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

Desulfurization of the exhaust gas with zeolite synthesized from diatomaceous earth

Energy Technology Data Exchange (ETDEWEB)

Miyamoto, M

1975-07-01

Both A type and X type zeolites were prepared from diatomaceous earth and tested for use in flue gas desulfurization. Several diatomaceous earths of known chemical compositions were mixed to obtain a desired molar ratio of silicates, whose maturation was achieved in two steps; room temperature maturation and reflux maturation by heating. If the second maturation was carried out for more than 12 hr, the X type zeolite formation was low. At the best conditions, 80% pure zeolite could be prepared for both types according to their x-ray diffraction spectra. The synthesized x type zeolite adsorbed sulfur dioxide more efficiently than A type zeolite. When a simulated flue gas containing 680 to 840 ppM sulfur dioxide was passed at a flow rate of 9.0 Nl/min through a 250 g zeolite column, the column breaking time (time required for the SO/sub 2/ concentration of the column effluent to reach 10% of the initial SO/sub 2/ concentration) was 5.3 hr, while that for the commercial zeolite and activated carbon was 6.8 hr and 8.0 hr, respectively. If the flue gas contained more than 1% moisture, the adsorbed water reacted with SO/sub 2/ and the zeolite crystal tended to break down. The use of zeolite for flue gas desulfurization was more costly than the use of activated carbon.

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%.

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

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.

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.

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.

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.)

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...

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

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

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)

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.

INVESTIGATION OF CLINOPTILOLITE NATURAL ZEOLITE REGENERATION BY AIR STRIPPING FOLLOWED BY ION EXCHANGE FOR REMOVAL OF AMMONIUM FROM AQUEOUS SOLUTIONS

Directory of Open Access Journals (Sweden)

A. R. Rahmani ، M. T. Samadi ، H. R. Ehsani

2009-07-01

Full Text Available The purpose of this study was to regenerate clinoptilolite natural zeolite by air stripping followed by removal of ammonium from aqueous solutions. The research was carried out in continuous system. The characteristics of graded clinoptilolite from Semnan (one of the central provinces in Iran mines were determined and then regeneration tests were done by contacting of 1 N NaCl solution with given weights of ammonium saturated zeolite. Then the brine of column was transferred to the air stripping column for regeneration. The pH of brine solution before entrance to a stripping column was increased to 11. Air stripped ammonia from the brine was converted to the ammonium ion by using acid scrubber. The outlet effluent from stripping column was collected for reuse. The results showed that the cation exchange capacities were 17.31 to 18.38 mg NH4+/g of zeolite weight. Regeneration efficiency of zeolite by NaCl solution and air stripping was in the range of 92%-97% under various operational conditions. However, the efficiency of acid absorption of released ammonia in stripping process was 55% with a major rejection of the surplus ammonia to the atmosphere. It could be concluded that the method studied may be considered as an advanced and supplementary process for treating effluents of aqueous solution and fishponds in existing treatment plants.

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

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....

Longitudinal dispersion coefficient depending on superficial velocity of hydrogen isotopes flowing in column packed with zeolite pellets at 77.4 K

Energy Technology Data Exchange (ETDEWEB)

Kotoh, K. [Faculty of Engineering, Kyushu University, Nishi-ku, Fukuoka (Japan); Graduate School of Engineering, Kyushu University, Nishi-ku, Fukuoka (Japan); Kubo, K.; Takashima, S.; Moriyama, S.T. [Graduate School of Engineering, Kyushu University, Nishi-ku, Fukuoka (Japan); Tanaka, M. [National Institute for Fusion Science, Oroshi-cho, Toki, Gifu (Japan); Sugiyama, T. [Faculty of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya (Japan)

2015-03-15

Authors have been developing a cryogenic pressure swing adsorption system for hydrogen isotope separation. In the problem of its design and operation, it is necessary to predict the concentration profiles developing in packed beds of adsorbent pellets. The profiling is affected by the longitudinal dispersion of gas flowing in packed beds, in addition to the mass transfer resistance in porous media of adsorbent pellets. In this work, an equation is derived for estimating the packed-bed dispersion coefficient of hydrogen isotopes, by analyzing the breakthrough curves of trace D{sub 2} or HD replacing H{sub 2} adsorbed in synthetic zeolite particles packed columns at the liquefied nitrogen temperature 77.4 K. Since specialized for hydrogen isotopes, this equation can be considered to estimate the dispersion coefficients more reliable for the cryogenic hydrogen isotope adsorption process, than the existing equations. (authors)

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.

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

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.

Denitration of simulated high-level liquid wastes and selective removal of cesium with zeolites

Energy Technology Data Exchange (ETDEWEB)

Mimura, Hitoshi; Kanno, Takuji [Tohoku Univ., Sendai (Japan). Research Inst. of Mineral Dressing and Metallurgy; Kimura, Toshiya

1982-03-01

Denitration of high-level liquid wastes (HLW) from nuclear fuel reprocessing has been studied. Selective removal of Cs has been also examined with various types of zeolites. The following zeolites were used in this study; Na-synthetic mordenite (NaSM), Na-natural mordenite (NaNM), Na-natural clinoptilolite (NaCP) and H-synthetic mordenites (HSM). The effective denitration is found in the simulated HLW (15 components, 2N HNO/sub 3/ soln.) containing platinum group elements in the case of the addition of formic acid, and the pH of the solution shows the value of 5.4 when the excess formic acid ((HCOOH)/(HNO/sub 3/) = 2.0) was added. Platinum group elements may react as a catalyst for the decomposition of nitric acid and the excess formic acid. The break-through properties of NaSM column are poor for the simulated HLW, and the selective removal of Cs appears to be difficult. On the other hand, good results are obtained in the denitrated HLW, i.e., break-through capacity, total capacity and column utilization are 59.4 (meq./100 g zeolite), 147 (meq./100 g zeolite) and 40.4 (%), respectively. The break-through properties of NaSM and NaNM are superior to those of HSM. The break-through capacity and column utilization increase with an increase in column temperature.

Denitration of simulated high-level liquid wastes and selective removal of cesium with zeolites

International Nuclear Information System (INIS)

Mimura, Hitoshi; Kanno, Takuji; Kimura, Toshiya.

1982-01-01

Denitration of high-level liquid wastes (HLW) from nuclear fuel reprocessing has been studied. Selective removal of Cs has been also examined with various types of zeolites. The following zeolites were used in this study; Na-synthetic mordenite (NaSM), Na-natural mordenite (NaNM), Na-natural clinoptilolite (NaCP) and H-synthetic mordenites (HSM). The effective denitration is found in the simulated HLW (15 components, 2N HNO 3 soln.) containing platinum group elements in the case of the addition of formic acid, and the pH of the solution shows the value of 5.4 when the excess formic acid ([HCOOH]/[HNO 3 ] = 2.0) was added. Platinum group elements may react as a catalyst for the decomposition of nitric acid and the excess formic acid. The break-through properties of NaSM column are poor for the simulated HLW, and the selective removal of Cs appears to be difficult. On the other hand, good results are obtained in the denitrated HLW, i.e., break-through capacity, total capacity and column utilization are 59.4 (meq./100 g zeolite), 147 (meq./100 g zeolite) and 40.4 (%), respectively. The break-through properties of NaSM and NaNM are superior to those of HSM. The break-through capacity and column utilization increase with an increase in column temperature. (author)

Separation of molecular hydrogen isotope mixtures on zeolite NaX-3M

International Nuclear Information System (INIS)

Polevoj, A.S.; Yudin, I.P.

1984-01-01

The transfer unito height (TUH) have been determined at separation of the H 2 -D 2 mixture using zeolite NaX-3M depending on temperature and linear gas flow rate in the column. Experimentally the TUH value has been determined by the method of stepped variation of the concentration of one of the separated components at the entrance into the column and measurement of the substance front wash-out at the outlet. The results of determining TUH in the column of 10 mm diameter filled by the zeolite immobile layer with granules of 2-3 mm size show that with increasing the temperature from 77 K to 87.3 K TUH decreases while at constant temperature it increases with the growth of linear gas flow rate. The mentioned above circumstances testify to the essential contribution to the TUH value of the hydrogen diffusion process in the sorbent grain. The given TUH absolute values indicate the high rate of interphase isotope exchange at separation of the H 2 -D 2 mixture using NaX-3M zeolite

Separation of molecular hydrogen isotope mixtures using zeolite NaX-3M

International Nuclear Information System (INIS)

Polevoj, A.S.; Yudin, I.P.

1984-01-01

The components of transfer unit height (TUH) at separation of the H 2 -D 2 mixture using zeolite NaX-3M in the countercurrent column are determined. It is shown that the interphase isotopic exchange in the column is limited by gaseous diffusion in sorbent primary pores. On the basis of the TUH dependence the value of the hydrogen diffusion coefficient in primary pores of NaX-3M zeolite equal at 77 K and 87.3 K, respectively, approximately 1.09x10 -15 and approximately 1.69x10 -15 m 2 /s is calculated

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.

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.

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.

Facile synthesis of mesostructured ZSM-5 zeolite with enhanced mass transport and catalytic performances

Energy Technology Data Exchange (ETDEWEB)

Li, Chao; Ren, Yanqun [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Tianhe District, Guangzhou 510641 (China); Gou, Jinsheng [College Material Science and Technology, Beijing Forestry University, Key Laboratory of Wooden Material Science and Application, Ministry of Education, 35 Tsinghua East Road, Haidian District, Beijing 100083 (China); Liu, Baoyu [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Tianhe District, Guangzhou 510641 (China); Xi, Hongxia, E-mail: cehxxi@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Tianhe District, Guangzhou 510641 (China)

2017-01-15

Highlights: • A mesostructured MFI zeolite was synthesized via dual-functional surfactant approach. • Mass transport was investigated by applying zero length column technique. • The catalyst exhibited excellent catalytic activity and long lifetime. • Gaussian DFT was employed to study the role of surfactant in crystallization process. - Abstract: A mesostructured ZSM-5 zeolite with multilamellar structure was successfully synthesized by employing a tetra-headgroup rigid bolaform quaternary ammonium surfactant. It was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), nitrogen adsorption/desorption isotherms, amines temperature programmed desorption (amines-TPD), and computer simulation. These results indicated that the dual-functional amphiphilic surfactants play a critical role for directing the multilamellar structure with high mesoporosity. The mass transport and catalytic performances of the zeolite were investigated by zero length column (ZLC) technique and aldol condensation reactions to evaluate the structure-property relationship. These results clearly indicated that the mass transport of selected molecules in hierarchical zeolite can be accelerated by introducing mesoporous structure with mesostructure with reduced diffusion length and an overall enhanced resistance against deactivation in reactions involving large molecules. Furthermore, the dual-functional surfactant approach of making hierarchical zeolite with MFI nanosheets framework would open up new opportunities for design and synthesis of hierarchical zeolites with controllable mesoporous structures.

Facile synthesis of mesostructured ZSM-5 zeolite with enhanced mass transport and catalytic performances

International Nuclear Information System (INIS)

Li, Chao; Ren, Yanqun; Gou, Jinsheng; Liu, Baoyu; Xi, Hongxia

2017-01-01

Highlights: • A mesostructured MFI zeolite was synthesized via dual-functional surfactant approach. • Mass transport was investigated by applying zero length column technique. • The catalyst exhibited excellent catalytic activity and long lifetime. • Gaussian DFT was employed to study the role of surfactant in crystallization process. - Abstract: A mesostructured ZSM-5 zeolite with multilamellar structure was successfully synthesized by employing a tetra-headgroup rigid bolaform quaternary ammonium surfactant. It was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), nitrogen adsorption/desorption isotherms, amines temperature programmed desorption (amines-TPD), and computer simulation. These results indicated that the dual-functional amphiphilic surfactants play a critical role for directing the multilamellar structure with high mesoporosity. The mass transport and catalytic performances of the zeolite were investigated by zero length column (ZLC) technique and aldol condensation reactions to evaluate the structure-property relationship. These results clearly indicated that the mass transport of selected molecules in hierarchical zeolite can be accelerated by introducing mesoporous structure with mesostructure with reduced diffusion length and an overall enhanced resistance against deactivation in reactions involving large molecules. Furthermore, the dual-functional surfactant approach of making hierarchical zeolite with MFI nanosheets framework would open up new opportunities for design and synthesis of hierarchical zeolites with controllable mesoporous structures.

