatments. (paper)

  14. Synthesis of Na-A and/or Na-X zeolite/porous carbon composites from carbonized rice husk

    International Nuclear Information System (INIS)

    Katsuki, Hiroaki; Komarneni, Sridhar

    2009-01-01

    Na-A and/or Na-X zeolite/porous carbon composites were prepared under hydrothermal conditions by NaOH dissolution of silica first from carbonized rice husk followed by addition of NaAlO 2 and in situ crystallization of zeolites i.e., using a two-step process. When a one-step process was used, both Na-A and Na-X zeolites crystallized on the surface of carbon. Na-A or Na-X zeolite crystals were prepared on the porous carbonized rice husk at 90 deg. C for 2-6 h by changing the SiO 2 /Al 2 O 3 , H 2 O/Na 2 O and Na 2 O/SiO 2 molar ratios of precursors in the two-step process. The surface area and NH 4 + -cation exchange capacity (CEC) of Na-A zeolite/porous carbon were found to be 171 m 2 /g and 506 meq/100 g, respectively, while those of Na-X zeolite/porous carbon composites were 676 m 2 /g and 317 meq/100 g, respectively. Na-A and Na-X zeolites are well-known microporous and hydrophilic materials while carbonized rice husk was found to be mesoporous (pores of ∼3.9 nm) and hydrophobic. These hybrid microporous-mesoporous and hydrophilic-hydrophobic composites are expected to be useful for decontamination of metal cations as well as organic contaminants simultaneously. - Graphical Abstract: Novel Na-X zeolite/porous carbon composite.

  15. β-Zeolite modified by ethylenediamine for sorption of Th(IV)

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Peng; Wu, Hanyu; Yuan, Ni; Yin, Zhuoxin; Pan, Duoqiang; Wu, Wangsuo [Lanzhou Univ. (China). Radiochemistry Lab.; Ministry of Education, Lanzhou (China). Key Lab. of Special Function Materials and Structure Design

    2017-08-01

    β-Zeolite-EDA was modified with ethylenediamine (EDA) after synthesized. The synthesized material was characterized and used for removal of Th(IV) from aqueous solutions. The influences of pH, ionic strength, contact time, temperature and humic acid (HA) on Th(IV) sorption onto synthesized β-zeolite-EDA was studied by batch technique. The dynamic process showed that the sorption of Th(IV) onto β-zeolite-EDA matched the pseudo-second-order kinetics model. The sorption of Th(IV) on β-zeolite-EDA was significantly dependent on pH values, the sorption percentage increased markedly at pH 3.5-4.5, and then maintained a steady state as pH values increased. Through simulating the sorption isotherms by Langmuir, Freundlich and Dubini-Radushkevich (D-R) models, it could be seen respectively that the sorption pattern of Th(IV) on β-zeolite-EDA was mainly controlled by surface complexation, and that the sorption processes was endothermic and spontaneous. The presence of HA increased Th(IV) sorption on β-zeolite-EDA.

  16. Influence of zeolite and cement additions on mechanical behavior of sandy soil

    Directory of Open Access Journals (Sweden)

    Hossein Mola-Abasi

    2016-10-01

    Full Text Available It is well known that the cemented sand is one of economic and environmental topics in soil stabilization. In this instance, a blend of sand, cement and other materials such as fiber, glass, nanoparticle and zeolite can be commercially available and effectively used in soil stabilization in road construction. However, the influence and effectiveness of zeolite on the properties of cemented sand systems have not been completely explored. In this study, based on an experimental program, the effects of zeolite on the characteristics of cemented sands are investigated. Stabilizing agent includes Portland cement of type II and zeolite. Results show the improvements of unconfined compressive strength (UCS and failure properties of cemented sand when the cement is replaced by zeolite at an optimum proportion of 30% after 28 days. The rate of strength improvement is approximately between 20% and 78%. The efficiency of using zeolite increases with the increases in cement amount and porosity. Finally, a power function of void-cement ratio and zeolite content is demonstrated to be an appropriate method to assess UCS of zeolite-cemented mixtures.

  17. Fluoride removal from double four-membered ring (D4R) units in As-synthesized Ge-containing zeolites

    KAUST Repository

    Liu, Xiaolong; Ravon, Ugo; Tuel, Alain

    2011-01-01

    Fluoride anions can be removed from the framework of as-prepared Ge-containing zeolites ITQ-13 and ITQ-17 without modification of the crystallinity and crystal habit. By contrast to all-silica ITQ-13 for which fluoride could not get out from D4R

  18. Removal of NO {sub x} by microwave reactor with ammonium bicarbonate and Ga-A zeolites at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Z.S. [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)]. E-mail: weizaishan98@163.com; Du, Z.Y. [School of Light Industry and Chemical Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Lin, Z.H. [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); He, H.M. [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Qiu, R.L. [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2007-08-15

    Microwave reactor with the mixture of ammonium bicarbonate (NH{sub 4}HCO{sub 3}) and Ga-A zeolites was set up to study the removal of nitrogen oxides (NO {sub x} ) from waste gas with excess oxygen concentration (14-19%) at low temperature (80-120 deg. C). The results showed that the microwave reactor filled with NH{sub 4}HCO{sub 3} and Ga-A zeolites could reduce NO {sub x} to nitrogen with the best purifying efficiency of 95.45% and the best denitrification amount of 89.28 mg h{sup -1}. The optimal microwave power and residence time (RT) on denitrification was 259-280 W and 0.259 s, respectively. Microwave denitrification effect of the experiment using ammonium bicarbonate and Ga-A zeolites was much higher than that using ammonium bicarbonate or Ga-A zeolites only. The mechanism for microwave-induced NO {sub x} reduction can be explained as the microwave-induced catalytic reaction between NO {sub x} and ammonium bicarbonate with Ga-A zeolites being the catalyst and microwave absorbent.

  19. Penggunaan Zeolit Sebagai Media Penyaring Pada Pengolahan Air LimbahDomestik

    Directory of Open Access Journals (Sweden)

    Yanto Yanto

    2011-02-01

    Full Text Available Sand filter is frequentlyused to treat contaminated water. Channel filter system is a modification of sand filter where the channel is shaped thus the land requirement could be minimized, water is flowed horizontallyfrom intial tank to finaltank through sand filter. Employing the channel filter to treat domestic wastewateris capable of reducing E. Coli up to 98.14%, increasing DO up to 27% and decreasing BOD5 up to 27%. Unfortunately, the final content of E.Coli after treatment process completed is still unacceptable for drinking water. Several options are available to improve the performance of the channel filter system. One of the promising alternativesis modifying the filter medium. Zeolite is natural material that has been utilized to improvewater quality based on several parameters such as Fe, Mn, organic materials, CO and others. Application of zeolite to diminish E. Coli is a challenge. This paper will investigate the effectiveness of zeolite to lower E. Coli contained in domestic wastewater . Zeolite was added to sand filter where thefraction of zeolite is about 5%. Two kind of zeolite-sand combination was implemented that is arranged and mixed zeolite-sand. Wastewater containing E.Coli was then put in the initial tank. Through the hole createdin the tank, wastewater then flowed passing through the combined zeolite-sand filter and accumulated in the final tank. Both E. Coli from initial and final tank was measured to compute treatment efficiency. The result showsE. Coli decreases up to99.99%, BOD5and DO decrease more than 71% and 66% respectively. It can be concluded that 5% addition ofzeolite is able to improve treatment efficiency ofsand filter.

  20. Thermal change and ion exchange properties of zeolite L with cesium and strontium

    International Nuclear Information System (INIS)

    Mimura, Hitoshi; Akiba, Kenichi

    1986-01-01

    Thermal change and ion exchange properties of Cs and Sr have been studied for zeolite L. The zeolite structure is stable below 900 deg C and converts to the amorphous phase above 1000 deg C. The cesium form of zeolite L recrystallized to pollucite (CsAlSi 2 O 6 ) by calcination at 1400 deg C for 1 h or under hydrothermal condition (300 deg C, 290 atm, 24 h). Hydrogen-form zeolites were prepared by the acid treatment in 10 -2 ∼ 10 -1 M HNO 3 solutions or thermal decomposition of NH 4 form zeolites at 460 ∼ 500 deg C. The distribution of Cs and Sr was dependent on equilibrium pH and the distribution coefficient (K d ) was about 10 4 (ml/g) at pH 5 ∼ 7. The exchange capacity of Cs and Sr was 0.89 (meq./g zeolite) and exchanging ratio was 68 % at D sites in main channel. These cations in zeolite were completely eluted with 10 -1 M HNO 3 solution. (author)

  1. Characterization of gallium-containing zeolites for catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Sanchez, M.

    2003-12-08

    The present study considers the synthesis, characterization, and catalytic evaluation of extra-framework gallium-containing zeolites. We focus on modification of zeolites by chemical vapor deposition of trimethylgallium on HZSM-5 and Mordenite zeolites. Chapter 2 is dedicated to the chemisorption and stability of TMG on HZSM-5 and HMOR zeolites. The effect of silylation is also addressed. Some theoretical calculations are also shown in this study to support part of the experimental results. In Chapter 3, the effect of oxidation and reduction treatments on these catalysts is investigated by FTIR, ICP and multinuclei NMR. In Chapter 4, the oxidation state and Ga coordination obtained during and after thermal treatment with H2 and O2 is analysed by X-ray adsorption spectroscopy (XANES and EXAFS) and IR analysis of CO adsorption. These results allow a better understanding of the catalytic behaviour of Ga-containing zeolites catalyst. Chapter 5 consists of two parts: one discusses the H2 activation over Ga/HZSM5 and Ga/MOR catalysts by H2/D2 isotopic exchange reaction, and the second part deals with the aromatization of n-heptane over the same catalysts.

  2. Synthesis of 4-tert-Butyltoluene by Vapor Phase tert-Butylation of Toluene with tert-Butylalcohol over USY Zeolite

    Directory of Open Access Journals (Sweden)

    Yan Ming Shen

    2015-03-01

    Full Text Available Vapour phase tert-butylation of toluene with tert-butylalcohol was studied over ultra-stable Y zeolite (USY catalyst. The effects of reaction temperature, toluene/TBA molar ratio and liquid space velocity on conversion of toluene and selectivity for 4-tert-butyltoluene were studied. The deactivation and regeneration of the catalyst was also investigated. The results showed that the USY zeolite catalyst offered better toluene conversion of about 30 % and 4-tert-butyltoluene selectivity of about 89 % at the suitable reaction condition as follows: reaction temperature of 120 oC, toluene/TBA ratio of 2:1 and liquid space velocity of 2 ml/g·h. The clogging of mocropores by the formed carbon or oligomers was the main reason for the deactivation of the catalyst. By combustion at 550 oC, the catalyst just lost about 5 % in toluene conversion and about 2 % in PTBT selectivity. © 2015 BCREC UNDIP. All rights reservedReceived: 17th July 2014; Revised: 31st August 2014; Accepted: 3rd September 2014How to Cite: Shen, Y.M., Yuan, S., Fan, L., Liu, D.B., Li, S.F. (2015. Synthesis of 4-tert-Butyltoluene by Vapor Phase tert-Butylation of Toluene with tert-Butylalcohol over USY Zeolite. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (1: 1-7. (doi:10.9767/bcrec.10.1.7140.1-7Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.1.7140.1-7

  3. Organic iodide capture using a zeolite dry filtration

    International Nuclear Information System (INIS)

    Park, Sanggil; Sung, Joonyoung; Kim, Gi-ppeum; Lee, Jaeyoung

    2017-01-01

    An organic iodide, especially, methyl iodide (CH 3 I) would generated non-negligibly from a severe accident in a nuclear power plant. This CH 3 I will be dangerous for human when it was inhaled, it is highly toxic and causes a serious nerve disorder. Even it is a major contributor to a thyroid cancer. In order to prevent its environmental release, it is required to decontaminate using a filtration system. For the removal of CH 3 I from the release gases, wet-type is not ideal due to a high re-volatile characteristics of CH 3 I. It may become volatile after dissolving in a pool and forms CH 3 I again at the surface of water pool. Therefore, a dry-filtration should be installed to remove the CH 3 I. In this study, we preliminary investigate the characteristics of zeolite filtration methods for the removal of CH 3 I. We used both silver ion exchanged ZSM-5-zeolite (Ag+-ZSM-5) to study the effect of silver ion for the removal of iodine from CH 3 I. In summary, the CH 3 I capture tests using a silver ion exchanged zeolite was conducted in the coupled TGAGC test set-up. The mass change of the sample and concentration of CH 3 I were measured. The samples were investigated by the SEM/EDS to see its surface characteristics.

  4. Characterization of modified zeolite as microbial immobilization media on POME anaerobic digestion

    Science.gov (United States)

    Cahyono, Rochim B.; Ismiyati, Sri; Ginting, Simparmin Br; Mellyanawaty, Melly; Budhijanto, Wiratni

    2018-03-01

    As the world’s biggest palm oil producer, Indonesia generates also huge amount of Palm Oil Mill Effluent (POME) wastewater and causes serious problem in environment. In conventional method, POME was converted into biogas using lagoon system which required extensive land area. Anaerobic Fluidized Bed Reactor (AFBR) proposes more effective biogas producing with smaller land area. In the proposed system, a immobilization media would be main factor for enhancing productivity. This research studied on characterization of Lampung natural zeolite as immobilization media in the AFBR system for POME treatment. Various activation method such as physical and chemical were attempted to create more suitable material which has larger surface area, pore size distribution as well as excellent surface structures. The physical method was applied by heating up the material till 400°C while HCl was used on the chemical activation. Based on the result, the chemical activation increased the surface area significantly into 71 m2/g compared to physical as well as original zeolite. The strong acid material was quite effective to enforce the impurities within zeolite pore structure compared to heating up the material. According to distribution data, the Lampung zeolite owned the pore size with the range of 3 – 5 μm which was mesopore material. The pore size was appropriate for immobilization media as it was smaller than size of biogas microbial. The XRD patterns verified that chemical activation could maintain the zeolite structure as the original. Obviously, the SEM photograph showed apparent structure and pore size on the modified zeolite using chemical method. The testing of modified zeolite on the batch system was done to evaluate the characterization process. The modified zeolite using chemical process resulted fast reduction of COD and stabilized the volatile fatty acid as the intermediate product of anaerobic digestion, especially in the beginning of the process. Therefore, the

  5. Preparation of highly ordered cubic NaA zeolite from halloysite mineral for adsorption of ammonium ions.

    Science.gov (United States)

    Zhao, Yafei; Zhang, Bing; Zhang, Xiang; Wang, Jinhua; Liu, Jindun; Chen, Rongfeng

    2010-06-15

    Well-ordered cubic NaA zeolite was first synthesized using natural halloysite mineral with nanotubular structure as source material by hydro-thermal method. SEM and HRTEM images indicate that the synthesized NaA zeolite is cubic-shaped crystal with planar surface, well-defined edges and symmetrical and uniform pore channels. The adsorption behavior of ammonium ions (NH(4)(+)) from aqueous solution onto NaA zeolite was investigated as a function of parameters such as equilibrium time, pH, initial NH(4)(+) concentration, temperature and competitive cations. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. A maximum adsorption capacity of 44.3 mg g(-1) of NH(4)(+) was achieved. The regeneration and reusable ability of this adsorbent was evaluated, and the results indicated that the recovered adsorbent could be used again for NH(4)(+) removal with nearly constant adsorption capacity. Thermodynamic parameters such as change in free energy (DeltaG(0)), enthalpy (DeltaH(0)) and entropy (DeltaS(0)) were also determined, which indicated that the adsorption was a spontaneous and exothermic process at ambient conditions. Compared with other adsorbents, the as-synthesized NaA zeolite displays a faster adsorption rate and higher adsorption capacity, which implies potential application for removing NH(4)(+) pollutants from wastewaters. Copyright 2010 Elsevier B.V. All rights reserved.

  6. Preparation of highly ordered cubic NaA zeolite from halloysite mineral for adsorption of ammonium ions

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Yafei [School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhang Bing, E-mail: zhangb@zzu.edu.cn [School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001 (China); Henan Academy of Sciences, Zhengzhou 450002 (China); Zhang Xiang; Wang Jinhua; Liu Jindun [School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001 (China); Chen Rongfeng [Henan Academy of Sciences, Zhengzhou 450002 (China)

    2010-06-15

    Well-ordered cubic NaA zeolite was first synthesized using natural halloysite mineral with nanotubular structure as source material by hydro-thermal method. SEM and HRTEM images indicate that the synthesized NaA zeolite is cubic-shaped crystal with planar surface, well-defined edges and symmetrical and uniform pore channels. The adsorption behavior of ammonium ions (NH{sub 4}{sup +}) from aqueous solution onto NaA zeolite was investigated as a function of parameters such as equilibrium time, pH, initial NH{sub 4}{sup +} concentration, temperature and competitive cations. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. A maximum adsorption capacity of 44.3 mg g{sup -1} of NH{sub 4}{sup +} was achieved. The regeneration and reusable ability of this adsorbent was evaluated, and the results indicated that the recovered adsorbent could be used again for NH{sub 4}{sup +} removal with nearly constant adsorption capacity. Thermodynamic parameters such as change in free energy ({Delta}G{sup 0}), enthalpy ({Delta}H{sup 0}) and entropy ({Delta}S{sup 0}) were also determined, which indicated that the adsorption was a spontaneous and exothermic process at ambient conditions. Compared with other adsorbents, the as-synthesized NaA zeolite displays a faster adsorption rate and higher adsorption capacity, which implies potential application for removing NH{sub 4}{sup +} pollutants from wastewaters.

  7. In situ fast pyrolysis of biomass with zeolite catalysts for bioaromatics/gasoline production: A review

    International Nuclear Information System (INIS)

    Galadima, Ahmad; Muraza, Oki

    2015-01-01

    Highlights: • Biomass upgrading by fast pyrolysis is an attractive bioaromatics production. • Zeolite catalysts are key important systems considered for the process. • Catalytic activity depend on zeolite structure, acidity and textural features. • Recent literature on the role of the zeolite catalysts critically tailored. • Hierarchical zeolites are prospective catalysts for industrial applications. - Abstract: The fast pyrolysis of biomass-based feedstocks is currently gaining considerable attention as an industrial and sustainable option for the production of gasoline-range bioaromatics. The complex composition of biomass molecules and a series of reactions involved during the upgrading process require the incorporation of sufficiently acidic and topological catalysts. This paper carefully documents and analyzes recent publications that have investigated the properties of zeolites to enhance the yield of bioaromatics during in situ fast pyrolysis. Issues related to the effects of zeolite’s textural, topological and acidic properties are critically examined. Factors responsible for catalyst deactivation and the mechanistic roles of the catalysts used are discussed. This paper also explores the prospects of hierarchical zeolites and municipal solid waste (MSW) as catalysts and feedstocks for the fast pyrolysis process.

  8. Synthesis of the zeolitic imidazolate framework ZIF-4 from the ionic liquid 1-butyl-3-methylimidazolium imidazolate

    Science.gov (United States)

    Hovestadt, Maximilian; Schwegler, Johannes; Schulz, Peter S.; Hartmann, Martin

    2018-05-01

    A new synthesis route for the zeolitic imidazolate framework ZIF-4 using imidazolium imidazolate is reported. Additionally, the ionic liquid-derived material is compared to conventional ZIF-4 with respect to the powder X-ray diffraction pattern pattern, nitrogen uptake, particle size, and separation potential for olefin/paraffin gas mixtures. Higher synthesis yields were obtained, and the different particle size affected the performance in the separation of ethane and ethylene.

  9. Adsorption of ions onto treated natural zeolite

    Directory of Open Access Journals (Sweden)

    Cristiane da Rosa Oliveira

    2007-12-01

    Full Text Available This work presents studies of modification of a natural zeolite by activation with Na+ cations and functionalisation with Ba+2 and/or Cu2+ ions (FZ. The zeolite was characterized, modified and applied in adsorption studies of sulphate and isopropilxanthate ions as flocculated and powdered forms. The reuse of SO4Ba-FZ was investigated by adsorption-removal of either Ba2+ or sulphate ions in stages. Equilibrium data showed that the FZ, flocculated or as powder, provide considerable removal of sulphate ions (q mLangmuir: 1.15 and 1.35 meq.g-1, respectively and isopropilxanthate (q mLangmuir: 0.35 and 0.93 meq.g-1, respectively. The reuse of the SO4-FZ, either powdered or flocculated also uptake significant amount of Ba2+ or sulphate ions (q mLangmuir: 1.15 meq.g-1, providing a new alternative for the exhausted adsorbent. Thus the activated and functionalised zeolites create new options on the materials engineering area with applications in environmental applied adsorption processes.

  10. Characteristics of Heavy Metals Adsorption Cu, Pb and Cd Using Synthetics Zeolite Zsm-5

    OpenAIRE

    Priyadi,; Iskandar,; Suwardi,; Mukti, Rino Rakhmata

    2015-01-01

    It is generally known that zeolite has potential for heavy metal adsorption. The objectives of this study were to synthesize and characterize zeolite ZSM-5 and to figure out the adsorption capacity of zeolite ZSM-5 for heavy metals of Cu2+, Pb2+ and Cd2+. Characterization of zeolite ZSM-5 included some variables i.e. crystal structure (XRD), morphology (SEM), specific surface area and total pore volume (N2 physisorption). Adsorption capacity of zeolite ZSM-5 was analysed using a batch system...

  11. H{sub 2} storage in microporous materials: a comparison between zeolites and Mos

    Energy Technology Data Exchange (ETDEWEB)

    Ricchiardi, G.; Regli, L.; Vitillo, J. G.; Cocina, D.; Bordiga, S.; Lamberti, C.; Spoto, G.; Zecchina, A.; Bjorgen, M.; Lillerud, K. P.

    2005-07-01

    One of the main concerns about a hydrogen-based energy economy is the efficient storage and transport of this highly flammable gas. Many strategies have been followed or suggested in recent years to solve this problem. The most important ones are: 1) storage in metals and alloys; 2) storage in complex hydrides (alanates, borides); 3) storage by trapping in clathrates (ice and others); 4) storage in microporous materials (carbons, zeolitic materials, metal-organic frameworks, polymers). [1, 2] In this work we have focused our attention on microporous materials, where the crucial point is the strength of the interaction between the molecular hydrogen and the internal surfaces of micropores and/ or of cages of entrapping materials. It is known from fundamental studies that H2 strongly interacts with ions in the gas but that the presence of counterions decreases the interaction energy substantially. The most prominent class of microporous materials, which contains isolated and exposed cations, are zeolites and zeotypes: ideal systems to investigate the interaction of H2 with both dispersive and electrostatic forces [3]. So, even if they are not sufficiently light to represent the final solution to H2 storage, the availability of a large variety of frameworks and chemical compositions combined with low cost and superior mechanical and thermal stabilities increases the interest in these materials. In this work we have studied in detail, by means of volumetric and spectroscopic measurements, zeolites with CHA topology (as they are characterized by a strong acidity and by a big surface area). H-SSZ-13 zeolite, characterized by a low Al content (Si/Al = 11), has shown the best properties in hydrogen storage in respect to all the other zeolites and zeotypes with different compositions and topologies [4]. The results have been compared with those obtained for MOF-5 [5], a well known Metal-Organic Framework, indicated as a very good material for molecular hydrogen storage [6

  12. Experimental testing of cooling by low pressure adsorption in a zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Redman, C.M.

    1985-01-01

    A small scale facility was designed, constructed, and utilized to test the use of zeolite adsorption of water vapor to augment chill storage in ice for conventional space cooling. The facility uses solar-derived energy, for the heat source and evaporatively chilled water for the heat sump. The product cooling uses sublimation of ice instead of melting. The ZCAT facility utilizes a heat pumping technique in which a water vapor adsorbent functions as the compressor and condenser. The design was based on use of 13X zeolite as the adsorber because of its high adsorbence at low pressures. However, it has been determined that other materials such as silica gel should give superior performance. While zeolite 13X holds more water in the pressure and temperature ranges of interest, silica gel cycles more water and has less residue water. Both points are very important in the design of an efficient and cost effective system.

  13. CONVERSION OF (±-CITRONELLAL AND ITS DERIVATIVES TO (--MENTHOL USING BIFUNCTIONAL NICKEL ZEOLITE CATALYSTS

    Directory of Open Access Journals (Sweden)

    Indri Badria Adilina

    2015-06-01

    Full Text Available (±-Citronellal and its derivatives were converted to (--menthol by a one-pot reaction system using zeolite based nickel catalysts. The catalysts were prepared by immobilization of nickel on natural zeolite (NZ or synthetic zeolite (ZSM-5 by a simple cation exchange method. Calcination and hydrogen treatment procedures were able to significantly increase the surface area and pore volume of NZ based catalysts whereas negligible changes in the properties were observed for that of ZSM-5. Catalytic reactions were carried out at 70ºC by stirring the mixture in the air for cyclization of (±-citronellal to (±-isopulegol followed by hydrogenation towards the desired (--menthol at 2 Mpa of H2 pressure. The Ni/NZ catalyst was able to convert a (±-citronellal derivative yielding 9% (--menthol (36% selectivity with conversion up to 24%, whereas Ni/ZSM5 catalyst directly converted 65% (±-citronellal to give 4% menthol (6% selectivity. These zeolite based catalysts are therefore potential materials for the conversion of biomass feed stock to value-added chemicals.

  14. Electrochemical water splitting using nano-zeolite Y supported tungsten oxide electrocatalysts

    Science.gov (United States)

    Anis, Shaheen Fatima; Hashaikeh, Raed

    2018-02-01

    Zeolites are often used as supports for metals and metal oxides because of their well-defined microporous structure and high surface area. In this study, nano-zeolite Y (50-150 nm range) and micro-zeolite Y (500-800 nm range) were loaded with WO3, by impregnating the zeolite support with ammonium metatungstate and thermally decomposing the salt thereafter. Two different loadings of WO3 were studied, 3 wt.% and 5 wt.% with respect to the overall catalyst. The prepared catalysts were characterized for their morphology, structure, and surface areas through scanning electron microscope (SEM), XRD, and BET. They were further compared for their electrocatalytic activity for hydrogen evolution reaction (HER) in 0.5 M H2SO4. On comparing the bare micro-zeolite particles with the nano-form, the nano-zeolite Y showed higher currents with comparable overpotentials and lower Tafel slope of 62.36 mV/dec. WO3 loading brought about a change in the electrocatalytic properties of the catalyst. The overpotentials and Tafel slopes were observed to decrease with zeolite-3 wt.% WO3. The smallest overpotential of 60 mV and Tafel slope of 31.9 mV/dec was registered for nano-zeolite with 3 wt.% WO3, while the micro-zeolite gave an overpotential of 370 mV and a Tafel slope of 98.1 mV/dec. It was concluded that even with the same metal oxide loading, nano-zeolite showed superior performance, which is attributed to its size and hence easier escape of hydrogen bubbles from the catalyst.

  15. Oxidative regeneration of toluene-saturated natural zeolite by gaseous ozone: the influence of zeolite chemical surface characteristics.

    Science.gov (United States)

    Alejandro, Serguei; Valdés, Héctor; Manéro, Marie-Hélène; Zaror, Claudio A

    2014-06-15

    In this study, the effect of zeolite chemical surface characteristics on the oxidative regeneration of toluene saturated-zeolite samples is investigated. A Chilean natural zeolite (53% clinoptilolite, 40% mordenite and 7% quartz) was chemically modified by acid treatment with hydrochloric acid and by ion-exchange with ammonium sulphate. Thermal pre-treatments at 623 and 823K were applied and six zeolite samples with different chemical surface characteristics were generated. Chemical modification of natural zeolite followed by thermal out-gassing allows distinguishing the role of acidic surface sites on the regeneration of exhausted zeolites. An increase in Brønsted acid sites on zeolite surface is observed as a result of ammonium-exchange treatment followed by thermal treatment at 623K, thus increasing the adsorption capacity toward toluene. High ozone consumption could be associated to a high content of Lewis acid sites, since these could decompose ozone into atomic active oxygen species. Then, surface oxidation reactions could take part among adsorbed toluene at Brønsted acid sites and surface atomic oxygen species, reducing the amount of adsorbed toluene after the regenerative oxidation with ozone. Experimental results show that the presence of adsorbed oxidation by-products has a negative impact on the recovery of zeolite adsorption capacity. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Inoculum and zeolite synergistic effect on anaerobic digestion of poultry manure

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Kougias, Panagiotis; Zaganas, Ioannis D.

    2014-01-01

    zeolite dosages on the mesophilic AD of poultry manure inoculated with a non-acclimatised to ammonia inoculum (dairy manure) was investigated. Additionally, a comparative analysis was performed between the data extracted from this study and the results of a previous study which has been conducted under...... the same experimental conditions but with the use of ammonia acclimatised inoculum (swine manure). At 5 and 10 g zeolite L−1, the methane yield of poultry manure was 43.4% and 80.3% higher compared with the experimental set without zeolite addition. However, the ammonia non-acclimatised inoculum...... was not efficient in digesting poultry manure even in the presence of 10 g zeolite L−1, due to low methane production (only 39%) compared to the maximum theoretical yield. Finally, ammonia acclimatised inoculum and zeolite have demonstrated a possible “synergistic effect” which led to a more efficient AD of poultry...

  17. Zeolites - a high resolution electron microscopy study

    International Nuclear Information System (INIS)

    Alfredsson, V.

    1994-10-01

    High resolution transmission electron microscopy (HRTEM) has been used to investigate a number of zeolites (EMT, FAU, LTL, MFI and MOR) and a member of the mesoporous M41S family. The electron optical artefact, manifested as a dark spot in the projected centre of the large zeolite channels, caused by insufficient transfer of certain reflections in the objective lens has been explained. The artefact severely hinders observation of materials confined in the zeolite channels and cavities. It is shown how to circumvent the artefact problem and how to image confined materials in spite of disturbance caused by the artefact. Image processing by means of a Wiener filter has been applied for removal of the artefact. The detailed surface structure of FAU has been investigated. Comparison of experimental micrographs with images simulated using different surface models indicates that the surface can be terminated in different ways depending on synthesis methods. The dealuminated form of FAU (USY) is covered by an amorphous region. Platinum incorporated in FAU has a preponderance to aggregate in the (111) twin planes, probably due to a local difference in cage structure with more spacious cages. It is shown that platinum is intra-zeolitic as opposed to being located on the external surface of the zeolite crystal. This could be deduced from tomography of ultra-thin sections among observations. HRTEM studies of the mesoporous MCM-41 show that the pores have a hexagonal shape and also supports the mechanistic model proposed which involves a cooperative formation of a mesophase including the silicate species as well as the surfactant. 66 refs, 24 figs

  18. Selective synthesis of FAU-type zeolites

    Science.gov (United States)

    Garcia, Gustavo; Cabrera, Saúl; Hedlund, Jonas; Mouzon, Johanne

    2018-05-01

    In the present work, parameters influencing the selectivity of the synthesis of FAU-zeolites from diatomite were studied. The final products after varying synthesis time were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and gas adsorption. It was found that high concentrations of NaCl could completely inhibit the formation of zeolite P, which otherwise usually forms as soon as maximum FAU crystallinity is reached. In the presence of NaCl, the FAU crystals were stable for extended time after completed crystallization of FAU before formation of sodalite. It was also found that addition of NaCl barely changed the crystallization kinetics of FAU zeolite and only reduced the final FAU particle size and SiO2/Al2O3 ratio slightly. Other salts containing either Na or Cl were also investigated. Our results suggest that there is a synergistic effect between Na+ and Cl-. This is attributed to the formation of (Na4Cl)3+ clusters that stabilize the sodalite cages. This new finding may be used to increase the selectivity of syntheses leading to FAU-zeolites and avoid the formation of undesirable by-products, especially if impure natural sources of aluminosilica are used.

  19. Zeolite formation from coal fly ash and its adsorption potential

    Energy Technology Data Exchange (ETDEWEB)

    Duangkamol Ruen-ngam; Doungmanee Rungsuk; Ronbanchob Apiratikul; Prasert Pavasant [Chulalongkorn University, Bangkok (Thailand). Department of Chemical Engineering

    2009-10-15

    The possibility in converting coal fly ash (CFA) to zeolite was evaluated. CFA samples from the local power plant in Prachinburi province, Thailand, were collected during a 3-month time span to account for the inconsistency of the CFA quality, and it was evident that the deviation of the quality of the raw material did not have significant effects on the synthesis. The zeolite product was found to be type X. The most suitable weight ratio of sodium hydroxide (NaOH) to CFA was approximately 2.25, because this gave reasonably high zeolite yield with good cation exchange capacity (CEC). The silica (Si)-to-aluminum (Al) molar ratio of 4.06 yielded the highest crystallinity level for zeolite X at 79% with a CEC of 240 meq/100 g and a surface area of 325 m{sup 2}/g. Optimal crystallization temperature and time were 90{sup o}C and 4 hr, respectively, which gave the highest CEC of approximately 305 meq/100 g. Yields obtained from all experiments were in the range of 50-72%. 29 refs., 5 tabs., 7 figs.