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

Evaluation of zeolite mixtures for decontaminating high-activity-level water at the Three Mile Island Unit 2 Nuclear Power Station

International Nuclear Information System (INIS)

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

1984-05-01

Mixtures of Linde Ionsiv IE-96 and Ionsiv A-51 were evaluated for use in the Submerged Demineralizer System (SDS) that was installed at the Three Mile Island Unit 2 Nuclear Power Station to decontaminate approx. 2780 m 3 of high-activity-level water. The original SDS flowsheet was conservatively designed for removal of cesium and strontium and would have required the use of approx. 60 SDS columns. Mixed zeolite tests were made on a 10 -5 scale and indicated that the appropriate ratio of IE-96/A-51 was 3/2. A mathematical model was used to predict the performance of the mixed zeolite columns in the SDS configuration and with the intended method of operation. Actual loading results were similar to those predicted for strontium and better than those predicted for cesium. The number of SDS columns needed to process the HALW was reduced to approx. 10. 6 references, 4 figures, 2 tables

Qualification testing and full-scale demonstration of titanium-treated zeolite for sludge wash processing

Energy Technology Data Exchange (ETDEWEB)

Dalton, W.J.

1997-06-30

Titanium-treated zeolite is a new ion-exchange material that is a variation of UOP (formerly Union Carbide) IONSIV IE-96 zeolite (IE-96) that has been treated with an aqueous titanium solution in a proprietary process. IE-96 zeolite, without the titanium treatment, has been used since 1988 in the West Valley Demonstration Project`s (WVDP) Supernatant Treatment System (STS) ion-exchange columns to remove Cs-137 from the liquid supernatant solution. The titanium-treated zeolite (TIE-96) was developed by Battelle-Pacific Northwest Laboratory (PNL). Following successful lab-scale testing of the PNL-prepared TIE-96, UOP was selected as a commercial supplier of the TIE-96 zeolite. Extensive laboratory tests conducted by both the WVDP and PNL indicate that the TIE-96 will successfully remove comparable quantities of Cs-137 from Tank 8D-2 high-level radioactive liquid as was done previously with IE-96. In addition to removing Cs-137, TIE-96 also removes trace quantities of Pu, as well as Sr-90, from the liquid being processed over a wide range of operating conditions: temperature, pH, and dilution. The exact mechanism responsible for the Pu removal is not fully understood. However, the Pu that is removed by the TIE-96 remains on the ion-exchange column under anticipated sludge wash processing conditions. From May 1988 to November 1990, the WVDP processed 560,000 gallons of liquid high-level radioactive supernatant waste stored in Tank 8D-2. Supernatant is an aqueous salt solution comprised primarily of soluble sodium salts. The second stage of the high-level waste treatment process began November 1991 with the initiation of sludge washing. Sludge washing involves the mixing of Tank 8D-2 contents, both sludge and liquid, to dissolve the sulfate salts present in the sludge. Two sludge washes were required to remove sulfates from the sludge.

Column-Oriented Database Systems (Tutorial)

OpenAIRE

Abadi, D.; Boncz, Peter; Harizopoulos, S.

2009-01-01

textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as opposed to traditional database systems that store entire records (rows) one after the other. Reading a subset of a table’s columns becomes faster, at the potential expense of excessive disk-head s...

Treatment of radioactive liquid waste (Co-60) by sorption on Zeolite Na-A prepared from Iraqi kaolin

International Nuclear Information System (INIS)

Mustafa, Yasmen A.; Zaiter, Maysoon J.

2011-01-01

Highlights: ► Iraqi synthetic zeolite type Na-A has been suggested as ion exchange material to treat cobalt-60 in radioactive liquid waste which came from neutron activation for corrosion products. ► The ability of Na-A zeolite to remove cobalt from wastewater was checked for high cobalt concentration (822 mg/L) in addition to low cobalt concentration in the source sample (0.093 mg/L). ► The effects of important design variables on the zeolite column performance were studied these include initial concentration, flow rate, and bed depth. ► The experimental results show that high sorption capacity can be obtained at high influent concentration, low flow rate, and high bed depth. ► Higher column performance was obtained at higher bed depth. - Abstract: Iraqi synthetic zeolite type Na-A has been suggested as ion exchange material to treat cobalt-60 in radioactive liquid waste which came from neutron activation for corrosion products. Batch experiments were conducted to find out the equilibrium isotherm for source sample .The equilibrium isotherm for radioactive cobalt in the source sample showed unfavorable type, while the equilibrium isotherm for the total cobalt (the radioactive and nonradioactive cobalt) in the source sample showed a favorable type. The ability of Na-A zeolite to remove cobalt from wastewater was checked for high cobalt concentration (822 mg/L) in addition to low cobalt concentration in the source sample (0.093 mg/L). A good fitting for the experimental data with Langmuir equilibrium model was observed. Langmuir constant qm which is related to monolayer adsorption capacity for low and high cobalt concentration was determined to be 0.021 and 140 mg/g zeolite . The effects of important design variables on the zeolite column performance were studied these include initial concentration, flow rate, and bed depth. The experimental results have shown that high sorption capacity can be obtained at high influent concentration, low flow rate, and

Is it cement to be? Downhole cement that uses zeolite additive may offer lightweight alternative

Energy Technology Data Exchange (ETDEWEB)

Mahoney, J.

2001-05-01

C2C Zeolite Corporation produces zeolites from a large deposit near Cache Creek, British Columbia, and processes them for use as an additive in downhole cement well casings. Early research indicates that zeolites can significantly improve the way downhole cement is made in the oil industry. Zeolites are made up mostly of silicates of aluminum and calcium. They have a great ability to absorb water, resulting in a lighter and more fluid cement than is currently available. C2C claims that zeolites will reduce cement weight, column pressure and operator costs. The cost benefits of using lighter cement downhole includes easier moving, processing and handling of the mix. Initial research suggests that zeolites might prove to be viable alternatives to other cement lighteners such as silica fumes or flyash. Zeolite-based cement also performed reasonably well in freeze-thaw tests and showed good adhesion and no evidence of shrinkage in downhole tests. 3 figs.

Column-Oriented Database Systems (Tutorial)

NARCIS (Netherlands)

D. Abadi; P.A. Boncz (Peter); S. Harizopoulos

2009-01-01

textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as

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.

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

Fluorescence labelling as tool for zeolite particle tracking in nanoremediation approaches

International Nuclear Information System (INIS)

Gillies, Glenn; Mackenzie, Katrin; Kopinke, Frank-Dieter; Georgi, Anett

2016-01-01

Colloidal Fe-zeolites such as Fe-BEA-35 are currently under study as new adsorbent and catalyst materials for in-situ chemical oxidation with H_2O_2. As for nanoremediation in general, the availability of suitable particle detection methods is a requirement for successful process development and particle tracing. Detection and distinguishing between natural colloids and introduced particles with a similar composition are a challenge. By means of fluorescence labelling, a highly specific detection option for Fe-BEA-35 was developed. ‘Ship-in-a-bottle’ synthesis of fluorescein within the zeolite pores, which was applied for the first time for a BEA type zeolite, provides a product with stable and non-extractable fluorescence. When the fluorescent labelled zeolite is added at a concentration of 1 wt.% referring to the total zeolite mass, a very low detection limit of 1 mg/L of total zeolite is obtained. Compared to commonly applied turbidity measurements, detection via fluorescence labelling is much more specific and sensitive. Fluorescence is only marginally affected by carboxymethyl cellulose, which is frequently applied as stabilizer in application suspensions but will be depleted upon contact with H_2O_2. Transport properties of fluorescent labelled and non-labelled Fe-zeolite particles are in agreement as determined in a column study with quartz sand and synthetic groundwater (classified as very hard). - Highlights: • Fluorescent BEA zeolite was prepared for first time by ‘ship-in-a-bottle’ synthesis. • Fluorescein synthesized inside zeolite channels is stable and non-extractable. • Detection limit of Fe-zeolite particles in suspension with 1 wt.% fluorescent zeolite is 1 mg/L. • Transport properties of fluorescent and Fe-loaded BEA particles are identical.

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

Column-oriented database management systems

OpenAIRE

Možina, David

2013-01-01

In the following thesis I will present column-oriented database. Among other things, I will answer on a question why there is a need for a column-oriented database. In recent years there have been a lot of attention regarding a column-oriented database, even if the existence of a columnar database management systems dates back in the early seventies of the last century. I will compare both systems for a database management – a colum-oriented database system and a row-oriented database system ...

Removal of cadmium in urban wastewater with systems based on zeolite type clinoptilolite; Remocion de cadmio en aguas residuales urbanas con sistemas a base de zeolita tipo clinoptilolita

Energy Technology Data Exchange (ETDEWEB)

Barragan P, P.

2016-07-01

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{sup -1} of Cd{sup 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{sup -1}, with R{sup 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{sup -1} solution of Cd{sup 2+}. influent at a flow rate of 1 mLmin{sup -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{sup -1} and 0.072 Lg{sup -1}min{sup -1} respectively for ZGuayNa with R{sup 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{sub p}= 0.815 m{sup 3}Kg{sup -}1 with R{sup 2}= 0.9789 for ZGuayNa, and K{sub p}= 3.1 m{sup 3}Kg

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

Experimental Study on Pressure Drop and Flow Dispersion in Packed Bed of Natural Zeolite

Directory of Open Access Journals (Sweden)

Ruya Petric Marc

2018-01-01

Full Text Available The use of conventional correlation for pressure drop and dispersion coefficient calculation may result in inaccurate values for zeolite packed bed as the correlations are generally developed for regularly shaped and uniformly sized particles. To support the research on the application of modified natural zeolite as tar cracking catalyst, the research on the hydrodynamic behaviour of zeolite packed bed has been conducted. Experiments were carried out using a glass column with diameter of 37.8 mm. Natural zeolite with particle size of about 2.91 to 6.4 mm was applied as packing material in the column, and the bed height was varied at 9, 19 and 29 cm. Air was used as the fluid that flows through the bed and nitrogen was used as a tracer for residence time distribution determination. Air flow rates were in the range of 20 to 100 mL/s which correspond to the laminar-transitional flow regime. The pressure drops through the bed were in the range of 1.7 to 95.6 Pa, depending on the air flow rate and bed height. From these values, the parameters in the Ergun equation were estimated, taking into account the contribution by wall effect when the ratio of column to particle diameter is low. The viscous and inertial term constants in the Ergun equation calculated ranges from 179 to 199 and 1.41 to 1.47 respectively while the particle sphericity ranges from 0.56 to 0.59. The reactor Peclet number were determined to range from 5.2 to 5.5, which indicated significant deviation from a plug flow condition.

Fission product removal from molten salt using zeolite

International Nuclear Information System (INIS)

Pereira, C.; Babcock, B.D.

1996-01-01

Spent nuclear fuel (SNF) can be treated in a molten salt electrorefiner for conversion into metal and mineral waste forms for geologic disposal. The fuel is dissolved in molten chloride salt. Non-transuranic fission products in the molten salt are ion-exchanged into zeolite A, which is subsequently mixed with glass and consolidated. Zeolite was found to be effective in removing fission product cations from the molten salt. Breakthrough of cesium and the alkaline earths occurred more rapidly than was observed for the rare earths. The effluent composition as a function of time is presented, as well as results for the distribution of fission products along the length of the column. Effects of temperature and salt flow rate are also discussed

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

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

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.

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.

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...

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.

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.