  20. Hierarchy concepts: classification and preparation strategies for zeolite containing materials with hierarchical porosity.

    Science.gov (United States)

    Schwieger, Wilhelm; Machoke, Albert Gonche; Weissenberger, Tobias; Inayat, Amer; Selvam, Thangaraj; Klumpp, Michael; Inayat, Alexandra

    2016-06-13

    'Hierarchy' is a property which can be attributed to a manifold of different immaterial systems, such as ideas, items and organisations or material ones like biological systems within living organisms or artificial, man-made constructions. The property 'hierarchy' is mainly characterised by a certain ordering of individual elements relative to each other, often in combination with a certain degree of branching. Especially mass-flow related systems in the natural environment feature special hierarchically branched patterns. This review is a survey into the world of hierarchical systems with special focus on hierarchically porous zeolite materials. A classification of hierarchical porosity is proposed based on the flow distribution pattern within the respective pore systems. In addition, this review might serve as a toolbox providing several synthetic and post-synthetic strategies to prepare zeolitic or zeolite containing material with tailored hierarchical porosity. Very often, such strategies with their underlying principles were developed for improving the performance of the final materials in different technical applications like adsorptive or catalytic processes. In the present review, besides on the hierarchically porous all-zeolite material, special focus is laid on the preparation of zeolitic composite materials with hierarchical porosity capable to face the demands of industrial application.

  1. Ion-exchange properties of zeolite/glass hybrid materials

    International Nuclear Information System (INIS)

    Taira, Nobuyuki; Yoshida, Kohei; Fukushima, Takuya

    2017-01-01

    Hybrid materials were prepared from ground glass powder and various zeolites such as A-type, mordenite, X-type, and Y-type zeolites, and their ion removal effect was investigated. The hybrid materials of A-type, Y-type, and mordenite zeolites showed similar Sr"2"+ removal rates from aqueous solutions. The removal rate of Sr"2"+ ions increased as the amount of zeolite in the hybrid materials increased. Compared with other hybrid materials, the hybrid materials of X-type zeolite showed higher Sr"2"+ removal rates, especially for zeolite content greater than 25%. As the amount of X-type zeolite in the hybrid materials increased, the Sr"2"+ removal rate increased greatly, with a 100% removal rate when the content of X-type zeolite exceeded 62.5%. (author)

  2. Zeolites modified with silver for the development of a water disinfection system

    International Nuclear Information System (INIS)

    Aparicio V, S.

    2013-01-01

    In spite of great strides that have been taken in sanitation technologies, there still exist health problems due to microbiological contamination by water. The waterborne diseases have not been completely eradicated and are a big problem of economic interest and health. Moreover, the microbicidal properties of silver have been used for a long time. The use of silver as a disinfectant has many advantages; for example it inhibits a wide spectrum of microorganisms, it has oligo dynamic properties and owing its mechanisms of cell inactivation, it also does not allow the emergence of new resistant strains. In the present research, the kinetics of water disinfection with silver has been investigated, to develop small system for water disinfection, based in silver modified Mexican clinoptilolite. The chemical species of silver play a significant role in the disinfection processes. For this reason, in this work, were both the Ag + and nanoparticles of Ag ο considered. The synthesis of nanoparticles of Ag ο woes performed by thermal and chemical reduction. It was found that the chemical reduction of Ag + to Ag ο was more efficient because it presented more defined nano structures and better distribution than those of thermal reduction. Clinoptilolite of Taxco (Guerrero) was chosen to exchange the native ions from the clinoptilolite by Ag + from the aqueous medium, or to deposit the nanoparticles of Ag ο on this surface. These silver modified zeolitic materials were characterized by scanning electron microscopy (Sem), elemental analyses (EDS), X-ray diffraction (XRD) and neutron activation analysis (NAA). The results showed that the crystallographic structure of the clinoptilolite did not change during thermal and chemical reduction treatments of Ag + to obtain the nanoparticles of Ag ο . The bactericide activity of the silver modified zeolitic materials (with Ag + or nanoparticles of Ag ο ) was evaluated on Escherichia coli Atcc 8739, in both distilled water and well

  3. Producing zeolites from fly ash

    International Nuclear Information System (INIS)

    Rayalu, S.; Labhestwar, N.K.; Biniwale, R.B.; Udhoji, J.S.; Meshram, S.U.; Khanna, P.

    1998-01-01

    Fly ash has virtually become a menace of thermal power generation, leading to its devastating effects on the environment. Development of alternate methods of its disposal - especially those with recourse to recovery of valuable materials-has thus become imperative. This paper deals with the utilisation of fly ash for the production of high value-added products, viz., commercial grade zeolites. The physico-chemical and morphological characteristics of fly ash based Zeolite-A (FAZ-A) compares well with commercial Zeolite-A. High calcium binding capacity, appropriate particle/pore size and other detergency characteristics of FAZ-A brings forth its potential as a substitute for phosphatic detergent builder. The technology is extremely versatile, and other products like Zeolite-X, Zeolite-Y, sodalite and mordenite are also amenable for cost effective production with modifications in certain reaction parameters. Low temperature operations, ready availability of major raw materials, simplicity of process and recycling of unused reactants and process water are special features of the process. (author)

  4. Zeolite A synthesis employing a brazilian coal ash as the silicon and aluminum source and its applications in adsorption and pigment formulation

    Directory of Open Access Journals (Sweden)

    Lindiane Bieseki

    2012-01-01

    Full Text Available Zeolite A was synthesized using the coal ash from Siderópolis/RS - Brazil. The synthesis was based on a standard IZA synthesis using coal ash as the Si and Al source. XRF analysis showed that the coal ash has a Si/Al ratio of 1.52, which is close to the Si/Al ratio required to produce zeolite A (1.0. The synthesized materials were analyzed by XRD, SEM and N2 adsorption. More crystalline materials were obtained during synthesis when an additional treatment was applied at a temperature of 353 K at the dissolution of NaOH step. The product formed after 4 hours was the most crystalline, but even the product formed after 1 hour proved to be better than that formed using the standard 4 hours IZA synthesis. The zeolites synthesized by this method had an adsorption capacity of 120 mg.g-1 for Ca2+, half the capacity of commercial zeolite A (300 mg.g-1. It was not possible to obtain blue or green pigments using the synthesized zeolite A.

  5. Preparation by the nano-casting process of novel porous carbons from large pore zeolite templates

    International Nuclear Information System (INIS)

    F Gaslain; J Parmentier; V Valtchev; J Patarin; C Vix Guterl

    2005-01-01

    The development of new growing industrial applications such as gas storage (e.g.: methane or hydrogen) or electric double-layer capacitors has focussed the attention of many research groups. For this kind of application, porous carbons with finely tailored micro-porosity (i.e.: pore size diameter ≤ 1 nm) appear as very promising materials due to their high surface area and their specific pore size distribution. In order to meet these requirements, attention has been paid towards the feasibility of preparing microporous carbons by the nano-casting process. Since the sizes and shapes of the pores and walls respectively become the walls and pores of the resultant carbons, using templates with different framework topologies leads to various carbon replicas. The works performed with commercially available zeolites employed as templates [1-4] showed that the most promising candidate is the FAU-type zeolite, which is a large zeolite with three-dimensional channel system. The promising results obtained on FAU-type matrices encouraged us to study the microporous carbon formation on large pore zeolites synthesized in our laboratory, such as EMC-1 (International Zeolite Association framework type FAU), zeolite β (BEA) or EMC-2 (EMT). The carbon replicas were prepared following largely the nano-casting method proposed for zeolite Y by the Kyotani research group [4]: either by liquid impregnation of furfuryl alcohol (FA) followed by carbonization or by vapour deposition (CVD) of propylene, or by an association of these two processes. Heat treatment of the mixed materials (zeolite / carbon) could also follow in order to improve the structural ordering of the carbon. After removal of the inorganic template by an acidic treatment, the carbon materials obtained were characterised by several analytical techniques (XRD, N 2 and CO 2 adsorption, electron microscopy, etc...). The unique characteristics of these carbons are discussed in details in this paper and compared to those

  6. Transformation of Indonesian Natural Zeolite into Analcime Phase under Hydrothermal Condition

    Science.gov (United States)

    Lestari, W. W.; Hasanah, D. N.; Putra, R.; Mukti, R. R.; Nugrahaningtyas, K. D.

    2018-04-01

    Natural zeolite is abundantly available in Indonesia and well distributed especially in the volcano area like Java, Sumatera, and Sulawesi. So far, natural zeolite from Klaten, Central Java is one of the most interesting zeolites has been widely studied. This research aims to know the effect of seed-assisted synthesis under a hydrothermal condition at 120 °C for 24 hours of Klaten’s zeolite toward the structural change and phase transformation of the original structure. According to XRD and XRF analysis, seed-assisted synthesis through the addition of aluminosilicate mother solution has transformed Klaten’s zeolite which contains (mordenite and clinoptilolite) into analcime type with decreasing Si/Al ratio from 4.51 into 1.38. Morphological analysis using SEM showed the shape changes from irregular into spherical looks like takraw ball in the range of 0.3 to 0.7 micrometer. Based on FTIR data, structure of TO4 site (T = Si or Al) was observed in the range of 300-1300 cm-1 and the occupancy of Brønsted acid site as OH stretching band from silanol groups was detected at 3440-3650 cm-1. Nitrogen adsorption-desorption analysis confirmed that transformation Klaten’s zeolite into analcime type has decreased the surface area from 55.41 to 22.89 m2/g and showed inhomogeneous pore distribution which can be classified as micro-mesoporous aluminosilicate materials.

  7. Characterization and antibacterial activity of silver exchanged regenerated NaY zeolite from surfactant-modified NaY zeolite.

    Science.gov (United States)

    Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik

    2016-02-01

    The antibacterial activity of regenerated NaY zeolite (thermal treatment from cetyltrimethyl ammonium bromide (CTAB)-modified NaY zeolite and pretreatment with Na ions) loaded with silver ions were examined using the broth dilution minimum inhibitory concentration (MIC) method against Escherichia coli (E. coli ATCC 11229) and Staphylococcus aureus (S. aureus ATCC 6538). X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and chemical elemental analyses were used to characterize the regenerated NaY and AgY zeolites. The XRD patterns indicated that the calcination and addition of silver ions on regenerated NaY zeolite did not affect the structure of the regenerated NaY zeolite as the characteristic peaks of the NaY zeolite were retained, and no new peaks were observed. The regenerated AgY zeolite showed good antibacterial activity against both bacteria strains in distilled water, and the antibacterial activity of the samples increased with increasing Ag loaded on the regenerated AgY zeolite; the regenerated AgY zeolite was more effective against E. coli than S. aureus. However, the antibacterial activity of the regenerated AgY was not effective in saline solution for both bacteria. The study showed that CTAB-modified NaY zeolite materials could be regenerated to NaY zeolite using thermal treatment (550°C, 5h) and this material has excellent performance as an antibacterial agent after silver ions loading. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Introduction to zeolite theory and modelling

    NARCIS (Netherlands)

    Santen, van R.A.; Graaf, van de B.; Smit, B.; Bekkum, van H.

    2001-01-01

    A review. Some of the recent advances in zeolite theory and modeling are present. In particular the current status of computational chem. in Bronsted acid zeolite catalysis, mol. dynamics simulations of mols. adsorbed in zeolites, and novel Monte Carlo technique are discussed to simulate the

  9. Copper removal using bio-inspired polydopamine coated natural zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yang; Shapter, Joseph G. [Flinders Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide 5042, SA (Australia); Popelka-Filcoff, Rachel [School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide 5042, SA (Australia); Bennett, John W. [Centre for Nuclear Applications, Australian Nuclear Science and Technology Organisation, Lucas Heights 2234, NSW (Australia); Ellis, Amanda V., E-mail: Amanda.Ellis@flinders.edu.au [Flinders Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide 5042, SA (Australia)

    2014-05-01

    Highlights: • Natural zeolites were modified with bio-inspired polydopamine. • A 91.4% increase in Cu(II) ion adsorption capacity was observed. • Atomic absorption and neutron activation analysis gave corroborative results. • Neutron activation analysis was used to provide accurate information on 30+ elements. • Approximately 90% of the adsorbed copper could be recovered by 0.1 M HCl treatment. - Abstract: Herein, for the first time, natural clinoptilolite-rich zeolite powders modified with a bio-inspired adhesive, polydopamine (PDA), have been systematically studied as an adsorbent for copper cations (Cu(II)) from aqueous solution. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) revealed successful grafting of PDA onto the zeolite surface. The effects of pH (2–5.5), PDA treatment time (3–24 h), contact time (0 to 24 h) and initial Cu(II) ion concentrations (1 to 500 mg dm{sup −3}) on the adsorption of Cu(II) ions were studied using atomic absorption spectroscopy (AAS) and neutron activation analysis (NAA). The adsorption behavior was fitted to a Langmuir isotherm and shown to follow a pseudo-second-order reaction model. The maximum adsorption capacities of Cu(II) were shown to be 14.93 mg g{sup −1} for pristine natural zeolite and 28.58 mg g{sup −1} for PDA treated zeolite powders. This impressive 91.4% increase in Cu(II) ion adsorption capacity is attributed to the chelating ability of the PDA on the zeolite surface. Furthermore studies of recyclability using NAA showed that over 50% of the adsorbed copper could be removed in mild concentrations (0.01 M or 0.1 M) of either acid or base.

  10. Copper removal using bio-inspired polydopamine coated natural zeolites

    International Nuclear Information System (INIS)

    Yu, Yang; Shapter, Joseph G.; Popelka-Filcoff, Rachel; Bennett, John W.; Ellis, Amanda V.

    2014-01-01

    Highlights: • Natural zeolites were modified with bio-inspired polydopamine. • A 91.4% increase in Cu(II) ion adsorption capacity was observed. • Atomic absorption and neutron activation analysis gave corroborative results. • Neutron activation analysis was used to provide accurate information on 30+ elements. • Approximately 90% of the adsorbed copper could be recovered by 0.1 M HCl treatment. - Abstract: Herein, for the first time, natural clinoptilolite-rich zeolite powders modified with a bio-inspired adhesive, polydopamine (PDA), have been systematically studied as an adsorbent for copper cations (Cu(II)) from aqueous solution. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) revealed successful grafting of PDA onto the zeolite surface. The effects of pH (2–5.5), PDA treatment time (3–24 h), contact time (0 to 24 h) and initial Cu(II) ion concentrations (1 to 500 mg dm −3 ) on the adsorption of Cu(II) ions were studied using atomic absorption spectroscopy (AAS) and neutron activation analysis (NAA). The adsorption behavior was fitted to a Langmuir isotherm and shown to follow a pseudo-second-order reaction model. The maximum adsorption capacities of Cu(II) were shown to be 14.93 mg g −1 for pristine natural zeolite and 28.58 mg g −1 for PDA treated zeolite powders. This impressive 91.4% increase in Cu(II) ion adsorption capacity is attributed to the chelating ability of the PDA on the zeolite surface. Furthermore studies of recyclability using NAA showed that over 50% of the adsorbed copper could be removed in mild concentrations (0.01 M or 0.1 M) of either acid or base

  11. Effect of combination of irradiation and zeolite on pyrolysis of polymer materials

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, S; Takesita, H; Yoshii, F; Makuuchi, K [Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Inst., Watanuki-machi, Takasaki-shi, Gunma-ken (Japan); Nishimoto, S I [Div. of Energy and Hydrocarbon Chemistry School of Engineering, Lab. of Excited State Hydrocarbon Chemistry, Kyoto Univ., Yoshida Hon-cho, Sakyo-ku, Kyoto (Japan)

    1998-06-01

    Fo0r recycling of waste polymers, degradation behavior of polypropylene (PP) and polyoxymethylene (POM) was studied by a combination of radiolysis and thermolysis methods. The results revealed that thermal degradation temperature of PP was significantly reduced when PP was irradiated in the presence of zeolite. Irradiation induced temperature reduction depended on zeolite structure and composition as well as on the morphology of the mixture. In the presence of zeolite, a series of oxidized products were formed. Initial temperature for the pyrolysis of POM was depressed by irradiation and the irradiated POM had lower final temperature of pyrolysis in the presence of zeolite 14 refs, 8 figs, 4 tabs

  12. Direct activation of microcrystalline zeolites

    NARCIS (Netherlands)

    Ortiz-Iniesta, Maria Jesus; Heeres, Hero Jan; Melian-Cabrera, Ignacio

    2013-01-01

    In this work a direct activation route of zeolites is assessed. It consists of NH4-exchanging the as-synthesized solids before removing the organic template. Calcination afterwards serves to combust the organic template and creates the Bronsted sites directly; thus applying merely a single thermal

  13. Electro-elastoviscous response of polyaniline functionalized nano-porous zeolite based colloidal dispersions.

    Science.gov (United States)

    Chattopadhyay, Ankur; Rani, Poonam; Srivastava, Rajendra; Dhar, Purbarun

    2018-06-01

    The present article discusses the typical influence of grafted conducting polymers in the mesoscale pores of dielectric particles on the static and dynamic electrorheology and electro-viscoelastic behavior of corresponding colloids. Nanocrystalline meso-nanoporous zeolite has been prepared by chemical synthesis and subsequently polyaniline (PANI) coating has been implemented. Electrorheological (ER) suspensions have been formed by dispersing the nanoparticles in silicone oil and their viscoelastic behaviors are examined to understand the nature of such complex colloidal systems under electric fields. PANI-Zeolite ER fluids demonstrate higher static electroviscous effects and yield stress potential than untreated Zeolite, typically studied in literature. Transient electro-viscous characterizations show a stable and negligible hysteresis behavior when both the fluids are exposed to constant as well as time varying electric field intensities. Further oscillatory shear experiments of frequency and strain sweeps exhibit predominant elastic behavior in case of Zeolite based ER suspensions as compared to PANI systems. Detailed investigations reveal Zeolite based ER suspensions display enhanced relative yielding as well as electro-viscoelastic stability than the PANI-Zeolite. The steady state viscous behaviors are scaled against the non-dimensional Mason number to model the system behavior for both fluids. Experimental data of flow behaviors of both the ER fluids are compared with semi-classical models and it is found that the CCJ model possesses a closer proximity than traditional Bingham model, thereby revealing the fluids to be generic pseudo-linear fluids. The present article reveals that while the PANI based fluids are typically hailed superior in literature, it is only restricted to steady shear utilities. In case of dynamic and oscillatory systems, the traditional Zeolite based fluids exhibit superior ER caliber. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Measurement of cation exchange capacity (CEC) on natural zeolite by percolation method

    Science.gov (United States)

    Wiyantoko, Bayu; Rahmah, Nafisa

    2017-12-01

    The cation exchange capacity (CEC)measurement has been carried out in natural zeolite by percolation method. The natural zeolite samples used for cation exchange capacity measurement were activated beforehand with physical activation and chemical activation. The physically activated zeolite was done by calcination process at 600 °C for 4 hours. The natural zeolite was activated chemically by using sodium hydroxide by refluxing process at 60-80 °C for 3 hours. In summary, cation exchange capacity (CEC) determination was performed by percolation, distillation and titration processes. Based on the measurement that has been done, the exchange rate results from physical activated and chemical activated of natural zeolite were 181.90cmol (+)/kg and 901.49cmol (+)/kg respectively.

  15. Properties of glass-bonded zeolite monoliths

    International Nuclear Information System (INIS)

    Lewis, M.A.; Fischer, D.F.; Murphy, C.D.

    1994-01-01

    It has been shown that mineral waste forms can be used to immobilize waste salt generated during the pyrochemical processing of spent fuel from the Integral Fast Reactor (IFR). Solid, leach resistant monoliths were formed by hot-pressing mixtures of salt-occluded zeolite A powders and glass frit at 990 K and 28 MPa. Additional samples have now been fabricated and tested. Normalized release rates for all elements, including iodide and chloride, were less than 1 g/m 2 d in 28-day tests in deionized water and in brine at 363 K (90 degrees C). Preliminary results indicate that these rates fall with time with both leachants and that the zeolite phase in the glass-bonded zeolite does not function as an ion exchanger. Some material properties were measured. The Poisson ratio and Young's modulus were slightly smaller in glass-bonded zeolite than in borosilicate glass. Density depended on zeolite fraction. The glass-bonded zeolite represents a promising mineral waste form for IFR salt

  16. Catalysis with hierarchical zeolites

    DEFF Research Database (Denmark)

    Holm, Martin Spangsberg; Taarning, Esben; Egeblad, Kresten

    2011-01-01

    Hierarchical (or mesoporous) zeolites have attracted significant attention during the first decade of the 21st century, and so far this interest continues to increase. There have already been several reviews giving detailed accounts of the developments emphasizing different aspects of this research...... topic. Until now, the main reason for developing hierarchical zeolites has been to achieve heterogeneous catalysts with improved performance but this particular facet has not yet been reviewed in detail. Thus, the present paper summaries and categorizes the catalytic studies utilizing hierarchical...... zeolites that have been reported hitherto. Prototypical examples from some of the different categories of catalytic reactions that have been studied using hierarchical zeolite catalysts are highlighted. This clearly illustrates the different ways that improved performance can be achieved with this family...

  17. Prediction of Splitting Tensile Strength of Concrete Containing Zeolite and Diatomite by ANN

    Directory of Open Access Journals (Sweden)

    E. Gülbandılar

    2017-01-01

    Full Text Available This study was designed to investigate with two different artificial neural network (ANN prediction model for the behavior of concrete containing zeolite and diatomite. For purpose of constructing this model, 7 different mixes with 63 specimens of the 28, 56 and 90 days splitting tensile strength experimental results of concrete containing zeolite, diatomite, both zeolite and diatomite used in training and testing for ANN systems was gathered from the tests. The data used in the ANN models are arranged in a format of seven input parameters that cover the age of samples, Portland cement, zeolite, diatomite, aggregate, water and hyper plasticizer and an output parameter which is splitting tensile strength of concrete. In the model, the training and testing results have shown that two different ANN systems have strong potential as a feasible tool for predicting 28, 56 and 90 days the splitting tensile strength of concrete containing zeolite and diatomite.

  18. Synthesis of zeolite membrane (Y / α-alumina)

    International Nuclear Information System (INIS)

    Araujo, Ana Paula; Silva, Valmir Jose da; Crispin, Alana Carolyne; Rodrigues, Meiry Glaucia F.; Menezes, Romualdo R.

    2009-01-01

    The general aim of this study was to develop materials of the type: Y zeolite (hydrothermal synthesis), ceramic support (forming of powder) and zeolite membrane (rubbing). The preparation of the Y zeolite was conducted in accordance with the hydrothermal synthesis method, the time of crystallization was one day. The ceramic support was prepared by means of the forming of powder technique and subsequently subjected to sintering at a temperature of 1400 deg C/1h. The zeolite membrane (Y/α- alumina) was prepared by secondary growth method (rubbing). These materials were characterized by XRD and SEM. Obtaining Y zeolite could be confirmed by X ray diffractograms. From the images obtained by SEM, it was possible to derive from analysis that the Y zeolite is composed of a homogeneous morphology, where the particles are crowded, with uniform size. The results obtained for the ceramic support (α-alumina) showed that it displays characteristics peaks of aluminum oxide. By using micrographs it was possible to observe a heterogeneous microstructure with a compact form, without cracks upon the layers. According to the XRD, for the method of secondary growth (rubbing), it was observed that the Y zeolite which had been synthesized on the ceramic support displayed a crystalline structure. The micrography of the zeolite membrane (Y/α-alumina) showed the formation of a layer of zeolite on the ceramic support. (author)

  19. Metal doped green zeolites for water treatment a sustainable remediation model

    International Nuclear Information System (INIS)

    Tabassum, N.; Rafique, U.

    2016-01-01

    The synthesis of zeolites from refused materials presents a greener model for environmental remediation. The present study offers a novel procedure to synthesize not only the basic framework but also Vanadium modified polymeric zeolites. The spent polythene bags, lunch boxes, and packaging are used as raw material for synthesis of zeolites. Characterization through EDX showed incorporation of vanadium is more than 35%, exhibiting FTIR frequencies in the range 601-995cm-1. Thermogravimetric (TG) analysis revealed a stabilizing effect of zeolites on addition of dopant upto 320 degree C as determined by higher residue percentage (> 98%). Vanadium doped synthesized zeolites (MP1, MP2, MP3) were applied in batch adsorption experiments for in-situ (synthetic metal salt solution) and ex-situ (industrial effluents) removal of metals (Pb, Cr, and Cd). Adsorption results indicated the successful metal removal of more than 90% in the sequence Pb > Cd > Cr. The sequence follows, higher is the ionic radius of the metal cation, more is the adsorption on zeolites. Application of adsorption isotherms demonstrated fitness of Freundlich and Temkin models, whereas pseudo first order kinetics depicts metal removal. The study concludes that synthesized zeolites are suitable candidates with improvised green economy for industrial sector to treat effectively industrial discharges. (author)

  20. Synthesis of Zeolite from Fly Ash and Removal of Heavy Metal Ions from Newly Synthesized Zeolite

    OpenAIRE

    Solanki, Parag; Gupta, Vikal; Kulshrestha, Ruchi

    2010-01-01

    Coal fly ash was used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. Characteristics of the various Fly ash samples were carried out. Coal proximate analysis was done. Batch experiment was carried out for the adsorption of some heavy metal ions on to synthesized Zeolite. The cost of synthesized zeolite was estimated to be almost one-fifth of that of commercial 13X zeolite available in the market.

  1. Magnetic and Moessbauer-spectroscopic studies of iron-clusters in zeolites. [Reduction of ferrous ions

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, F; Gunsser, W; Knappwost, A [Hamburg Univ. (F.R. Germany). Inst. fuer Physikalische Chemie

    1975-12-01

    Iron clusters have been prepared within zeolite holes by reduction of zeolites containing ferrous ions. The diameter of these particles must therefore be smaller that 13 A. They are superparamagnetic and their Moessbauer spectra show no HFS, even at 4K. The temperature dependence of the magnetic susceptibility of the unreduced zeolites obeys a Curie-Weiss law with p/sub eff/ = 4.45 ..mu..B and THETA = 105K. The Weiss curves of the reduced samples lie distinctly below those of the bulk material.

  2. Acidity in zeolite catalysis

    NARCIS (Netherlands)

    Santen, van R.A.; Gauw, de F.J.M.M.; Corma, A.; Melo, F.; Mendioroz, S.; Fierro, J.L.G.

    2000-01-01

    A review with 21 refs. is provided on our current understanding of the activation of hydrocarbons by protonic zeolites. One has to distinguish the proton affinity of a zeolite, measured in an equil. expt., from proton activation that dets. a kinetic catalytic result. The proton affinity depends on

  3. Intracellular delivery of peptide nucleic acid and organic molecules using zeolite-L nanocrystals.

    Science.gov (United States)

    Bertucci, Alessandro; Lülf, Henning; Septiadi, Dedy; Manicardi, Alex; Corradini, Roberto; De Cola, Luisa

    2014-11-01

    The design and synthesis of smart nanomaterials can provide interesting potential applications for biomedical purposes from bioimaging to drug delivery. Manufacturing multifunctional systems in a way to carry bioactive molecules, like peptide nucleic acids able to recognize specific targets in living cells, represents an achievement towards the development of highly selective tools for both diagnosis and therapeutics. This work describes a very first example of the use of zeolite nanocrystals as multifunctional nanocarriers to deliver simultaneously PNA and organic molecules into living cells. Zeolite-L nanocrystals are functionalized by covalently attaching the PNA probes onto the surface, while the channel system is filled with fluorescent guest molecules. The cellular uptake of the PNA/Zeolite-L hybrid material is then significantly increased by coating the whole system with a thin layer of biodegradable poly-L-lysine. The delivery of DAPI as a model drug molecule, inserted into the zeolite pores, is also demonstrated to occur in the cells, proving the multifunctional ability of the system. Using this zeolite nanosystem carrying PNA probes designed to target specific RNA sequences of interest in living cells could open new possibilities for theranostic and gene therapy applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Hot topic: prevention of parturient paresis and subclinical hypocalcemia in dairy cows by zeolite A administration in the dry period

    DEFF Research Database (Denmark)

    Thilsing-Hansen, T; Jørgensen, R J; Thilsing, Trine

    2001-01-01

    To test the effects of a zeolite feed supplement on parturient calcium status and milk fever, two groups of dry cows were treated with either 1 kg of zeolite/d or none for 4 wk prepartum. At calving and d 1 and 2 after calving all cows were given 250 g of calcium carbonate as a drench, and a blood...... sample was taken. Serum calcium analysis revealed a greater calcium concentration in zeolite-treated cows. While three control cows contracted milk fever, necessitating intravenous calcium therapy, and six out of eight control cows experienced serum calcium levels below 2 mmol/L in one or more samples...... taken, none of the zeolite-treated cows contracted milk fever or experienced subclinical hypocalcemia....

  5. Using zeolites for fixation and long-term storage of krypton

    International Nuclear Information System (INIS)

    Pirogova, G.N.; Voronin, Yu.V.; Pribylov, A.A.; Serpinskii, V.V.; Mirskii, Ya.V.; Almazova, B.B.; Golitsina, V.V.

    1993-01-01

    It is known that large quantities of 85 Kr are liberated during the operation of nuclear power plants and, in particular, during the processing of nuclear fuel. At the present time, there are several methods of its fixation (accumulation), viz., storage in high-pressure gas balloons, adsorption, plasma-aided implantation into metals, introduction into clathrate compounds, and obtaining kryptonates. Encapsulation in zeolites is one of the most promising methods. The merits of this method include safety during storage, a favorable volume-to-mass ratio, the possibility of separating krypton from a mixture of different gases, and purity of the encapsulated gas. The encapsulation technique has been developed quite recently. Several recent reports established the possibility of encapsulating krypton in the 3A-type zeolites. However, most of the investigators observed leakage during the storage of the zeolite-gas system and complete liberation of krypton from the zeolite during prolonged storage. This paper deals with a study of the encapsulation process of krypton in the zeolites obtained by cation exchange from NaA. The experimental specimens were characterized by the degree of exchange of sodium into potassium and cesium. It is known that the introduction of cesium into the structure (body) of a zeolite reduces the size of the window of entrance. All the synthesized specimens were used in their granulated form. The aim of this study was to develop zeolite specimens for carrying out long-term storage of krypton

  6. Increased thermal conductivity monolithic zeolite structures

    Science.gov (United States)

    Klett, James; Klett, Lynn; Kaufman, Jonathan

    2008-11-25

    A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/mK to more than 1,000 W/mK. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.

  7. An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lingling, E-mail: lasier_wang@hotmail.com [College of Chemical Engineering and Materials, Quanzhou Normal University, Quanzhou 362000, Fujian (China); Environmental Engineering and Science Program, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Han, Changseok [ORISE Post-doctoral Fellow, The U.S. Environmental Protection Agency, ORD, NRMRL, STD, CPB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268 (United States); Nadagouda, Mallikarjuna N. [The U.S. Environmental Protection Agency, ORD, NRMRL, WSWRD, WQMB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268 (United States); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678, Nicosia (Cyprus)

    2016-08-05

    Highlights: • An innovative adsorbent was successfully synthesized to remove humic acid. • The adsorbent possessed high adsorption capacity for humic acid. • The adsorption capacity remarkably increased after an acid modification. • The adsorption capacity was proportional to the amount of ZnO coated on zeolite. • Electrostatic interactions are a major factor at the first stage of the process. - Abstract: Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO{sub 3}){sub 2}·6H{sub 2}O functionalization of zeolite 4A. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The synthesized materials were characterized by porosimetry analysis, scanning electron microscopy, X-Ray diffraction analysis, and high resolution transmission electron microscopy. The maximum adsorption capacity of the adsorbents at 21 ± 1 °C was about 60 mgC g{sup −1}. The results showed that the positive charge density of ZnO-coated zeolite adsorbents was proportional to the amount of ZnO coated on zeolite and thus, ZnO-coated zeolite adsorbents exhibited a greater affinity for negatively charged ions. Furthermore, the adsorption capacity of ZnO-coated zeolite adsorbents increased markedly after acid modification. Adsorption experiments demonstrated ZnO-coated zeolite adsorbents possessed high adsorption capacity to remove HA from aqueous solutions mainly due to strong electrostatic interactions between negative functional groups of HA and the positive charges of ZnO-coated zeolite adsorbents.

  8. An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

    International Nuclear Information System (INIS)

    Wang, Lingling; Han, Changseok; Nadagouda, Mallikarjuna N.; Dionysiou, Dionysios D.