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)

Synthesis of zeolites coal ash in surfactant modified in application and removal of orange 8 acid solution: study in batch, fixed bed column and evaluation ecotoxicological; Sintese de zeolitas de cinzas de carvao modificada por surfactante e aplicacao na remocao de acido laranja 8 de solucao aquosa: estudo em leito movel, coluna de leito fixo e avaliacao ecotoxicologica

Energy Technology Data Exchange (ETDEWEB)

Magdalena, Carina Pitwak

2015-09-01

In this study, synthesized zeolitic material from coal ash and modified cationic surfactant was used for removing the acid dye Orange 8 (AL8) by adsorption process using moving bed and fixed-bed column. The raw material and adsorbents were characterized by different techniques, such as X-ray diffraction, X-ray fluorescence spectroscopy, among others. The adsorption of AL8 was performed by moving bed in order to optimize the results when they are launched in a fixed bed. The effects of adsorption on zeolite AL8 were compared: (1) Effect of counterions Br{sup -} and Cl{sup -} surfactant used in the modification of the zeolite; (2) effect of type of coal ash used as raw material in the synthesis of zeolites (fly and bottom). The following adsorbents were used in the study: fly and bottom zeolite modified by surfactant hexadecyltrimethylammonium bromide (ZLMS-Br-Br and ZPMS-Br) and fly zeolite modified by surfactant hexadecyltrimethylammonium chloride (ZLMS-Cl). The pseudo-second-order kinetic described the adsorption of the dye on all adsorbents. The equilibrium time was reached 40, 60 and 120 min for ZLMS-Br, ZLMS-Cl and ZPMS-Br, respectively. The adsorption equilibrium was analyzed by the equations of the models of linear and nonlinear isotherms of Langmuir, Freundlich, Temkin and Dubinin- Radushkevivh (DR) and the criterion of best fit was evaluated using the error functions.The DR model was adjusted better to the experimental data for the system AL8 / ZLMS-Br, the Freundlich model for AL8 / ZLMS-Cl and Langmuir for AL8 / ZPMS. According to the Langmuir maximum adsorption capacity was 4.67, 1.48 and 1.38 mg g{sup -1} for ZLMS-Br, ZLMS-Cl and ZPMS-Br, in order. In studies employing fixed bed columns, the effects of inlet concentration (20- 30 mg L{sup -1}), flow rate (4.0 -5.3 mL min{sup -1}) and the bed height (5, 5 - 6.5 cm) above the breakthrough curves characteristics in the adsorption system were determined. The Adams-Bohart, Thomas, Yoon-Nelson models were

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...

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...

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 ...

Early construction and operation of the highly contaminated water treatment system in Fukushima Daiichi Nuclear Power Station (3). A unique simulation code to evaluate time-dependent Cs adsorption/desorption behavior in column system

International Nuclear Information System (INIS)

Inagaki, Kenta; Hijikata, Takatoshi; Tsukada, Takeshi; Koyama, Tadafumi; Ishikawa, Keiji; Ono, Shoichi; Suzuki, Shunichi

2014-01-01

A simulation code was developed to evaluate the performance of the cesium adsorption instrument operating in Fukushima Daiichi Nuclear Power Station. Since contaminated water contains seawater whose salinity is not constant, a new model was introduced to the conventional zeolite column simulation code to deal with the variable salinity of the seawater. Another feature of the cesium adsorption instrument is that it consists of several columns arranged in both series and parallel. The spent columns are replaced in a unique manner using a merry-go-round system. The code is designed by taking those factors into account. Consequently, it enables the evaluation of the performance characteristics of the cesium adsorption instrument, such as the time history of the decontamination factor, the cesium adsorption amount in each column, and the axial distribution of the adsorbed cesium in the spent columns. The simulation is conducted for different operation patterns and its results are given to Tokyo Electric Power Company (TEPCO) to support the optimization of the operation schedule. The code is also used to investigate the cause of some events that actually occurred in the operation of the cesium adsorption instrument. (author)

Treatment options of low level liquid waste of ETP origin by synthetic zeolites

International Nuclear Information System (INIS)

Singh, I.J.; Jain, Savita; Sathi Sasidharan, N.; Deshingkar, D.S.

2001-08-01

Mixture of synthetic zeolites, AR1, 4A and 13X of Indian origin were tested in a single fixed bed column operation for the treatment of low level liquid waste received at Effluents Treatment Plant (ETP) Trombay, under dynamic conditions. The mixed bed of zeolites was highly effective in decontaminating thousands of bed volumes of waste stream from radio cesium, radio strontium and gross beta gamma activity. High volume reduction factors, upwards of 10,000 are available in this process compared to less than 100 available with chemical precipitation process, currently followed. Containment of entrapped activity in zeolite bed was studied by solidifying them in Portland cement matrix as stable waste form. Incorporation of minerals like vermiculite as minor additive for improving the leaching characteristics of the final waste form was evaluated. Zeolite incorporated cement blocks were subjected to leach tests in distilled water for over 200 days to assess the incremental and cumulative leach rates of individual activity components. Leachability index of radio cesium and strontium were computed, which indicated the suitability of the matrix for safe shallow land burial. (author)

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.

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.

Bacterial biofilm supported on granular activated carbon and on natural zeolites- an application to wastewater treatment

OpenAIRE

Lameiras, Sandra Raquel de Vasconcelos; Quintelas, C.; Tavares, M. T.

2004-01-01

The removal of many heavy metals from industrial wastewater is one of the most important environmental problems to be solved today. The retention of this contaminants by a biofilm supported on granular activated carbon or on natural zeolites is one of the promising technologies for the reduction of this problem, because it is cheap and it removes a broad range of substances, heavy metals and organic compounds. This study aims the development of a system of two mini-columns in series ...

TREATMENT OF PRODUCED OIL AND GAS WATERS WITH SURFACTANT-MODIFIED ZEOLITE

Energy Technology Data Exchange (ETDEWEB)

Lynn E. Katz; R.S. Bowman; E.J. Sullivan

2003-11-01

Co-produced water from the oil and gas industry accounts for a significant waste stream in the United States. It is by some estimates the largest single waste stream in the country, aside from nonhazardous industrial wastes. Characteristics of produced water include high total dissolved solids content, dissolved organic constituents such as benzene and toluene, an oil and grease component, and chemicals added during the oil-production process. While most of the produced water is disposed via reinjection, some must be treated to remove organic constituents before the water is discharged. Current treatment options are successful in reducing the organic content; however, they cannot always meet the levels of current or proposed regulations for discharged water. Therefore, an efficient, cost-effective treatment technology is needed. Surfactant-modified zeolite (SMZ) has been used successfully to treat contaminated ground water for organic and inorganic constituents. In addition, the low cost of natural zeolites makes their use attractive in water-treatment applications. This report summarizes the work and results of this four-year project. We tested the effectiveness of surfactant-modified zeolite (SMZ) for removal of BTEX with batch and column experiments using waters with BTEX concentrations that are comparable to those of produced waters. The data from our experimental investigations showed that BTEX sorption to SMZ can be described by a linear isotherm model, and competitive effects between compounds were not significant. The SMZ can be readily regenerated using air stripping. We field-tested a prototype SMZ-based water treatment system at produced water treatment facilities and found that the SMZ successfully removes BTEX from produced waters as predicted by laboratory studies. When compared to other existing treatment technologies, the cost of the SMZ system is very competitive. Furthermore, the SMZ system is relatively compact, does not require the storage of

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)

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.

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

Effect Of Particle Size Of Zeolite On The Mass Transfer Coefficient Of Strontium In The Radioactive Waste Ion-Exchange Process

International Nuclear Information System (INIS)

Dewi-Susilowati; Suyitno

1998-01-01

This research is aimed for finding out the volumetric mass transfer coefficient of the zeolite particle, ks. The experiment has been conducted using an ion exchange column. The column diameter and length are 4.2 cm and 28 cm, respectively. The experiments have been conducted by flowing in the feed to the ion-exchange column containing zeolite with the varied particle diameters, I.e. 20, 40, 60, 80 and 100 mesh. The feed concentrations of Sr(NO 3 ) 2 , have been varied, I.e. 100, 250, 450, 550 and 650 ppm, and so have been the flow rates, I.e/ 35, 49, 70, 90 and 105 ml/minute. Samples of the effluents have been taken at certain series of time and subjected to analysis using an Atomic Absorption Spectrophotometer. The analytical data obtained have shown that the mass transfer coefficient of the zeolite particle is predominantly affected by the zeolite structure, in particular is effected by the number of AI atoms that hold the K ions. The analytical result from the above parameters has been presented in the forms of several groups of dimensionless number. The equations obtained are: (k L *dp)/D L 18.902(Re) 0 ,378 (dp/D) 0 ,6972(Co * ) 0 ,2667 with a mean error of 7.26%; k S 2240.268(dp/D) 1 .553; and each of them is valid in range of: Re: 0.182 - 0.856; dp/D: 0.004 - 0.022; Co * : 9.5408x10 - 5 - 6.2827x10 - 4

CUB DI (Deionization) column control system

International Nuclear Information System (INIS)

Seino, K.C.

1999-01-01

For the old MR (Main Ring), deionization was done with two columns in CUB, using an ion exchange process. Typically 65 GPM of LCW flew through a column, and the resistivity was raised from 3 Mohm-cm to over 12 Mohm-cm. After a few weeks, columns lost their effectiveness and had to be regenerated in a process involving backwashing and adding hydrochloric acid and sodium hydroxide. For normal MR operations, LCW returned from the ring and passed through the two columns in parallel for deionization, although the system could have been operated satisfactorily with only one in use. A 3000 gallon reservoir (the Spheres) provided a reserve of LCW for allowing water leaks and expansions in the MR. During the MI (Main Injector) construction period, the third DI column was added to satisfy requirements for the MI. When the third column was added, the old regeneration controller was replaced with a new controller based on an Allen-Bradley PLC (i.e., SLC-5/04). The PLC is widely used and well documented, and therefore it may allow us to modify the regeneration programs in the future. In addition to the above regeneration controller, the old control panels (which were used to manipulate pumps and valves to supply LCW in Normal mode and to do Int. Recir. (Internal Recirculation) and Makeup) were replaced with a new control system based on Sixtrak Gateway and I/O modules. For simplicity, the new regeneration controller is called as the US Filter system, and the new control system is called as the Fermilab system in this writing

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 ...

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.

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

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 ...

Diffusion coefficients of D2 and HT in the medium of gaseous protium and in crystals of NaX zeolite

International Nuclear Information System (INIS)

Polevoj, A.S.

1993-01-01

Coefficients of HT diffusion (absent in literature) in gaseous protium medium and in crystals of the NaX zeolite compared with similar values of these coefficients for deuterium are determined on the basis of analysis of experimental data on effect NaX zeolite grain size and of H 2 -HT gaseous mixture consumption in the sorption column at separation of hydrogen atoms on the value of transfer unit. 15 refs., 1 fig., 1 tab

Early construction and operation of the highly contaminated water treatment system in Fukushima Daiichi Nuclear Power Station (2). Dynamic characteristics of KURION media for Cs removal in simulated contaminated water

International Nuclear Information System (INIS)

Hijikata, Takatoshi; Uozumi, Koichi; Tsukada, Takeshi; Koyama, Tadafumi; Ishikawa, Keiji; Ono, Shoichi; Suzuki, Shunichi; Denton, Mark; Raymont, John

2014-01-01

The kinetic characteristics of the column were necessary property to be understood before actual operation. Hence, a functional small-scale zeolite column system was installed for conducting the experiments to understand decontamination behaviors. Each column has a 2 cm inner diameter and a 12 cm height, and 12 g of zeolite-type media was packed into the column. The column experiments were carried out with Kurion-zeolite, herschelite, at different feed rates of simulated water with different concentrations of Cs and sea salt. As expected from equilibrium ion-exchange isotherms obtained for KURION-herschelite, the adsorption of Cs is hampered by the existence of sea salt ratio. The difference in breakthrough behaviors can be ascribed to the difference in sea salt ratio. Above 1000 bed volumes, the adsorption rate of Cs was the same at a solution velocity of between 14 and 81 cm/min. Under the condition of a 3.4 wt% sea salt ratio, the performance of the media supplied by KURION was in the order surfactant modified zeolite < silver-impregnated engineered herschelite = herschelite (H). This result was suggested to evaluate the performance of KURION media on the actual columns. (author)

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

Use to titanium-treated zeolite for plutonium, strontium, and cesium removal from West Valley alkaline wastes and sludge wash wastes

International Nuclear Information System (INIS)

Bray, L.A.; Hara, F.T.

1993-01-01

Zeolite (IONSIV IE-96) treated with a titanium (Ti) solution will extract traces of plutonium (Pu), strontium (Sr), and cesium (Cs) found in the West Valley Nuclear Services Co., Inc. (WVNS) alkaline supernatant and alkaline sludge water washes. Small ion exchange columns containing Ti-treated zeolite have been successfully tested at WVNS and Pacific Northwest Laboratory (PNL) for the removal of Pu. Full-scale ion exchange processing of sludge wash solution is now being developed at WVNS for use in FY 1992. Commercial manufacturing options for the production of the Ti-treated zeolite were investigated. The Ti-treated zeolite may have application at Hanford and at other U.S. Department of Energy (DOE) sites for the removal of low-level concentrations of Cs, Sr, and Pu from alkaline waste streams

Treatment of radioactive liquid waste (Co-60) by sorption on Zeolite Na-A prepared from Iraqi kaolin.

Science.gov (United States)

Mustafa, Yasmen A; Zaiter, Maysoon J

2011-11-30

Iraqi synthetic zeolite type Na-A has been suggested as ion exchange material to treat cobalt-60 in radioactive liquid waste which came from neutron activation for corrosion products. Batch experiments were conducted to find out the equilibrium isotherm for source sample. The equilibrium isotherm for radioactive cobalt in the source sample showed unfavorable type, while the equilibrium isotherm for the total cobalt (the radioactive and nonradioactive cobalt) in the source sample showed a favorable type. The ability of Na-A zeolite to remove cobalt from wastewater was checked for high cobalt concentration (822 mg/L) in addition to low cobalt concentration in the source sample (0.093 mg/L). A good fitting for the experimental data with Langmuir equilibrium model was observed. Langmuir constant qm which is related to monolayer adsorption capacity for low and high cobalt concentration was determined to be 0.021 and 140 mg/g(zeolite). The effects of important design variables on the zeolite column performance were studied these include initial concentration, flow rate, and bed depth. The experimental results have shown that high sorption capacity can be obtained at high influent concentration, low flow rate, and high bed depth. Higher column performance was obtained at higher bed depth. Thomas model was employed to predict the breakthrough carves for the above variables. A good fitting was observed with correlation coefficients between 0.915 and 0.985. Copyright © 2011 Elsevier B.V. All rights reserved.

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

Uptake of Cd(II Using Natural Zeolite: Batch and Continuous Fixed-Bed Studies

Directory of Open Access Journals (Sweden)

Luna M. LMarashdeh

2009-12-01

Full Text Available Uptake of Cd(II ions by natural phillipsite tuff was investigated both in shake-flask and fixed-bed columns. Equilibrium uptake, qe, was found to best fit Langmuir adsorption isotherm with a maximum value of 25.78 mg/g. Percent removal of Cd ions was close to 100% from initial metal ion concentrations in the range 50 - 75 mg/L at 5.0 g zeolite/L. Also, qe was found to vary exponentially with zeolite dose. Break points as high as 350 minutes were obtained from bed treatment at favorable conditions of a low solution flow rate and high bed depth. In batch experiments, equilibrium pH increased to < 8.0 excluding chemical precipitation as part of the removal while in fixed-beds the final pH exceeded 9.0. It is suggested that a sieve action of zeolite porous structure plays a role as an uptake mechanism in addition to the ion exchange.

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

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.

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.

Comparison of neptunium sorption results using batch and column techniques

International Nuclear Information System (INIS)

Triay, I.R.; Furlano, A.C.; Weaver, S.C.; Chipera, S.J.; Bish, D.L.

1996-08-01

We used crushed-rock columns to study the sorption retardation of neptunium by zeolitic, devitrified, and vitric tuffs typical of those at the site of the potential high-level nuclear waste repository at Yucca Mountain, Nevada. We used two sodium bicarbonate waters (groundwater from Well J-13 at the site and water prepared to simulate groundwater from Well UE-25p No. 1) under oxidizing conditions. It was found that values of the sorption distribution coefficient, Kd, obtained from these column experiments under flowing conditions, regardless of the water or the water velocity used, agreed well with those obtained earlier from batch sorption experiments under static conditions. The batch sorption distribution coefficient can be used to predict the arrival time for neptunium eluted through the columns. On the other hand, the elution curves showed dispersivity, which implies that neptunium sorption in these tuffs may be nonlinear, irreversible, or noninstantaneous. As a result, use of a batch sorption distribution coefficient to calculate neptunium transport through Yucca Mountain tuffs would yield conservative values for neptunium release from the site. We also noted that neptunium (present as the anionic neptunyl carbonate complex) never eluted prior to tritiated water, which implies that charge exclusion does not appear to exclude neptunium from the tuff pores. The column experiments corroborated the trends observed in batch sorption experiments: neptunium sorption onto devitrified and vitric tuffs is minimal and sorption onto zeolitic tuffs decreases as the amount of sodium and bicarbonate/carbonate in the water increases

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

DISPERSION AND SORPTION CHARACTERISTICS OF URANIUM IN THE ZEOLITE-QUARTZ MIXTURE AS BACKFILL MATERIAL IN THE RADIOACTIVE WASTE REPOSITORY

Directory of Open Access Journals (Sweden)

Herry Poernomo

2010-06-01

Full Text Available The experiment of sorption and dispersion characteristics of uranium in the zeolite-quartz mixture as candidate of raw material of backfill material in the radioactive waste repository has been performed. The objective is to know the effect of zeolite and quartz grain size on the zeolite-to-quartz weight ratio that gives porosity (ε, permeability (K, and dispersivity (α of uranium in the zeolite-quartz mixture as backfill material. The experiment was carried out by fixed bed method in the column filled by the zeolite-quartz mixture with zeolite-to-quartz weight percent ratio of 100/0, 80/20, 60/40, 40/60, 20/80, 0/100 wt. % in the water saturated condition flowed by uranyl nitrate solution of 500 ppm concentration (Co as uranium simulation which was leached from immobilized radioactive waste in the repository. The concentration of uranium in the effluents represented as Ct were analyzed by spectrophotometer Corning Colorimeter 253 every 15 minutes, then using Co and Ct uranium dispersivity (α in the backfill material was determined. The experiment data shown that 0.196 mm particle size of zeolite and 0.116 mm particle size of quartz on the zeolite-to-quartz weight ratio of 60/40 wt. % with ε = 0.678, K = 3.345x10-4 cm/second, and α = 0.759 cm can be proposed as candidate of raw material of backfill material in the radioactive waste repository.   Keywords: backfill material, quartz, radioactive waste, zeolite

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

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.)

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

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)

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.

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...

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...

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...

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.

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.

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

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

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.

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.

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

Full Text Available ABSTRAK Kromium (VI merupakan polutan logam berat berbahaya bagi kesehatan dan lingkungan oleh karena itu pengambilan ion Cr(VI dalam air penting dilakukan untuk mengatasi pencemaran lingkungan. Proses adsorpsi merupakan salah satu teknik sederhana yang dapat digunakan untuk pengambilan ion logam. Pada penelitian ini telah dilakukan kajian adsorpsi ion dikromat sebagai model limbah Cr(VI dalam air menggunakan adsorben zeolit alam termodifikasi amina. Penelitian diawali dengan preparasi adsorben zeolit alam termodifikasi amina. Preparasi dimulai dengan pencucian zeolit alam menggunakan akuades, kemudian refluks zeolit alam menggunakan HCl 3M. Zeolit hasil refluks selanjutnya dimodifikasi menggunakan garam ammonium kuarterner, N-cethyl-N,N,N-trimethylammonium bromide (CTAB dan amina primer, propilamin (PA. Zeolit alam (Z, zeolit teraktivasi asam (ZA dan zeolit hasil modifikasi amina selanjutnya digunakan sebagai adsorben untuk adsorpsi anion dikromat. Karakterisasi adsorben dilakukan dengan mengunakan metode spektroskopi infaramerah dan difraksi sinar-X, sedangkan jumlah anion dikromat yang teradsorpsi dianalisis dengan spektroskopi serapan atom. Hasil penelitian menunjukkan bahwa sampel zeolit mengandung mineral klinoptilolit, mordernit dan kuarsa. Struktur zeolit tidak mengalami kerusakan oleh perlakuan termal dan perlakuan kimia. Modifikasi zeolit meningkatkan efisiensi adsorpsi zeolit alam. Ion dikromat dapat teradsorpsi dengan lebih baik oleh zeolit termodifikasi amina daripada zeolit teraktivasi asam dan zeolit tanpa modifikasi, dengan kemampuan adsorpsi zeolit termodifikasi CTAB (CTAB-Z lebih besar daripada zeolit termodifikasi propilamin (PA-Z. Adsorpsi ion dikromat pada adsorben zeolit berlangsung baik dengan urutan CTAB-Z > PA-Z > ZA > Z, dengan kemampuan adsorpsi masing-masing sebesar 1,96; 1,74; 0,90 dan 0,48 mg/g. Adsorpsi anion dikromat oleh zeolit termodifikasi CTAB merupakan adsorpsi kimia (kemisorpsi dengan energi adsorpsi sebesar

MCM-41 impregnated with A zeolite precursor: Synthesis, characterization and tetracycline antibiotics removal from aqueous solution.

Science.gov (United States)

Liu, Minmin; Hou, Li-An; Yu, Shuili; Xi, Beidou; Zhao, Ying; Xia, Xunfeng

2013-05-01

In this paper, the MCM-41 has been modified by impregnation with zeolite A to prepare a kind of new adsorbent. The adsorption of TC from aqueous solutions onto modified MCM-41 has been studied. It was discovered that the adsorption capability of zeolite A modified MCM-41 (A-MCM-41) increased dramatically after modification. The modified MCM-41 was characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, Fourier Transform Infrared (FTIR) analysis, Transmission electron microscopy (TEM) images, and 29 Si and 27 Al Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectra. The modified MCM-41 structure was still retained after impregnated with zeolite A but the surface area and pore diameter decreased due to pore blockage. The adsorption of TC on modified MCM-41 was discussed regarding various parameters such as pH, initial TC concentration, and the reaction time. The pH effects on TC adsorption indicated that the adsorbents had better adsorption performances in acidic and neutral conditions. The adsorption isotherms were fitted well by the Langmuir model. The adsorption kinetics was well described by both pseudo-second order equation and the intra-particle diffusion model. The adsorption behavior in a fixed-bed column system followed Thomas model. The adsorption behavior of TC was the chemical adsorption with an ion exchange process and electrostatic adsorption.

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.

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)

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

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

Multi-column adsorption systems with condenser for tritiated water vapor removal

International Nuclear Information System (INIS)

Kotoh, Kenji; Kudo, Kazuhiko

1996-01-01

Two types of multi-column adsorption system are proposed as the system for removal of tritiated moisture from tritium process gases or/and handling room atmospheres. The types are of recycle use of adsorption columns, and are composed of twin or triplet columns and one condenser which is used for collecting the adsorbed moisture from columns in desorption process. The systems utilize the dry gas from a working column as the purge gas for regenerating a saturated column and appropriate an active column for recovery of the tritiated moisture passing through the condenser. Each column hence needs the additional amount of adsorbent for collecting the moisture from the condenser. In the modeling and design of an adsorption column, it is primary to estimate the necessary amount of a candidate adsorbent for its packed-bed. The performance of the proposed systems is examined here by analyzing the dependence of the necessary amount of adsorbent for their columns on process operational conditions and adsorbent moisture-adsorption characteristics. The result shows that the necessary amount is sensitive to the types of adsorption isotherm, and suggests that these systems should employ adsorbents which exhibit the Langmuir-type isotherms. (author)

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

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.

Ammonium ion interaction with conditioned natural zeolite with silver and its effect on the disinfection of polluted water in front of a consortium of gram (+) and gram (-) microorganisms

International Nuclear Information System (INIS)

Gonzaga G, V. E.

2013-01-01

Clinoptilolite zeolite material is a relative abundance in Mexico, which has ion exchange properties, therefore, has the ability to retain metal ions giving it an application in the process of disinfecting of water contaminated with pathogenic microorganisms. In this research, we conducted a study of disinfection of water contaminated with a microbial consortium, from a zeolite rock clinoptilolite from a deposit located in the State of Guerrero. Initially, the zeolite prepared by the grinding and sieving, for conditioning with NaCl and subsequently with AgNO 3 , finally to be characterized using the techniques of scanning electron microscopy and X-ray diffraction. Tests using columns packed with zeolite material, the effect of zeolite bactericidal conditioned with silver (ZGAg) against a microbial consortium consisting of Escherichia coli and Sthapyloccocus aureus in aqueous solution in the presence of ammonium ions used to increase the ion exchange with zeolite fitted with silver. To describe curves disinfecting a continuous flow system is adapted Gu pta model, which describes the kinetics and equilibrium adsorption process, considering the microorganisms as the adsorbate and the sanitizing agent (conditioned with silver zeolite) as the adsorbent. Characterization results show that in the scanning electron microscopy (Sem), no changes were obtained on the morphology of typical clinoptilolite crystals before and after that was modified with sodium and then with silver, it is worth mentioning however that fitted with silver zeolite (ZGAg), small particles are seen on the zeolite material which when analyzed by energy dispersive spectroscopy (EDS), we found a high concentration of Ag +. The disinfection period is increased as the concentration increased ammonium ions, this behavior is attributed to the ion exchange that occurs between the ammonium ions and silver ions. A lower percentage of inactivation is due, therefore, to a lesser amount of money available to be

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.