    2016-01-01

    Highlights: • An innovative adsorbent was successfully synthesized to remove humic acid. • The adsorbent possessed high adsorption capacity for humic acid. • The adsorption capacity remarkably increased after an acid modification. • The adsorption capacity was proportional to the amount of ZnO coated on zeolite. • Electrostatic interactions are a major factor at the first stage of the process. - Abstract: Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO_3)_2·6H_2O functionalization of zeolite 4A. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The synthesized materials were characterized by porosimetry analysis, scanning electron microscopy, X-Ray diffraction analysis, and high resolution transmission electron microscopy. The maximum adsorption capacity of the adsorbents at 21 ± 1 °C was about 60 mgC g"−"1. The results showed that the positive charge density of ZnO-coated zeolite adsorbents was proportional to the amount of ZnO coated on zeolite and thus, ZnO-coated zeolite adsorbents exhibited a greater affinity for negatively charged ions. Furthermore, the adsorption capacity of ZnO-coated zeolite adsorbents increased markedly after acid modification. Adsorption experiments demonstrated ZnO-coated zeolite adsorbents possessed high adsorption capacity to remove HA from aqueous solutions mainly due to strong electrostatic interactions between negative functional groups of HA and the positive charges of ZnO-coated zeolite adsorbents.

  9. Nanosized zeolites as a perspective material for conductometric biosensors creation

    Science.gov (United States)

    Kucherenko, Ivan; Soldatkin, Oleksandr; Kasap, Berna Ozansoy; Kirdeciler, Salih Kaan; Kurc, Burcu Akata; Jaffrezic-Renault, Nicole; Soldatkin, Alexei; Lagarde, Florence; Dzyadevych, Sergei

    2015-05-01

    In this work, the method of enzyme adsorption on different zeolites and mesoporous silica spheres (MSS) was investigated for the creation of conductometric biosensors. The conductometric transducers consisted of gold interdigitated electrodes were placed on the ceramic support. The transducers were modified with zeolites and MSS, and then the enzymes were adsorbed on the transducer surface. Different methods of zeolite attachment to the transducer surface were used; drop coating with heating to 200°C turned out to be the best one. Nanozeolites beta and L, zeolite L, MSS, and silicalite-1 (80 to 450 nm) were tested as the adsorbents for enzyme urease. The biosensors with all tested particles except zeolite L had good analytical characteristics. Silicalite-1 (450 nm) was also used for adsorption of glucose oxidase, acetylcholinesterase, and butyrylcholinesterase. The glucose and acetylcholine biosensors were successfully created, whereas butyrylcholinesterase was not adsorbed on silicalite-1. The enzyme adsorption on zeolites and MSS is simple, quick, well reproducible, does not require use of toxic compounds, and therefore can be recommended for the development of biosensors when these advantages are especially important.

  10. Inelastic neutron scattering from non-framework species within zeolites

    International Nuclear Information System (INIS)

    Newsam, J.M.; Brun, T.O.; Trouw, F.; Iton, L.E.; Curtiss, L.A.

    1990-01-01

    Inelastic and quasielastic neutron scattering have special advantages for studying certain of the motional properties of protonated or organic species within zeolites and related microporous materials. In this paper these advantages and various experimental methods are outlined, and illustrated by measurements of torsional vibrations and rotational diffusion of tetramethylammonium (TMA) cations occluded within zeolites TMA-sodalite, omega, ZK-4 and SAPO-20

  11. Human bile sorption by cancrinite-type zeolites

    International Nuclear Information System (INIS)

    Linares, Carlos F.; Colmenares, Maryi; Ocanto, Freddy; Valbuena, Oscar

    2009-01-01

    A nitrated cancrinite-type zeolite was synthesized from zeolite X, NaOH and NaNO 3 solutions under autogeneous pressure at 80 deg. C for 48 h. This zeolite was characterized by X-ray diffraction (XRD), FT-IR-spectroscopy, scanning electron microscopy (SEM) and BET surface area. XRD, SEM and FT-IR confirmed the presence of nitrated cancrinite-type zeolite without other collateral phases as sodalite. Then, this sodium zeolite was exchanged with potassium and calcium cations and finally, these modified zeolites were reacted with biliar solutions from human gallbladder. Several factors such as: mass of used cancrinite, nature of the exchanged cation and reaction time of the cancrinite-bile solution interactions were studied. The composition of bile solutions (bile acids, phospholipids and bilirubin) was analyzed before and after the cancrinite-bile solution reaction. Results showed that the components of the bile were notably reduced after the contact with solids. Ca-cancrinite, 120 min of reaction time and 500 mg of solids were the best conditions determined for the bile acid reduction in human bile. When the modified zeolites were compared with the commercial cholestyramine, it was found that zeolites were more active than the latter. These zeolites may be an alternative choice to diminish cholesterol levels in hypercholesterolemic patients

  12. Removal of cadmium in urban wastewater with systems based on zeolite type clinoptilolite

    International Nuclear Information System (INIS)

    Barragan P, P.

    2016-01-01

    From an environmental issue detected in wastewater samples taken in a municipal wastewater collector in Nogales, Sonora, which is related to cadmium pollution, a research project came out where the principal aim was to implement a system to remove metallic ions of cadmium in wastewater, based on modified and unmodified natural zeolites. The zeolitic material used was natural clinoptilolite modified with NaCl and thiourea, sourced in El Cajon and Guaymas, Sonora. The materials were characterized with X-ray diffraction, Sem, Ft-IR spectra, and Bet analysis. The kinetics of four modified zeolites was investigated at ph=5 and initial concentration of 30 mgL"-"1 of Cd"2"+. The pseudo-first, the pseudo-second order, and Elovich models were applied to the experimental results. The results best fitted to pseudo-second order model. The maximum sorption capacity of modified zeolites was investigated through isotherms, The Langmuir model, Freundlich, and the combined Langmuir-Freundlich models were applied to the experimental results afterwards. ZGuayThio showed the highest sorption capacity, 11.60 mgg"-"1, with R"2=0.978 according to Langmuir-Freundlich model. Fixed-bed column adsorption experiments were carried out with ZGuayNa and ZGuayThio with three bed heights with 30 mgL"-"1 solution of Cd"2"+. influent at a flow rate of 1 mLmin"-"1, at ph=5. The Thomas, mass balance, and Bed Depth Service Time models were applied to the results. The dynamic adsorption capacity (No) and the constant of sorption velocity (K a) were determined, 28.67 gL"-"1 and 0.072 Lg"-"1min"-"1 respectively for ZGuayNa with R"2= 0.9954. Column experiments with municipal wastewater from Colinas del Yaqui sub-collector, previously characterized, were conducted using ZGuayNa and ZGuayThio. A mass transference model was applied to the results which accounted for K_p= 0.815 m"3Kg"-1 with R"2= 0.9789 for ZGuayNa, and K_p= 3.1 m"3Kg"-1 for ZGuayThio with R"2= 0.78. Finally, the capacity of the column system

  13. Characterization of Mexican zeolite minerals

    International Nuclear Information System (INIS)

    Jimenez C, M.J.

    2005-01-01

    50% of the Mexican territory is formed by volcanic sequences of the Pliocene type, which appear extensively in the northwest states (Sonora, Sinaloa, Chihuahua, Durango) and west of Mexico (Jalisco and Nayarit), in central Mexico (Zacatecas, Guanajuato, San Luis Potosi, Queretaro, Hidalgo) and south of Mexico (Guerrero, Oaxaca); therefore, it is to be expected that in our country big locations of natural zeolites exist in its majority of the clinoptilolite type. The present study was focused toward the characterization of two Mexican natural zeolite rocks presumably of the clinoptilolite and filipsite types, one of them comes from the state of Chihuahua and the other of a trader company of non metallic minerals, due that these materials are not characterized, its are not known their properties completely and therefore, the uses that can be given to these materials. In this investigation work it was carried out the characterization of two Mexican zeolite rocks, one coming from the Arroyo zone, municipality of La Haciendita, in the state of Chihuahua; and the other one was bought to a trader company of non metallic minerals. The two zeolites so much in their natural form as conditioned with sodium; they were characterized by means of X-ray diffraction, scanning electron microscopy of high vacuum and elementary microanalysis (EDS), surface area analysis (BET), thermal gravimetric analysis. To differentiate the heulandite crystalline phase of the other clinoptilolite rock, its were carried out thermal treatments. The quantification of Al, Na, Ca, K, Mg, Fe was carried out in solution, by means of atomic absorption spectroscopy and the quantity of Si was determined by gravimetry. The zeolite rocks presented for the major part the crystalline heulandite and clinoptilolite phases for the most part, and it was found that the zeolite coming from the state of Chihuahua possesses a bigger content of heulandite and the denominated filipsite it is really a zeolite

  14. A Hierarchically Micro-Meso-Macroporous Zeolite CaA for Methanol Conversion to Dimethyl Ether

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2016-11-01

    Full Text Available A hierarchical zeolite CaA with microporous, mesoporous and macroporous structure was hydrothermally synthesized by a ”Bond-Blocking” method using organo-functionalized mesoporous silica (MS as a silica source. The characterization by XRD, SEM/TEM and N2 adsorption/desorption techniques showed that the prepared material had well-crystalline zeolite Linde Type A (LTA topological structure, microspherical particle morphologies, and hierarchically intracrystalline micro-meso-macropores structure. With the Bond-Blocking principle, the external surface area and macro-mesoporosity of the hierarchical zeolite CaA can be adjusted by varying the organo-functionalized degree of the mesoporous silica surface. Similarly, the distribution of the micro-meso-macroporous structure in the zeolite CaA can be controlled purposely. Compared with the conventional microporous zeolite CaA, the hierarchical zeolite CaA as a catalyst in the conversion of methanol to dimethyl ether (DME, exhibited complete DME selectivity and stable catalytic activity with high methanol conversion. The catalytic performances of the hierarchical zeolite CaA results clearly from the micro-meso-macroporous structure, improving diffusion properties, favoring the access to the active surface and avoiding secondary reactions (no hydrocarbon products were detected after 3 h of reaction.

  15. Mesoporous Zeolite Single Crystals for Catalytic Hydrocarbon Conversion

    DEFF Research Database (Denmark)

    Schmidt, I.; Christensen, Claus H.; Kustova, Marina

    2005-01-01

    Recently, mesoporous zeolite single crystals were discovered. They constitute a novel family of materials that features a combined micropore and mesopore architecture within each individual crystal. Here, we briefly summarize recent catalytic results from cracking and isomerization of alkalies......, alkylation of aromatics and present new results on isomerization of aromatics. Specifically, the shape-selective isomerization of meta-xylenc into para-xylene and ortho-xylene is studied. In all these reactions, rnesoporous zeolite single crystals prove to be unique catalysts since they provide easy...... transport to and from active sites and at the same time maintain the shape-selectivity required. Thus, all these results support the idea that the beneficial effect of the mesopores system in the mesoporous zeolite single crystals call be solely attributed to enhanced mass transport....

  16. Effects of heating on salt-occluded zeolite

    International Nuclear Information System (INIS)

    Lewis, M.A.; Hash, M.C.; Pereira, C.; Ackerman, J.P.

    1996-01-01

    The electrometallurgical treatment of spent nuclear fuel generates a waste stream of fission products in the electrolyte, LiCl-KCl eutectic salt. Argonne National Laboratory is developing a mineral waste form for this waste stream. The waste form consists of a composite formed by hot pressing salt-occluded zeolite and a glass binder. Pressing conditions must be judiciously chosen. For a given pressure, increasing temperatures and hold times give denser products but the zeolite is frequently converted to sodalite. Reducing the temperature or hold time leads to a porous zeolite composite. Therefore, conditions that affect the thermal stability of salt-occluded zeolite both with and without glass are being investigated in an ongoing study. The parameters varied in this stage of the work were heating time, temperature, salt loading, and glass content. The heat-treated samples were examined primarily by X-ray diffraction. Large variations were found in the rate at which salt-occluded zeolite converted to other phases such as nepheline, salt, and sodalite. The products depended on the initial salt loading. Heating times required for these transitions depended on the procedure and temperature used to prepare the salt-occluded zeolite. Mixtures of glass and zeolite reacted much faster than the pure salt-occluded zeolite and were almost always converted to sodalite

  17. Kinetics and thermodynamic for sorption of arsenate by Lanthanum-exchanged zeolite

    International Nuclear Information System (INIS)

    Mohd Jelas Haron; Saiful Adli Masdan; Mohd Zobir Hussein; Zulkarnain Zainal; Anuar Kassim

    2007-01-01

    Zeolites are crystalline, hydrated aluminosilicate containing exchangeable alkaline and alkaline earth cations in their structural frameworks. Since zeolites have permanent negative charges on their surfaces, they have no affinity for anions. However recent studies have shown that modification of zeolites with certain surfactants or metal cations yield sorbents with a strong affinity for many anions. In this paper, modification of zeolites (zeolite A, X and ZSM5) were performed by exchange of naturally occurring cations with lanthanum ion that forms low solubility arsenate salt. The exchanged zeolites were used to sorb arsenate from aqueous solution. Among parameters investigated were effect of pH, arsenate initial concentrations, contact time and temperature. The maximum exchanged capacity of La (III) ion was obtained when using solution with initial pH of 4. Zeolite X gives the highest La (III) exchanged capacity compared to other zeolites. The results showed that As (V) sorption by La-zeolites occurred at about pH 6.5 and increased as pH increased and reaching maximum at equilibrium pH about 7.8. On the other hand, almost no arsenate sorption occurred on un exchanged zeolites. This indicates that La (III) ion on the exchanged zeolites is taking part on the As(V) sorption via surface precipitation. The results also showed that the sorption capacities increased with increasing initial As (V) concentrations. The sorption followed Langmuir model with maximum sorption capacities of 0.41, 0.21 and 0.19 mmol/g at 25 degree Celsius for La exchanged zeolite X (La-ZX), La exchanged zeolite ZSM5 (La-ZSM) and La exchanged zeolite A (La-ZA), respectively. The amounts of sorption of As (V) by La exchanged zeolite increased as temperature increased from 25 to 70 degree Celsius indicating that the process is endothermic. The free energy changes ( ΔG degree) for the sorption at 25 degree Celsius were -10.25, -9.65 and -8.49 kJ/ mol for La-ZX, La-ZSM and La-ZA, respectively. The

  18. Supported Zeolite Beta Layers via an Organic Template-Free Preparation Route.

    Science.gov (United States)

    Reuss, Stephanie; Sanwald, Dirk; Schülein, Marion; Schwieger, Wilhelm; Al-Thabaiti, Shaeel A; Mokhtar, Mohamed; Basahel, Sulaiman N

    2018-01-21

    Layers of high silica zeolites, synthesized with an organic structure directing agent (OSDA) and grown onto porous support structures, frequently suffer from the thermal stress during the removal of OSDA via the calcination process. The different thermal expansion coefficients of the zeolite and the support material, especially when stainless steel is used as a support, causes enormous tension resulting in defect formation in the zeolite layer. However, the calcination is an easy procedure to decompose the OSDA in the pore system of the zeolite. Recently, methods to synthesize zeolite beta without the use of an organic structure directing agent have been described. In the present study, a seed-directed synthesis is used to prepare OSDA-free zeolite beta layers on stainless steel supports via an in situ preparation route. For the application as membrane, a porous stainless steel support has been chosen. The beta/stainless steel composites are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). To prove its possible application as a membrane, the beta/stainless steel composites were also tested by single gas permeances of H₂, He, CO₂, N₂, and CH₄.

  19. Antibacterial properties of Ag-exchanged Philippine natural zeolite-chitosan composites

    Science.gov (United States)

    Taaca, Kathrina Lois M.; Olegario, Eleanor M.; Vasquez, Magdaleno R.

    2017-12-01

    Zeolites are microporous minerals composed of silicon, aluminum and oxygen. These aluminosilicates consist of tetrahedral units which produce open framework structures to generate a system of pores and cavities of molecular dimensions. Zeolites are naturally abundant and can be mined in most parts of the world. In this study, natural zeolites (NaZ) which are locally-sourced here in the Philippines were investigated to determine its properties. An ion-exchange process was utilized, using the zeolite to silver (Ag) solution ratio of 1:20 (w/v), to incorporate Ag into the zeolite framework. Characterizations such as XRD, AAS, and Agar diffusion assay were used to evaluate the properties of the synthesized Ag-exchanged zeolites (AgZ). X-ray diffraction revealed that both NaZ and AgZ have peaks mostly corresponding to the clinoptilolite structure, with some trace peaks of the mordenite and quartz. Absorption spectroscopy revealed that the ion exchange process added about 0.61188g of silver into the zeolite structure. This Ag content was seen to be enough to make the AgZ sample exhibit an antibacterial effect where clearing zones against E. coli and S. aureus were observed in the agar diffusion assay, respectively. The AgZ sample was also tested as ceramic filler to a polymer matrix-chitosan. The diffusion assay revealed presence of antibacterial activity to the polymer composite with AgZ fillers. These results indicate that the Philippine natural zeolite, incorporated with metals such as Ag, can be used as an antibacterial agent and can be developed as a ceramic filler to improve the antibacterial property of composite materials for biomedical application.

  20. ANAEROBIC DIGESTION OF WASTEWATER WITH HIGH SULFATE CONCENTRATION USING MICRO-AERATION AND NATURAL ZEOLITES

    Directory of Open Access Journals (Sweden)

    S. Montalvo

    Full Text Available Abstract The behavior of anaerobic digestion in batch and UASB reactors using a microaerobic process and natural zeolites was studied. Laboratory assays were carried out across 4 sets of variables: different COD/SO42- ratios, different airflow levels, with and without natural zeolites and room and mesophilic controlled temperatures. The microaerobic process demonstrated hydrogen sulfide removal levels exceeding 90% in most cases, while maintaining the flammable condition of the generated biogas. The level of COD removal exceeded 75% in UASB reactors despite their operation under very low hydraulic retention times (2.8-4.8 hours. The effectiveness of natural zeolites in accelerating UASB reactor startup was demonstrated. Results showing the positive influence of zeolites on the granulation process in UASB reactors were also achieved.

  1. Preparation and Characterization of Zeolite Membrane for Bioethanol Purification

    Directory of Open Access Journals (Sweden)

    Aprilina Purbasari

    2013-06-01

    Full Text Available The use of bioethanol as an alternative fuel with a purity of more than 99.5% wt has prompted research on bioethanol purification. One of the promising methods used for bioethanol purification is pervaporation membrane. This research is aimed to prepare and characterize zeolite membranes for pervaporation membrane. The membrane preparation consisted of two stages, namely support preparation and zeolite deposition on the support. In support preparation, α- alumina and kaolin with specific composition (50:30; 40:40; 50:30 was mixed with additives and water. After pugging and aging process, the mixture became paste and extruded into tubular shape. The tube was then calcined at temperature of 1250 °C for 3 hours. After that, zeolite 4A was deposited on the tubes using clear solution made of 10 %wt zeolite and 90 %wt water and heated at temperature of 80 °C for 3 hours. Furthermore, the resulting zeolite membranes was washed with deionized water for 5 minutes and dried in oven at temperature of 100 °C for 24 hours. Characterization of zeolite membranes included mechanical strength test, XRD, and SEM. In the mechanical strength test, the membrane sample with α- alumina:kaolin = 50:30 (membrane A has the highest mechanical strength of 46.65 N/mm2. Result of XRD analysis for the membrane A indicated that mullite and corundum phases were formed, which mullite phase was more dominant. Meanwhile the result of SEM analysis shows that zeolite crystals have been formed and covered the pores support, but the deposition of zeolite has not been optimal yet. The performance examination for bioethanol purification showed that the membrane could increase the purity of bioethanol from 95% to 98.5% wt. © 2013 BCREC UNDIP. All rights reservedReceived: 23rd October 2012; Revised: 15th February 2013; Accepted: 16th February 2013[How to Cite: Purbasari, A., Istirokhatun, T., Devi, A.M., Mahsunnah, L. , Susanto, H. (2013. Preparation and Characterization of Zeolite

  2. Effects of ultrasonic treatment on zeolite NaA synthesized from by-product silica.

    Science.gov (United States)

    Vaičiukynienė, Danutė; Kantautas, Aras; Vaitkevičius, Vitoldas; Jakevičius, Leonas; Rudžionis, Žymantas; Paškevičius, Mantas

    2015-11-01

    The synthesis of zeolite NaA from silica by-product was carried out in the presence of 20 kHz ultrasound at room temperature. Zeolites obtained in this type of synthesis were compared to zeolites obtained by performing conventional static syntheses under similar conditions. The sonication effects on zeolite NaA synthesis were characterized by phase identification, crystallinity etc. The effects of different parameters such as crystallization time and initial materials preparation methods on the crystallinity and morphology of the synthesized zeolites were investigated. The final products were characterized by XRD and FT-IR. It was possible to obtain crystalline zeolite NaA from by-product silica in the presence of ultrasound. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Adsorption of aqueous Zn(II) species on synthetic zeolites

    International Nuclear Information System (INIS)

    Badillo-Almaraz, Veronica; Trocellier, Patrick; Davila-Rangel, Ignacio

    2003-01-01

    To supply a good quality drinkable water tends to become a strategic task in both developed and under development countries in the world due to the number of potential contamination sources. One of the major problems is derived from the presence of heavy toxic metals like zinc or lead resulting from industrial activities. Zeolites are known as very efficient mineral substrates for fixing aqueous ionic species through their wide range of channels present in the crystalline structure and due to their strong surface reactivity. MicroPIXE coupled with microRBS (3.05 MeV 4 He + ions) have been used to quantify the incorporation of zinc within two commercial zeolites containing alkali elements (zeolite X and clinoptilolite) in the concentration range of: 0.0002-0.05 M at neutral pH. At the beginning of the interaction between zeolite and Zn(II) solution, the adsorption process exhibits a direct proportionality between the content of zinc fixed on the mineral substrate and the aqueous concentration up to 0.01 M. Beyond this point a saturation effect seems to occur, indicating the strong decrease of available adsorption sites. Sodium or potassium ions are probably exchanged with Zn(II) ions during this process. The compared behaviour of the two zeolites is then discussed in terms of kinetic effects based on ionic radius values. A co-adsorption test carried on with a 50-50% Zn(II) 0.001 M-Pb(II) 0.001 M solution shows that lead does not occupy the same sites as zinc because the content of zinc fixed on the zeolite sample exactly corresponds to the result obtained with a pure 0.001 M Zn(II) solution. All these data clearly showed that zeolite surface reactivity is greatly influenced by the mineral cage-like structure and particularly the presence of pockets, spaces and channels

  4. Examination of zeolites by neutron reflection method

    International Nuclear Information System (INIS)

    Szegedi, S.; Varadi, M.; Boedy, Z.T.; Vas, L.

    1991-01-01

    Neutron reflection method has been used for the determination of zeolite content in minerals. The basis of this measurement is to observe the large difference between the water content of zeolite and that of other mineralic parts of the sample. The method suggested can be used in a zeolite mine for measuring the zeolite content continuously and controlling the quality of the end products. (author) 5 refs.; 3 figs.; 3 tabs

  5. Simultaneous desulfurization and denitrification by microwave reactor with ammonium bicarbonate and zeolite

    International Nuclear Information System (INIS)

    Wei Zaishan; Lin Zhehang; Niu Hejingying; He Haiming; Ji Yongfeng

    2009-01-01

    Microwave reactor with ammonium bicarbonate (NH 4 HCO 3 ) and zeolite was set up to study the simultaneous removal of sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) from flue gas. The results showed that the microwave reactor filled with NH 4 HCO 3 and zeolite could reduce SO 2 to sulfur with the best desulfurization efficiency of 99.1% and reduce NO x to nitrogen with the best NO x purifying efficiency of 86.5%. Microwave desulfurization and denitrification effect of the experiment using ammonium bicarbonate and zeolite together is much higher than that using ammonium bicarbonate or zeolite only. NO x concentration has little effect on denitrification but has no influence on desulfurization, SO 2 concentration has no effect on denitrification. The optimal microwave power and empty bed residence time (EBRT) on simultaneous desulfurization and dentrification are 211-280 W and 0.315 s, respectively. The mechanism for microwave reduced desulfurization and denitrification can be described as the microwave-induced catalytic reduction reaction between SO 2 , NO x and ammonium bicarbonate with zeolite being the catalyst and microwave absorbent

  6. Evaluation of zeolite mixtures for decontamination of high-activity-level water in the Submerged Demineralizer System (SDS) flowsheet at the Three Mile Island Nuclear Power Station, Unit 2

    International Nuclear Information System (INIS)

    King, L.J.; Campbell, D.O.; Collins, E.D.; Knauer, J.B.; Wallace, R.M.

    1983-01-01

    Mixtures of Linde Ionsiv IE-96 and Ionsiv A-51 zeolites were evaluated for use in the Submerged Demineralizer System (SDS) that was installed at the Three Mile Island Nuclear Power Station, Unit 2 (TMI-2) for decontaminating approx. 3000 m 3 (approx. 700,000 gal) of high-activity-level water in the containment building sump. Small-scale, tracer-level column tests were made using various mixtures of the zeolites to evaluate the capability for simultaneous removal of cesium and strontium. A column loading test was made in a hot cell using a mixture of equal parts of the zeolites to evaluate the performance of the mixture in removing cesium and strontium from a sample of TMI-2 sump water. A computerized mathematical model of the mixed-bed SDS system was used to evaluate the test data in order to select a zeolite mixture and predict system performance

  7. Dissolution of Iron During Biochemical Leaching of Natural Zeolite

    Directory of Open Access Journals (Sweden)

    Lengauer C.

    2004-12-01

    Full Text Available Natural zeolite, including clinoptilolite, often contains iron and manganese which decrease the whiteness of this sharp angular material.The biological treatment of zeolite enables its use as an substitute for tripolyphosphates in wash powders which have to comply with strict requirements as far as whiteness is concerned and rounded off grain content. Insoluble Fe3+ and Mn4+ in the zeolite could be reduced to soluble Fe2+ and Mn2+ by silicate bacteria of Bacillus spp. These metals were efficiently removed from zeolite as documented by Fe2O3 decrease (from 1.37% to 1.08% and MnO decrease (from 0.022% to 0.005% after bioleaching. The whiteness of zeolite was increased by 8%. The leaching effect, observed by scanning electron microscopy, caused also a chamfer of the edges of sharp angular grains. Despite the enrichment by fine-grained fraction, the decrease of the surface area of clinoptilolite grains from the value 24.94 m2/g to value 22.53 m2/g was observed. This fact confirms the activity of bacteria of Bacillus genus in the edge corrosion of mineral grains.Removal of iron and manganese as well as of sharp edges together with the whiteness increase would provide a product suitable for industrial applications.

  8. Effects of Zeolite and Vermicompost on Changes of Zn Chemical Fractionation in a Polluted Soil

    Directory of Open Access Journals (Sweden)

    Mohsen Hamidpour

    2017-02-01

    treatments were evaluated in a 3 × 3 factorial design and were arranged in a randomized block design with three replications. After incubation for 45 days, five seeds of corn were sown in each pot. After germination the seedlings were thinned to 3 per pot. Plants were grown for 2 months under control conditions. After the corn had been harvested, soil samples were air-dried, and analyzed for pH, cation exchange capacity (CEC, and electrical conductivity (EC. Chemical fractionations of Zn in soils collected after the pot trial were investigated using the procedure of Salbu et al. (1998. This procedure subdivides the heavy-metal distribution into an water-extractable+exchangeable fraction, a form bound to carbonates, a form bound to Fe and Mn oxides, a form bound to organics, and a residual form. An analysis of variance was used to test significance (P≤0.05 of treatment effects and Duncan multiple range test (P≤0.05 was used to compare the means (SAS, 2002. Results and Discussion: Soil pH gradually decreased with application of both vermicompost and zeolite amendments. This may be due to degradation of organic matter and releasing of organic and inorganic acids such as carbonic, citric and malic acids as well as H+ produced from mineralization of nitrogen in the organic matter. Electrical conductivity (EC of soils increased with increasing amounts of vermicompost and zeolite applications. The highest EC was observed in pots containing 10% w/w zeolite and 10% w/w vermicompost. Addition of zeolite significantly increased soil CEC. The overall distribution of Zn in different fractions was in the sequence residual (38.6%> Fe and Mn oxides bound (31.0 % > carbonated (21.6%> organic (4.3%≈exchangeable +water soluble (4.4 %. The application of vermicompost significantly decreased concentration of Zn in water+exchangeable fraction as compared to the control soil. Although singly zeolite amendment had not significant effect on water+exchangeable Zn concentration, this form

  9. Biogas Improvement by Adding Australian Zeolite During the Anaerobic Digestion of C:N Ratio Adjusted Swine Manure

    DEFF Research Database (Denmark)

    Wijesinghe, D. Thushari N.; Dassanayake, Kithsiri B.; Sommer, Sven G.

    2018-01-01

    Abstract: Maintenance of the ideal carbon: nitrogen (C:N) ratio with a minimum level of TAN is a key challenge for achieving maximum potential CH4 production through the anaerobic digestion process of agricultural waste such as swine manure. Biogas production can be enhanced by adding zeolite...... into the anaerobic digestion medium. However, the effects of zeolite addition to C:N ratio adjusted feedstock, on the digester performance is unknown. The objectives of this study were to investigate the effect of Australian zeolite on anaerobic digestion of swine manure with a C:N ratio adjusted to 30...... and to determine the optimal zeolite application rate to achieve the best performance. The Australian zeolite significantly enhanced CH4 production and reduced the lag phase of anaerobic digestion in batch production. The optimal addition rate of zeolite was appeared to be around 40 g/L. The better digester...

  10. Zeolites as supports for transition-metal complexes

    Energy Technology Data Exchange (ETDEWEB)

    Le Van Mao, R

    1979-01-01

    The unique structural characteristics of the zeolites, including the presence of molecular-size cages and channels and of an internal electrostatic field, make them promising as supports for converting homogeneous to heterogeneous catalysts. The acidic sites on the zeolites may also contribute to catalysis of reactions, such as hydrocracking; may stabilize metal complexes in a highly disperse state; and may improve activity or selectivity. Recent studies on the synthesis of new types of zeolite-supported complexes of transition metals (TM), such as Co, Cu, Ag, Fe, Mo, Ru, Rh, Re, and Os, suggest the feasibility of the direct introduction of some TM complexes into the zeolitic cages during zeolite synthesis, especially during the crystallization phase. This method may considerably reduce the structural limitations associated with the incorporation of TM complexes into zeolites by conventional methods.

  11. Methods of using structures including catalytic materials disposed within porous zeolite materials to synthesize hydrocarbons

    Science.gov (United States)

    Rollins, Harry W [Idaho Falls, ID; Petkovic, Lucia M [Idaho Falls, ID; Ginosar, Daniel M [Idaho Falls, ID

    2011-02-01

    Catalytic structures include a catalytic material disposed within a zeolite material. The catalytic material may be capable of catalyzing a formation of methanol from carbon monoxide and/or carbon dioxide, and the zeolite material may be capable of catalyzing a formation of hydrocarbon molecules from methanol. The catalytic material may include copper and zinc oxide. The zeolite material may include a first plurality of pores substantially defined by a crystal structure of the zeolite material and a second plurality of pores dispersed throughout the zeolite material. Systems for synthesizing hydrocarbon molecules also include catalytic structures. Methods for synthesizing hydrocarbon molecules include contacting hydrogen and at least one of carbon monoxide and carbon dioxide with such catalytic structures. Catalytic structures are fabricated by forming a zeolite material at least partially around a template structure, removing the template structure, and introducing a catalytic material into the zeolite material.

  12. THE EFFECT OF TYPE ZEOLITE ON THE GAS TRANSPORT PROPERTIES OF POLYIMIDE-BASED MIXED MATRIX MEMBRANES

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2012-01-01

    Full Text Available The permeation rates of O2, N2, CO2 and CH4 has been studied for polyimide-polyethersulfone (PI/PES blends-zeolite mixed matrix membranes synthesized in our laboratory. The study investigated the effect of zeolite loading and different zeolite type on the gas separation performance of these mixed matrix membranes. Frequency shifts and absorption intensity changes in the FTIR spectra of the PI/PES blends as compared with those of the pure polymers indicate that there is a mixing of polymer blends at the molecular level. Differential scanning calorimetry measurements of pure and PI/PES blends membranes have showed one unique glass transition temperature that supports the miscible character of the PI/PES mixture. The PI/PES-zeolite 4A mixed matrix membrane with 25 wt % zeolite loading produced the highest O2/N2 and CO2/CH4 selectivity of around 7.45 and 46.05, respectively.

  13. Effect of Annealing Temperature on Broad Luminescence of Silver-Exchanged Zeolites Y and A

    Science.gov (United States)

    Gui, Sa Chu Rong; Lin, H.; Bao, W.; Wang, W.