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

The selective separation of Cs and Sr ion on the inorganic ion-exchanger zeolites

Energy Technology Data Exchange (ETDEWEB)

Park, Hun Hwee; Min, Byeog Heon [Hoseo University, Taegu (Korea)

1998-04-01

This study shows the selective separation of Cs and Sr ion on the inorganic ion-exchanger zeolites such as clinoptilolite, Y-type CBV760, CBV780 and A-type 3A. The selective separation of Cs and Sr on these zeolites was examined using batch and continuous column experiments. For the selective separation of Cs and Sr from a synthetic wastewater, adsorption rate of Cs increased in the order, clinoptilolite> 3A>> CBV760> CBV780, adsorption rate of Sr increased in the other, 3A>> clinoptilolite> CBV760> CBV780. For the clinoptilolite, the adsorption rate of Cs reached about 96 {approx} 98% within 3h. The adsorption rate of Sr on 3A reached about 99% within 3h. (author). 40 refs., 27 figs., 4 tabs.

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+.

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.

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

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.

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

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

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.

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.

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

On-Site Decontamination System for Liquid Low Level Radioactive Waste - 13010

Energy Technology Data Exchange (ETDEWEB)

OSMANLIOGLU, Ahmet Erdal [Cekmece Nuclear Research and Training Center, Kucukcekmece Istanbul (Turkey)

2013-07-01

This study is based on an evaluation of purification methods for liquid low-level radioactive waste (LLLW) by using natural zeolite. Generally the volume of liquid low-level waste is relatively large and the specific activity is rather low when compared to other radioactive waste types. In this study, a pilot scale column was used with natural zeolite as an ion exchanger media. Decontamination and minimization of LLLW especially at the generation site decrease operational cost in waste management operations. Portable pilot scale column was constructed for decontamination of LLW on site. Effect of temperature on the radionuclide adsorption of the zeolite was determined to optimize the waste solution temperature for the plant scale operations. In addition, effect of pH on the radionuclide uptake of the zeolite column was determined to optimize the waste solution pH for the plant scale operations. The advantages of this method used for the processing of LLLW are discussed in this paper. (authors)

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)

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

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)

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

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

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.

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.

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...

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

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.

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.

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...

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.

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.

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.

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...

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.

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

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...

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

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.

Design concept of control system for cryogenic distillation columns of fusion reactor

International Nuclear Information System (INIS)

Yamanishi, Toshihiko; Okuno, Kenji

1993-09-01

Control systems were designed for cryogenic distillation columns in the main fuel cycle and the breeder blanket interface systems of fusion reactors. Three basic control modes were proposed for the column whose top product was more important; the column whose bottom product is more important; and the column having a feed back stream. The key component in the important product stream was selected for each column, and the analysis method for measurement of this key component was discussed. Some of the columns need the gas chromatography as the analysis instrument of the control system. The time required for the measurement of product purity by the gas chromatography considerably affects the stability of the control system. A significant conclusion is that permissible time is about 20 min. It is possible to complete the measurement within 20 minute by the gas chromatography. The gas chromatography is applicable for the control system of the column. (author)

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

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.

Removal of radioactive material by so-called manganese-zeolite. [Mn-54, Fe-59, Co-60, Cs-137, Ru-complexes

Energy Technology Data Exchange (ETDEWEB)

Matsumura, T; Ishiyama, T [Radiation Center of Osaka Prefecture, Sakai (Japan)

1975-03-01

Decontamination property of the so-called manganese-zeolite which was made from montmorillonite was studied by a column method. The following results were obtained: (1) /sup 54/Mn or /sup 59/Fe is removed completely. (2) /sup 60/Co or /sup 137/Cs is removed effectively. It is attributed to the adsorption on a broken-bond of quartz or feldsper. (3) Nitro nitrosylruthenium and (RuORu) nitrate are hardly removed, however, a little amount of nitrato nitrosylruthenium is removed. (4) Contact time of radioactive material with manganese-zeolite is the important factor for the removal of radioactive material. Each radioactive material was hardly removed at the contact time less than 20 min.

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.

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.

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.

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)

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

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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.

In vitro study of vitamins B1, B2 and B6 adsorption on zeolite

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Basić Zorica

2011-01-01

Full Text Available Background/Aim. Zeolites are the hydratised alumosilicates of alcali and earthalcali cations, which have a long three-dimensional crystal structure. Preparations on the basis of zeolites are used for adsorption of organic and nonorganic toxic substances and they, also, find more and more use in veterinary and human medicine and pharmacy. The aim of this study was to evaluate the possibilities of zeolite to adsorb vitamins B1, B2 and B6 in acid and neutral solutions, as well as the characteristics of the process (saturability, reversibility and competitivness. Methods. The specific and sensitive HPLC method with fluorescent detector was used for determination of vitamins B1, B2 and B6. Analyte separation and detection were carried out by applying the reverse-phase method on column C18. An in vitro experiment was done by testing the influence of pH value (2 and 7, concentration of vitamin solution (1, 2 and 5 mg/L, the lenght of contact with zeolite (10-180 min and cation competitiveness on the exchange capacity, which is achieved by media and zeolite contact, as well as a possible vitamins desorption through changing pH value of the solution at 37°C. Jon competitiveness was examined by adding commercial feed mixture (grower with a defined content of the examined vitamines in zeolite solutions the pH = 2 and pH = 7. Results. Vitamins B1, B2 and B6 were stable in both pH=2 and pH = 7 solutions at 37°C, in the defined time intervals. In acid solution concentrations of vitamins significantly declined in the first 10 min, with no significant decline in further 30 min for all the three concentrations testch. In neutral solution, after the addition of 1% zeolite, decrease in vitamins concentrations was slightly lower than in acid solution, but also significant in the first 10 min of the contact with zeolite. It was found that zeolite, which adsorbed vitamins in acid solution, transferred in the neutral one released a significant quantity of adsorbed

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

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.

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)

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

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

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.

Application of Nanosize Zeolite Molecular Sieves for Medical Oxygen Concentration

Directory of Open Access Journals (Sweden)

Mingfei Pan

2017-07-01

Full Text Available The development of a portable oxygen concentrator is of prime significance for patients with respiratory problems. This paper presents a portable concentrator prototype design using the pressure/vacuum swing adsorption (PVSA cycle with a deep evacuation step (−0.82 barg instead of desorption with purge flow to simplify the oxygen production process. The output of the oxygen concentrator is a ~90 vol % enriched oxygen stream in a continuous adsorption and desorption cycle (cycle time ~90 s. The size of the adsorption column is 3 cm in diameter and 20 cm in length. A Li+ exchanged 13X nanosize zeolite is used as the adsorbent to selectively adsorb nitrogen from air. A dynamic model of the pressure and vacuum swing adsorption units was developed to study the pressurization and depressurization process inside the microporous area of nanosized zeolites. The describing equations were solved using COMSOL Multiphysics Chemical Engineering module. The output flow rate and oxygen concentration results from the simulation model were compared with the experimental data. Velocity and concentration profiles were obtained to study the adsorption process and optimize the operational parameters.

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.

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.

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

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.

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

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)

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

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.

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....

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.

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

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

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.

Removal of the blue 1 dye of aqueous solutions using ferric zeolite

International Nuclear Information System (INIS)

Pinedo H, S. Y.

2010-01-01

Water is essential to all life forms, including humans. In recent years water use has increased substantially, also has been altered in its capacity as a result of various human activities, such as domestic, industrial and agricultural, also by natural activity. Undoubtedly one of the main pollutants today are the waste generated by the food industry, due to the use of dyes for the production of their products. So it is necessary to restore water quality through treatment systems to remove contaminants, and thus prevent disease and imbalance of ecosystems. Due to the above, it is important to conduct research directed towards finding new ways to remove dyes such as blue 1 used in the food industry, using low cost materials and abundant in nature as zeolites. To accomplish the above, the present study has the purpose to evaluate the adsorption capacity of the blue dye 1 in aqueous solutions. To accomplish that objective, the zeolite material was reconditioned to improve its sorption properties of the material and provide the ability to adsorb pollutants such as this dye. The zeolite material was characterized by scanning electron microscopy and elemental analysis, X-ray diffraction and infrared spectroscopy. To evaluate the ability of blue 1 dye sorption the kinetics and sorption isotherms were determined; the experimental results were adjusted to mathematical models such as pseudo-first order, pseudo second order and Elovich to describe the kinetic process, and the Langmuir, Freundlich and Langmuir-Freundlich to describe sorption isotherms. The results showed that ferric zeolite surface is a heterogeneous material and has a considerable adsorption capacity, which makes it a potential adsorbent for removing color from aqueous streams. Also the sorption of the dye was evaluated at different ph values; the most sorption was carried out at ph values 1, 3 and 11. We also evaluated the change in mass where the sorption capacities for the blue 1 increase by increasing

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.

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

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

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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.

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.

Applicability of zeolites in potassium and nitrate retention in different soil types

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Pavlović Jelena B.

2017-01-01

Full Text Available Environmental protection and sustainable agricultural production require the use of inexpensive and environmentally acceptable soil supplements. Objectives of this study were to investigate the influence of the addition of the natural zeolite – clinoptilolite (NZ and its iron(III-modified form (FeZ on the potassium and nitrate leaching from sandy, silty loam and silty clay soils. The zeolites were added in two amounts: 0.5 (FeZ and 1.0 wt. % (NZ and FeZ. The experiments were carried out in columns organized in eight experimental systems containing unamended (control specimens and amended soils. The concentration of K+ and NO3–N in the leachates was monitored during 7 days. The obtained results indicate that the K+ and NO3–N leaching mainly depends on the soil type and pH of the soil. The NZ and FeZ addition has the highest impact on the K+ retention in the acidic sandy soil. The highest NO3–N retention is obtained with FeZ in acidic silty loam soil. The K+ leaching kinetics for all the studied soils follow the Avrami kinetics model with the parameter n < 1. This study demonstrates that NZ and FeZ can be a good soil supplement for the K+ retention for all studied soils and in the NO3–N retention for silty loam and silty clay soils. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172018

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.

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

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.

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

Type of adsorbent and column height in adsorption process of used cooking oil

Science.gov (United States)

Hasnelly, Hervelly, Taufik, Yusman; Melany, Ivo Nila

2015-12-01

The purpose of this research was to find out the best adsorbent and column height that can adsorb color and soluble impurities substances in used cooking oil. This research was meant for knowledge development of refined cooking oil technology. The used of this research was giving out information on the recycling process of used cooking oil. Research design used 2 × 2 factorial pattern in randomized group design with 6 repetitions. The first factor is adsorbent type (J) that consist of activated carbon (J1) and Zeolit (J2). The second factor is column height (K) with variations of 15 cm (k1) and 20 cm (k2). Chemical analysis parameter are free fatty acid, water content and saponification value. Physical parameter measurement was done on color with Hunter Lab system analysis and viscosity using viscometer method. Chemical analysis result of preliminary research on used cooking oil showed water content of 1,9%, free fatty acid 1,58%, saponification value 130,79 mg KOH/g oil, viscosity 0,6 d Pas and color with L value of -27,60, a value 1,04 and b value 1,54. Result on main research showed that adsorbent type only gave effect on water content whereas column height and its interaction was not gave significant effect on water content. Interaction between adsorbent type (J) and column height (K) gave significant effect to free fatty acid, saponification value, viscosity and color for L, a and b value of recycled cooking oil.

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

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.

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.)

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.

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.

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.

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,

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.

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.

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.

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.

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.

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)

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)

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.

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

Using copper hexacyanoferrate (II) impregnated zeolite for cesium removal from radioactive liquid waste

International Nuclear Information System (INIS)

Fumio, K.; Kenji, M.