    2018-05-01

    The annealing temperature dependence of luminescence properties of silver (Ag)-exchanged zeolites Y and A was studied. It was found that the absorbance and excitation/emission bands are strongly affected by the thermal treatments. With increase in annealing temperature, the absorbance of Ag in zeolite Y increases at first and then decreases. However, the position of the excitation/emission band in zeolite Y was found to be insensitive to the annealing temperature. In contrast, the excitation/emission bands in zeolite A are particularly sensitive to the annealing temperature. The difference of such temperature dependence in zeolites Y and A may be due to the different microporous structure of the two minerals. Moreover, the fact that this dependence is not observed in Ag-exchanged zeolite Y is likely to be due to the difficulty in dehydration of zeolite Y in air or due to the weak Ag+-Ag+ interaction in zeolite Y.

  14. Densification of Silica Spheres: A New Pathway to Nano-Dimensioned Zeolite-Based Catalysts.

    Science.gov (United States)

    Machoke, Albert Gonche Fortunatus; Apeleo Zubiri, Benjamin; Leonhardt, Rainer; Marthala, Venkata Ramana Reddy; Schmiele, Martin; Unruh, Tobias; Hartmann, Martin; Spiecker, Erdman; Schwieger, Wilhelm

    2017-08-16

    Nanosized materials are expected to play a unique role in the development of future catalytic processes. Herein, pre-prepared and geometrically well-defined amorphous silica spheres are densified into silica-rich zeolites with nanosized dimensions. After the densification, the obtained nanosized zeolites exhibit the same spherical morphology like the starting precursor but characterized by a drastically reduced size, higher density, and high crystallinity. The phase transformation into crystalline zeolite material and the densification effect are achieved through a well-controlled steam-assisted treatment of the larger precursor particles so that the transformation process proceeds always towards the center of the spheres, just like a shrinking process. Furthermore, this procedure is applicable also to commercially available silica particles, as well as aluminum-containing systems (precursors) leading to acidic nano-catalysts with improved catalytic performance. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Synthesis of zeolite NaA membrane from fused fly ash extract.

    Science.gov (United States)

    Ameh, Alechine E; Musyoka, Nicholas M; Fatoba, Ojo O; Syrtsova, Daria A; Teplyakov, Vladimir V; Petrik, Leslie F

    2016-01-01

    Zeolite-NaA membranes were synthesized from an extract of fused South African fly ash on a porous titanium support by a secondary growth method. The influence of the synthesis molar regime on the formation of zeolite NaA membrane layer was investigated. Two synthesis mixtures were generated by adding either aluminium hydroxide or sodium aluminate to the fused fly ash extract. The feedstock material and the synthesized membranes were characterized by X-diffraction (XRD), scanning electron microscopy (SEM) and X-ray fluorescence spectroscopy (XRF). It was found by XRD and SEM that the cubic crystals of a typical zeolite NaA with a dense intergrown layer was formed on the porous Ti support. The study shows that the source of Al used had an effect on the membrane integrity as sodium aluminate provided the appropriate amount of Na(+) to form a coherent membrane of zeolite NaA, whereas aluminium hydroxide did not. Morphological, the single hydrothermal stage seeded support formed an interlocked array of zeolite NaA particles with neighbouring crystals. Also, a robust, continuous and well-intergrown zeolite NaA membrane was formed with neighbouring crystals of zeolite fused to each other after the multiple stage synthesis. The synthesized membrane was permeable to He (6.0 × 10(6) L m(-2)h(-1) atm(-1)) and CO2 (5.6 × 10(6) L m(-2)h(-1) atm(-1)), which indicate that the layer of the membrane was firmly attached to the porous Ti support. Membrane selectivity was maintained showing membrane integrity with permselectivity of 1.1, showing that a waste feedstock, fly ash, could be utilized for preparing robust zeolite NaA membranes on Ti support.

  16. Remarkable catalytic properties of hierarchical zeolite-Beta in epoxide rearrangement reactions

    Czech Academy of Sciences Publication Activity Database

    García-Munoz, J.L.; Serrano, D. P.; Vicente, G.; Linares, M.; Vitvarová, Dana; Čejka, Jiří

    2015-01-01

    Roč. 243, APR 2015 (2015), s. 141-152 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : hierarchical zeolites * zeolite beta * hybridzeolitic - mesostructured materials Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.312, year: 2015

  17. Carbon dioxide selective adsorption within a highly stable mixed-ligand Zeolitic Imidazolate Framework

    KAUST Repository

    Huang, Lin

    2014-08-01

    A new mixed-ligand Zeolitic Imidazolate Framework Zn4(2-mbIm) 3(bIm)5·4H2O (named JUC-160, 2-mbIm = 2-methylbenzimidazole, bIm = benzimidazole and JUC = Jilin University China) was synthesized with a solvothermal reaction of Zn(NO3) 2·6H2O, bIm and 2-mbIm in DMF solution at 180 °C. Topological analysis indicated that JUC-160 has a zeolite GIS (gismondine) topology. Study of the gas adsorption and thermal and chemical stability of JUC-160 demonstrated its selective adsorption property for carbon dioxide, high thermal stability, and remarkable chemical resistance to boiling alkaline water and organic solvent for up to one week. © 2014 Elsevier B.V.

  18. Exfoliation of two-dimensional zeolites in liquid polybutadienes

    KAUST Repository

    Sabnis, Sanket

    2017-06-16

    Layered zeolite precursors were successfully exfoliated by brief shearing or sonication with the assistance of commercially available telechelic liquid polybutadienes at room temperature. The exfoliated zeolite nanosheets can form a stable suspension in an organic solvent, providing exciting potential for the fabrication of zeolite membranes, composite materials and hierarchical zeolites.

  19. Inhibition of microbial concrete corrosion by Acidithiobacillus thiooxidans with functionalised zeolite-A coating.

    Science.gov (United States)

    Haile, Tesfaalem; Nakhla, George

    2009-01-01

    The inhibition of the corrosive action of Acidithiobacillus thiooxidans on concrete specimens coated by functionalised zeolite-A containing 14% zinc and 5% silver by weight was studied. Uncoated concrete specimens, epoxy-coated concrete specimens (EP), and functionalised zeolite-A coated concrete specimens with epoxy to zeolite weight ratios of 3:1 (Z1), 2:2 (Z2) and 1:3 (Z3) were studied. Specimens were characterised by x-ray powder diffraction and field emission scanning electron microscopy for the identification of corrosion products and morphological changes. Biomass growth at the conclusion of the 32-day experiments was 4, 179 and 193 mg volatile suspended solids g(-1) sulphur for the uncoated, EP and Z1 specimens, whereas that of Z2 and Z3 were negligible. In the uncoated, EP and Z1 specimens, sulphate production rates were 0.83, 9.1 and 8.8 mM SO(4)(2-) day(-1) and the specific growth rates, mu, were 0.14, 0.57 and 0.47 day(-1), respectively. The corresponding values for Z2 and Z3 were negligible due to their bacterial inhibition characteristics.

  20. Removal of calcium and magnesium ions from shale gas flowback water by chemically activated zeolite.

    Science.gov (United States)

    Chang, Haiqing; Liu, Teng; He, Qiping; Li, Duo; Crittenden, John; Liu, Baicang

    2017-07-01

    Shale gas has become a new sweet spot of global oil and gas exploration, and the large amount of flowback water produced during shale gas extraction is attracting increased attention. Internal recycling of flowback water for future hydraulic fracturing is currently the most effective, and it is necessary to decrease the content of divalent cations for eliminating scaling and maintaining effectiveness of friction reducer. Zeolite has been widely used as a sorbent to remove cations from wastewater. This work was carried out to investigate the effects of zeolite type, zeolite form, activation chemical, activation condition, and sorption condition on removal of Ca 2+ and Mg 2+ from shale gas flowback water. Results showed that low removal of Ca 2+ and Mg 2+ was found for raw zeolite 4A and zeolite 13X, and the efficiency of the mixture of both zeolites was slightly higher. Compared with the raw zeolites, the zeolites after activation using NaOH and NaCl greatly improved the sorption performance, and there was no significant difference between dynamic activation and static activation. Dynamic sorption outperformed static sorption, the difference exceeding 40% and 7-70% for removal of Ca 2+ and Mg 2+ , respectively. Moreover, powdered zeolites outperformed granulated zeolites in divalent cation removal.

  1. Electrorheology of a zeolite/silicone oil suspension under dc fields

    International Nuclear Information System (INIS)

    Tian, Yu; Meng, Yonggang; Wen, Shizhu

    2001-01-01

    The electrorheology of electrorheological (ER) fluids based on zeolite and silicone oil under dc fields was investigated at room temperature. ER fluids with volume fractions of 27% and 30% were prepared and tested. When a 5 kV/mm dc field was applied, shear yield stress of 26.7 kPa was obtained for the latter. The ER fluid with a higher volume fraction of zeolite had a higher current density and a higher shear yield stress under the same electric field. Compared with other ER fluids based on zeolite particles with low shear yield stress, the zeolite employed by us was found to have high dielectric constant and conductivity. The high permittivity mismatch and the high conductivity mismatch of the components of the fluids were considered responsible for the high shear yield stress. [copyright] 2001 American Institute of Physics

  2. Nuclear waste treatment using Iranian natural zeolites

    International Nuclear Information System (INIS)

    Kazemian, H.; Ghannadi Maraghe, M.

    2001-01-01

    Full text: The zeolite researches in Iran is a relatively new subject which has started about 10 years ago. The motivation for this scientific and interesting field was provided after discovery of significant deposits of natural zeolites in different regions of Iran as well as further developments of research institutions and the national concern to environmental protection especially the wastewater clean-up in point of view of recycling of such waste water to compensate some needs to water in other utilizations. This paper intends to review and describes scientific researches which have done on using zeolites in the field of nuclear waste treatment in Iran to introduce the potential resources to the world in more details. Zeolite tuffs are widely distributed in huge deposits in different regions of Iran. So far, the clinoptilolite tuffs are the most abundant natural zeolite which exist with zeolite content of 65%- 95%. Nowadays several different types of Iranian natural zeolites are characterized in point of view of chemical composition, type of structure, chemical, thermal, and radiation resistance using different instrumental and classical methods such as; X-ray diffraction (XRD), X-ray fluoresce (XRF), thermal methods of analysis (TA), scanning electron microscopy (SEM), analytical chemistry and radioanalytical methods as well as different ion-exchange techniques (e.g.3-7). The ability of Iranian natural clinoptilolite for removal of some fission products from nuclear wastewaters have been investigated. The selectivity of all investigated zeolites toward radiocesium and radiostrontium have been promising (e.g. 8-10). The successful synthesize of P zeolite from Iranian clinoptilolite-reach tuffs under different conditions were performed. The compatibility of zeolites with glass and cement matrices, for final disposal of radwaste, as well as their selectivity toward most dangerous heat generating radionuclides (e.g. 137 Cs and 90 Sr) is very important in using

  3. Adsorption cold storage system with zeolite-water working pair used for locomotive air conditioning

    International Nuclear Information System (INIS)

    Lu, Y.Z.; Wang, R.Z.; Zhang, M.; Jiangzhou, S.

    2003-01-01

    Adsorption cold storage has lately attracted attention for its large storage capacity and zero cold energy loss during the storing process. Thermodynamic and experimental studies on the cold storage capacity and the cold discharging process, in which the adsorber is either air cooled or adiabatic, have been presented. An adsorption cold storage system with zeolite-water working pair has been developed, and some operating results are summarized. This system is used for providing air conditioning for the driver's cab of an internal combustion locomotive. Unlike a normal adsorption air conditioner, the system starts running with the adsorption process, during which the cold energy stored is discharged, and ends running with the generation process. The adsorbent temperature decreases during the cold storing period between two runs. The refrigeration power output for the whole running cycle is about 4.1 kW. It appears that such a system is quite energetically efficient and is comparatively suitable for providing discontinuous refrigeration capacity when powered by low grade thermal energy, such as industrial exhausted heat or solar energy

  4. Enhancing nitrification at low temperature with zeolite in a mining operations retention pond

    Directory of Open Access Journals (Sweden)

    Misha eMiazga-Rodriguez

    2012-07-01

    Full Text Available Ammonium nitrate explosives are used in mining operations at Diavik Diamond Mines Inc. in the Northwest Territories, Canada. Residual nitrogen is washed into the mine pit and piped to a nearby retention pond where its removal is accomplished by microbial activity prior to a final water treatment step and release into the sub-Arctic lake, Lac de Gras. Microbial removal of ammonium in the retention pond is rapid during the brief ice-free summer, but often slows under ice cover that persists up to nine months of the year. The aluminosilicate mineral zeolite was tested as an additive to retention pond water to increase rates of ammonium removal at 4 °C. Water samples were collected across the length of the retention pond monthly over a year. The structure of the microbial community (bacteria, archaea, and eukarya, as determined by denaturing gradient gel electrophoresis of PCR-amplified small subunit ribosomal RNA genes, was more stable during cold months than during July-September, when there was a marked phytoplankton bloom. Of the ammonia-oxidizing community, only bacterial amoA genes were consistently detected. Zeolite (10 g was added to retention pond water (100 mL amended with 5 mM ammonium and incubated at 12 °C to encourage development of a nitrifying biofilm. The biofilm community was composed of different amoA phylotypes from those identified in gene clone libraries of native water samples. Zeolite biofilm was added to fresh water samples collected at different times of the year, resulting in a significant increase in laboratory measurements of potential nitrification activity at 4 °C. A significant positive correlation between the amount of zeolite biofilm and potential nitrification activity was observed; rates were unaffected in incubations containing 1-20 mM ammonium. Addition of zeolite to retention ponds in cold environments could effectively increase nitrification rates year round by concentrating active nitrifying biomass.

  5. Enhancing nitrification at low temperature with zeolite in a mining operations retention pond.

    Science.gov (United States)

    Miazga-Rodriguez, Misha; Han, Sukkyun; Yakiwchuk, Brian; Wei, Kai; English, Colleen; Bourn, Steven; Bohnert, Seth; Stein, Lisa Y

    2012-01-01

    Ammonium nitrate explosives are used in mining operations at Diavik Diamond Mines Inc. in the Northwest Territories, Canada. Residual nitrogen is washed into the mine pit and piped to a nearby retention pond where its removal is accomplished by microbial activity prior to a final water treatment step and release into the sub-Arctic lake, Lac de Gras. Microbial removal of ammonium in the retention pond is rapid during the brief ice-free summer, but often slows under ice cover that persists up to 9 months of the year. The aluminosilicate mineral zeolite was tested as an additive to retention pond water to increase rates of ammonium removal at 4°C. Water samples were collected across the length of the retention pond monthly over a year. The structure of the microbial community (bacteria, archaea, and eukarya), as determined by denaturing gradient gel electrophoresis of PCR-amplified small subunit ribosomal RNA genes, was more stable during cold months than during July-September, when there was a marked phytoplankton bloom. Of the ammonia-oxidizing community, only bacterial amoA genes were consistently detected. Zeolite (10 g) was added to retention pond water (100 mL) amended with 5 mM ammonium and incubated at 12°C to encourage development of a nitrifying biofilm. The biofilm community was composed of different amoA phylotypes from those identified in gene clone libraries of native water samples. Zeolite biofilm was added to fresh water samples collected at different times of the year, resulting in a significant increase in laboratory measurements of potential nitrification activity at 4°C. A significant positive correlation between the amount of zeolite biofilm and potential nitrification activity was observed; rates were unaffected in incubations containing 1-20 mM ammonium. Addition of zeolite to retention ponds in cold environments could effectively increase nitrification rates year-round by concentrating active nitrifying biomass.

  6. Zeolite and wollastonite synthesis from rice hull ash

    International Nuclear Information System (INIS)

    Fernandes, Alberto de Andrade

    2006-01-01

    Rice hull ash (RHA) is a industry scrap rich in amorphous silica. A simple and low-energy cost method for the extraction of this silica was researched. A low level of impurity and high reactivity material was produced, which is appropriate for the synthesis of zeolites and wollastonite (CaSiO 3 ). The synthetic zeolites has not similar structures in nature, and they have been more and more valued in the market due to their purity and efficiency in specific applications like ion exchange, molecular sieve and catalysis areas. High purity wollastonite has many applications in manufacturing and agriculture. The mineral wollastonite can be formed in nature in different ways; it is generally accepted two forming processes, both encompassing limestone metamorphism (heat and pressure). In this work, a new process for the synthesis of zeolites and wollastonite from RHA colloidal silica was developed. Moreover, the process is aimed at lower energy costs, fewer stages and fewer reactants consume. In this work, zeolite A used in detergent and zeolite ZSM-5, employed in the petrochemical industry due to its high selectivity in catalytic reactions and its high thermo and acid stability, were synthesized. The first step of the wollastonite synthesis was studied, with the purpose of obtaining calcium hydrosilicate. Eleven different hydrosilicates occur in the system Ca(OH) 2 -SiO 2 -H 2 O, in the second step it was annealed to form the wollastonite phase. (author)

  7. Transition phases of zeolite Faujasite type to Sodalite by thermal treatment

    Directory of Open Access Journals (Sweden)

    Katia K. Kaminishikawahara

    2015-10-01

    Full Text Available The zeolites can have several functions as catalysts (biofuel production and molecular sieves (treatment of contaminated areas. This study aims to characterize the zeolites obtained in the transition of a Faujasite like zeolite into a Sodalite, when submitted to different thermal treatment times. The synthesized zeolites were characterized by X-ray diffraction where the crystalline phases were identified: Faujasite, Sodalite, SiO2 and amorphous material. The 4 hours heat treatment produces zeolite crystal structure similar to Faujasite, having basic sites, surface area of 552.7 m2 g-1 , and pore volume of 0.3391 cm3 g-1. With increasing time of heat treatment was observed the transition to the Sodalite phase witch containing 0.277 mmol g-1 of basic active sites with surface area of 11.38 m2 g-1 and pore volume of 0.0651 cm3 g-1. By the Rietveld method was identified and quantified the presence of Sodalite and Hidrossodalite in samples with 24 and 30 hours of reaction times.

  8. Effects of aeration and natural zeolite on ammonium removal during the treatment of sewage by mesocosm-scale constructed wetlands.

    Science.gov (United States)

    Araya, F; Vera, I; Sáez, K; Vidal, G

    2016-01-01

    The objective was to evaluate the effects of intermittent artificial aeration cycles and natural zeolite as a support medium, in addition to the contribution of plants (Schoenoplectus californicus) on NH4(+)-N removal during sewage treatment by Constructed Wetlands (CW). Two lines of Mesocosm Constructed Wetland (MCW) were installed: (a) gravel line (i.e. G-Line) and (b) zeolite line (i.e. Z-Line). Aeration increased the NH4(+)-N removal efficiency by 20-45% in the G-Line. Natural zeolite increased the NH4(+)-N removal efficiency by up to 60% in the Z-Line. Plants contributed 15-30% of the NH4(+)-N removal efficiency and no difference between the G-Line and the Z-Line. Conversely, the NH4(+)-N removal rate was shown to only increase with the use of natural zeolite. However, the MCW with natural zeolite, the NH4(+)-N removal rate showed a direct relationship only with the NH4(+)-N influent concentration. Additionally, relationship between the oxygen, energy and area regarding the NH4(+)-N removal efficiency was established for 2.5-12.5 gO2/(kWh-m(2)) in the G-Line and 0.1-2.6 gO2/(kWh-m(2)) in the Z-Line. Finally, it was established that a combination of natural zeolite as a support medium and the aeration strategy in a single CW could regenerate the zeolite's adsorption sites and maintain a given NH4(+)-N removal efficiency over time.

  9. Zeolite Synthesized from Coal Fly Ash Produced by a Gasification Process for Ni2+ Removal from Water

    Directory of Open Access Journals (Sweden)

    Yixin Zhang

    2018-03-01

    Full Text Available There are increasing demands and great potential of coal gasification in China, but there is a lack of studies focused on the disposal and utilization of coal fly ash produced by the gasification process. In this study, a coal fly ash sample derived from a gasifier in Jincheng, China, was utilized as raw material for the synthesis of zeolite by alkali fusion followed by hydrothermal treatments. The effects of operation conditions on the cation exchange capacity (CEC of synthesized zeolite were investigated. The synthesized zeolite with the highest CEC (270.4 meq/100 g, with abundant zeolite X and small amount of zeolite A, was produced by 1.5 h alkali fusion under 550 °C with NaOH/coal fly ash ratio 1.2 g/g followed by 15 h hydrothermal treatment under 90 °C with liquid/solid ratio 5 mL/g and applied in Ni2+ removal from water. The removal rate and the adsorption capacity of Ni2+ from water by the synthesized zeolite were determined at the different pH, contact time, adsorbent dose and initial Ni2+ concentration. The experimental data of adsorption were interpreted in terms of Freundlich and Langmuir equations. The adsorption of Ni2+ by the synthesized zeolite was found to fit sufficient using the Langmuir isotherm. More than 90% of Ni2+ in water could be removed by synthesized zeolite under the proper conditions. We show that the coal fly ash produced by the gasification process has great potential to be used as an alternative and cheap source in the production of adsorbents.

  10. Metal immobilization in soils using synthetic zeolites

    NARCIS (Netherlands)

    Osté, L.A.; Lexmond, T.M.; Riemsdijk, van W.H.

    2002-01-01

    In situ immobilization of heavy metals in contaminated soils is a technique to improve soil quality. Synthetic zeolites are potentially useful additives to bind heavy metals. This study selected the most effective zeolite in cadmium and zinc binding out of six synthetic zeolites (mordenite-type,

  11. Effects of Chemical Fertilizer, Algea Compost and Zeolite on Green Bean Yield

    Directory of Open Access Journals (Sweden)

    Aysun Türkmen

    2017-03-01

    Full Text Available The present study used chemical fertilizer, brown algae compost and zeolite carried out in the field of Giresun Hazelnut Research Center between May-November 2014 in pots according to randomized blog design as three replicate each. Treatment groups were consist of eight different combinations as follow; G1-Control, G2-Zeolite, G3-Compost, G4-Chemical Fertilizer, G5-Zeolite+Compost, G6-Zeolite+Chemical Fertilizer, G7-Compost+ Chemical Fertilizer, G8-Compost+Zeolite+ Chemical Fertilizer. The brown algae (Cystoseira sp. were used as compost material. These combinations were applied to green beans (Phaseolus vulgaris. The green beans were seeded by hand to arrange planting depth of 5-6 cm and 20 seeds/m2. Except control group, each treatment was added fertilizers as 50 g zeolite, 50 g compost, and 25 g chemical according to treatment design. Half of the chemical fertilizers were added at seeding time and the rest after two weeks. Collected soil samples were analyzed right after harvest, the greatest values of treatment groups were determined as; Carbon% G1: 5.08, nitrogen G3: 0.09 ppm, sodium G5: 139 ppm, potassium G6 and G8: 5 ppm, magnesium G2: 1865 ppm, calcium G6: 8.33 ppm, manganese G2: 359 ppm, iron G6 : 16070 ppm, cobalt G6 and G7: 7.91 ppm, copper G2: 17.5 ppm, zinc G8: 28.0 ppm, selenium G7: 4.17 ppm, cadmium G5: 0.08 ppm, lead G4: 5.31 ppm. The greatest harvest value as g/m2 was obtained from zeolite only group G2 with 273 while the lowest was obtained from Compost only group G3 with 113 g/m2, obviously showing the effectiveness of zeolite only application moreover, also thinking that better results may get if the present study run for longer period.

  12. A Sensor Based on LiCl/NaA Zeolite Composites for Effective Humidity Sensing.

    Science.gov (United States)

    Zhang, Ying; Xiang, Hongyu; Sun, Liang; Xie, Qiuhong; Liu, Man; Chen, Yu; Ruan, Shengping

    2018-03-01

    LiCl/NaA zeolite composites were successfully prepared by doping 1 wt%, 2 wt%, 5 wt%, and 8 wt% of LiCl into NaA zeolite. The humidity sensing properties of LiCl/NaA composites were investigated among 11% 95% relative humidity (RH). The LiCl/NaA composites exhibited better humidity sensing properties than pure NaA zeolite. The sensor made by 2 wt% Li-doped NaA zeolite possesses the best linearly in the whole RH. These results demonstrate that the LiCl/NaA composites have the potential application in humidity sensing.

  13. Evaluation of synthetic zeolites as oral delivery vehicle for anti-inflammatory drugs

    Directory of Open Access Journals (Sweden)

    Elham Khodaverdi

    2014-05-01

    Full Text Available Objective(s: In this research, zeolite X and zeolite Y were used as vehicle to prepare intestine targeted oral delivery systems of indomethacin and ibuprofen. Materials and Methods: A soaking procedure was implemented to encapsulate indomethacin or ibuprofen within synthetic zeolites. Gravimetric methods and IR spectra of prepared formulations were used to assess drug loading efficiencies into zeolite structures. Scanning Electron Microscopy (SEM was also utilized to determine morphologies changes in synthetic zeolites after drug loading. At the next stage, dissolution studies were used to predict the in vivo performance of prepared formulations at HCl 0.1 N and PBS pH 6.5 as simulated gastric fluid (SGF and simulated intestine fluid (SIF, respectively. Results: Drug loadings of prepared formulations was determined between 24-26 % w/w. Dissolution tests at SGF were shown that zeolites could retain acidic model drugs in their porous structures and can be able to limit their release into the stomach. On the other hand, all prepared formulations completely released model drugs during 3 hr in simulated intestine fluid. Conclusion: Obtained results indicated zeolites could potentially be able to release indomethacin and ibuprofen in a sustained and controlled manner and reduced adverse effects commonly accompanying oral administrations of NSAIDs.

  14. Blood biochemical changes in common carp (Cyprinus carpio Linnaeus, 1758 fed different levels of copper sulphate and zeolite

    Directory of Open Access Journals (Sweden)

    Arzu Aydın Uncumusaoğlu

    2018-02-01

    Full Text Available In this study, copper toxicity, was investigated after the addition of zeolite to the diet of common carps (Cyprinus carpio. The experiment included four groups with three replicates each. The 4 group feeds were [CuSO4; CuSO4 + Zeolite; Zeolite, and the control without CuSO4 or Zeolite with three replicates each. Fishes were kept in 80 L glass aquariums with 10 fishes with a mean weight of 60.6 ± 0.2 g. At the end of each period, a necropsy was performed on fishes from each treatment, and gross clinical signs were recorded. We found significant changes in the blood parameters of the common carps with or without different levels of zeolite and copper. Changes in cholesterol (CHOL, triglyceride (TG, low density lipoprotein (LDL, alanine aminotransferase (ALT, aspartate aminotransferase (AST, alkaline phosphatase (ALP, calcium (Ca2+, phosphorus (P+, sodium (Na+, potassium (K+, chloride (Cl-, magnesium (Mg2+, and ferrous (Fe+2 were also significant. Our results suggest that zeolite can be used in fish feeds at a rate of 40 mg/l to mitigate the toxic effects of copper.

  15. Optimum conditions of the synthesis of zeolite A by the direct hydrolysis of ethyl orthosilicate

    Energy Technology Data Exchange (ETDEWEB)

    Hino, R; Toki, K

    1975-11-01

    Synthesis of various types of zeolites has been reported using as a starting material silica sols, gels, silicates or silicate minerals, all of which are polymers of silicic acid. In this study Zeolite A was synthesized from ethyl orthosilicate which was probably a monomer at the beginning of hydrolysis. Optimum conditions of synthesis and factors which influence the formation of Zeolite A were examined. Ethyl orthosilicate was directly hydrolyzed by sodium aluminate solution in the presence of excess sodium hydroxide. After ultrasonic and mechanical stirring for an hour at 70/sup 0/C, the solution was kept in the air bath at 70/sup 0/C under atmospheric pressure for 48 approximately 120 hours. Zeolite A with high purity and crystallinity was obtained in a good yield from the starting mixture with the composition of 2 approximately 4.5 Na/sub 2/O . Al/sub 2/O/sub 3/ . 0.5 approximately 2 SiO/sub 2/ . 200 approximately 400 H/sub 2/O. Present method was effective for the synthesis of Zeolite A in the lower molar ratios of SiO/sub 2//Al/sub 2/O/sub 3/ as compared with the ordinary methods using silica or silicates. The species formed were also investigated by the optical, x-ray diffraction, DTA, TGA, IR and chemical methods.

  16. Zeolite-like metal-organic frameworks with ana topology

    KAUST Repository

    Eddaoudi, Mohamed

    2017-04-20

    Embodiments of the present disclosure describe a zeolite-like metal-organic framework composition comprising a metal-organic framework composition with ana topology characterized by the formula [MIII(4, 5-imidazole dicarboxylic acid)2X(solvent)a]n wherein MIII comprises a trivalent cation of a rare earth element, X comprises an alkali metal element or alkaline earth metal element, and solvent comprises a guest molecule occupying pores. Embodiments of the present disclosure describe a method of separating paraffins comprising contacting a zeolite-like metal-organic framework with ana topology with a flow of paraffins, and separating the paraffins by size.

  17. New developments in zeolite science and technology

    International Nuclear Information System (INIS)

    Murakami, Y.

    1986-01-01

    The contributions in this volume introduce numerous new results and concepts. MAS-NMR has become a powerful tool in the structural analysis of zeolite, metallosilicate and aluminophosphate, enabling definition at the atomic level of the silicon and aluminum forming the zeolite framework. Detailed knowledge on the structure of natural zeolite has increased. Regarding synthesis, studies on the preparation of various metallosilicates, the role of various organic compounds at templates and the kinetics of crystallization and crystal growth are presented. Developments in zeolite catalysts focus not only on the solid-acid catalysts and the shape selective catalysts but on the bifunctional type catalysts as well. Catalyses by metallosilicates or silicoaluminophosphates are reported. Attempts to improve the catalytic performance by modification are presented. Effort is also being devoted to the analysis of adsorption state and diffusion in zeolites. Zeolite deposits of economic value are reported from several countries. (Auth.)

  18. Zeolitic materials with hierarchical porous structures.

    Science.gov (United States)

    Lopez-Orozco, Sofia; Inayat, Amer; Schwab, Andreas; Selvam, Thangaraj; Schwieger, Wilhelm

    2011-06-17

    During the past several years, different kinds of hierarchical structured zeolitic materials have been synthesized due to their highly attractive properties, such as superior mass/heat transfer characteristics, lower restriction of the diffusion of reactants in the mesopores, and low pressure drop. Our contribution provides general information regarding types and preparation methods of hierarchical zeolitic materials and their relative advantages and disadvantages. Thereafter, recent advances in the preparation and characterization of hierarchical zeolitic structures within the crystallites by post-synthetic treatment methods, such as dealumination or desilication; and structured devices by in situ and ex situ zeolite coatings on open-cellular ceramic foams as (non-reactive as well as reactive) supports are highlighted. Specific advantages of using hierarchical zeolitic catalysts/structures in selected catalytic reactions, such as benzene to phenol (BTOP) and methanol to olefins (MTO) are presented. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. PENJERAPAN P-KHLOROFENOL DALAM AIR LIMBAH DENGAN ZEOLIT (Adsorption of p-Chlorophenol from Wastewater using Zeolite

    Directory of Open Access Journals (Sweden)

    Sarto Sarto

    2007-07-01

    Full Text Available ABSTRAK Penelitian ini bertujuan untuk mempelajari kemampuan zeolit untuk menjerap p-khlorofenol dari limbah cair secara batch, pada suhu 30 °C dan tekanan 1 atmosfer. Hasil penelitian menunjukkan bahwa proses penjerapan mengikuti persamaan Freundlich dan bersifat reversibel sebagian. Nisbah kinerja desorbsi dan penjerapan adalah antara 31,85 % dan 49,36 %. Kemampuan zeolit untuk menjerap p-khlorofenol meningkat dengan semakin rendahnya pH. pada nilai pH 3,92, berat zeolit 30 g, dan konsentrasi awal p-khlorofenol 97,302 mg/L. Adapun jumlah p-khlorofenol yang terjerap adalah sebesar 8,319 mg/L.   ABSTRACT The aim of this research is to study the characteristics of zeolit to adsorb p-chlorophenol from wastewater in a batch reactor at 30 oC and atmospheric conditions. The experimental results show that the adsorbtion process is partially reversible and fits with Freundlich Equation. The ratio of  desorption and adsortion performance is between 31.85 % and 49.36 %.  The performance of zeolit to adsorb p-chlorophenol increases with decreasing pH. At  pH about 3.92, using 30 g zeolit and 97.302 mg  p-chlorophenol/L. The concentration of adsorbed p-chlorophenol is about 8.319 mg/L.