1982-01-01

Experiments were performed to obtain fundamental data on cesium ion removal characteristics of metal hexacyanoferrate (II) impregnated zeolite in radioactive liquid waste containing a large amount of sodium sulfate. Copper hexacyanoferrate (II) impregnated zeolite (CuFZ) was prepared and showed a high selectivity for cesium ion. The material was suitable for use in an ion exchange column. This exchanger could selectively and efficiently remove the cesium even if there is 15 wt% Na 2 SO 4 in the solution. Cesium removal ability and stability of CuFZ were excellent over a wide pH range between 1.5 and 10. The cesium ion exchange ability was not influenced by the presence of the alkali metal ions, calcium and magnesium, and carbonate ions even at concentrations 25 times greater than the cesium ion. However, since ammonium ion behaves similarly to cesium ion and interrupts latter ion adsorption, the presence of ammonium ion is not desirable. The CuFZ offers the possibility of separating and removing cesium from liquid wastes produced in facilities handling radioactive materials

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....

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

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...

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.

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.)

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.

MINIMUM BRACING STIFFNESS FOR MULTI-COLUMN SYSTEMS: THEORY

OpenAIRE

ARISTIZÁBAL-OCHOA, J. DARÍO

2011-01-01

A method that determines the minimum bracing stiffness required by a multi-column elastic system to achieve non-sway buckling conditions is proposed. Equations that evaluate the required minimum stiffness of the lateral and torsional bracings and the corresponding “braced" critical buckling load for each column of the story level are derived using the modified stability functions. The following effects are included: 1) the types of end connections (rigid, semirigid, and simple); 2) the bluepr...

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)

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.

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.

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.

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

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

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

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

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)

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.

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.

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.

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

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

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.

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.

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....

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.

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.

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.

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

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

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.

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.

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)

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

Process wastewater treatment with hydrogen-form CST and chabazite zeolite

International Nuclear Information System (INIS)

DePaoli, S.M.; Bostick, D.T.

1998-05-01

Ion-exchange materials have been investigated for the removal of radionuclides from near-neutral-pH wastewaters containing competing cations at concentrations greater than those of the targeted species. Natural chabazite zeolite was chosen as the baseline material for the removal of fission products, namely 90 Sr and 137 Cs, from wastewater and groundwater. The sorbent IONSIV reg-sign IE-911, a crystalline silicotitanate manufactured by UOP, was recently tested in this capacity and found to compare extremely well against the baseline material in removing 90 Sr and 137 Cs from process wastewater. This paper presents results of similar column tests performed using both materials, as well as results from batch experiments on actual wastewaters using IONSIV reg-sign IE-911

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

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

Seismic Response of a Platform-Frame System with Steel Columns

Directory of Open Access Journals (Sweden)

Davide Trutalli

2017-04-01

Full Text Available Timber platform-frame shear walls are characterized by high ductility and diffuse energy dissipation but limited in-plane shear resistance. A novel lightweight constructive system composed of steel columns braced with oriented strand board (OSB panels was conceived and tested. Preliminary laboratory tests were performed to study the OSB-to-column connections with self-drilling screws. Then, the seismic response of a shear wall was determined performing a quasi-static cyclic-loading test of a full-scale specimen. Results presented in this work in terms of force-displacement capacity show that this system confers to shear walls high in-plane strength and stiffness with good ductility and dissipative capacity. Therefore, the incorporation of steel columns within OSB bracing panels results in a strong and stiff platform-frame system with high potential for low- and medium-rise buildings in seismic-prone areas.

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.

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.

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

Removal of blue indigo and cadmium present in aqueous solutions using a modified zeolitic material and an activated carbonaceous material

International Nuclear Information System (INIS)

Gutierrez S, E. E.

2011-01-01

, and Z Na material showed a sorption capacity for cadmium higher than the carbonaceous material. Then the sorption process of dye from aqueous solutions using Z Fe material at different equilibrium ph was investigated, the process was analyzed using a generalized sorption model, the results indicate that the removal of denim blue is favored when the molecule is not dissociated in an acid medium and that the sorption capacity rapidly decreased at ph values higher than 8. Desorption studies were performed, it was observed that the denim blue dye could be removed from the adsorbents using H 2 O 2 , and in the second sorption cycle, the results also indicate a degradation of the dye by Z Fe material. For the case of cadmium, desorption study was carried out using NaCl, showing better results for the Z Na material than for the carbonaceous material. Sorption tests were performed in column experiments, breakthrough curves were obtained and analyzed, the effects of column sizes was determined, the results were analyzed using the Thomas model to determine the maximum sorption capacity. The experimental results showed that the carbonaceous material has the highest sorption capacity for denim blue and Z Na material for cadmium. Breakthrough curves at different height showed that Bo hart-Adams model and EBCT method could be used to represent the initial part of the curves and to predict the service time for the columns under different operating conditions. Comparing the results of both adsorbents in batch studies and column systems, the sorption capacities determined in column systems are lower than those obtained in batch systems because the sorption equilibrium is not reached in the first case. From this study it can be suggested that it is possible to expand the application field of alternative materials such as zeolites and carbonaceous material for the removal of dyes and heavy metals from wastewater. (Author)

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.

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

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)

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 zeolite.  Zeolite 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...

Multi-elemental characterization of Cuban natural zeolites

International Nuclear Information System (INIS)

Rizo, O.D.; Peraza, E.F.H.

1997-01-01

Concentration of 38 elements in samples from four important Cuban zeolite beds have been obtained by Instrumental Neutron Activation (INAA) and X-ray Fluorescence analyses (XRFA). In comparison with other analytical techniques good agreement was reached. The concentration values of minor element Ba, Sr, Zn and Mn and 25 trace element (including 9 REE) are at the first time reported in Cuban zeolite. It is important for the zeolite evaluation in different industrial uses. (author)

Multi-elemental characterization of Cuban natural zeolites

International Nuclear Information System (INIS)

Diaz Rizo, O.; Herrera Peraza, E.F.

1996-01-01

Concentrations of 38 elements in samples from four important Cuban zeolite bed have beam obtained by Instrumental Neutron Activation (INAA) and X-Ray Fluorescence Analysis (XRFA). In comparison with other analytical techniques good agreement was achieved. The concentration values of minor element Ba, Sr, Zn, and Mn, and 25 trace element (including 9 REE) are at the first time reported in Cuban zeolite. It is important for the zeolite evaluation in different industrial uses

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.

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.

Multi-column step-gradient chromatography system for automated ion exchange separations

International Nuclear Information System (INIS)

Rucker, T.L.

1985-01-01

A multi-column step-gradient chromatography system has been designed to perform automated sequential separations of radionuclides by ion exchange chromatography. The system consists of a digital programmer with automatic stream selection valve, two peristaltic pumps, ten columns, and a fraction collector. The automation allows complicated separations of radionuclides to be made with minimal analyst attention and allows for increased productivity and reduced cost of analyses. Results are reported for test separations on mixtures of radionuclides by the system

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.

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

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

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.

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)

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

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.

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.

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)

Semi-automated 86Y purification using a three-column system

International Nuclear Information System (INIS)

Park, Luke S.; Szajek, Lawrence P.; Wong, Karen J.; Plascjak, Paul S.; Garmestani, Kayhan; Googins, Shawn; Eckelman, William C.; Carrasquillo, Jorge A.; Paik, Chang H.

2004-01-01

The separation of 86 Y from 86 Sr was optimized by a semi-automated purification system involving the passage of the target sample through three sequential columns. The target material was dissolved in 4 N HNO 3 and loaded onto a Sr-selective (Sr-Spec) column to retain the 86 Sr. The yttrium was eluted with 4 N HNO 3 onto the second Y-selective (RE-Spec) column with quantitative retention. The RE-Spec column was eluted with a stepwise decreasing concentration of HNO 3 to wash out potential metallic impurities to a waste container. The eluate was then pumped onto an Aminex A5 column with 0.1 N HCl and finally with 3 N HCl to collect the radioyttrium in 0.6-0.8 mL with a >80% recovery. This method enabled us to decontaminate Sr by 250,000 times and label 30 μ g of DOTA-Biotin with a >95% yield

Ion exchange properties of zeolite-containing catalysts

Energy Technology Data Exchange (ETDEWEB)

Koval' chuk, L V; Takhtarova, G N; Topchieva, K V [Moskovskii Gosudarstvennyi Univ. (USSR). Kafedra Fizicheskoi Khimii

1975-03-01

In the paper the reaction of sodium ion exchange for ammonium cations, cations of calcium and lanthanum in the amorphous aluminium silicate Na/sub 0,856/(AlO/sub 2/)(SiO/sub 2/)/sub 9,831/, zeolite Na/sub 1/(AlO/sub 2/)(SiO/sub 2/)/sub 2,33/ and zeolite containing catalyst Na/sub 1,09/(AlO/sub 2/)(SiOsub(2))/sub 7,93/ were studied; exchange isotherms of sodium for ammonium, calcium and lanthanium are presented. Results received in the study indicate high selectivity of zeolite for calcium and lanthanum cations in comparison with amorphous aluminium silicate and also display electroselectivity effect. The highest separation coefficient takes place for lanthanum in the sodium exchange in zeolite.

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

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.

Compensated Row-Column Ultrasound Imaging System Using Multilayered Edge Guided Stochastically Fully Connected Random Fields.

Science.gov (United States)

Ben Daya, Ibrahim; Chen, Albert I H; Shafiee, Mohammad Javad; Wong, Alexander; Yeow, John T W

2017-09-06

The row-column method received a lot of attention for 3-D ultrasound imaging. By reducing the number of connections required to address the 2-D array and therefore reducing the amount of data to handle, this addressing method allows for real time 3-D imaging. Row-column still has its limitations: the issues of sparsity, speckle noise inherent to ultrasound, the spatially varying point spread function, and the ghosting artifacts inherent to the row-column method must all be taken into account when building a reconstruction framework. In this research, we build on a previously published system and propose an edge-guided, compensated row-column ultrasound imaging system that incorporates multilayered edge-guided stochastically fully connected conditional random fields to address the limitations of the row-column method. Tests carried out on simulated and real row-column ultrasound images show the effectiveness of our proposed system over other published systems. Visual assessment show our proposed system's potential at preserving edges and reducing speckle. Quantitative analysis shows that our proposed system outperforms previously published systems when evaluated with metrics such as Peak Signal-to-Noise Ratio, Coefficient of Correlation, and Effective Number of Looks. These results show the potential of our proposed system as an effective tool for enhancing 3-D row-column imaging.

Advances in nanosized zeolites

Science.gov (United States)

Mintova, Svetlana; Gilson, Jean-Pierre; Valtchev, Valentin

2013-07-01

This review highlights recent developments in the synthesis of nanosized zeolites. The strategies available for their preparation (organic-template assisted, organic-template free, and alternative procedures) are discussed. Major breakthroughs achieved by the so-called zeolite crystal engineering and encompass items such as mastering and using the physicochemical properties of the precursor synthesis gel/suspension, optimizing the use of silicon and aluminium precursor sources, the rational use of organic templates and structure-directing inorganic cations, and careful adjustment of synthesis conditions (temperature, pressure, time, heating processes from conventional to microwave and sonication) are addressed. An on-going broad and deep fundamental understanding of the crystallization process, explaining the influence of all variables of this complex set of reactions, underpins an even more rational design of nanosized zeolites with exceptional properties. Finally, the advantages and limitations of these methods are addressed with particular attention to their industrial prospects and utilization in existing and advanced applications.

Thermal Analysis for Ion-Exchange Column System

Energy Technology Data Exchange (ETDEWEB)

Lee, Si Y.; King, William D.

2012-12-20

Models have been developed to simulate the thermal characteristics of crystalline silicotitanate ion exchange media fully loaded with radioactive cesium either in a column configuration or distributed within a waste storage tank. This work was conducted to support the design and operation of a waste treatment process focused on treating dissolved, high-sodium salt waste solutions for the removal of specific radionuclides. The ion exchange column will be installed inside a high level waste storage tank at the Savannah River Site. After cesium loading, the ion exchange media may be transferred to the waste tank floor for interim storage. Models were used to predict temperature profiles in these areas of the system where the cesium-loaded media is expected to lead to localized regions of elevated temperature due to radiolytic decay. Normal operating conditions and accident scenarios (including loss of solution flow, inadvertent drainage, and loss of active cooling) were evaluated for the ion exchange column using bounding conditions to establish the design safety basis. The modeling results demonstrate that the baseline design using one central and four outer cooling tubes provides a highly efficient cooling mechanism for reducing the maximum column temperature. In-tank modeling results revealed that an idealized hemispherical mound shape leads to the highest tank floor temperatures. In contrast, even large volumes of CST distributed in a flat layer with a cylindrical shape do not result in significant floor heating.