  20. Zeolites in poultry and swine production

    Directory of Open Access Journals (Sweden)

    Aline Félix Schneider

    Full Text Available ABSTRACT: Zeolites are minerals that have intriguing properties such as water absorption, ion adsorption and cation exchange capacity. There are approximately 80 species of natural zeolites recognized and hundreds of artificial zeolites, which have been researched in several fields. Due to their chemical characteristics, zeolites have great potential for use in animal production, especially in poultry and swine farms, as food additives, litter amendment and treatment of residues, with direct and indirect effects on performance, yield and quality of carcass, ambience of farm sheds and reduction of environmental pollution.

  1. Availability of zeolite as an eliminant for the incorporated radionuclides, (3)

    International Nuclear Information System (INIS)

    Sato, Itaru; Matsusaka, Naonori; Kobayashi, Haruo; Nishimura, Yoshikazu.

    1994-01-01

    Zeolite is an inorganic ion-exchanger that is widely used in chemistry, livestock and industry. The authors have tried to apply it to an eliminant for the incorporated radionuclides. In this study, several experiments in vitro and in vivo were carried out to evaluate the effectiveness of zeolite (A-3) in eliminating the incorporated 137 Cs from the body. Zeolite could adsorb 2.2 mmol of cesium ions per one gram of zeolite in cesium chloride solution. This value was only 44% of its ion-exchange capacity but it completely adsorbed 137 Cs within that limit. Coexistence of magnesium, calcium, manganese, cobalt and zinc ions hardly interfered with the adsorption of 137 Cs, but sodium, potassium and copper ions hindered the adsorption in proportion to their concentration. Therefore, sodium and potassium ions may be principal factors inhibiting the adsorption of 137 Cs in the intestinal tract. Biological half-life of 137 Cs was about 5.5 days in control mice. This half-life was significantly reduced to 5.2, 4.5 and 3.9 days by feeding the diet with 1%, 3% and 10% of zeolite, respectively. These results suggest the effectiveness of zeolite in eliminating the 137 Cs from contaminated persons. (author)

  2. The effect of zeolite A supplementation in the dry period on blood mineral status around calving

    DEFF Research Database (Denmark)

    Thilsing-Hansen, T; Jørgensen, R J; Enemark, J M

    2003-01-01

    This article summarizes the results obtained in 6 separate studies concerned with the effect of zeolite A supplementation in the dry period on blood calcium, magnesium and phosphorus status around calving. The experiments were conducted on 5 different farms, and comprised a total of 117 cows. Two...... of the experiments (exp. 5 and 6) were conducted under extensive farming conditions whereas the rest (exp. 1-4) were conducted on intensively driven farms. All cows included in the experiments had completed at least 2 lactations. The cows were allocated as either untreated control cows or zeolite treated...... experimental cows according to expected date of calving and parity. The experimental cows were fed between 0.5 and 1.0 kg of zeolite A per day during the last 2 to 4 weeks of the dry period. Blood samples were drawn on the day of calving and day one and two after calving (all experiments), three weeks before...

  3. Use of zeolite for removing ammonia and ammonia-caused toxicity in marine toxicity identification evaluations.

    Science.gov (United States)

    Burgess, R M; Perron, M M; Cantwell, M G; Ho, K T; Serbst, J R; Pelletier, M C

    2004-11-01

    Ammonia occurs in marine waters including effluents, receiving waters, and sediment interstitial waters. At sufficiently high concentrations, ammonia can be toxic to aquatic species. Toxicity identification evaluation (TIE) methods provide researchers with tools for identifying aquatic toxicants. For identifying ammonia toxicity, there are several possible methods including pH alteration and volatilization, Ulva lactuca addition, microbial degradation, and zeolite addition. Zeolite addition has been used successfully in freshwater systems to decrease ammonia concentrations and toxicity for several decades. However, zeolite in marine systems has been used less because ions in the seawater interfere with zeolite's ability to adsorb ammonia. The objective of this study was to develop a zeolite method for removing ammonia from marine waters. To accomplish this objective, we performed a series of zeolite slurry and column chromatography studies to determine uptake rate and capacity and to evaluate the effects of salinity and pH on ammonia removal. We also assessed the interaction of zeolite with several toxic metals. Success of the methods was also evaluated by measuring toxicity to two marine species: the mysid Americamysis bahia and the amphipod Ampelisca abdita. Column chromatography proved to be effective at removing a wide range of ammonia concentrations under several experimental conditions. Conversely, the slurry method was inconsistent and variable in its overall performance in removing ammonia and cannot be recommended. The metals copper, lead, and zinc were removed by zeolite in both the slurry and column treatments. The zeolite column was successful in removing ammonia toxicity for both the mysid and the amphipod, whereas the slurry was less effective. This study demonstrated that zeolite column chromatography is a useful tool for conducting marine water TIEs to decrease ammonia concentrations and characterize toxicity.

  4. The potential of medium-pore zeolites for improved propene yields from catalytic cracking

    Energy Technology Data Exchange (ETDEWEB)

    Bager, F.; Salas, N.; Ernst, S. [Technische Univ. Kaiserslautern (Germany). Dept. of Chemistry, Chemical Technology

    2011-07-01

    The medium-pore zeolites ZSM-5 (MFI), ZSM-22 (TON), ZSM-23 (MTT), and EU-1 (EUO) were synthesized under hydrothermal conditions and modified by ion exchange to obtain the Broensted-acid forms. The activity and selectivity of these catalysts in catalytic cracking of a model compound, viz. n-octane, was studied in a fixed-bed flow-type reactor. The catalytic results clearly reflect the differences in the pore architectures of the tested zeolites on n-octane conversion and on the product selectivities. Over the zeolites with one-dimensional pore systems and without large intracrystalline cavities, a remarkable increase of the contribution of the monomolecular cracking mechanism could be observed as compared to the standard catalyst zeolite ZSM-5. This is indicated by a high selectivity for unsaturated products and, hence, increasing yields of propene. Large cavities in the pore system, viz. in the case of zeolite EU-1, increase the conversion in particular at lower temperatures. However, the large cavities also favor the formation of large transition states required for the classical bimolecular cracking mechanism, resulting in decreased selectivities for unsaturated products, increased selectivities for aromatics formation and faster deactivation. (orig.)

  5. Simultaneous desulfurization and denitrification by microwave reactor with ammonium bicarbonate and zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Wei Zaishan [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)], E-mail: weizaishan98@163.com; Lin Zhehang; Niu Hejingying; He Haiming; Ji Yongfeng [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2009-03-15

    Microwave reactor with ammonium bicarbonate (NH{sub 4}HCO{sub 3}) and zeolite was set up to study the simultaneous removal of sulfur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}) from flue gas. The results showed that the microwave reactor filled with NH{sub 4}HCO{sub 3} and zeolite could reduce SO{sub 2} to sulfur with the best desulfurization efficiency of 99.1% and reduce NO{sub x} to nitrogen with the best NO{sub x} purifying efficiency of 86.5%. Microwave desulfurization and denitrification effect of the experiment using ammonium bicarbonate and zeolite together is much higher than that using ammonium bicarbonate or zeolite only. NO{sub x} concentration has little effect on denitrification but has no influence on desulfurization, SO{sub 2} concentration has no effect on denitrification. The optimal microwave power and empty bed residence time (EBRT) on simultaneous desulfurization and dentrification are 211-280 W and 0.315 s, respectively. The mechanism for microwave reduced desulfurization and denitrification can be described as the microwave-induced catalytic reduction reaction between SO{sub 2}, NO{sub x} and ammonium bicarbonate with zeolite being the catalyst and microwave absorbent.

  6. Synthesis of LTA zeolite on corundum supports: Preliminary assessment for heavy metal removal from waste water

    International Nuclear Information System (INIS)

    Jacas, A.; Ortega, P.; Velasco, M. J.; Camblor, M. A.; Rodriguez, M. A.

    2012-01-01

    The effectiveness of materials based on LTA Zeolite as active phase, for their incorporation into systems aimed at the removal of heavy metals on waste water is evaluated in a preliminary way. This type of Zeolite with the main channel of a minimum free diameter of 0,41 nm and a low SiO 2 /Al 2 O 3 ratio is an interesting molecular sieve, which in turn display a high ion exchange capacity. From this point of view, LTA Zeolite crystals were obtained in situ by hydrothermal synthesis and characterized by x ray diffraction (XRD) and scanning electron microscopy (SEM). We have studied the effect of hydrothermal synthesis time at 378 K. Likewise, the removal capacity of heavy metal from the active phase was evaluated in as a first step on diluted solutions of cooper salts at slightly acidic pH (∼ 4,7). (Author) 28 refs.

  7. Differential behaviour of combustion and gasification fly ash from Puertollano Power Plants (Spain) for the synthesis of zeolites and silica extraction

    International Nuclear Information System (INIS)

    Font, O.; Moreno, N.; Diez, S.; Querol, X.; Lopez-Soler, A.; Coca, P.; Garcia Pena, F.

    2009-01-01

    Coal gasification (IGCC) and pulverised coal combustion (PCC) fly ashes (FAs), obtained from two power plants fed with the carboniferous bituminous coal from Puertollano (Spain), were characterised and used as raw materials for zeolite synthesis by direct conversion (DC) and by alkaline fusion (Fu), and SiO 2 extraction (Si-Ex) at laboratory scale. The Puertollano FAs are characterised by a high SiO 2 content (59%) with respect to EU coal FAs. High zeolite synthesis yields were obtained from both FAs by using conventional alkaline activation. However, the Si extraction yields were very different. The results of the zeolite synthesis from the Si-bearing extracts from both FAs demonstrated that high purity zeolites with high cation exchange capacity (CEC, between 4.3 and 5.3 meq/g) can be produced. The solid residue arising from Si-Ex is also a relatively high NaP1 zeolite product (CEC 2.4-2.7 meq/g) equivalent to the DC products. The zeolitic materials synthesised from both FAs by Fu showed an intermediate (between the high purity zeolites and the DC products) zeolite content with CEC values from 3.4 to 3.7 meq/g. Low leachable metal contents were obtained from high purity A and X zeolites and zeolite material synthesised by Fu for PCC FA.

  8. Alkali-activated blast furnace slag-zeolite cements and concretes

    International Nuclear Information System (INIS)

    Rakhimov, R.; Rakhimova, N.

    2012-01-01

    The aim of this work has been the study of alkali-activated slag-zeolite cements and concretes based on them. Various compositions have been tested and some characteristics such as the compressive strength have been measured versus zeolite additions. A table lists the specific surface area and particle size distributions of different cements. The conclusions of the study are the following. First, alkali-activated slag cements and concretes based on them are effective for immobilization of radioactive wastes and the production of building structures, designed for high radiation load. Secondly, zeolite-containing mineral additions are able to increase the immobilization capacity and radiation resistance of alkali-activated blast furnace slag cements and concretes. Thirdly, the efficiency of different zeolite-containing additions - 10% to increase alkali-activated blast furnace slag-zeolite cement strength was established. It is with alkaline components of water-glass, sodium carbonate, sodium sulphate. Fourth, the effective way of introducing zeolite additions in alkali-activated blast furnace slag-zeolite cement is inter-grinding of the slag and addition. Increase in strength of alkali-activated blast furnace slag-zeolite cement stone is 40% higher than that of the stone of a mixture of separately milled components. Fifth, Alkali-activated blast furnace slag-zeolite cements with zeolite-containing additions with a compressive strength of 10.1 to 140 MPa; alkali-activated blast furnace slag-zeolite cements mortars with compressive strength from 35.2 to 97.7 MPa; alkali-activated blast furnace slag-zeolite cements concretes with compressive strength up to 84.5 MPa and frost resistant up to 800 cycles were obtained

  9. Dietary supplementation of Zeolite on growth performance, immunological role, and disease resistance in Channa striatus against Aphanomyces invadans.

    Science.gov (United States)

    Jawahar, Suntharam; Nafar, Adil; Vasanth, Krishnan; Musthafa, Mohamed Saiyad; Arockiaraj, Jesu; Balasundaram, Chellam; Harikrishnan, Ramasamy

    2016-04-01

    Epizootic Ulcerative Syndrome (EUS) caused by Aphanomyces invadans which is a primary fungal parasitic pathogen, inflicts serious economic loss in tropical freshwater fish including snakehead murrel, Channa striatus. In the present study with an aim to circumvent the adverse effects of the traditional measures in graded levels (2%, 4%, and 6%) of Zeolite enriched diet on growth performance, hematology, immunological response, and disease resistance in C. striatus against A. invadans is reported. The final weight (FW), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), and average daily gain (ADG) were significantly high in infected fish fed with 4% or 6% Zeolite incorporated diets on 4th week. The maximum survival rates (SR) of 96% and 98% were observed when fed with 2% or 4% diets on 4th week. Similarly, the white blood cell (WBC), red blood cell (RBC), hematocrit (Hct), mean corpuscular volume (MCV), and mean corpuscular haemoglobin concentration (MCHC) were significantly high when fed with any Zeolite enriched diet. However, the haemoglobin (Hb) and mean corpuscular haemoglobin (MCH) were significantly high with 4% and 6% Zeolite diets. The total protein and globulin were significantly high with 4% and 6% diets; the albumin, glucose, cholesterol, and triglyceride were significantly elevated with any enriched diet. The 4% and 6% Zeolite diets significantly enhanced the phagocytic activity on 2nd week but the 2% diet could increase it on 4th week. The respiratory burst (RB) activity, complement activity, and lymphocyte proliferation level were significantly enhanced with 4% and 6% Zeolite diets on weeks 1 and 2 while with 2% diet on 4th week. All enriched diets significantly increased the lysozyme activity during the experimental period. Superoxide anion (SOA) production significantly enhanced with 6% diet on weeks 1 and 2 whereas with 2% diet on week 4. Lower cumulative mortality of 10% and 15% was found with 4% and 6

  10. NaA zeolite derived from blast furnace slag: its application for ammonium removal.

    Science.gov (United States)

    Guo, Hongwei; Tang, Lizhen; Yan, Bingji; Wan, Kang; Li, Peng

    2017-09-01

    In this paper, high value added NaA zeolite material was prepared from blast furnace (BF) slag by hydrothermal method and its adsorption behavior on the removal of ammonium ion was investigated. It was found out that the synthetic NaA cubic zeolite with smaller crystal size obtained at nSiO 2 /nAl 2 O 3 = 2 and nH 2 O/nNaOH = 20 showed better adsorption performance. The kinetics of the adsorption of ammonium ion by synthesized NaA zeolite was fitted by the pseudo-second-order kinetic model. The intra-particle diffusion modeling reveals that two mixed rate-controlling mechanisms were involved in the adsorption process. The relatively high value of activation energy of 92.3 kJ·mol -1 indicates a high impact of temperature on the adsorption rate, and the nature of ammonium adsorption is chemical reaction rather than physisorption. Based on the thermodynamics calculations, the adsorption of ammonium was found to be an endothermic, spontaneous process. The adsorption isothermal analysis showed that the Langmuir model could be well fitted and a maximum adsorption capacity of 83.3 mg·g -1 of NH 4 + was obtained. Thus, it was demonstrated that by forming low cost NaA zeolite and using it for environmental remediation, the synchronous minimization of BF slag and ammonia nitrogen contamination could be achieved.

  11. Alternative interpretation of infrared spectra of the zeolite NaHY and 1-butene system

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, H.; Seelemann, R.

    1979-01-01

    A Fourier transform IR study of the adsorption and isomerization of n-butenes on type A zeolites showed an essential similarity of the IR spectra of pure 1-butene absorbed on NaY and NaA zeolites. This led to an interpretation of the IR spectra of 1-butene on NaHY zeolites in terms of the isomerization to the cis- and trans-2-butene, rather than oligomerization on NaY and oligomerization, isomerization, fragmentation, or further side reaction on NaHY, as suggested by Ceckiewicz et al. The temperature-programed desorption measurements at temperatures up to 700/sup 0/K used by Ceckiewicz to analyze IR spectra taken at room temperature seem to be unsuitable for this purpose since subsequent reactions at higher temperatures cannot be ruled out.

  12. Room temperature zeolitization of boiler slag from a Bulgarian thermal power plant

    Directory of Open Access Journals (Sweden)

    Pascova Radost D.

    2017-01-01

    Full Text Available A simple and cost-effective method was applied for the synthesis of zeolite composites utilising wet bottom boiler slag from the Bulgarian coal-fired thermal power plant “Sviloza”, near the town of Svishtov. The method consisted of a prolonged alkali treatment at room temperature of this waste. Experimental techniques, such as scanning electron microscopy, energy-dispersive X-ray and X-ray diffraction analyses, are employed to characterize the initial slag and the final products with respect to their morphology, and elemental and mineral compositions. The composites synthesized in this way contained two Na-type zeolite phases: zeolite X (type FAU and zeolite Linde F (type EDI. The zeolited products and the starting slag were tested as adsorbents for a textile dye (Malachite Green from aqueous solutions. In comparison with the initial slag, the zeolite composite possessed substantially better adsorption properties: it almost completely adsorbs the dye in much shorter times. The results of this investigations revealed a new, easy and low cost route for recycling boiler slag into a material with good adsorption characteristics, which could find different applications, e.g., for purifying polluted waters, including those from the textile industry.

  13. Zeolite scaffolds for cultures of human breast cancer cells. Part II: Effect of pure and hybrid zeolite membranes on neoplastic and metastatic activity control.

    Science.gov (United States)

    Tavolaro, Palmira; Martino, Guglielmo; Andò, Sebastiano; Tavolaro, Adalgisa

    2016-11-01

    This work is focused on the response of two invasive phenotypes of human breast cancer cells, MCF-7 and MDA-MB-231, grown on synthesized zeolite scaffolds in order to study the influence of those biomaterials in controlled conditions with and without anti-tumoral drug treatments. Our research was directed to the use of doxorubicin (DOX) and bergapten (5-MOP). The former is broadly considered the most active single agent available for the treatment of breast cancer, the second is a natural psoralen with an apoptotic effect. The results indicate that both drugs inhibit the cell viability of all cell lines grown on all zeolite scaffolds and that all Pure Zeolite Membranes are more responsive with respect to all Mixed Matrix Membranes. Moreover, the results after treatment with DOX at a concentration of 7.4μM for 24h, show that the expression of the matrix metalloproteinases (MMP-2 and MMP-9) is greatly reduced in both cell lines, especially in those adherent on Pure Zeolite Scaffolds. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Exploring Mass Transfer in Mesoporous Zeolites by NMR Diffusometry

    Directory of Open Access Journals (Sweden)

    Ryong Ryoo

    2012-04-01

    Full Text Available With the advent of mesoporous zeolites, the exploration of their transport properties has become a task of primary importance for the auspicious application of such materials in separation technology and heterogeneous catalysis. After reviewing the potential of the pulsed field gradient method of NMR (PFG NMR for this purpose in general, in a case study using a specially prepared mesoporous zeolite NaCaA as a host system and propane as a guest molecule, examples of the attainable information are provided.

  15. Halloysite nanotube-based electrospun ceramic nanofibre mat: a novel support for zeolite membranes

    Science.gov (United States)

    Chen, Zhuwen; Zeng, Jiaying; Lv, Dong; Gao, Jinqiang; Zhang, Jian; Bai, Shan; Li, Ruili; Hong, Mei; Wu, Jingshen

    2016-12-01

    Some key parameters of supports such as porosity, pore shape and size are of great importance for fabrication and performance of zeolite membranes. In this study, we fabricated millimetre-thick, self-standing electrospun ceramic nanofibre mats and employed them as a novel support for zeolite membranes. The nanofibre mats were prepared by electrospinning a halloysite nanotubes/polyvinyl pyrrolidone composite followed by a programmed sintering process. The interwoven nanofibre mats possess up to 80% porosity, narrow pore size distribution, low pore tortuosity and highly interconnected pore structure. Compared with the commercial α-Al2O3 supports prepared by powder compaction and sintering, the halloysite nanotube-based mats (HNMs) show higher flux, better adsorption of zeolite seeds, adhesion of zeolite membranes and lower Al leaching. Four types of zeolite membranes supported on HNMs have been successfully synthesized with either in situ crystallization or a secondary growth method, demonstrating good universality of HNMs for supporting zeolite membranes.

  16. Using of synthetic Zeolites in the treatment of low-level liquid radioactive waste

    International Nuclear Information System (INIS)

    Ganjizadeh, M.; Bayat, I.; Sadatipoor, M.T.; Yavari, I.

    2002-01-01

    The removal of Cesium-137 from low active waste solution from research reactors by ion exchange using synthetic zeolites 4 A and A R-1 has been investigated by using batch and column technique. In batch tests we have studied the distribution coefficient (k d ) of Cesium-137 on the zeolites as a function of P H, Sodium concentration, contact time, and particle size of zeolites. The decontamination factor determined in column test. The accuracy of the method is investigated by comparing results obtained by this method here with results obtained by other techniques

  17. Progress on Zeolite-membrane-aided Organic Acid Esterification

    Science.gov (United States)

    Makertiharta, I. G. B. N.; Dharmawijaya, P. T.

    2017-07-01

    Esterification is a common route to produce carboxylic acid esters as important intermediates in chemical and pharmaceutical industries. However, the reaction is equilibrium limited and needs to be driven forward by selective removal one of the products. There have been some efforts to selectively remove water from reaction mixture via several separation processes (such as pervaporation and reactive distillation). Integrated pervaporation and esterification has gained increasing attention towards. Inorganic zeolite is the most popular material for pervaporation due to its high chemical resistant and separation performance towards water. Zeolite also has proven to be an effective material in removing water from organic compound. Zeolite can act not only as selective layer but also simultaneously act as a catalyst on promoting the reaction. Hence, there are many configurations in integrating zeolite membrane for esterification reaction. As a selective layer to remove water from reaction mixture, high Si/Al zeolite is preferred to enhance its hydrophilicity. However, low Si/Al zeolite is unstable in acid condition due to dealumination thus eliminate its advantages. As a catalyst, acid zeolites (e.g. H-ZSM-5) provide protons for autoprotolysis of the carboxylic acid similar to other catalyst for esterification (e.g. inorganic acid, and ion exchange resins). There are many studies related to zeolite membrane aided esterification. This paper will give brief information related to zeolite membrane role in esterification and also research trend towards it.

  18. Highly mesoporous single-crystalline zeolite beta synthesized using a nonsurfactant cationic polymer as a dual-function template

    KAUST Repository

    Zhu, Jie

    2014-02-12

    Mesoporous zeolites are useful solid catalysts for conversion of bulky molecules because they offer fast mass transfer along with size and shape selectivity. We report here the successful synthesis of mesoporous aluminosilicate zeolite Beta from a commercial cationic polymer that acts as a dual-function template to generate zeolitic micropores and mesopores simultaneously. This is the first demonstration of a single nonsurfactant polymer acting as such a template. Using high-resolution electron microscopy and tomography, we discovered that the resulting material (Beta-MS) has abundant and highly interconnected mesopores. More importantly, we demonstrated using a three-dimensional electron diffraction technique that each Beta-MS particle is a single crystal, whereas most previously reported mesoporous zeolites are comprised of nanosized zeolitic grains with random orientations. The use of nonsurfactant templates is essential to gaining single-crystalline mesoporous zeolites. The single-crystalline nature endows Beta-MS with better hydrothermal stability compared with surfactant-derived mesoporous zeolite Beta. Beta-MS also exhibited remarkably higher catalytic activity than did conventional zeolite Beta in acid-catalyzed reactions involving large molecules. © 2014 American Chemical Society.

  19. Pioneering In Situ Recrystallization during Bead Milling: A Top-down Approach to Prepare Zeolite A Nanocrystals.

    Science.gov (United States)

    Anand, Chokkalingam; Yamaguchi, Yudai; Liu, Zhendong; Ibe, Sayoko; Elangovan, Shanmugam P; Ishii, Toshihiro; Ishikawa, Tsuyoshi; Endo, Akira; Okubo, Tatsuya; Wakihara, Toru

    2016-07-05

    Top-down approach has been viewed as an efficient and straightforward method to prepare nanosized zeolites. Yet, the mechanical breaking of zeolite causes amorphization, which usually requires a post-milling recrystallization to obtain fully crystalline nanoparticles. Herein we present a facile methodology to prepare zeolite nanocrystals, where milling and recrystallization can be performed in situ. A milling apparatus specially designed to work under conditions of high alkalinity and temperature enables the in situ recrystallization during milling. Taking zeolite A as an example, we demonstrate its size reduction from ~3 μm to 66 nm in 30 min, which is quite faster than previous methods reported. Three functions, viz., miniaturization, amorphization and recrystallization were found to take effect concurrently during this one-pot process. The dynamic balance between these three functions was achieved by adjusting the milling period and temperature, which lead to the tuning of zeolite A particle size. Particle size and crystallinity of the zeolite A nanocrystals were confirmed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and water adsorption-desorption. This work presents a pioneering advancement in this field of nanosized zeolites, and will facilitate the mass production as well as boost the wide applications of nanosized zeolites.

  20. Speciation of chromium compounds from humic acid-zeolite Y to an ionic liquid during extraction.

    Science.gov (United States)

    Huang, Hsin-Liang; Wei, Yu Jhe

    2018-03-01

    By synchrotron X-ray absorption spectroscopy, chemical structures of hexavalent chromium (Cr(VI))/trivalent chromium (Cr(III)) adsorbed on humic acid (HA)-zeolite Y and extracted in an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate ([C 4 mim][BF 4 ])) have been studied. By combining the competitive adsorption results and reduction of Cr(VI)-HA with the carboxyl groups of HA, Cr(III)-HA (58%) was shown to be the major compound in HA-zeolite Y using synchrotron X-ray absorption near-edge structure (XANES) spectroscopy. In an ionic liquid phase, the reduction of Cr(VI)-HA to Cr(III)-HA and the desorption of Cr(III) from HA were caused by [C 4 mim][BF 4 ]. The 9 F nuclear magnetic resonance (NMR) spectra show that the perturbation of the [C 4 mim][BF 4 ] anion was affected by the extractable chromium species. The formation of a Cr(III) ion affected the increase in the bond distance for the 1st shell CrO of the chromium species in [C 4 mim][BF 4 ] using extended X-ray absorption fine structure (EXAFS) spectroscopy. The changes in the non-extractable chromium species remaining in HA-zeolite Y were also caused by [C 4 mim][BF 4 ] during extraction. The desorption of the absorbed Cr(III) on HA and zeolite Y was observed to form Cr(III) ions. As the percentage of Cr(III) ions remaining in HA-zeolite Y increased, a slightly greater bond distance for CrO was found at 2.01 Å. The enhanced reduction of Cr(VI)-HA and desorption of Cr(III) adsorbed on the HA and zeolite Y to form Cr(III) ions were affected by [C 4 mim][BF 4 ]. Increased mobility of Cr(III) in the simulated soil can promote the migration of Cr(III) ions into the H 2 O during soil washing for remediation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. PHOTODEGRADATION OF ALIZARIN S DYE USING TiO2-ZEOLITE AND UV RADIATION

    Directory of Open Access Journals (Sweden)

    Karna Wijaya

    2010-06-01

    Full Text Available An investigation of Alizarin S photodegradation using TiO2-zeolite and UV radiation was performed. TiO2-zeolite was prepared by dispersing oligocations of titanium into suspension of zeolite. The suspension was stirred and then filtered to separate the solid phase from the filtrate. the solid phase was calcined by microwave oven at 800 Watt for 5 minutes to convert the oligocations into its oxide forms. The calcined product and unmodified zeolite were characterized using x-ray diffractometry, FT-IR spectrophotometry, X-ray fluorescence and gas sorption analysis methods to determine their physicochemical properties. Photocatalytic activity of TiO2-zeolite was tested on Alizarin S solution using following method: 50 mg of zeolite was dispersed into 25 mL of 10-4 M Alizarin S. The dispersion was irradiated using 365 nm UV light at room temperature on various irradiation times, i.e. 10, 20, 30, 40 and 60 minutes. At certain irradiation time, the dispersion was filtered and the filtrate was then analyzed its concentration using UV-Vis spectrophotometry method. Characterization results exhibited that the formation of TiO2 on internal as well as external surfaces of zeolite could not be detected  with x-ray diffractometry and FT-IR spectrophotometry, however determination of titanium using x-ray fluorescence analysis on the calcined product showed that the concentration of titanium was much higher than zeolite (0.22% on zeolite and 12.08% on TiO2-zeolite. Gas sorption analysis result indicated that the the calcination  resulted in the increase of specific surface area (16,31 m2/g on zeolite and 100.96 m2/g on TiO2-zeolite as well as total pore volume of calcined product (13.34 mL/Å/g on zeolite and 57.54 mL/Å/g on TiO2-zeolite. The result of photocatalytic activitiy study showed that ca 99 % of Alizarin S was degraded by TiO2-zeolite after UV irradiation for 60 min.   Keywords: TiO2-zeolite, photocatalytic, Alizarin S.

  2. The effect of dietary calcium and phosphorus supplementation in zeolite A treated dry cows on periparturient calcium and phosphorus homeostasis

    DEFF Research Database (Denmark)

    Thilsing, Trine; Larsen, T.; Jørgensen, Rolf Jess

    2007-01-01

    Previous studies have proved the possibility of preventing parturient hypocalcaemia by zeolite A supplementation during the dry period, and a recent in vitro study has indicated a marked calcium (Ca) as well as phosphorus (P) binding effect of zeolite A in rumen fluid solutions. Because...... of the connection between the Ca and P homeostatic systems, the preventive effect against parturient hypocalcaemia may arise from zeolite induced decreased availability of dietary Ca as well as P. In the present study, the expected Ca and P binding capacity was challenged by feeding high and low levels of dietary...... Ca and/or P to zeolite A treated dry cows. Twenty-one pregnant dry cows were assigned to four experimental groups receiving a dry cow ration unsupplemented or supplemented with extra Ca and/or P. During the last 2 weeks of the dry period all cows additionally received 600 g of zeolite A per day...

  3. Experimental and Simulation Studies of the Toluene on Pure-Silica MEL Zeolite

    DEFF Research Database (Denmark)

    Sanchez-Gil, Vicente; Noya, Eva G.; Sanz, Alejandro

    2016-01-01

    of roughly 4 molecules per unit cell that shifts to higher pressures at higher temperatures and that coincides with a sudden increase in the isosteric heat of adsorption. Grand canonical Monte Carlo simulations reveal that the substep at half load is caused by the adsorption of toluene molecules at different......-ray powder diffraction experiments of the zeolite at three different loads: empty, at half load (before the substep), and at high load (after the substep). Numerous new low intensity peaks and splittings of existing peaks at the empty and half-loaded diffractograms appear in the diffraction pattern...... possible when the flexibility of the zeolite is incorporated. In this structural model, the channel cross sections are deformed from a nearly circular shape in the empty zeolite to a more elliptical shape in the case of the high load zeolite....

  4. Procedure for the reversible confinement of gases or vapours in a natural or synthetic zeolite

    International Nuclear Information System (INIS)

    1980-01-01

    The zeolite is treated with silane at a temperature of 100-140 0 C to silanise it in the H-form. This narrows the pores in the zeolite and the grains bind together creating cavities. The silanised zeolite and the material to be confined are brought into contact at high pressure, for example at an excess pressure of 0.5 atm. Contact is continued until the required quantity of gas or vapour has been adsorbed by the zeolite. Under the same high pressure water is added to the system which causes further narrowing of the pores. Preferably the process of silanising and treating with water is then repeated one or more times to close the pores and ensure confinement. The process is reversed by heating the product above 300 0 C. The bonds formed by silanising are then broken and the confined material is liberated. This process has applications in the confinement of valuable gases such as enriched isotopes, and of dangerous gases such as radioactive waste gases. (Th.W.P.)

  5. Zeolite-like metal-organic frameworks with ana topology

    KAUST Repository

    Eddaoudi, Mohamed; Mohideen, Mohamed Infas Haja; Adil, Karim; Belmabkhout, Youssef; Bhatt, Prashant M.; Shekhah, Osama; Chernikova, Valeriya

    2017-01-01

    Embodiments of the present disclosure describe a zeolite-like metal-organic framework composition comprising a metal-organic framework composition with ana topology characterized by the formula [MIII(4, 5-imidazole dicarboxylic acid)2X

  6. Zeolitization at uranium ore manifestation

    International Nuclear Information System (INIS)

    Petrosyan, R.V.; Buntikova, A.F.

    1981-01-01

    The process of zeolitization at uranium ore manifestation is studied. A specific type of low-temperature wall endogenous alteration of rocks due to the effect of primary acid solution with low content of carbonic acid is established. Leaching of calcium from enclosing rocks and its deposition in ore-accompanying calcium zeolites is a characteristic feature of wall-metasomatosis. Formation of desmin- calcite-laumontite and quartz-fluoroapatite of vein associations, including ore minerals (uranophane and metaotenite), is genetically connected with calcium metasomatosis. On the basis of the connection of ore minerals with endogeneous process of zeolitization a conclusion can be made on endogenous origin of uranophane and metaotenite [ru

  7. Hierarchical zeolites from class F coal fly ash

    Science.gov (United States)

    Chitta, Pallavi

    Fly ash, a coal combustion byproduct is classified as types class C and class F. Class C fly ash is traditionally recycled for concrete applications and Class F fly ash often disposed in landfills. Class F poses an environmental hazard due to disposal and leaching of heavy metals into ground water and is important to be recycled in order to mitigate the environmental challenges. A major recycling option is to reuse the fly ash as a low-cost raw material for the production of crystalline zeolites, which serve as catalysts, detergents and adsorbents in the chemical industry. Most of the prior literature of fly ash conversion to zeolites does not focus on creating high zeolite surface area zeolites specifically with hierarchical pore structure, which are very important properties in developing a heterogeneous catalyst for catalysis applications. This research work aids in the development of an economical process for the synthesis of high surface area hierarchical zeolites from class F coal fly ash. In this work, synthesis of zeolites from fly ash using classic hydrothermal treatment approach and fusion pretreatment approach were examined. The fusion pretreatment method led to higher extent of dissolution of silica from quartz and mullite phases, which in turn led to higher surface area and pore size of the zeolite. A qualitative kinetic model developed here attributes the difference in silica content to Si/Al ratio of the beginning fraction of fly ash. At near ambient crystallization temperatures and longer crystallization times, the zeolite formed is a hierarchical faujasite with high surface area of at least 360 m2/g. This work enables the large scale recycling of class F coal fly ash to produce zeolites and mitigate environmental concerns. Design of experiments was used to predict surface area and pore sizes of zeolites - thus obviating the need for intense experimentation. The hierarchical zeolite catalyst supports tested for CO2 conversion, yielded hydrocarbons

  8. Electrical conductivity of polyaniline/zeolite composites and synergetic interaction with CO

    International Nuclear Information System (INIS)

    Densakulprasert, Nataporn; Wannatong, Ladawan; Chotpattananont, Datchanee; Hiamtup, Piyanoot; Sirivat, Anuvat; Schwank, Johannes

    2005-01-01

    The effects of zeolite content, pore size and ion exchange capacity on electrical conductivity response to carbon monoxide (CO) of polyaniline/zeolite composites were investigated. Zeolite Y, 13X, and synthesized AlMCM41, all having the common cation Cu 2+ , were dry mixed with synthesized maleic acid (MA) doped polyaniline and compressed to form polyaniline (PANI)/zeolite pellet composites. The Y, 13X and AlMCM41 zeolite have the nominal pore sizes of 7, 10, 36 A, and the Cu 2+ exchange capacities of 0.161, 0.087, and 0.044 mol/g, respectively. With an addition of 13X zeolite to pristine polyaniline, the electrical conductivity sensitivity to CO/N 2 gas increases with zeolite content. For the effect of zeolite type, the highest electrical conductivity sensitivity is obtained with the 13X zeolite, followed by the Y zeolite, and the AlMCM41 zeolite, respectively. Poor sensitivity of zeolite AlMCM41 is probably due to its very large pore size and its lowest Cu 2+ exchange capacity. Y zeolite and 13X zeolite have comparable pore sizes but the latter has a greater pore free volume and a more favorable location distribution of the Cu 2+ ions within the pore. The temporal response time increases with the amount of zeolite in the composites but it is inversely related to the amount of ion exchange capacity

  9. Reaction mechanisms in zeolite catalysis

    NARCIS (Netherlands)

    Rozanska, X.; Santen, van R.A.; Auerbach, S.C.; Carrado, K.A.; Dutta, P.D.

    2003-01-01

    A review; described are the most basic mechanistic reaction steps that are induced by zeolite catalysts. Details on the zeolitic properties that are relevant to mol. reactivity are also provided. The theor. methods and models at hand to allow the investigation of these reaction steps and that have

  10. Preparation of Synthetic Zeolites from Myanmar Clay Mineral

    International Nuclear Information System (INIS)

    Phyu Phyu Win

    2004-04-01

    Faujasite type zeolite X was successfully synthesized from Myanmar clay mineral kaolinite, by treating with sodium hydroxide at 820 C followed by dissolution in water and hydrothermal treatment. It was found that the solution of fused clay powder can be crystallized at 90C under ambient pressure to synthesize faujasite type zeolite X. The effects of aging time and the amount of water on the formation of the product phase and Si/ Al ratios of the resulting products were investigated. Most of the Si and Al components in kaolinite might be dissolved into an alkaline solution and reacted to form ring-like structures. Then it was effectively transformed into zeolite materials. The maximum relative crystallinity of faujasite zeolite obtained was found to be 100%. Zeolite P was found to be a competitive phase present in some resulting products during hydrothermal treatment. The cation exchange capacity of kaolinite is very low, but increased after a proper treatment. It was found that the prepared faujasite type zeolite X, zeolite P and hydrogen zeolite (HZ) can reduce the hardness, the alkalinity, the total dissolved solid and the dissolved iron of raw water in the batch wise operation of water treatment. Therefore, it can be used as the cation exchanged resin for water treatment

  11. Surface modification of a natural zeolite by treatment with cold oxygen plasma: Characterization and application in water treatment

    Science.gov (United States)

    De Velasco-Maldonado, Paola S.; Hernández-Montoya, Virginia; Montes-Morán, Miguel A.; Vázquez, Norma Aurea-Rangel; Pérez-Cruz, Ma. Ana

    2018-03-01

    In the present work the possible surface modification of natural zeolite using cold oxygen plasma was studied. The sample with and without treatment was characterized using nitrogen adsorption isotherms at -196 °C, FT-IR spectroscopy, SEM/EDX analysis and X-Ray Diffraction. Additionally, the two samples were used for the removal of lead and acid, basic, reactive and food dyes in batch systems. The natural zeolite was found to be a mesoporous material with a low specific surface area (23 m2/g). X-ray patterns confirmed that clinoptilolite was the main crystal structure present in the natural zeolite. The molecular properties of dyes and the zeolitic structure were studied using molecular simulation, with the purpose to understand the adsorption mechanism. The results pointed out that only the roughness of the clinoptilolite was affected by the plasma treatment, whereas the specific surface area, chemical functionality and crystal structure remained constant. Finally, adsorption results confirmed that the plasma treatment had no significant effects on the dyes and lead retention capacities of the natural zeolite.

  12. Properties of diclofenac sodium sorption onto natural zeolite modified with cetylpyridinium chloride.

    Science.gov (United States)

    Krajišnik, Danina; Daković, Aleksandra; Milojević, Maja; Malenović, Anđelija; Kragović, Milan; Bogdanović, Danica Bajuk; Dondur, Vera; Milić, Jela

    2011-03-01

    In this study an investigation of a model drug sorption onto cationic surfactant-modified natural zeolites as a drug formulation excipient was performed. Natural zeolite was modified with cetylpyridinium chloride in amounts equivalent to 100, 200 and 300% of its external cation-exchange capacity. The starting material and obtained organozeolites were characterized by Fourier transform infrared spectroscopy, zeta potential measurements and thermal analysis. In vitro sorption of diclofenac sodium as a model drug was studied for all surfactant/zeolite composites by means of sorption isotherm measurements in aqueous solutions (pH 7.4). The modified zeolites with three levels of surfactant coverage within the short activation time were prepared. Zeta potential measurements and thermal analysis showed that when the surfactant loading level was equal to external cation-exchange value, almost monolayer of organic phase were present at the zeolitic surface while higher amounts of surfactant produced less extended bilayers, ordered bilayers or admicelles at the zeolitic surface. Modified zeolites, obtained in this manner, were effective in diclofenac sodium sorption and the organic phase derived from adsorbed cetylpyridinium chloride was the primary sorption phase for the model drug. The Langmuir isotherm was found to describe the equilibrium sorption data well over the entire concentration range. The separate contributions of the adsorption and partition to the total sorption of DS were analyzed mathematically. Results revealed that that adsorption and partitioning of the model drug take place simultaneously. 2010 Elsevier B.V. All rights reserved.

  13. Zeolitic adsorbent synthesized from powdered waste porcelain, and its capacity for heavy metal removal

    International Nuclear Information System (INIS)

    Wajima, T.; Ikegami, Y.

    2006-01-01

    A zeolitic adsorbent was synthesized from powdered waste porcelain kept at 80 o C for 24 h. The product contained the zeolite phases Na-P1 and hydroxysodalite. The product with the highest cation exchange capacity (CEC) was synthesized using 4 M NaOH and the sample weight / volume of alkali solution ratio was 1/4. The highest CEC obtained for the product was almost 1900 mmol/kg, which is the same as that of natural zeolite. The product with the highest CEC was tested for its ability to remove heavy metals (Fe, Cu, Ni, Zn, Pb, Cd, Mn, Cr, Al, B,Mo) from an acidic solution (pH 2). The product can neutralize the acidic solution to almost pH 7, and the capacity of the product for the removal of heavy metals is higher than that of the natural zeolite, except for Mo and B. (authors)

  14. Synthesis of zeolites 'type A' for adsorption of CO{sub 2}; Sintese de zeolitas 'tipo A' para adsorcao de CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, L.O.; Madeira, A.C.; Merlini, A.; Melo, C.R.; Mendes, E.; Santos, M.G.S.; Angioletto, E., E-mail: elidio@unesc.net [Universidade do Extremo Sul Catarinense (IPARQUE/UNESC), Criciuma, SC (Brazil). Parque Cientifico e Tecnologico

    2012-07-01

    The separation of gases is a very expensive step in the chemical industry and unquestionable relevance. In this work it was found the effectiveness of using zeolites of type A in the separation of CO{sub 2} in a gas mixture containing 25% CO{sub 2}, 4% O{sub 2} and 71% N{sub 2} concentrations similar to exhaust gases from combustion processes. To this end, was synthesized using zeolites type A commercial kaolin and mounted to an adsorption column to test the efficiency of zeolites in the adsorption of CO{sub 2}. The synthesized zeolites showed surface area of 66.22m{sup 2}/g. The CO{sub 2} concentration was determined by gas chromatography with TCD detector. Adjusting the data to the Langmuir model, there was obtained the kinetics of adsorption. From these, we found the ability of zeolite to adsorb CO{sub 2} used in the column of 0.461285mg/g. The results of adsorption proved promising and showed maximum adsorption of 78.4% at a time of 10 seconds. (author)

  15. Dry method for recycling iodine-loaded silver zeolite

    International Nuclear Information System (INIS)

    Thomas, T.R.; Staples, B.A.; Murphy, L.P.

    1978-01-01

    Fission product iodine is removed from a waste gas stream and stored by passing the gas stream through a bed of silver-exchanged zeolite until the zeolite is loaded with iodine, passing dry hydrogen gas through the bed to remove the iodine and regenerate the bed, and passing the hydrogen stream containing the hydrogen iodide thus formed through a lead-exchanged zeolite which absorbs the radioactive iodine from the gas stream and permanently storing the lead-exchanged zeolite loaded with radioactive iodine

  16. Some unusual properties of activated and reduced AgNaA zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, P.A. (Katholieke Univ. Leuven); Uytterhoeven, J.B.; Beyer, H.K.

    1979-01-01

    In a study of chemisorption on dehydrated silver-exchanged A zeolite by volumetric sorption and temperature-programed desorption techniques, an autoreductive process which created intense color centers, occurred on degassing the zeolite because of the formation of silver covalent bonds. The chemisorption of hydrogen was proportional to the amount of autoreduction, indicating that the process occurred on the color centers. Both oxygen and hydrogen chemisorbed dissociatively, as shown by tracing with labeled oxygen and by the ability of one water molecule to replace two hydrogen atoms. Carbon monoxide, however, was chemisorbed on the available silver ions in the zeolite supercages, whether or not they were a part of the cluster formation. Linear silver ion/silver/silver ion clusters are apparently formed in the zeolite cubo-octahedra upon activation; the ends form chemisorption sites for hydrogen and oxygen.

  17. Highly crystallized nanometer-sized zeolite a with large Cs adsorption capability for the decontamination of water.

    Science.gov (United States)

    Torad, Nagy L; Naito, Masanobu; Tatami, Junichi; Endo, Akira; Leo, Sin-Yen; Ishihara, Shinsuke; Wu, Kevin C-W; Wakihara, Toru; Yamauchi, Yusuke

    2014-03-01

    Nanometer-sized zeolite A with a large cesium (Cs) uptake capability is prepared through a simple post-milling recrystallization method. This method is suitable for producing nanometer-sized zeolite in large scale, as additional organic compounds are not needed to control zeolite nucleation and crystal growth. Herein, we perform a quartz crystal microbalance (QCM) study to evaluate the uptake ability of Cs ions by zeolite, to the best of our knowledge, for the first time. In comparison to micrometer-sized zeolite A, nanometer-sized zeolite A can rapidly accommodate a larger amount of Cs ions into the zeolite crystal structure, owing to its high external surface area. Nanometer-sized zeolite is a promising candidate for the removal of radioactive Cs ions from polluted water. Our QCM study on Cs adsorption uptake behavior provides the information of adsorption kinetics (e.g., adsorption amounts and rates). This technique is applicable to other zeolites, which will be highly valuable for further consideration of radioactive Cs removal in the future. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Investigation of Y, FAU-zeolites containing rare earth cations

    International Nuclear Information System (INIS)

    Gardos, G.; De Jonge, A.; Halmos, F.; Kristof, J.; Redey, A.

    1984-01-01

    Polycationic zeolites were made of the H (NHsub(4))-Y, FAU form one. The change of Broensted acid sites was followed as a function of the pretreating temperature by infrared spectroscopy for mixed (La, Ce) form zeolites. It was stated that the 3630 cmsup(-1) absorption band can be related to the acidic OH-groups responsible for the catalytic activity in the alkylating reaction of isobutane with 1-butene, while the band at 3510 cmsup(-1) is characteristic of the non-acidic hydroxyl-groups and has no relation with the catalytic activity. (author)

  19. Effects of ultrasonic irradiation on crystallization and structural properties of EMT-type zeolite nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Eng-Poh, E-mail: epng@usm.my [School of Chemical Sciences, Universiti Sains Malaysia, USM, 11800 Penang (Malaysia); Awala, Hussein [Laboratoire Catalyse & Spectrochimie, CNRS-ENSICAEN, Université de Caen (France); Ghoy, Jia-Pei [School of Chemical Sciences, Universiti Sains Malaysia, USM, 11800 Penang (Malaysia); Vicente, Aurélie [Laboratoire Catalyse & Spectrochimie, CNRS-ENSICAEN, Université de Caen (France); Ling, Tau Chuan [Institute of Biological Sciences, Faculty of Science, University of Malaya (Malaysia); Ng, Yun Hau [School of Chemical Engineering, The University of New South Wales, Sydney (Australia); Mintova, Svetlana [Laboratoire Catalyse & Spectrochimie, CNRS-ENSICAEN, Université de Caen (France); Adam, Farook, E-mail: farook@usm.my [School of Chemical Sciences, Universiti Sains Malaysia, USM, 11800 Penang (Malaysia)

    2015-06-01

    Synthesis of EMT zeolite nanocrystals from rice husk ash biomass (RHA) under continuous ultrasonic irradiation is reported. The aging, nucleation and crystallization stages of EMT zeolite in the system were monitored at ambient temperature, and compared with the conventional hydrothermal method. It was found that ultrasonic wave induced rapid crystal growth of the nanosized EMT zeolite. Complete crystallization of EMT nanocrystals was achieved within 24 h which was much faster than conventional hydrothermal synthesis (36 h). Furthermore, XRD and TEM analyses revealed that more nuclei were formed during the nucleation stage, allowing the preparation of smaller zeolite nanocrystals with high crystallinity. The results also showed that sonocrystallization produced EMT zeolite with high yield (ca. 80%). The ultrasound-prepared EMT nanocrystals were also found to have high porosity and high hydrophilicity, making the material promising for water sorption applications including vapor sensing, heat pump and adsorption technologies. - Highlights: • Nanosized EMT zeolites are formed from rice husk ash under ultrasonic irradiation. • The effects of ultrasonic waves in nanosized EMT zeolite synthesis are studied. • Ultrasound induces rapid crystal growth and produces high zeolite yield. • Smaller zeolite nanocrystals with high crystallinity and large defect sites are obtained. • Improved surface hydrophilicity of crystals is beneficial for water sorption applications.

  20. Removal of Cs+, Sr2+, and Co2+ ions from the mixture of organics and suspended solids aqueous solutions by zeolites

    International Nuclear Information System (INIS)

    Fang, Xiang Hong; Fang, Fang; Lu, Chun Hai; Zheng, Lei

    2017-01-01

    Serving as an excellent adsorbent and inorganic ion exchanger in the water purification field, zeolite 4A has in this work presented a strong capability for purifying radioactive waste, such as Sr 2+ , Cs + , and Co 2+ in water. During the processes of decontamination and decommissioning of suspended solids and organics in low-level radioactive wastewater, the purification performance of zeolite 4A has been studied. Under ambient temperature and neutral condition, zeolite 4A absorbed simulated radionuclides such as Sr 2+ , Cs + , and Co 2+ with an absorption rate of almost 90%. Additionally, in alkaline condition, the adsorption percentage even approached 98.7%. After conducting research on suspended solids and organics of zeolite 4A for the treatment of radionuclides, it was found that the suspended clay was conducive to absorption, whereas the absorption of organics in solution was determined by the species of radionuclides and organics. Therefore, zeolite 4A has considerable potential in the treatment of radioactive wastewater

  1. Natural zeolites in diet or litter of broilers.

    Science.gov (United States)

    Schneider, A F; Almeida, D S De; Yuri, F M; Zimmermann, O F; Gerber, M W; Gewehr, C E

    2016-04-01

    This study aims to analyse the influence of adding natural zeolites (clinoptilolite) to the diet or litter of broilers and their effects on growth performance, carcass yield and litter quality. Three consecutive flocks of broilers were raised on the same sawdust litter, from d 1 to d 42 of age, and distributed in three treatments (control with no added zeolites, addition of 5 g/kg zeolite to diet and addition of 100 g/kg zeolites to litter). The addition of zeolites to the diet or litter did not affect growth performance or carcass yield. The addition of zeolites to the diet did not influence moisture content of the litter, ammonia volatilisation was reduced only in the first flock and pH of litter was reduced in the second and third flock. However, the addition of zeolites to the litter reduced moisture content, litter pH and ammonia volatilisation in all flocks analysed. The addition of 5 g/kg zeolite to the diet in three consecutive flocks was not effective in maintaining litter quality, whereas the addition of 100 g/kg natural zeolites to sawdust litter reduced litter moisture and ammonia volatilisation in three consecutive flocks raised on the same litter.

  2. Natural zeolite reactivity towards ozone: the role of compensating cations.

    Science.gov (United States)

    Valdés, Héctor; Alejandro, Serguei; Zaror, Claudio A

    2012-08-15

    Among indoor pollutants, ozone is recognised to pose a threat to human health. Recently, low cost natural zeolites have been applied as alternative materials for ozone abatement. In this work, the effect of compensating cation content of natural zeolite on ozone removal is studied. A Chilean natural zeolite is used here as starting material. The amount of compensating cations in the zeolite framework was modified by ion exchange using an ammonium sulphate solution (0.1 mol L(-1)). Characterisation of natural and modified zeolites were performed by X-ray powder diffraction (XRD), nitrogen adsorption at 77K, elemental analysis, X-ray fluorescence (XRF), thermogravimetric analysis coupled with mass spectroscopy (TGA-MS), and temperature-programmed desorption of ammonia (NH(3)-TPD). Ozone adsorption and/or decomposition on natural and modified zeolites were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Results show that the zeolite compensating cation content affects ozone interaction with zeolite active sites. Ammonium ion-exchange treatments followed by thermal out-gassing at 823 K, reduces ozone diffusion resistance inside the zeolite framework, increasing ozone abatement on zeolite surface active sites. Weak and strong Lewis acid sites of zeolite surface are identified here as the main active sites responsible of ozone removal. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Synthesis of Zeolite A from Kaolin (Shwe Taung Clay)

    International Nuclear Information System (INIS)

    Mie Mie Han Htun; Mu Mu Htay

    2010-12-01

    The synthesis of Zeolite A from locally available kaolin clay (Shwe Taung) in Myanmar has been attempted. The kaolinite was converted to metakaoli, by treating with NaOH at 820C for 1hr, and hydrothermal treatment.It was found that the solution of fused clay powder can be crystallized at 100C under ambient pressure to synthesize Zeolite A. The process variables for synthesis have been optimized in order to produce Zeolite A at a lower price. The mole ratio of SiO2/Al2O3 for kaolin was fixed at 2.54. The effects of various factors (aging time and agitation time) on the structure of the sample were extensively investigated. The Shwe Taung clay was characterized by X-ray Diffraction (XRD), X-ray fluorescence (XRF) and Scanning Electron Microscopy (SEM). The samples were characterized by XRD. The results show that the pure form Zeolite A can be prepared with a molar composition of (2.54 SiO3: Al2O3: 5.8Na2O: 256 H2O) by agitation at room temperature for 30min. The mixture was aged for 24 hour at the same temperature and crystallized at 100C for 48 hour.

  4. Zeolites and Zeotypes for Oil and Gas Conversion

    NARCIS (Netherlands)

    Vogt, Eelco T C; Whiting, Gareth T.; Dutta Chowdhury, Abhishek; Weckhuysen, Bert M.

    2015-01-01

    Zeolite-based catalyst materials are widely used in chemical industry. In this chapter, the applications of zeolites and zeotypes in the catalytic conversion of oil and gas are reviewed. After a general introduction to zeolite science and technology, we discuss refinery applications, such as fluid

  5. Evaluation of the potentiality of a Mexican natural zeolite chabazite-type in the lead removal in water

    International Nuclear Information System (INIS)

    Alvarado I, J.; Sotelo L, M.; Meza F, D.; Paz M, F. A.; Maubert F, M.

    2013-01-01

    The intention of this paper is to present the characterization of a natural zeolite, chabazite-type, from the Mexican reservoir La Palma, at Divisaderos, Sonora, where their potential use as ion exchange material to remove lead in water is assessed. The chabazite was characterized through X-ray diffraction, Icp-OES, Icp-Ms, EDX, Bet and TG/TGD. The results indicate the presence of Ba(1930 ppm) and Sr(1220 ppm), which are characteristic of aluminium rich phases. A chabazite modification treatment is proposed by using solutions of NaOH (0.1 M) and NH 4 NO 3 (1 M). The lead removal kinetics both in natural zeolite as in their chemically modified forms was obtained by using the ion exchange process in a batch reactor. The results show how unnecessary natural zeolite homo ionization is for the removal of lead, thereby obtaining the equilibrium concentration of unmodified zeolite for plotting the adsorption isotherm, which was adjusted to Langmuir model. The Langmuir isotherm has a good fit of the results at equilibrium (R 2 =0.92), which demonstrates that natural zeolites studied, in its natural form, contains exchangeable cations required (Ca +2 , Mg 2+ and Na + ) for potentially be used as an adsorbent material/ion exchanger for water treatment impacted by lead. (Author)

  6. Ethylene formation by dehydration of ethanol over medium pore zeolites

    Science.gov (United States)

    Gołąbek, Kinga; Tarach, Karolina A.; Filek, Urszula; Góra-Marek, Kinga

    2018-03-01

    In this work, the role of pore arrangement of 10-ring zeolites ZSM-5, TNU-9 and IM-5 on their catalytic properties in ethanol transformation were investigated. Among all the studied catalysts, the zeolite IM-5, characterized by limited 3-dimensionality, presented the highest conversion of ethanol and the highest yields of diethyl ether (DEE) and ethylene. The least active and selective to ethylene and C3 + products was zeolite TNU-9 with the largest cavities formed on the intersection of 10-ring channels. The catalysts varied, however, in lifetime, and their deactivation followed the order: IM-5 > TNU-9 > ZSM-5. The processes taking place in the microporous zeolite environment were tracked by IR spectroscopy and analysed by the 2D correlation analysis (2D COS) allowing for an insight into the nature of chemisorbed adducts and transition products of the reaction. The cage dimension was found as a decisive factor influencing the tendency for coke deposition, herein identified as polymethylated benzenes, mainly 1,2,4-trimethyl-benzene.

  7. Kinetic Modelling of the Removal of Multiple Heavy Metallic Ions from Mine Waste by Natural Zeolite Sorption

    Directory of Open Access Journals (Sweden)

    Amanda L. Ciosek

    2017-07-01

    Full Text Available This study investigates the sorption of heavy metallic ions (HMIs, specifically lead (Pb2+, copper (Cu2+, iron (Fe3+, nickel (Ni2+ and zinc (Zn2+, by natural zeolite (clinoptilolite. These HMIs are combined in single-, dual-, triple-, and multi-component systems. The batch mode experiments consist of a total initial concentration of 10 meq/L normality for all systems, acidified to a pH of 2 by concentrated nitric (HNO3 acid. A zeolite dosage of 4 g per 100 mL of synthetic nitrate salt aqueous solution is applied, for a contact period of 5 to 180 min. Existing kinetic models on HMIs sorption are limited for multi-component system combinations. Therefore, this study conducts kinetic analysis by both reaction and diffusion models, to quantify the sorption process. The study concludes that the process correlates best with the pseudo-second-order (PSO kinetic model. In the multi-component system combining all five HMIs, the initial sorption rate and theoretical equilibrium capacity are determined as 0.0033 meq/g·min and 0.1159 meq/g, respectively. This provides significant insight into the mechanisms associated with the sorption process, as well as contributing to the assessment of natural zeolite as a sorbent material in its application in industrial wastewater treatment.

  8. Inoculum and zeolite synergistic effect on anaerobic digestion of poultry manure.

    Science.gov (United States)

    Fotidis, Ioannis A; Kougias, Panagiotis G; Zaganas, Ioannis D; Kotsopoulos, Thomas A; Martzopoulos, Gerasimos G

    2014-01-01

    Poultry manure is an ammonia-rich substrate due to its high content of proteins and amino acids. Ammonia is the major inhibitor of anaerobic digestion (AD) process, affecting biogas production and causing great economic losses to the biogas plants. In this study, the effect of different natural zeolite dosages on the mesophilic AD of poultry manure inoculated with a non-acclimatized to ammonia inoculum (dairy manure) was investigated. Additionally, a comparative analysis was performed between the data extracted from this study and the results of a previous study, which has been conducted under the same experimental conditions but with the use of ammonia acclimatized inoculum (swine manure). At 5 and 10 g zeolite L(-1), the methane yield of poultry manure was 43.4% and 80.3% higher compared with the experimental set without zeolite addition. However, the ammonia non-acclimatized inoculum was not efficient in digesting poultry manure even in the presence of 10 g zeolite L(-1), due to low methane production (only 39%) compared with the maximum theoretical yield. Finally, ammonia acclimatized inoculum and zeolite have demonstrated a possible 'synergistic effect', which led to a more efficient AD of poultry manure. The results of this study could potentially been used by the biogas plant operators to efficiently digest poultry manure.

  9. Carbon dioxide selective adsorption within a highly stable mixed-ligand Zeolitic Imidazolate Framework

    KAUST Repository

    Huang, Lin; Xue, Ming; Song, Qingshan; Chen, Siru; Pan, Ying; Qiu, Shilun

    2014-01-01

    A new mixed-ligand Zeolitic Imidazolate Framework Zn4(2-mbIm) 3(bIm)5·4H2O (named JUC-160, 2-mbIm = 2-methylbenzimidazole, bIm = benzimidazole and JUC = Jilin University China) was synthesized with a solvothermal reaction of Zn(NO3) 2·6H2O, b

  10. PENYARINGAN AIR TANAH DENGAN ZEOLIT ALAMI UNTUK MENURUNKAN KADAR BESI DAN MANGAN

    Directory of Open Access Journals (Sweden)

    Budi Hartono

    2004-06-01

    Full Text Available Ground Water Filtration by Natural Zeolit to Reduce Iron and Manganese Levels. In rural areas most people use ground water for their daily purposes. Frequently, the water has high levels of Fe dan Mn. To provide a simple, cheap and reliable apparatus to reduce Fe and Mn, a zeolit column has been designed for filtering ground water. The objective of this experiment was to establish the optimal condition of the filtration. Natural zeolit of Bayah origin was crushed and grounded into small particles of approximately 3 mm in diameter. After washed with distilled water and dried in open air, the particles were then packed in a 4 × 50-cm glass column. The zeolit column was installed vertically, watered with distilled water to compact, and dried. Then 500 mL of ground water sample was poured onto the prepared zeolit column. By adjusting the stopcock, the water samples were filtered off at a flowrate of 16 mL/min. Filtrates werecollected with interval of 30 minutes for 2.5 hours and subjected to Fe and Mn analysis. The experiment was repeated for filtration rates of 14, 12, 10, 8, 6, 4, and 2 mL/min. Fe and Mn concentrations, contact times, and flowrates were converted into scattered-plot graphs of contact times versus concentrations. The graphs show that the optimum condition for Fe and Mn removals were 30-minute contact time and 2-mL/minute flowrate. At this, the Bayah zeolit Fe was reduced for 55% but it was only 40% for Mn in ground water containing 3.6 mg/L Fe and 0.7 mg/L Mn. However, at the optimum condition water debit of the zeolit column was only 2.88 L/day. Quantitatively, with filtration rate of 2 mL/minute, up to 2.5 hours contact time the Fe was only reduced to as much 1.12 mg/L (standard: 1.0 mg/L while theMn reduced to nil. It was concluded that the Bayah zeolit was effective to reduce Fe and Mn in ground water, although reducing capacity for Mn was better than for Fe, whereas the column could not be applied for daily purposes due to

  11. Computational approach in zeolite science

    NARCIS (Netherlands)

    Pidko, E.A.; Santen, van R.A.; Chester, A.W.; Derouane, E.G.

    2009-01-01

    This chapter presents an overview of different computational methods and their application to various fields of zeolite chemistry. We will discuss static lattice methods based on interatomic potentials to predict zeolite structures and topologies, Monte Carlo simulations for the investigation of

  12. Treatment of effluent containing uranium with magnetic zeolite

    International Nuclear Information System (INIS)

    Craesmeyer, Gabriel Ramos

    2013-01-01

    Within this work, a magnetic-zeolite composite was successfully synthesized using ferrous sulfate as raw material for the magnetic part of the composite, magnetite, and coal fly ash as raw material for the zeolitic phase. The synthesis of the zeolitic phase was made by alkali hydrothermal treatment and the magnetite nanoparticles were obtained through Fe 2+ precipitation on alkali medium. The synthetic process was repeated many times and showed good reproducibility comparing the zeolitic nanocomposite from different batches. The final product was characterized using infrared spectroscopy, powder X-ray diffraction, X-ray fluorescence, scanning electron microscopy with coupled EDS. Specific mass, specific surface area and other physicochemical proprieties. The main crystalline phases found in the final product were magnetite, zeolites types NaP1 and hydroxysodalite, quartz and mullite, those last two remaining from the raw materials. Uranium removal capacity of the magnetic zeolite composite was tested using batch techniques. The effects of contact time and initial concentration of the adsorbate over the adsorption process were evaluated. Equilibrium time was resolved and the following kinetics and diffusion models were evaluated: pseudo-first order kinetic model, pseudo-second order kinetic model and interparticle diffusion model. A contact time of 120 min turned out to be enough to reach equilibrium of the adsorption process. The rate of adsorption followed the pseudo-second order model and the intra particle diffusion did not turn out to be a speed determinant step. Two adsorption isotherms models, the Langmuir model and the Freundlich model, were also evaluated. The Langmuir model was the best fit for the obtained experimental data. Using the best fitted adsorption isotherm and kinetic model, the theoretical maximum adsorption capacity of uranium over the composite was determined for both models. The maximum removal capacity calculated was 20.7 mg.g -1 for the

  13. Zeolite and swine inoculum effect on poultry manure biomethanation

    DEFF Research Database (Denmark)

    Kougias, Panagiotis; Fotidis, Ioannis; Zaganas, I.D.

    2013-01-01

    Poultry manure is an ammonia-rich substrate that inhibits methanogenesis, causing severe problems to the anaerobic digestion process. In this study, the effect of different natural zeolite concentrations on the mesophilic anaerobic digestion of poultry waste inoculated with well-digested swine...... manure was investigated. A significant increase in methane production was observed in treatments where zeolite was added, compared to the treatment without zeolite.Methane production in the treatment with 10 g dm-3 of natural zeolite was found to be 109.75% higher compared to the treatment without...... zeolite addition. The results appear to be influenced by the addition of zeolite, which reduces ammonia toxicity in anaerobic digestion and by the ammonia-tolerant swine inoculum....