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.

Pengaruh Kandungan Ca Pada Cao-zeolit Terhadap Kemampuan Adsorpsi Nitrogen

OpenAIRE

M Nasikin; Tania Surya Utami; Agustina TP Siahaan

2002-01-01

In industry, Ca zeolite is used as nitrogen selective adsorbent with the use of PSA (Pressure Swing Adsorption)/VSA (Vacuum Swing Adsorption) methods. Natural zeolite modified to be Cao-zeolite by ion exchange process using Ca(OH)2. Adsorption test was done on CaO-zeolite with different Ca concentration to understand how it's adsorption phenomena on oxygen and nitrogen. Adsorption test has been done for CaO-zeolite with Ca concentration = 0,682%, 0,849% and 1,244% to oxygen and nitrogen with ...

Analysis of trace levels of impurities and hydrogen isotopes in helium purge gas using gas chromatography for tritium extraction system of an Indian lead lithium ceramic breeder test blanket module.

Science.gov (United States)

Devi, V Gayathri; Sircar, Amit; Yadav, Deepak; Parmar, Jayraj

2018-01-12

In the fusion fuel cycle, the accurate analysis and understanding of the chemical composition of any gas mixture is of great importance for the efficient design of a tritium extraction and purification system or any tritium handling system. Methods like laser Raman spectroscopy and gas chromatography with thermal conductivity detector have been considered for hydrogen isotopes analyses in fuel cycles. Gas chromatography with a cryogenic separation column has been used for the analysis of hydrogen isotopes gas mixtures in general due to its high reliability and ease of operation. Hydrogen isotopes gas mixture analysis with cryogenic columns has been reported earlier using different column materials for percentage level composition. In the present work, trace levels of hydrogen isotopes (∼100 ppm of H 2 and D 2 ) have been analyzed with a Zeolite 5A and a modified γ-Al 2 O 3 column. Impurities in He gas (∼10 ppm of H 2 , O 2 , and N 2 ) have been analyzed using a Zeolite 13-X column. Gas chromatography with discharge ionization detection has been utilized for this purpose. The results of these experiments suggest that the columns developed were able to separate ppm levels of the desired components with a small response time (<6 min) and good resolution in both cases. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of Zeolite Nanomolecular Sieves of Different Si/Al Ratios

Directory of Open Access Journals (Sweden)

Pankaj Sharma

2015-01-01

Full Text Available Nanosized zeolite molecular sieves of different Si/Al ratios have been prepared using microwave hydrothermal reactor (MHR for their greater application in separation and catalytic science. The as-synthesized molecular sieves belong to four different type zeolite families: MFI (infinite and high silica, FAU (moderate silica, LTA (low silica and high alumina, and AFI (alumina rich and silica-free. The phase purity of molecular sieves has been assessed by X-ray diffraction (XRD analysis and morphological evaluation done by electron microscopy. Broad XRD peaks reveal that each zeolite molecular sieve sample is composed of nanocrystallites. Scanning electron microscopic images feature the notion that the incorporation of aluminum to MFI zeolite synthesis results in morphological change. The crystals of pure silica MFI zeolite (silicalite-1 have hexagon lump/disk-like shape, whereas MFI zeolite particles with Si/Al molar ratios 250 and 100 have distorted hexagonal lump/disk and pseudo spherical shapes, respectively. Furthermore, phase pure zeolite nanocrystals of octahedron (FAU, cubic (LTA, and rod (AFI shape have been synthesized. The average sizes of MFI, FAU, LTA, and AFI zeolite crystals are 250, 150, 50, and 3000 nm, respectively. Although the length of AFI zeolite rods is in micron scale, the thickness and width are of a few nanometers.

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...

Characterization of UO22+ exchanged Y zeolite

International Nuclear Information System (INIS)

Olguin, M.T.; Bosch, P.; Bulbulian, S.; Duque, J.; Pomes, R.; Villafuerte-Castrejon, M.E.; Sansores, L.E.; Bosch, P.

1997-01-01

The present study discusses the incorporation of uranyl ion into Y-zeolite framework. The UO 2 2+ sorption was measured by neutron activation analyses. The Y-zeolite framework distorts in response to the cations present in the structure. Hence, depending on the amount and the location of the exchanged cations, the features of the X-ray diffraction pattern may vary. From the Rietveld analysis of these patterns, the positions occupied by the UO 2 2 + cations in the zeolite network were determined. (author)

Influencing the selectivity of zeolite Y for triglycine adsorption

NARCIS (Netherlands)

Wijntje, R.; Bosch, H.; Haan, A.B. de; Bussmann, P.J.T.

2007-01-01

In prior work we studied the adsorption of triglycine on zeolite Y under reference conditions. This study aims to solve the question of which adsorbent properties and process conditions influence the adsorption triglycine from an aqueous solution by zeolite Y. Relevant zeolite parameters to study

Crystallization and melting behavior of isotactic polypropylene composites filled by zeolite supported β-nucleator

International Nuclear Information System (INIS)

Jiang, Juan; Li, Gu; Tan, Nanshu; Ding, Qian; Mai, Kancheng

2012-01-01

Highlights: ► The supported calcium pimelate β-zeolite was prepared. ► The β-nucleation of zeolite was enhanced dramatically through reaction. ► High β-phase content iPP composites were obtained by introducing the β-zeolite into iPP. - Abstract: In order to prepare the zeolite filled β-iPP composites, the calcium pimelate as β-nucleator supported on the surface of zeolite (β-zeolite) was prepared by the interaction between calcified zeolite and pimelic acid. The β-nucleation, crystallization behavior and melting characteristic of zeolite, calcified zeolite and β-zeolite filled iPP composites were investigated by differential scanning calorimetry and wide-angle X-ray diffractometer. The results indicated that addition of the zeolite and calcified zeolite as well as β-zeolite increased the crystallization temperature of iPP. The zeolite and calcified zeolite filled iPP composites mainly crystallized in the α-crystal form and the strong β-heterogeneous nucleation of β-zeolite results in the formation of only β-crystal in β-zeolite filled iPP composites. The zeolite filled β-iPP composites with high β-crystal contents (above 0.90) can be easily obtained by adding β-zeolite into iPP matrix.

PREPARASI DAN KARAKTERISASI ZEOLIT DARI ABU LAYANG BATUBARA SECARA ALKALI HIDROTERMAL

Directory of Open Access Journals (Sweden)

Jumaeri Jumaeri

2012-01-01

Full Text Available Preparasi zeolit dari abu layang batubara PLTU Suralaya secara alkali hidrotermal telah dilakukan. Preparasi dilakukan terhadap abu layang yang telah direfluks dengan HCl 1M dan tanpa refluks. Larutan NaOH dengan konsentrasi tertentu ( 1 ; 2 dan 3 M dicampur dengan abu layang batu bara dengan rasio 10 ml larutan tiap 1 gram abu layang, ke dalam tabung Teflon 100 ml dalam suatu autoclave stainless-steel. Autoclave kemudian dipanaskan pada temperature 80-16 oC selama tiga hari. Zeolit sintesis yang dihasilkan selanjutnya diuji secara kualitatif dengan menggunakan Spektroskopi Inframerah, dan Difraksi Sinar-X. Hasil penelitian menunjukkan bahwa aktivasi abu layang dengan proses alkali hidrotermal dapat menghasilkan material yang mempunyai struktur mirip zeolit (zeolit-like. Produk hidrotermal terdiri dari campuran zeolit (Zeolit P, Zeolit Y serta kristal sodalit dan mullit. Pada temperatur 160 oC, diperoleh zeolit dengan kristalinitas lebih tinggi dari pada 100 oC, baik melalui refluks atau tanpa refluks. Karakteristik zeolit yang terbentuk sangat ditentukan oleh kondisi proses, yang meliputi konsentrasi NaOH, waktu, dan temperatur.

Basic deposits of zeolites of the Republic of Tajikistan

International Nuclear Information System (INIS)

Normatov, I.Sh.; Mirsaidov, U.M.

2003-01-01

Natural zeolites increasingly using in the different fields of human economical activity. As a result of investigations of last years was determined that zeolites are the wide-spread rock forming minerals. In the Republic of Tajikistan zeolites was found out an the north of the Republic

The performance of pelletized Ce-Y and Ni-Y zeolites for removal of thiophene from model gasoline solutions

Energy Technology Data Exchange (ETDEWEB)

Montazerolghaem, Maryam; Seyedeyn-Azad, Fakhry; Rahimi, Amir [University of Isfahan, Isfahan (Iran, Islamic Republic of)

2015-02-15

H-Y zeolite was prepared with Na-Y zeolite via ion-exchange method. Ni-Y and Ce-Y zeolites were then prepared with H-Y zeolite via solid-state ion-exchange (SSIE) method. The pellet form of the zeolites was employed for removal of thiophene from samples containing 194, 116 and 72 ppmw sulfur in a batch system at ambient condition. The removal of sulfur over the three types of the adsorbents decreased according to the following order: Ce-Y (81..7%)>Ni-Y (75.2%)>Na-Y (51.7%), indicating that the Ce-Y zeolite was the most effective adsorbent for removing of sulfur compounds from gasoline. Adsorption isotherms of thiophene on Ni-Y and Ce-Y zeolites were obtained and correlated with six well-known isotherms. The equilibrium data of thiophene adsorption were well fitted to the isotherms and the corresponding parameters and fitting error criteria of the isotherm equations were obtained.

The performance of pelletized Ce-Y and Ni-Y zeolites for removal of thiophene from model gasoline solutions

International Nuclear Information System (INIS)

Montazerolghaem, Maryam; Seyedeyn-Azad, Fakhry; Rahimi, Amir

2015-01-01

H-Y zeolite was prepared with Na-Y zeolite via ion-exchange method. Ni-Y and Ce-Y zeolites were then prepared with H-Y zeolite via solid-state ion-exchange (SSIE) method. The pellet form of the zeolites was employed for removal of thiophene from samples containing 194, 116 and 72 ppmw sulfur in a batch system at ambient condition. The removal of sulfur over the three types of the adsorbents decreased according to the following order: Ce-Y (81..7%)>Ni-Y (75.2%)>Na-Y (51.7%), indicating that the Ce-Y zeolite was the most effective adsorbent for removing of sulfur compounds from gasoline. Adsorption isotherms of thiophene on Ni-Y and Ce-Y zeolites were obtained and correlated with six well-known isotherms. The equilibrium data of thiophene adsorption were well fitted to the isotherms and the corresponding parameters and fitting error criteria of the isotherm equations were obtained

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)

Safety operation of chromatography column system with discharging hydrogen radiolytically generated

International Nuclear Information System (INIS)

Watanabe, S; Sano, Y.; Nomura, K.; Koma, Y.; Okamoto, Y.

2015-01-01

The extraction chromatography technology is one of the promising methods for the partitioning of minor actinides (Am and Cm) from spent nuclear fuels. In the extraction chromatography system, the accumulation of hydrogen gas in the chromatography column is suspected to lead to fire or explosion. In order to prevent hazardous accidents, it is necessary to evaluate behaviors of gas radiolytically generated inside the column. In this study, behaviors of gas inside the extraction chromatography column were investigated through experiments and Computation Fluid Dynamics (CFD) simulation. N_2 gas once accumulated as bubbles in the packed bed was hardly discharged by the flow of mobile phase. However, the CFD simulation and X-ray imaging on γ-ray irradiated column revealed that during operation the hydrogen gas generated in the column was dissolved into the mobile phase without accumulation and then discharged. (authors)

Chemical changes associated with zeolitization of the tuffaceous beds of Calico Hills at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Broxton, D.E.