  14. Zeolite and swine inoculum effect on poultry manure biomethanation

    Science.gov (United States)

    Kougias, P. G.; Fotidis, I. A.; Zaganas, I. D.; Kotsopoulos, T. A.; Martzopoulos, G. G.

    2013-03-01

    Poultry manure is an ammonia-rich substrate that inhibits methanogenesis, causing severe problems to the anaerobic digestion process. In this study, the effect of different natural zeolite concentrations on the mesophilic anaerobic digestion of poultry waste inoculated with well-digested swine manure was investigated. A significant increase in methane production was observed in treatments where zeolite was added, compared to the treatment without zeolite.Methane production in the treatment with 10 g dm-3 of natural zeolite was found to be 109.75% higher compared to the treatment without zeolite addition. The results appear to be influenced by the addition of zeolite, which reduces ammonia toxicity in anaerobic digestion and by the ammonia-tolerant swine inoculum.

  15. CoX zeolites and their exchange with deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Novakova, J; Kubelkova, L; Jiru, P [Ceskoslovenska Akademie Ved, Prague. Ustav Fyzikalni Chemie

    1976-04-01

    An analysis of the gaseous phase using a mass spectrometer and analysis of the solid phase using an infrared spectrophotometer was made to investigate the deuterium exchange with hydrogen mostly bound in hydroxyl groups of zeolites CoX(21 and 47%) and NaX. It was found that with the increasing amount of cobalt ions the number of exchangeable hydrogens of the zeolite increases; the respective types of the hydrogen are discussed with respect to the particular dehydration temperatures. The rate of the D/sub 2/+OH exchange is substantially faster with the CoX than with the NaX zeolite, and exhibits a decrease with increasing dehydration. On the other hand, the rate of D/sub 2/+H/sub 2/ exchange without zeolite hydrogen incorporation, catalyzed by CoX zeolites, increases with increasing dehydration. The increased activation of gaseous hydrogen molecules is related to the presence in the zeolite of cobalt ions whose properties change during dehydration with the change in their environment. Hydroxyl groups of the CoX zeolites are not equivalent during the exchange; the hydroxyl hydrogens of the 3740 cm/sup -1/ band are exchanged more slowly than are the other hydrogens.

  16. CoX zeolites and their exchange with deuterium

    International Nuclear Information System (INIS)

    Novakova, J.; Kubelkova, L.; Jiru, P.

    1976-01-01

    An analysis of the gaseous phase using a mass spectrometer and analysis of the solid phase using an infrared spectrophotometer was made to investigate the deuterium exchange with hydrogen mostly bound in hydroxyl groups of zeolites CoX(21 and 47%) and NaX. It was found that with the increasing amount of cobalt ions the number of exchangeable hydrogens of the zeolite increases; the respective types of the hydrogen are discussed with respect to the particular dehydration temperatures. The rate of the D 2 +OH exchange is substantially faster with the CoX than with the NaX zeolite, and exhibits a decrease with increasing dehydration. On the other hand, the rate of D 2 +H 2 exchange without zeolite hydrogen incorporation, catalyzed by CoX zeolites, increases with increasing dehydration. The increased activation of gaseous hydrogen molecules is related to the presence in the zeolite of cobalt ions whose properties change during dehydration with the change in their environment. Hydroxyl groups of the CoX zeolites are not equivalent during the exchange; the hydroxyl hydrogens of the 3740 cm -1 band are exchanged more slowly than are the other hydrogens. (author)

  17. Synthesis of zeolite NaA membrane from fused fly ash extract

    CSIR Research Space (South Africa)

    Ameh, AE

    2016-01-01

    Full Text Available Zeolite-NaA membranes were synthesized from an extract of fused South African fly ash on a porous titanium support by a secondary growth method. The influence of the synthesis molar regime on the formation of zeolite NaA membrane layer...

  18. Equilibrium CO{sub 2} adsorption on zeolite 13X prepared from natural clays

    Energy Technology Data Exchange (ETDEWEB)

    Garshasbi, Vahid [Faculty of Chemical, Petroleum and Gas Eng., Semnan University, P.O. Box 35196-45399, Semnan, Islamic Republic of Iran (Iran, Islamic Republic of); Jahangiri, Mansour, E-mail: mjahangiri@semnan.ac.ir [Faculty of Chemical, Petroleum and Gas Eng., Semnan University, P.O. Box 35196-45399, Semnan, Islamic Republic of Iran (Iran, Islamic Republic of); Anbia, Mansoor [Research Laboratory of Nanoporous Materials, Faculty of Chemistry, Iran University of Science and Technology, Tehran 16846-13114, Islamic Republic of Iran (Iran, Islamic Republic of)

    2017-01-30

    Highlights: • Zeolite 13X was successfully synthesized by hydrothermal treatment using natural kaolin, natural bentonite and natural feldspath. • The optimum conditions of synthesis zeolite 13X were found to be NaOH concentration = 4 M and crystallized at 65 °C for 72 h after homogenization by agitated at room temperature for 120 h. • The prepared zeolite 13X from natural kaolin (13X-K) showed a high BET surface area of 591 m{sup 2}/g and high micropore volume (0.250 cm{sup 3}/g) than other materials in this study. • The adsorption behavior of carbon dioxide and methane on zeolite 13X sample at different temperature from 298 K to 328 K was investigated. • It was found that the Langmuir–Freundlich model was more suitable than the others for description of CO{sub 2} adsorption isotherms. - Abstract: Zeolite 13X was successfully synthesized by hydrothermal treatment using natural clays extracted from Iranian resources. The preliminary natural materials and the final zeolite 13X samples were characterized by X-ray Diffraction (XRD), Fourier-Transfer Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and N{sub 2} adsorption–desorption isotherm. The effects of various factors such as NaOH addition amount and aging time on the crystalline products were studied during the synthesis process. The optimum conditions related to the synthesis of zeolite 13X were set. Accordingly, NaOH concentration was equal to 4 M. It was further crystallized at 65 °C for 72 h after its homogenization by agitation at room temperature for 120 h. In this study, the zeolite 13X prepared from natural kaolin (13X-K) showed a high BET surface area of 591 m{sup 2}/g with higher micropore volume (0.250 cm{sup 3}/g) than other materials. Adsorption equilibrium isotherms of CO{sub 2} were investigated using a static, volumetric method. In addition, pressures for the pure component data extended up to 20 bar. The adsorption equilibrium data of CO{sub 2} was fitted to

  19. Effect of different glass and zeolite A compositions on the leach resistance of ceramic waste forms

    International Nuclear Information System (INIS)

    Lewis, M.A.; Hash, M.; Glandorf, D.

    1996-01-01

    A ceramic waste form is being developed for waste generated during electrometallurgical treatment of spent nuclear fuel. The waste is generated when fission products are removed from the electrolyte, LiCl-KCl eutectic. The waste form is a composite fabricated by hot isostatic pressing a mixture of glass frit and zeolite occluded with fission products and salt. Normalized release rate is less than 1 g/m 2 d for all elements in MCC-1 leach test run for 28 days in deionized water at 90 C. This leach resistance is comparable to that of early Savannah River glasses. We are investigating how leach resistance is affected by changes in cationic form of zeolite and in glass composition. Composites were made with 3 forms of zeolite A and 6 glasses. We used 3-day ASTM C1220-92 (formerly MCC-1) leach tests to screen samples for development purposes only. The leach test results show that the glass composites of zeolites 5A and 4A retain fission products equally well. Loss of Cs is small (0.1-0.5 wt%), while the loss of divalent and trivalent fission products is one or more orders of magnitude smaller. Composites of 5A retain chloride ion better in these short-term screens than 4A and 3A. The more leach resistant composites were made with durable glasses rich in silica and poor in alkaline earth oxides. XRD show that a salt phase was absent in the leach resistant composites of 5A and the better glasses but was present in the other composites with poorer leach performance. Thus, absence of salt phase corresponds to improved leach resistance. Interactions between zeolite and glass depend on composition of both

  20. Removal of strontium ions from solutions using granulated zeolites

    International Nuclear Information System (INIS)

    Bronic, J.; Subotic, B.

    1992-01-01

    The ion-exchange process on columns filled with granulated zeolites is determined by several physico-chemical parameters. The influence of these parameters (zeolite type, concentration of exchangeable ions in solution, temperature, flow rate, etc.) on the kinetics of ion-exchange process was studied by measuring the Sr 2+ ion concentration in solution before and after passing through a column filled with various granulated zeolites (zeolite 13X, zeolite A and synthetic mordenite). Using the experimental technique of radioactive labeling by 89 Sr, the distribution of Sr 2+ ions in column fillings were also determined. From the results obtained, the optimal conditions for the most efficient removal of strontium ions from solutions using granulated zeolites can be defined. (author) 24 refs.; 9 figs

  1. Suspending Zeolite Particles In Tanks

    International Nuclear Information System (INIS)

    Poirier, M.R.

    1999-01-01

    The Savannah River Site (SRS) is in the process of removing waste (sludge and salt cake) from million gallon waste tanks. The current practice for removing waste from the tanks is adding water, agitating the tanks with long shaft vertical centrifugal pumps, and pumping the sludge/salt solution from the tank to downstream treatment processes. This practice has left sludge heels (tilde 30,000 gallons) in the bottom of the tanks. SRS is evaluating shrouded axial impeller mixers for removing the sludge heels in the waste tanks. The authors conducted a test program to determine mixer requirements for suspending sludge heels using the shrouded axial impeller mixers. The tests were performed with zeolite in scaled tanks which have diameters of 1.5, 6.0, and 18.75 feet. The mixer speeds required to suspend zeolite particles were measured at each scale. The data were analyzed with various scaling methods to compare their ability to describe the suspension of insoluble solids with the mixers and to apply the data to a full-scale waste tank. The impact of changes in particle properties and operating parameters was also evaluated. The conclusions of the work are: Scaling of the suspension of fast settling zeolite particles was best described by the constant power per unit volume method. Increasing the zeolite particle concentration increased the required mixer power needed to suspend the particles. Decreasing the zeolite particle size from 0.7 mm 0.3 mm decreased the required mixer power needed to suspend the particles. Increasing the number of mixers in the tank decreased the required mixer power needed to suspend the particles. A velocity of 1.6 ft/sec two inches above the tank bottom is needed to suspend zeolite particles

  2. Insecticide Effect of Zeolites on the Tomato Leafminer Tuta absoluta (Lepidoptera: Gelechiidae

    Directory of Open Access Journals (Sweden)

    Caroline De Smedt

    2016-12-01

    Full Text Available (1 Background: The tomato leafminer Tuta absoluta (Lepidoptera: Gelechiidae is a key tomato insect pest. At present, it is considered to be a serious threat in various countries in Europe, North Africa, and Middle East. The extensive use and the developed resistance of T. absoluta to spinosad causes some concern, which leads to the need for alternative products. (2 Materials and Methods: Several laboratory experiments were conducted to investigate the ovicidal properties of a zeolite particle film on T. absoluta. The toxicity of three different zeolites and six zeolite formulations to T. absoluta eggs and larvae was determined using different exposure methods. (3 Results: In general, the formulated zeolites yielded higher egg and larvae mortality values, especially when the zeolite particle film was residually applied. Notable differences in mortality rates from exposure to zeolites compared to other products, such as kaolin, its formulated product Surround, and the insecticide spinosad, were observed. Kaolin and Surround exhibited little or no effect for both application methods, while the hatch rate was reduced by 95% when spinosad was applied topically. Spinosad yielded egg and larvae mortality rates of 100% for both application methods. Additionally, increased oviposition activity was observed in adults exposed to the wettable powder (WP formulations. These WP formulations increased egg deposition, while Surround and spinosad elicited a negative oviposition response. (4 Conclusions: It can be derived that the tested products, zeolites BEA (Beta polymorph A, FAU (Faujasite, LTA (Linde type A, and their formulations, had no real insecticidal activity against the eggs of T. absoluta. Nevertheless, egg exposure to zeolites seemed to affect the development process by weakening the first instar larvae and increasing their mortality. Subsequently, based on the choice test, no significant difference was observed between the number of eggs laid on

  3. Diagnosing the Internal Architecture of Zeolite Ferrierite

    Science.gov (United States)

    Schmidt, Joel E.; Hendriks, Frank C.; Lutz, Martin; Post, L. Christiaan; Fu, Donglong

    2017-01-01

    Abstract Large crystals of zeolite ferrierite (FER) are important model systems for spatially resolved catalysis and diffusion studies, though there is considerable variation in crystal habit depending on the chemical composition and employed synthesis conditions. A synergistic combination of techniques has been applied, including single crystal X‐ray diffraction, high‐temperature in situ confocal fluorescence microscopy, fluorescent probe molecules, wide‐field microscopy and atomic force microscopy to unravel the internal architecture of three distinct FER zeolites. Pyrolyzed template species can be used as markers for the 8‐membered ring direction as they are trapped in the terraced roof of the FER crystals. This happens as the materials grow in a layer‐by‐layer, defect‐free manner normal to the large crystal surface, and leads to a facile method to diagnose the pore system orientation, which avoids tedious single crystal X‐ray diffraction experiments. PMID:28809081

  4. Synthesis of uniform-sized zeolite from windshield waste

    International Nuclear Information System (INIS)

    Kim, Jae-Chan; Choi, Mingu; Song, Hee Jo; Park, Jung Eun; Yoon, Jin-Ho; Park, Kyung-Soo; Lee, Chan Gi; Kim, Dong-Wan

    2015-01-01

    We demonstrate the synthesis of A-type zeolite from mechanically milled windshield waste via acid treatment and a low-temperature hydrothermal method. As-received windshield cullet was crushed to a fine powder and impurities were removed by HNO 3 treatment. The resulting glass powder was used as the source material for the hydrothermal synthesis of A-type zeolite. Crystal structure, morphology, and elemental composition changes of the windshield waste were evaluated at each step of the process through scanning electron microscopy, X-ray diffraction, X-ray fluorescence spectrometry, etc. After a high-energy milling process, the glass had an average particle size of 520 nm; after acid treatment, its composition was over 94% silica. Zeolite was successfully synthesized in the A-type phase with a uniform cubic shape. - Highlights: • Environmental-friendly recycling of windshield waste for high valuable product of zeolite. • Synthesis of zeolite form windshield waste via a low-temperature hydrothermal process. • High-energy milling effect on the uniform cubic shape and high-purity A-type zeolite.

  5. Selectivity of the adsorption process of modified zeolite rock with hexadecyl trimethylammonium bromide in front to chromates and dichromates

    International Nuclear Information System (INIS)

    Salgado G, N.

    2011-01-01

    In the present investigation natural zeolite (clinoptilolite) from the Chihuahua state, which was conditioned with sodium chloride solution and subsequently modified with a hexadecyl trimethylammonium bromide solution was used to evaluate the removal of Cr (Vi) from chromate or dichromate solutions. The zeolite materials were characterized by scanning electron microscopy and X-ray diffraction. The surface area was also determined. The experiments were performed in a batch system, the influence of ph, contact time between phases were investigated and during the adsorption process was calculated the concentration of chromium ion present in aqueous solution (CrO 4 2- , Cr 2 O 7 2- ). The quantification of chromium removed from the aqueous solution by atomic absorption spectrometry technique was done. In order to understand the behaviour of the adsorption kinetics the pseudo first and pseudo second order models were applied, and to determine the adsorption capacity of the zeolite materials for Cr the Langmuir, Freundlich and Langmuir-Freundlich models were chosen. It was found that the removal efficiency of chromium ion is influenced by ph and the chemical species present: chromate or dichromate. The chromate and dichromate sorption kinetic data were best fitted to the pseudo-second and pseudo-first order models, respectively; and the Langmuir and Langmuir-Freundlich models described adequately the isotherms data considering a mono component system. In a mixture of Cr (Vi) ad CrO 4 2- and Cr 2 O 7 2- , the surfactant modified zeolite has a greater selectivity for Cr 2 O 7 2- ion than CrO 4 2- . In this case the Langmuir-Freundlich model described the adsorption isotherm behavior. (Author)

  6. A new united atom force field for adsorption of alkenes in zeolites

    NARCIS (Netherlands)

    Liu, B.; Smit, B.; Rey, F.; Valencia, S.; Calero, S.

    2008-01-01

    A new united atom force field was developed that accurately describes the adsorption properties of linear alkenes in zeolites. The force field was specifically designed for use in the inhomogeneous system and therefore a truncated and shifted potential was used. With the determined force field, we

  7. Optimization of sodium loading on zeolite support for catalyzed transesterification of triolein with methanol.

    Science.gov (United States)

    Wang, Yu-Yuan; Chou, Hsin-Yu; Chen, Bing-Hung; Lee, Duu-Jong

    2013-10-01

    Optimization of sodium loading on zeolite HY for catalyzed transesterification of triolein in excess methanol to biodiesel was studied. Zeolite HY catalyst was activated by loading sodium ions to their surface via an ion-exchange method. The effects of ion-exchange process parameters, including the temperature, the process time, the pH value, as well as concentrations and sources of Na(+) cations (NaOH, NaCl and Na2SO4), on the conversion yield of triolein to biodiesel were investigated. Most of these Na(+)-activated zeolite HY catalysts could really facilitate the catalyzed transesterification reaction of triolein to biodiesel at a lower temperature near 65°C. Consequently, a high conversion yield of triglycerides to biodiesel at 97.3% was obtained at 65°C. Moreover, the durability of zeolite catalysts was examined as well. Catalytic performance tests of these zeolite catalysts in transesterification did not show a significant decrease in catalysis at least for three batch cycles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Microwave catalytic NOx and SO{sub 2} removal using FeCu/zeolite as catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Z.S. Wei; G.H. Zeng; Z.R. Xie; C.Y. Ma; X.H. Liu; J.L. Sun; L.H. Liu [Sun Yat-sen University, Guangzhou (China). School of Environmental Science and Engineering

    2011-04-15

    Non-thermal plasma technology is a promising process for flue gas treatment. Microwave catalytic NOx and SO{sub 2} removal simultaneously has been investigated using FeCu/zeolite as catalyst. The experimental results showed that a microwave reactor with FeCu/zeolite only could be used to microwave catalytic oxidative 91.7% NOx to nitrates and 79.6% SO{sub 2} to sulfate; the reaction efficiencies of microwave catalytic reduction of NOx and SO{sub 2} in a microwave reactor with FeCu/zeolite and ammonium bicarbonate (NH{sub 4}HCO{sub 3}) as a reducing agent could be up to 95.8% and 93.4% respectively. Microwave irradiation accentuates catalytic reduction of SO{sub 2} and NOx treatment, and microwave addition can increases SO{sub 2} removal efficiency from 14.5% to 18.7%, and NOx removal efficiency from 13.4% to 18.7%, separately. FeCu/zeolite catalyst was characterized by X-ray diffraction (XRD), X-ray photoelectron spectrum analysis (XPS), scanning electron microscopy (SEM) and the Brunauer Emmett Teller (BET) method. Microwave catalytic NOx and SO{sub 2} removal follows Langmuir-Hinshelwood (L-H) kinetics. 25 refs., 7 figs., 1 tab.

  9. Diagenetic Quartz Morphologies and Zeolite formation

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari; Hansen, Rikke Weibel; Friis, Henrik

    the Siri Canyon wells.  Volcanic lithoclasts are strongly altered and associated with diagenetic opal/ microquartz coatings and zeoliteZeolite crystals formed simultaneously with opal and prior to microquartz but dissolved with increased burial depth.  The dissolution of zeolite followed two steps...... in samples where no volcanic ash is demonstrated; it seems that a rapid supply of dissolved silica from dissolution of siliceous fossils was the main reason for the early co-precipitation of opal and zeolite. There are two important sources for Si: 1) Biogenic opal from diatoms or radiolarians, which...... are abundant in some of associated shales; and 2) volcanic ash. The dissolution of biogenic silica may result in a rapid release of silica thereby promoting the formation of diagenetic opal/microquartz, but there may be a limited release of Al. A limited release of Al may result in precipitation of Si...

  10. Oxidation of cyclohexane catalyzed by metal-ion-exchanged zeolites.

    Science.gov (United States)

    Sökmen, Ilkay; Sevin, Fatma

    2003-08-01

    The ion-exchange rates and capacities of the zeolite NaY for the Cu(II), Co(II), and Pb(II) metal ions were investigated. Ion-exchange equilibria were achieved in approximately 72 h for all the metal ions. The maximum ion exchange of metal ions into the zeolite was found to be 120 mg Pb(II), 110 mg Cu(II), and 100 mg Co(II) per gram of zeolite NaY. It is observed that the exchange capacity of a zeolite varies with the exchanged metal ion and the amount of metal ions exchanged into zeolite decreases in the sequence Pb(II) > Cu(II) > Co(II). Application of the metal-ion-exchanged zeolites in oxidation of cyclohexane in liquid phase with visible light was examined and it is observed that the order of reactivity of the zeolites for the conversion of cyclohexane to cyclohexanone and cyclohexanol is CuY > CoY > PbY. It is found that conversion increases by increase of the empty active sites of a zeolite and the formation of cyclohexanol is favored initially, but the cyclohexanol is subsequently converted to cyclohexanone.

  11. Zeolites with Continuously Tuneable Porosity**

    Science.gov (United States)

    Wheatley, Paul S; Chlubná-Eliášová, Pavla; Greer, Heather; Zhou, Wuzong; Seymour, Valerie R; Dawson, Daniel M; Ashbrook, Sharon E; Pinar, Ana B; McCusker, Lynne B; Opanasenko, Maksym; Čejka, Jiří; Morris, Russell E

    2014-01-01

    Zeolites are important materials whose utility in industry depends on the nature of their porous structure. Control over microporosity is therefore a vitally important target. Unfortunately, traditional methods for controlling porosity, in particular the use of organic structure-directing agents, are relatively coarse and provide almost no opportunity to tune the porosity as required. Here we show how zeolites with a continuously tuneable surface area and micropore volume over a wide range can be prepared. This means that a particular surface area or micropore volume can be precisely tuned. The range of porosity we can target covers the whole range of useful zeolite porosity: from small pores consisting of 8-rings all the way to extra-large pores consisting of 14-rings. PMID:25284344

  12. Exchange of deuterium with hydrogen of zeolite catalyst surface

    International Nuclear Information System (INIS)

    Minachev, Kh.M.; Dmitriev, R.V.; Penchev, V.; Kanazirev, V.; Minchev, Kh.; Kasimov, Ch.K.; Bylgarska Akademiya na Naukite, Sofia. Inst. za Obshta i Organichna Khimiya; AN Azerbajdzhanskoj SSR, Baku. Inst. Neftekhimicheskikh Protsessov)

    1981-01-01

    Isotope heteromolecular exchange of hydrogen on the reduced nickel-containing zeolites takes places at the temperatures above 100 deg and it is controlled by activated hydrogen transfer from metal particles on the substrate surface. High-temperature redox treatment of nickel-containing zeolites results in the formation of large nickel crystallites on zeolite external faces. The rest part of nickel remains in zeolite pores and conditions a high promoting effect in the exchange reaction. Catalytic activity of reduced zeolites NiCaNaY in toluene disproportionation increases considerably only in the cases when nickel is introduced into zeolite by means of ion exchange. Close spatial location of nickel particles and OH groups promotes the procedure of both isotope exchange and disproportionation of toluene [ru

  13. Redox behavior of transition metal ions in zeolites--7. Characterization of a nickel metal phase in zeolite NaY

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, P.A. (Katholieke Univ. Leuven); Derouane, E.G.; Nijs, H.; Verdonck, J.; Gilson, J.P.; Simoens, A.J.

    1979-01-01

    NiY zeolite was calcined under steaming and nonsteaming conditions, at 823/sup 0/ and 1200/sup 0/K, respectively, then reduced in hydrogen at 673/sup 0/ to 873/sup 0/K for two hours. Characterization of the Ni(0) metal phase by temperature programed reduction and oxidation techniques and by ferromagnetic resonance spectroscopy indicated a bidisperse metal particle size distribution. Inside the zeolite, small Ni(0) particles were found, the sizes of which were limited by the dimensions of the supercage or of the structural defects occurring with high reduction temperatures; the particles interacted strongly with the support or were Vertical Bar3; 100Vertical Bar3< reduced. On the zeolite surface, large Ni(0) particles were formed which were ellipsoidal and completely reduced and did not interact with the support. Calcining under steaming conditions did not affect the reducibility of the nickel but did promote sintering during reduction.

  14. Chemical reactivity of cation-exchanged zeolites

    OpenAIRE

    Pidko, E.A.

    2008-01-01

    Zeolites modified with metal cations have been extensively studied during the last two decades because of their wide application in different technologically important fields such as catalysis, adsorption and gas separation. Contrary to the well-understood mechanisms of chemical reactions catalyzed by Brønsted acid sites in the hydrogen forms of zeolites, the nature of chemical reactivity, and related, the structure of the metal-containing ions in cation-exchanged zeolites remains the subject...

  15. Formation of zeolite A. Properties of the alumina--silicate hydrogel. Formation of zeolite A on prolonged maturation of the hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Polak, F; Cichocki, A

    1974-01-01

    Analytic, adsorption, and x-ray investigations of a maturated hydrogel A, crystallized at 94/sup 0/ during 6 hr and of a hydrogel A kept for 2 months at room temperature showed that the zeolite A was formed easily and that maturation of the hydrogel A had little effect on its crystallization at 94/sup 0/. The hydrogel A kept for 2 months at room temperature passed almost completely into the crystalline zeolite A. Changes in the content of SiO/sub 2/, Al/sub 2/O/sub 3/, and Na/sub 2/O in the liquid and solid phases during the maturation and crystallization of the hydrogels A were studied.

  16. Mechanism of nitric acid generation on Ag-X Zeolite

    International Nuclear Information System (INIS)

    Kanazawa, T.; Kishimoto, T.; Haseba, S.; Mitoh, Y.; Itoh, S.; Nakai, I.

    1983-01-01

    When Ag-X Zeolite is used for the removal of iodine from the off gas streams of nuclear facilities, it is possible that nitric acid is formed on Ag-X Zeolite from co-existing nitrogen dioxide and water vapor. If nitric acid is formed on the surface of Ag-X zeolite, Ag-X zeolite is damaged and is not able to operate for a long time. When Ag-X zeolite is used in NO 2 -O 2 -H 2 O mixture, the nitric acid generation reaction is varied, depending upon the reaction temperature, and concentration of NO 2 and H 2 O. At a temperature of more than 40 deg. C, however, only the surface reaction will be progressed on the zeolite surface. The generation of nitric acid solution on the zeolite can be forecasted through the relationship between the concentration of nitric acid solution, equilibrium vapor pressure of H 2 O, and equilibrium vapor pressure of HNO 3 . Concerning the surface reaction caused on the zeolite, the adsorption water reacts on NO 2 , and the resulting HNO 3 is adsorbed firmly by the zeolite, which is thought to interfere with the surface reaction for generation of the HNO 3 . When the adsorption bed is long, the time required for adsorbed HNO 3 to saturate is increased in proportion to the bed length

  17. Photoelectron spectroscopic studies of AgNaA and AgCaNaA zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Finster, J. (Univ. Leipz.); Lorenz, P.; Angele, E.

    1978-01-01

    During the separation of n-butene mixtures with silver- and silver/calcium-exchanged sodium A zeolites, oxidation to 1,3-butadiene occurred above 250/sup 0/C. An ESCA study of the zeolites, which contained 8Vertical Bar3< silver and 0-34Vertical Bar3< calcium (referred to the degree of sodium exchanged), before and after use in butene adsorption revealed that on the unused catalysts and without calcium, excess silver was located on the outer zeolite surfaces; that with increasing calcium content, the surface silver content approached 8Vertical Bar3<, and that the surfaces were deficient in sodium. On the used catalysts and without calcium, reduced silver apparently formed clusters on the surfaces; in zeolites with above 20Vertical Bar3< calcium, such reduced silver tended to form clusters and migrate to the surface.

  18. One-pot pseudomorphic crystallization of mesoporous porous silica to hierarchical porous zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Jun-Ling; Jiang, Shu-Hua; Pang, Jun-Ling; Yuan, En-Hui; Ma, Xiao-Jing [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, College of Chemistry and Molecular Engineering, East China Normal University, No. 3663 Zhongshan North Road, 200062 Shanghai (China); Lam, Koon-Fung [Department of Chemical Engineering, University College London, Torrington Place, London (United Kingdom); Xue, Qing-Song, E-mail: qsxue@chem.ecnu.edu.cn [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, College of Chemistry and Molecular Engineering, East China Normal University, No. 3663 Zhongshan North Road, 200062 Shanghai (China); Zhang, Kun, E-mail: kzhang@chem.ecnu.edu.cn [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, College of Chemistry and Molecular Engineering, East China Normal University, No. 3663 Zhongshan North Road, 200062 Shanghai (China)

    2015-09-15

    Hierarchically porous silica with mesopore and zeolitic micropore was synthesized via pseudomorphic crystallization under high-temperature hydrothermal treatment in the presence of cetyltrimethylammonium tosylate and tetrapropylammonium ions. A combined characterization using small-angle X-ray diffraction (XRD), nitrogen adsorption, high-resolution transmission electron microscopy (TEM), thermogravimetric analysis (TG), and elemental analysis showed that dual templates, CTA{sup +} and TPA{sup +} molecules, can work in a cooperative manner to synthesize mesoporous zeolite in a one-pot system by precisely tuning the reaction conditions, such as reaction time and temperature, and type and amount of heterometal atoms. It is found that the presence of Ti precursor is critical to the successful synthesis of such nanostructure. It not only retards the nucleation and growth of crystalline MFI domains, but also acts as nano-binder or nano-glue to favor the assembly of zeolite nanoblocks. - Graphical abstract: Display Omitted - Highlights: • A facile method to synthesize mesoporous zeolites with hierarchical porosity was presented. • It gives a new insight into keeping the balance between mesoscopic and molecular ordering in hierarchical porous materials. • A new understanding on the solid–solid transformation mechanism for the synthesis of titanosilicate zeolites was proposed.

  19. Mexican natural zeolite, material for their possible use in the hydrogen storage

    International Nuclear Information System (INIS)

    Iturbe G, J. L.; Vazquez A, O.

    2009-01-01

    In this work a study is presented on the use of a Mexican natural zeolite as possible alternative to storage hydrogen. This zeolite material comes from the Sonora State (Mexico), to which is diminished the particle size by means of a mill treatment with a mechanical alloyed system during 5 hours. Later on, the zeolite in powder form was characterized by means of X-ray diffraction and scanning electron microscopy. It was also exposed to heating in a micro-reactor at 350 C and at the same time making empty during 2 hours, to eliminate humidity and possible gases that were caught in their structure. Soon after, it was diminished the temperature at 10 C and it was contacted with hydrogen of ultra high purity to a pressure of 10 bars during 10 minutes. The hydrogen analysis caught in the zeolite was realized through gas chromatography. The results by means of the chromatograms indicate that the zeolite adsorbed and liberate to hydrogen under conditions completely different to that reported in the literature, being understood that under our experimental conditions to low pressure and temperature, the hydrogen is adsorbed in this material type. (Author)

  20. Preparation of a zeolite-modified polymer monolith for identification of synthetic colorants in lipsticks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huiqi; Li, Zheng [College of Chemistry, Jilin University, Changchun 130012 (China); Niu, Qian [Jilin Entry-Exit Inspection and Quarantine Bureau, Changchun 130062 (China); Ma, Jiutong [College of Chemistry, Jilin University, Changchun 130012 (China); Jia, Qiong, E-mail: jiaqiong@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130012 (China)

    2015-10-30

    Graphical abstract: Poly(methacrylic acid-ethylene dimethacrylate) monolithic column embedded with zeolites was prepared and employed for the polymer monolith microextraction of colorants combined with HPLC. - Highlights: • Zeolite, as a kind of mesoporous material, was firstly combined with PMME. • Zeolite@poly(MAA-EDMA) monolith columns were prepared for the enrichment of colorants. • Zeolite@poly(MAA-EDMA) monolith columns demonstrated relatively high extraction capacity. - Abstract: A novel zeolite-modified poly(methacrylic acid-ethylenedimethacrylate) (zeolite@poly(MAA-EDMA)) monolithic column was prepared with the in situ polymerization method and employed in polymer monolith microextraction for the separation and preconcentration of synthetic colorants combined with high performance liquid chromatography. The polymer was characterized by scanning electronmicroscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermo-gravimetric analysis. Various parameters affecting the extraction efficiency were investigated and optimized. Under the optimum experimental conditions, we obtained acceptable linearities, low limits of detection, and good intra-day/inter-day relative standard deviations. The method was applied to the determination of synthetic colorants in lipsticks with recoveries ranged from 70.7% to 109.7%. Compared with conventional methacrylic acid-based monoliths, the developed monolith exhibited high enrichment capacity because of the introduction of zeolites into the preparation process. The extraction efficiency followed the order: zeolite@poly(MAA-EDMA) > poly(MAA-EDMA) > direct HPLC analysis.

  1. Adsorption and separation of n/iso-pentane on zeolites: A GCMC study.

    Science.gov (United States)

    Fu, Hui; Qin, Hansong; Wang, Yajun; Liu, Yibin; Yang, Chaohe; Shan, Honghong

    2018-03-01

    Separation of branched chain hydrocarbons and straight chain hydrocarbons is very important in the isomerization process. Grand canonical ensemble Monte Carlo simulations were used to investigate the adsorption and separation of iso-pentane and n-pentane in four types of zeolites: MWW, BOG, MFI, and LTA. The computation of the pure components indicates that the adsorption capacity is affected by physical properties of zeolite, like pore size and structures, and isosteric heat. In BOG, MFI and LTA, the amount of adsorption of n-pentane is higher than iso-pentane, while the phenomenon is contrary in MWW. For a given zeolite, a stronger adsorption heat corresponds to a higher loading. In the binary mixture simulations, the separation capacity of n-and iso-pentane increases with the elevated pressure and the increasing iso-pentane composition. The adsorption mechanism and competition process have been examined. Preferential adsorption contributions prevail at low pressure, however, the size effect becomes important with the increasing pressure, and the relatively smaller n-pentane gradually competes successfully in binary adsorption. Among these zeolites, MFI has the best separation performance due to its high shape selectivity. This work helps to better understand the adsorption and separation performance of n- and iso-pentane in different zeolites and explain the relationship between zeolite structures and adsorption performance. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Effect of precipitation conditions on the magnetic and sorption properties of zeolite-maghemite composites

    International Nuclear Information System (INIS)

    Matik, M.; Pechousek, J.; Zboril, R.; Sepelak, V.

    2006-01-01

    Natural zeolite (clinoptilolite) from Nizny Hrabovec (Slovakia) has been magnetically modified through maghemite (γ-Fe 2 O 3 ) nanoparticles by precipitation route at various reaction conditions. An effect of the precipitation temperature, weight ratio of Fe/zeolite and interaction time on the magnetic and surface properties of maghemite-zeolite composites was monitored by Moessbauer spectroscopy, TEM and BET surface area measurements. A decrease in reaction time and the Fe/zeolite ratio leads to smaller particles of γ-Fe 2 O 3 while lowering the precipitation temperature results in the larger crystallites. The reflection of the precipitation temperature being the key variable in the sorption properties of composites was tested with selected heavy metal ions. The sample prepared at highest temperature of 85 grad C reveals much higher maximum sorption capacity for Pb 2+ than commonly observed for magnetically modified natural zeolites. Good ability for sorption of anions was demonstrated with AsO 4 3- , which offers new applications of such modified zeolites. The sample with the best sorption properties was characterized by SEM, XRD, in-field Moessbauer spectroscopy and magnetic measurements. Following these data, maghemite nanoparticles form aggregates, which are sorbed on zeolite inhomogeneously with some free active surface of zeolite. The particles are about 15 nm in size and reveal the partial vacancies ordering as documented through the increased ratio of tetrahedral and octahedral positions being of 1/3. FC/ZFC curves confirm strongly interacting superparamagnetic particles with a blocking temperature of 230 K. (authors)

  3. Silver-Ion-Exchanged Nanostructured Zeolite X as Antibacterial Agent with Superior Ion Release Kinetics and Efficacy against Methicillin-Resistant Staphylococcus aureus.

    Science.gov (United States)

    Chen, Shaojiang; Popovich, John; Iannuzo, Natalie; Haydel, Shelley E; Seo, Dong-Kyun

    2017-11-15

    As antibiotic resistance continues to be a major public health problem, antimicrobial alternatives have become critically important. Nanostructured zeolites have been considered as an ideal host for improving popular antimicrobial silver-ion-exchanged zeolites, because with very short diffusion path lengths they offer advantages in ion diffusion and release over their conventional microsized zeolite counterparts. Herein, comprehensive studies are reported on materials characteristics, silver-ion release kinetics, and antibacterial properties of silver-ion-exchanged nanostructured zeolite X with comparisons to conventional microsized silver-ion-exchanged zeolite (∼2 μm) as a reference. The nanostructured zeolites are submicrometer-sized aggregates (100-700 nm) made up of primary zeolite particles with an average primary particle size of 24 nm. The silver-ion-exchanged nanostructured zeolite released twice the concentration of silver ions at a rate approximately three times faster than the reference. The material exhibited rapid antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) with minimum inhibitory concentration (MIC) values ranging from 4 to 16 μg/mL after 24 h exposure in various growth media and a minimum bactericidal concentration (MBC; >99.9% population reduction) of 1 μg/mL after 2 h in water. While high concentrations of silver-ion-exchanged nanostructured zeolite X were ineffective at reducing MRSA biofilm cell viability, efficacy increased at lower concentrations. In consideration of potential medical applications, cytotoxicity of the silver-ion-exchanged nanostructured zeolite X was also investigated. After 4 days of incubation, significant reduction in eukaryotic cell viability was observed only at concentrations 4-16-fold greater than the 24 h MIC, indicating low cytotoxicity of the material. Our results establish silver-ion-exchanged nanostructured zeolites as an effective antibacterial material against dangerous

  4. Substitution clustering in a non-stoichiometric celsian synthesized by the thermal transformation of barium exchanged zeolite X

    International Nuclear Information System (INIS)

    Clayden, Nigel J.; Esposito, Serena; Ferone, Claudio; Pansini, Michele

    2006-01-01

    The thermal transformation of Ba exchanged zeolite X to celsian has been studied by 27 Al and 29 Si MAS NMR spectroscopy. Evidence for the degradation of the zeolite framework is present in the 29 Si NMR spectra after thermal treatment at 850 deg. C. Confirmation is provided by the 29 Si NMR data that synthesis of celsian via the decomposition of Ba exchanged zeolite leads to a single defect phase. Clustering of the isomorphous replacement of aluminium by silicon must occur to explain the observed 29 Si chemical shifts. The 27 Al NMR data show distorted aluminium co-ordination sites upon the thermal transformation of Ba exchanged zeolite X. The distortions present in the amorphous matrix are greater than those present in the monoclinic and hexagonal crystalline phases of celsian. - Graphical abstract: Monte Carlo simulation of the Q 4 (mAl) silicon connectivity in the α-hexagonal celsian lattice, for a Si/Al ratio of 1:1. Si atoms are shown in yellow and the Al atoms in black

  5. Synthesis of LTA zeolite for bacterial adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Belaabed, R.; Eabed, S.; Addaou, A.; Laajab, A.; Rodriguez, M.A.; Lahsini, A.

    2016-07-01

    High affinity and adhesion capacity for Gram-positive bacteria on minerals has been widely studied. In this work the adhesion of bacteria on synthesized zeolite has been studied. The Zeolite Linde Type A (LTA) has been synthesized using hydrothermal route using processing parameters to obtain low cost materials. For adhesion studies Staphylococcus aureus and Bacillus subtilis were used as Gram-positive bacteria, Escherichia coli and Pseudomonas aeruginosa are used as Gram-negative bacteria. X-ray diffraction, environmental scanning electron microscope and attenuated total reflection-Fourier transform infrared spectroscopy were used to characterize the synthesized zeolite. To evaluate the bacterial adhesion to zeolite LTA the hydrophobicity and surface properties are examined using contact angle measurement. (Author)

  6. Studies of the water adsorption on Lampung’s natural zeolite of Indonesia for cooling application

    Science.gov (United States)

    Wulandari, D. A.; Nasruddin; Lemington

    2018-03-01

    Part of minerals that originally formed from volcanic rock and ash layers reacting further with alkaline groundwater is called natural zeolite, where its sources are not always available in all countries. Indonesia is located in the ring of fire which have a huge sources of zeolite, one of the area is Lampung, South Sumatra. Natural zeolite has been considered as one of potential heat adsorbent medium which can contribute to the energy consumption and reduce air pollution in the using of cooling application. The characteristic of this Lampung natural zeolite such as adsorption kinetics, adsorption water uptake, and adsorption capacity were test with ASAP 2020 system. Sorption kinetics by this experiment of zeolite samples were carried out in a constant temperature and humidity chamber. The chamber can supply constant air condition with deviations of ±0.5 °C for temperature and ±3% for relative humidity. The data based on rate of adsorption and the defined working condition was set as 20°C and 70% RH. Pore volume is a significant parameter for determining the limitation of water uptake, which can describe the saturated condition of zeolite. Sorption isotherm models used to describe sorption phenomena are commonly deduced from the Polanyi potential theory were investigated. The water adsorption quantity increased with the increase of relative pressure. To sum up, this pure zeolite has a less heat and mass transfer performance so its need to be activated before using in cooling application to get their great potential and by being coated in a desiccant heat exchanger systems.

  7. Development of electrochemical biosensors with various types of zeolites

    Science.gov (United States)

    Soldatkina, O. V.; Kucherenko, I. S.; Soldatkin, O. O.; Pyeshkova, V. M.; Dudchenko, O. Y.; Akata Kurç, B.; Dzyadevych, S. V.

    2018-03-01

    In the work, different types of zeolites were used for the development of enzyme-based electrochemical biosensors. Zeolites were added to the biorecognition elements of the biosensors and served as additional components of the biomembranes or adsorbents for enzymes. Three types of biosensors (conductometric, amperometric and potentiometric) were studied. The developed biosensors were compared with the similar biosensors without zeolites. The biosensors contained the following enzymes: urease, glucose oxidase, glutamate oxidase, and acetylcholinesterase and were intended for the detection of urea, glucose, glutamate, and acetylcholine, respectively. Construction of the biosensors using the adsorption of enzymes on zeolites has several advantages: simplicity, good reproducibility, quickness, absence of toxic compounds. These benefits are particularly important for the standardization and further mass production of the biosensors. Furthermore, a biosensor for the sucrose determination contained a three-enzyme system (invertase/mutatorase/glucose oxidase), immobilized by a combination of adsorption on silicalite and cross-linking via glutaraldehyde; such combined immobilization demonstrated better results as compared with adsorption or cross-linking separately. The analysis of urea and sucrose concentrations in the real samples was carried out. The results, obtained with biosensors, had high correlation with the results of traditional analytical methods, thus the developed biosensors are promising for practical applications.

  8. Unravelling the High-Pressure Behaviour of Dye-Zeolite L Hybrid Materials

    Directory of Open Access Journals (Sweden)

    Lara Gigli

    2018-02-01

    Full Text Available Self-assembly of chromophores nanoconfined in porous materials such as zeolite L has led to technologically relevant host-guest systems exploited in solar energy harvesting, photonics, nanodiagnostics and information technology. The response of these hybrid materials to compression, which would be crucial to enhance their application range, has never been explored to date. By a joint high-pressure in situ synchrotron X-ray powder diffraction and ab initio molecular dynamics approach, herein we unravel the high-pressure behaviour of hybrid composites of zeolite L with fluorenone dye. High-pressure experiments were performed up to 6 GPa using non-penetrating pressure transmitting media to study the effect of dye loading on the structural properties of the materials under compression. Computational modelling provided molecular-level insight on the response to compression of the confined dye assemblies, evidencing a pressure-induced strengthening of the interaction between the fluorenone carbonyl group and zeolite L potassium cations. Our results reveal an impressive stability of the fluorenone-zeolite L composites at GPa pressures. The remarkable resilience of the supramolecular organization of dye molecules hyperconfined in zeolite L channels may open the way to the realization of optical devices able to maintain their functionality under extreme conditions.

  9. Improved Automotive NO (x) Aftertreatment System: Metal Ammine Complexes as NH3 Source for SCR Using Fe-Containing Zeolite Catalysts

    DEFF Research Database (Denmark)

    Johannessen, Tue; Schmidt, Henning; Frey, Anne Mette

    2009-01-01

    Ammonia storage is a challenge in the selective catalytic reduction of NO (x) in vehicles. We propose a new system, based on metal ammines as the ammonia source. In combination with iron containing zeolites as the SCR catalyst it should be possible to obtain a low temperature system for NO (x...

  10. Strong white photoluminescence from annealed zeolites

    International Nuclear Information System (INIS)

    Bai, Zhenhua; Fujii, Minoru; Imakita, Kenji; Hayashi, Shinji

    2014-01-01

    The optical properties of zeolites annealed at various temperatures are investigated for the first time. The annealed zeolites exhibit strong white photoluminescence (PL) under ultraviolet light excitation. With increasing annealing temperature, the emission intensity of annealed zeolites first increases and then decreases. At the same time, the PL peak red-shifts from 495 nm to 530 nm, and then returns to 500 nm. The strongest emission appears when the annealing temperature is 500 °C. The quantum yield of the sample is measured to be ∼10%. The PL lifetime monotonously increases from 223 μs to 251 μs with increasing annealing temperature. The origin of white PL is ascribed to oxygen vacancies formed during the annealing process. -- Highlights: • The optical properties of zeolites annealed at various temperatures are investigated. • The annealed zeolites exhibit strong white photoluminescence. • The maximum PL enhancement reaches as large as 62 times. • The lifetime shows little dependence on annealing temperature. • The origin of white emission is ascribed to the oxygen vacancies

  11. Fabrication and evaluation of hybrid materials from A-zeolite and ground glass powders for vitrified radioactive waste

    International Nuclear Information System (INIS)

    Kamitani, Masataka; Kondo, Mitsunori; Hiki, Tomonori; Tagami, Toru; Nakahira, Atsushi; Wakihara, Toru

    2014-01-01

    The samples from A-type zeolite and ground soda-lime glass powders were solidified by calcinations at 600 to 800°C in air atmosphere. These hybrid zeolite/glass samples at 700°C were in part insufficiently densified and hybrid samples were fully densified at 800°C, although the densification was not generated at 600°C. A-zeolites were still stable in glass melt at 800°C for hybrid zeolite/glass samples. These hybrid zeolite/glass samples had the ion exchange ability of 20% against Sr 2+ and the high ability over 80% against Cs + as well as A-zeolite. Microstructures of obtained hybrid zeolite/glass samples were evaluated. (author)

  12. Catalytic Ozonation of Toluene Using Chilean Natural Zeolite: The Key Role of Brønsted and Lewis Acid Sites

    Directory of Open Access Journals (Sweden)

    Serguei Alejandro-Martín

    2018-05-01

    Full Text Available The influence of surface physical-chemical characteristics of Chilean natural zeolite on the catalytic ozonation of toluene is presented in this article. Surface characteristics of natural zeolite were modified by acid treatment with hydrochloric acid and ion-exchange with ammonium sulphate. Prior to catalytic ozonation assays, natural and chemically modified zeolite samples were thermally treated at 623 and 823 K in order to enhance Brønsted and Lewis acid sites formation, respectively. Natural and modified zeolite samples were characterised by N2 adsorption at 77 K, elemental analysis, X-ray fluorescence, and Fourier transform infrared (FTIR spectroscopy, using pyridine as a probe molecule. The highest values of the reaction rate of toluene oxidation were observed when NH4Z1 and 2NH4Z1 zeolite samples were used. Those samples registered the highest density values of Lewis acid sites compared to other samples used here. Results indicate that the presence of strong Lewis acid sites at the 2NH4Z1 zeolite surface causes an increase in the reaction rate of toluene oxidation, confirming the role of Lewis acid sites during the catalytic ozonation of toluene at room temperature. Lewis acid sites decompose gaseous ozone into atomic oxygen, which reacts with the adsorbed toluene at Brønsted acid sites. On the other hand, no significant contribution of Brønsted acid sites on the reaction rate was registered when NH4Z1 and 2NH4Z1 zeolite samples were used.

  13. Surface effect of natural zeolite (clinoptilolite) on the photocatalytic activity of TiO2

    International Nuclear Information System (INIS)

    Li Fangfei; Jiang Yinshan; Yu Lixin; Yang Zhengwen; Hou Tianyi; Sun Shenmei

    2005-01-01

    The surface interaction between TiO 2 and natural zeolite, clinoptilolite, has been investigated by means of transmission electron microscope (TEM), atom force microscope (AFM), X-ray diffractometer (XRD), diffuse reflectance infrared Fourier transform (DRIFT) and far Fourier transform infrared ray (FTIR) spectroscopy. And the photocatalytic degradation (PCD) rate of methyl orange (MO), a model of recalcitrant azo dye, in aqueous system has been measured to compare the photocatalytic activities of different photocatalysts. A model has been carried out to explain the incorporation between TiO 2 particles and natural zeolite. The results show that the TiO 2 particles loaded on zeolite are 50 nm or so, smaller than the pure one, and combine with zeolite via chemical force. Since the reserved adsorption ability and the existence of electron trapper, the TiO 2 -zeolite performed more efficient at low initial concentration and in the later period of PCD process, as compared with pure TiO 2 nanopowders

  14. Formation of hydroxyl groups and exchange with deuterium on NaHX and NaHY zeolites

    International Nuclear Information System (INIS)

    Kubelkova, L.; Novakova, J.

    1976-01-01

    Deammoniation and dehydroxylation of Na(NH 4 )X and Na(NH 4 )Y zeolites were compared. With the X type, both processes overlapped and proceeded more easily than with the Y type. Both H forms contained structural OH groups and hydroxyls denoted as SiOH, to which the 3740 cm -1 band in the IR spectrum was assigned. In addition, the NaHX zeolite contained OH groups characterized by the 3700 and 3600 cm -1 bands. Certain differences in the behaviour of NaHX and NaHY zeolites during deammoniation and dehydroxylation might be attributed to the presence of ''non-localizable'' H atoms. The active sites for the D 2 -OH exchange were probably formed during dehydroxylation. Hydrogen in SiOH groups was replaced by deuterium in both zeolite types more slowly than H atoms in other OH groups, which influenced the kinetic variations in the gaseous phase. The presence of water in the gaseous phase affected the kinetics and could distort the determination of the number of H atoms bound in the zeolites. (author)

  15. Possibilities of utilizing zeolites for the reduction of toxical noxious gases of combustion engines

    Directory of Open Access Journals (Sweden)

    Pandová Iveta

    2001-12-01

    Full Text Available Combustion engines produce exhalations that contribute by 50% to the contamination of the environment. The subject of this work is the research of zeolites´ as the adsorbent of toxical gases. The decisive influence on the adsorbing power has the capacity of porous in unit of volume of the sorbent and dimensions of canals. The active component of zeolite from the deposit Bystré is mineral clinoptilolite. Recently, there is an increased interest to utilize zeolites in the partial reduction of NOx, CO and hydrocarbons in the combustion products. The catalysts used to detoxication of exhalation combustion engines are less effective during periods of relatively low temperature operation, such as the initial cold-start period of engine operation. Some European, American and Japones patents are directed to the use of a zeolite catalyst for the reduction of hydrocarbons, CO and NOx. The noble metals and acid zeolites are used as a catalyst of noxious components. The adsorbent material, which may be a zeolite is part treatment system in order to adsorb gaseous pollutants during of cold start period of engine operation.

  16. Synthesis of 2,2-dimethyl-4-phenyl-[1,3]-dioxolane using zeolite ...

    African Journals Online (AJOL)

    Zeolite encapsulated Co(II), Cu(II) and Zn(II) complexes with 2-methyl benzimidazole (Mebzlh) have been used to catalyze the reaction of styrene oxide with acetone under reflux condition. The yield of the isolated product using various catalysts range from good to excellent and the efficiency of the recycled catalyst was ...

  17. Copper removal and nickel for exchange cationic with a natural zeolite

    International Nuclear Information System (INIS)

    Estupinan, Arnoldy; Sarmiento, Diego; Belalcazar de Galvis, Ana Maria

    1998-01-01

    Natural zeolite clinoptilolite, was used to remove copper and nickel from waste waters of a galvanotechnical company. Exchange capacity determined for the zeolite after its transformation to homoionic sodium form, was 0.794 meq/g for copper and 0.447 meq/g for nickel. There were made batch and column experiments, reaching the last one a better approach to the equilibrium. From the degeneration essays, the sodical zeolite concentrates the copper in the waste waters to 23.5 up times the level found for the acid rinsing waters; it shows its potential use in treatment of these waste, because its effectiveness and low cost

  18. Limestone and Zeolite as Alternative Media in Horizontal Subsurface Flow Constructed Wetlands: Laboratory-Scale Studies

    Science.gov (United States)

    Lizama, K.; Jaque, I.; Ayala, J.

    2016-12-01

    Arsenic is well known for its chronic toxicity. Millions of people around the world are currently at risk, drinking water with As concentrations above 10 ppb, the WHO drinking water guideline. Although different treatment options exist, they are often limited by elevated costs and maintenance requirements. Constructed wetlands are a natural water treatment system, capable to remove metals and metalloids -including As- via different physical, chemical and biological processes. The use of alternative supporting media to enhance As removal in subsurface flow wetlands has been recommended, but not sufficiently studied. Limestone and zeolite have been identified as effective supporting media in subsurface flow wetlands aiming As removal. However, there are still key aspects to be addressed, such as the implications of using these media, the speciation in the solid phase, the role of vegetation, etc. This study investigated the performance of limestone and zeolite in three types of experiments: batch, column and as main supporting media in a bench scale horizontal subsurface flow wetland system. Synthetic water resembling a contaminated river in Chile (As concentration=3 mg/L, Fe concentration= 100 mg/L, pH=2) was used in all experiments. In the batch experiments, the As concentration, the mass of media and the contact time were varied. The column system consisted of three limestone columns and three zeolite columns, operated under a hydraulic loading of 20 mm/d. The wetland system consisted of twelve PVC cells: six filled with zeolite and six with limestone. Phragmites australis were planted in three cells of each media type, as control cells. From the batch experiments, maximum As sorption capacities as indicated by Langmuir model were 1.3 mg/g for limestone and 0.17 mg/g for zeolite, at 18 h contact time and 6.3 g/L medium concentration. EDS and XPS analyses revealed that As and Fe were retained in zeolite at the end of the batch experiments. Zeolite and limestone

  19. Selective Ring Opening of 1-Methylnaphthalene Over NiW-Supported Catalyst Using Dealuminated Beta Zeolite.

    Science.gov (United States)

    Kim, Eun-Sang; Lee, You-Jin; Kim, Jeong-Rang; Kim, Joo-Wan; Kim, Tae-Wan; Chae, Ho-Jeong; Kim, Chul-Ung; Lee, Chang-Ha; Jeong, Soon-Yong

    2016-02-01

    Nanoporous Beta zeolite was dealuminated by weak acid treatment for reducing the acidity. Bi-functional catalysts were prepared using commercial Beta zeolites and the dealuminated zeolites for acidic function, NiW for metallic function. 1-Methylnaphthalene was selected as a model compound for multi-ring aromatics in heavy oil, and its selective ring opening reaction has been investigated using the prepared bi-functional catalysts with different acidity in fixed bed reaction system. The dealuminated Beta zeolites, which crystal structure and nanoporosity were maintained, showed the higher SiO2/Al2O3 ratio and smaller acidity than their original zeolite. NiW-supported catalyst using the dealuminated Beta zeolite with SiO2/Al203 mole ratio of 55 showed the highest performance for the selective ring opening. The acidity of catalyst seemed to play an important role as active sites for the selective ring opening of 1-methylnaphthalene but there should be some optimum catalyst acidity for the reaction. The acidity of Beta zeolite could be controlled by the acid treatment and the catalyst with the optimum acidity for the selective ring opening could be prepared.

  20. Effect of SrO content on Zeolite Structure

    Science.gov (United States)

    Widiarti, N.; Sari, U. S.; Mahatmanti, F. W.; Harjito; Kurniawan, C.; Prasetyoko, D.; Suprapto

    2018-04-01

    The aims of current studies is to investigate the effect of strontium oxide content (SrO) on synthesized zeolite. Zeolite was synthesized from Tetraethyl orthosilicate (TEOS) as precursors of SiO2 and aluminum isopropoxide (AIP) precursors. The mixture was aged for 3 days and hydrothermally treated for 6 days. The SrO content was added by impregnation method. The products were then characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and Surface Area Analyzer (SAA). The diffractogram confirmed the formation of Faujasite-like zeolite. However, after the addition of SrO, the crystallinity of zeolite was deformed. The diffractograms shows the amorphous phase of zeolite were decrease as the SrO content is increase. The structural changes was also observed from FTIR spectra which shows the shifting and peak formation. The surface area analysis showed that the increasing loading of SrO/Zeolites reduced the catalyst surface area.

  1. Preparation of Zeolite/Zinc Oxide Nanocomposites for toxic metals removal from water

    Directory of Open Access Journals (Sweden)

    Abdullah A. Alswata

    Full Text Available This research work has proposed preparation of Zeolite/Zinc Oxide Nanocomposite (Zeolite/ZnO NCs by using a co-precipitation method. Then, the prepared Nanocomposite has been tested for adsorption of Lead Pb (II and Arsenic As (V from aqueous solution under the room pressure and temperature. After that, the prepared adsorbent has been studied by several techniques. For adsorption process; the effect of the adsorbent masses, contact time, PH and initial metals concentration as well as, the kinetics and isotherm for adsorption process have been investigated. The results revealed that; ZnO nanoparticles (NPs with average diameter 4.5 nm have successfully been loaded into Zeolite. The optimum parameters for the removal of the toxic metals 93% and 89% of Pb (II and As (V, respectively, in 100 mg/L aqua solutions were pH4, 0.15 g and 30 min. According to the obtained results; pseudo second-order kinetic and Langmuir isotherm model have higher correlation coefficients and provided a better agreement with the experimental data. The prepared sorbent showed an economical and effective way to remove the heavy toxic metals due to its ambient operation conditions, low- consumption energy and facile regeneration method. Keywords: Zeolite, ZnO, Nanocomposites, Adsorbent, Kinetic, Isotherm

  2. Development a solid state sensor based on SnO_2 nanoparticles for underground coal mine methane detection using zeolites as filter

    International Nuclear Information System (INIS)

    Abruzzi, R.C.; Dedavid, B.A.; Pires, M.J.R.; Luvizon, N.S.

    2016-01-01

    Aiming the monitoring of methane (CH_4) in underground coal mines, the tin oxide (SnO_2) was synthesis and applied to the development of a MOS sensor (metal oxide semiconductor). Zeolite have been tested as a filter of carbon dioxide (CO_2) to ensure the selectivity in the detection of CH_4. Analysis of Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) indicated a synthesis of nanoscaled structures. The energy band gap showed characteristic values for a potential application of SnO_2 in CH_4 sensors. Analysis of surface area by BET isotherms showed high values for the zeolite 13X and Y, while adsorption tests indicated that the zeolite 13X presents greater adsorption efficiency of CO_2. The sputtering technique for deposition of the electrodes, as well as the method of drop coating for deposition of SnO_2, proved effective in developing the sensor. (author)

  3. Zeolite H-BEA catalysed multicomponent reaction: One-pot ...

    Indian Academy of Sciences (India)

    zeolites are broadly used in the synthesis of specialty and fine chemicals. ... Further, when a solid aldehyde or high amounts of catalyst is used, an organic .... −1. ; MS m/z : 292 ([M+H]+). 2.2b N-[(4-Methylphenyl)-(2-hydroxynapthalen-1-.

  4. The vibrational dynamics of carbon monoxide in a confined space-CO in zeolites.

    Science.gov (United States)

    Nachtigallová, Dana; Bludský, Ota; Otero Areán, Carlos; Bulánek, Roman; Nachtigall, Petr

    2006-11-14

    Based on theoretical calculations, and a survey of infrared spectra of CO adsorbed on different cation exchanged zeolites, a model is proposed to explain the influence of the zeolite framework on the vibrational behaviour of CO confined into small void spaces (zeolite channels and cavities). The concepts developed should help to understand a number of details relevant to both, precise interpretation of IR spectra and a better understanding of the vibrational dynamics of small molecules in a confined space.

  5. Improved Catalysts for Heavy Oil Upgrading Based on Zeolite Y Nanoparticles Encapsulated Stable Nanoporous Host

    Energy Technology Data Exchange (ETDEWEB)

    Conrad Ingram; Mark Mitchell

    2007-09-30

    The objective of this project is to synthesize nanocrystals of highly acidic zeolite Y nanoclusters, encapsulate them within the channels of mesoporous (nanoporous) silicates or nanoporous organosilicates, and evaluate the 'zeolite Y/Nanoporous host' composites as catalysts for the upgrading of heavy petroleum feedstocks. In comparison to conventionally-used zeolite Y catalysts of micron size particles, the nanocrystals (< 100 nm particle size) which contain shorter path lengths, are expected to allow faster diffusion of large hydrocarbon substrates and the catalysis products within and out of the zeolite's channels and cages (<1 nm size). This is expected to significantly reduce deactivation of the catalyst and to prolong their period of reactivity. Encapsulating zeolite Y nanocrystals within the nanoporous materials is expected to protect its external surfaces and pore entrances from being blocked by large hydrocarbon substrates, since these substrates will initially be converted to small molecules by the nanoporous host (a catalyst in its own right). The project consisted of four major tasks as follows: (1) synthesis of the nanoparticles of zeolite Y (of various chemical compositions) using various techniques such as the addition of organic additives to conventional zeolite Y synthesis mixtures to suppress zeolite Y crystal growth; (2) synthesis of nanoporous silicate host materials of up to 30 nm pore diameter, using poly (alkylene oxide) copolymers which when removed will yield a mesoporous material; (3) synthesis of zeolite Y/Nanoporous Host composite materials as potential catalysts; and (4) evaluation of the catalyst for the upgrading of heavy petroleum feedstocks.

  6. Fixing noble gas in zeolites

    International Nuclear Information System (INIS)

    Rocha Dorea, A.L. da.

    1980-09-01

    In order to increase safety during the long-term storage of Kr-85 it has been proposed to encaosulate this gas in zeolite 5A. Due to the decay heat of Kr-85 it is expected, however, that the inorganic matrix will be at an increased temperature over several decades. Below 600 0 C only very small Kr-desorption rates are observed when a linear temperature gradient is applied to a loaded 5A zeolite sample. If heating is interrupted and the temperature kept konstant at a certain value (>600 0 C), it is observed that the desorption rate either decreased below the detection limit or stayed constant at some measurable value. The overall activation energy in the temperature range 570 0 C-745 0 C is found to be 250 kJ/mol. At temperature above 790 0 C the total encapsulated gas is rapidly liberated. No significant leakage was apparent from zeolite 5A samples containing between 19 and 57 cm 3 STP Kr/g kept at 200 0 C for up to 2500 h and 400 0 C for up to 3500 h. From these studies it is found that type 5A zeolites are particularly suitable as a matrix for the inmobilization of Kr-85. (Author) [pt

  7. Simultaneous removal of ammonia and N-nitrosamine precursors from high ammonia water by zeolite and powdered activated carbon.

    Science.gov (United States)

    Xue, Runmiao; Donovan, Ariel; Zhang, Haiting; Ma, Yinfa; Adams, Craig; Yang, John; Hua, Bin; Inniss, Enos; Eichholz, Todd; Shi, Honglan

    2018-02-01

    When adding sufficient chlorine to achieve breakpoint chlorination to source water containing high concentration of ammonia during drinking water treatment, high concentrations of disinfection by-products (DBPs) may form. If N-nitrosamine precursors are present, highly toxic N-nitrosamines, primarily N-nitrosodimethylamine (NDMA), may also form. Removing their precursors before disinfection should be a more effective way to minimize these DBPs formation. In this study, zeolites and activated carbon were examined for ammonia and N-nitrosamine precursor removal when incorporated into drinking water treatment processes. The test results indicate that Mordenite zeolite can remove ammonia and five of seven N-nitrosamine precursors efficiently by single step adsorption test. The practical applicability was evaluated by simulation of typical drinking water treatment processes using six-gang stirring system. The Mordenite zeolite was applied at the steps of lime softening, alum coagulation, and alum coagulation with powdered activated carbon (PAC) sorption. While the lime softening process resulted in poor zeolite performance, alum coagulation did not impact ammonia and N-nitrosamine precursor removal. During alum coagulation, more than 67% ammonia and 70%-100% N-nitrosamine precursors were removed by Mordenite zeolite (except 3-(dimethylaminomethyl)indole (DMAI) and 4-dimethylaminoantipyrine (DMAP)). PAC effectively removed DMAI and DMAP when added during alum coagulation. A combination of the zeolite and PAC selected efficiently removed ammonia and all tested seven N-nitrosamine precursors (dimethylamine (DMA), ethylmethylamine (EMA), diethylamine (DEA), dipropylamine (DPA), trimethylamine (TMA), DMAP, and DMAI) during the alum coagulation process. Copyright © 2017. Published by Elsevier B.V.