1992-01-01

The chemistry of the tuffaceous beds of Calico Hills was examined in samples collected over a 100 2 km area south of the Timber Mountain-Oasis Valley caldera complex to determine regional geochemical patterns during zeolitization. Samples of 58 vitric and zeolitic tuffs were analyzed for 48 elements by a combination of x-ray fluorescence, atomic absorption spectrophotometry, and neutron activation analysis. Major and trace element concentrations for zeolitic tuffs vary significantly from those for vitric tuffs. Complex, geographically-controlled patterns of elemental enrichment and depletion in the zeolitic tuffs are found for Na, K, Ca, Mg, U, Rb, Sr, Ba and Cs. Vitric and zeolitic tuffs generally have the same SiO 2 contents on an anhydrous basis, but minor net silica gain or loss has occurred in some samples. Zeolitic tuffs from the northern part of the study area, adjacent to the caldera complex, are notably K-rich and Na- and U-poor compared to zeolitic tuffs to the south. The compositions of the K-rich zeolitic tuffs are similar to those found in other areas of the western US where volcanic rocks are affected by potassium metasomatism. Alteration of vitric tuffs took place in an open chemical system and geographic control of major element compositions probably reflects regional variations in groundwater chemistry during alteration. The K-rich zeolitic tuffs in the northern part of the study area were probably altered by hydrothermal fluids whereas tuffs further south were altered by lower-temperature groundwaters

Experimental investigation on the optimal performance of Zeolite-water adsorption chiller

KAUST Repository

Myat, Aung

2013-02-01

This paper presents the performance testing of Zeolite adsorption cooling system driven by low grade waste heat source extracted from prime mover\\'s exhaust, power plant\\'s exhaust and the solar energy. The adsorbent FAM Z01 is used as an adsorbent in the adsorption chiller facility. Owing to its large equilibrium pore volume, it has the high affinity for the water vapor adsorbate. The key advantages of the Zeolite adsorption cooling system are: (i) it has no moving parts rendering less maintenance, (ii) the energy efficient means of cooling by the adsorption process with a low temperature heat source, (iii) the use of vapor pipes are replaced by self actuating vapor valves rendering smaller footprint area and (iv) it is environmental friendly with low carbon footprint. The experimental investigations were carried out for Zeolite adsorption chiller at different key operating conditions namely (i) heat source temperature, (ii) the cycle time and (iii) the heat recovery time. It is investigated that performance of coefficient (COP) of this system could be as high as 0.48 while the waste heat source temperature is applicable as low as 55 °C. © 2012.

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

Influence of ultrasonic radiation on the amorphous zeolite - Portland cement system

NARCIS (Netherlands)

Jakevicius, L.; Vaiciukyniene, D.; Demcenko, A.

2012-01-01

This paper considers the investigation of influence of an amorphous synthetic zeolite with inserted $Ca^{2+}$ ions additive (ASZ) on the hydration temperature of Portland cement paste. In this investigation the sonicated Portland cement paste is compared to the non-sonicated paste; and then the

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

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

Surfactant modified zeolite as amphiphilic and dual-electronic adsorbent for removal of cationic and oxyanionic metal ions and organic compounds.

Science.gov (United States)

Tran, Hai Nguyen; Viet, Pham Van; Chao, Huan-Ping

2018-01-01

A hydrophilic Y zeolite was primarily treated with sodium hydroxide to enhance its cation exchange capacity (Na-zeolite). The organo-zeolite (Na-H-zeolite) was prepared by a modification process of the external surface of Na-zeolite with a cationic surfactant (hexadecyltrimethylammonium; HDTMA). Three adsorbents (i.e., pristine zeolite, Na-zeolite, and Na-H-zeolite) were characterized with nitrogen adsorption/desorption isotherms, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, cation exchange capacities, and zeta potential. Results demonstrated that HDTMA can be adsorbed on the surface of Na-zeolite to form patchy bilayers. The adsorption capacity of several hazardous pollutants (i.e., Pb 2+ , Cu 2+ , Ni 2+ , Cr 2 O 7 2- , propylbenzene, ethylbenzene, toluene, benzene, and phenol) onto Na-H-zeolite was investigated in a single system and multiple-components. Adsorption isotherm was measured to further understand the effects of the modification process on the adsorption behaviors of Na-H-zeolite. Adsorption performances indicated that Na-H-zeolite can simultaneously adsorb the metal cations (on the surface not covered by HDTMA), oxyanions (on the surface covered by HDTMA). Na-H-zeolite also exhibited both hydrophilic and hydrophobic surfaces to uptake organic compounds with various water solubilities (from 55 to 75,000mg/L). It was experimentally concluded that Na-H-zeolite is a potential dual-electronic and amphiphilic adsorbent for efficiently removing a wide range of potentially toxic pollutants from aquatic environments. Copyright © 2017 Elsevier Inc. All rights reserved.

Post column derivatisation analyses review. Is post-column derivatisation incompatible with modern HPLC columns?

Science.gov (United States)

Jones, Andrew; Pravadali-Cekic, Sercan; Dennis, Gary R; Shalliker, R Andrew

2015-08-19

Post Column derivatisation (PCD) coupled with high performance liquid chromatography or ultra-high performance liquid chromatography is a powerful tool in the modern analytical laboratory, or at least it should be. One drawback with PCD techniques is the extra post-column dead volume due to reaction coils used to enable adequate reaction time and the mixing of reagents which causes peak broadening, hence a loss of separation power. This loss of efficiency is counter-productive to modern HPLC technologies, -such as UHPLC. We reviewed 87 PCD methods published from 2009 to 2014. We restricted our review to methods published between 2009 and 2014, because we were interested in the uptake of PCD methods in UHPLC environments. Our review focused on a range of system parameters including: column dimensions, stationary phase and particle size, as well as the geometry of the reaction loop. The most commonly used column in the methods investigated was not in fact a modern UHPLC version with sub-2-micron, (or even sub-3-micron) particles, but rather, work-house columns, such as, 250 × 4.6 mm i.d. columns packed with 5 μm C18 particles. Reaction loops were varied, even within the same type of analysis, but the majority of methods employed loop systems with volumes greater than 500 μL. A second part of this review illustrated briefly the effect of dead volume on column performance. The experiment evaluated the change in resolution and separation efficiency of some weak to moderately retained solutes on a 250 × 4.6 mm i.d. column packed with 5 μm particles. The data showed that reaction loops beyond 100 μL resulted in a very serious loss of performance. Our study concluded that practitioners of PCD methods largely avoid the use of UHPLC-type column formats, so yes, very much, PCD is incompatible with the modern HPLC column. Copyright © 2015. Published by Elsevier B.V.

Recent Advances on Bioethanol Dehydration using Zeolite Membrane

Science.gov (United States)

Makertihartha, I. G. B. N.; Dharmawijaya, P. T.; Wenten, I. G.

2017-07-01

Renewable energy has gained increasing attention throughout the world. Bioethanol has the potential to replace existing fossil fuel usage without much modification in existing facilities. Bioethanol which generally produced from fermentation route produces low ethanol concentration. However, fuel grade ethanol requires low water content to avoid engine stall. Dehydration process has been increasingly important in fuel grade ethanol production. Among all dehydration processes, pervaporation is considered as the most promising technology. Zeolite possesses high potential in pervaporation of bioethanol into fuel grade ethanol. Zeolite membrane can either remove organic (ethanol) from aqueous mixture or water from the mixture, depending on the framework used. Hydrophilic zeolite membrane, e.g. LTA, can easily remove water from the mixture leaving high ethanol concentration. On the other hand, hydrophobic zeolite membrane, e.g. silicate-1, can remove ethanol from aqueous solution. This review presents the concept of bioethanol dehydration using zeolite membrane. Special attention is given to the performance of selected pathway related to framework selection.

Synthesis and characterization of zeolite material from coal ashes modified by surfactant

International Nuclear Information System (INIS)

Fungaro, D.A.; Borrely, S.I.

2010-01-01

Coal ash was used as starting material for zeolite synthesis by means of hydrothermal treatment. The surfactant-modified zeolite (SMZ) was prepared by adsorbing the cationic surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) on the external surface of the zeolite from coal ash. The zeolite structure stability was monitored during the characterization of the materials by FTIR, XDR and SEM. The structural parameters of surfactant-modified zeolite are very close to that of corresponding non-modified zeolite which indicates that the crystalline nature of the zeolite remained intact after required chemical treatment with HDTMA-Br molecules and heating treatment for drying. The most intense peaks in the FTIR spectrum of HDTMA-Br were observed in SMZ spectrum confirming adsorption of surfactant on zeolites. (author)

Investigation of zeolites by solid state quadrapole NMR

International Nuclear Information System (INIS)

Janssen, R.

1990-01-01

The subject of this thesis is the NMR investigation of zeolites. The nature and properties of zeolites are discussed. Some of the basic priniples of NMR techniques on quadrupole nuclei are presented. A special technique, namely a two-dimensional nutation experiment is discussed in detail. The theory of the nutation experiment for quadrupole spin species with spin quantum number 3/2 as well as 5/2 is presented. For both spin spcies the theoretical spectra are compared with experimental results. It is also shown that the nutation expeirment can be performed with several pulse schemes. It is shown how phase-sensitive pure-absorption nutation spectra can be obtained and an NMR-probe is presented that is capable of performing NMR experiments at high (up to 500 degree C) temperatures. The two-dimensional nutation NMR technique has been applied to sodium cations in zeolite NaA. For this purpose a numbre of zeolite samples were prepared that contained different amounts of water. With the aid of nutation NMR the hydration of the zeolite can be studied and conclusions can be drawn about the symmetry of the surrounding of the sodium cations. With the aid of an extension of the nutation NMR experiment: Rotary Echo Nutation NMR, it is shown that in zeolite NaA, in various stages of hydration, the sodium cations or water molecules are mobile. Proof is given by means of high-temperature 23 Na-NMR that dehydrates zeolite NaA undergoes a phase transition at ca. 120 degree C. In a high-temperature NMR investigation of zeolite ZSM-5 it is shown that the sodium ions start to execute motions when the temperature is increased. (author). 198 refs.; 72 figs.; 6 tabs

Multicolor photoluminescence in ITQ-16 zeolite film

KAUST Repository

Chen, Yanli; Dong, Xinglong; Zhang, Zhenyu; Feng, Lai

2016-01-01

Exploring the native defects of zeolites is highly important for understanding the properties of zeolites, such as catalysis and optics. Here, ITQ-16 films were prepared via the secondary growth method in the presence of Ge atoms. Various intrinsic

Study of 63Ni adsorption on NKF-6 zeolite

International Nuclear Information System (INIS)

Zhang Hui; Yu Xianjin; Chen Lei; Jing Yongjie; Ge Zhiwei

2010-01-01

The adsorption of 63 Ni from aqueous solutions using NKF-6 zeolite was investigated by a batch technique under ambient conditions. The adsorption was investigated as a function of contact time, pH, ionic strength, foreign ions, humic substances (FA/HA) and temperature. The kinetic adsorption was well described by the pseudo-second-order rate equation. The adsorption of 63 Ni on NKF-6 zeolite was strongly dependent on pH and ionic strength, and the adsorption of 63 Ni increased with increasing NKF-6 zeolite content. At low pH values, the presence of FA enhanced the adsorption of 63 Ni on NKF-6 zeolite, but the presence of HA had no drastic effect. At high pH values, the presence of FA or HA decreased the adsorption of 63 Ni on NKF-6 zeolite. The adsorption isotherms were well represented by the Langmuir model. The thermodynamic parameters (i.e., ΔH 0 , ΔS 0 and ΔG 0 ) for the adsorption of 63 Ni were determined from the temperature dependent isotherms at 293.15, 313.15 and 333.15 o K, respectively, and the results indicate that the adsorption reaction was favored at high temperature. The results suggest that the adsorption process of 63 Ni on NKF-6 zeolite is spontaneous and endothermic. - Research highlights: → As an economical and efficient method, adsorption technique has been widely applied in the disposal of wastewaters. The study of 63 Ni on NKF-6 zeolite, especially the thermodynamic data of 63 Ni adsorption on NKF-6 zeolite and the effect of humic substances on 63 Ni uptake to humic-zeolite hybrids, is still scarce. In this paper, the sorption of 63 Ni on NKF-6 zeolite is studied as a function of various environmental conditions such as contact time, pH, ionic strength, foreign ions, humic substances and temperature. Based on the obtained experimental results, the adsorption mechanism of 63 Ni on NKF-6 zeolite is stated in detail. This study will have an important reference value in evaluating the physiochemical behavior of radionuclide 63 Ni.

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

Evenly-spaced columns in the Bishop Tuff as relicts of hydrothermal convection

Science.gov (United States)

Randolph-Flagg, N. G.; Breen, S. J.; Hernandez, A.; Self, S.; Manga, M.

2015-12-01

A few square km of the Bishop Tuff in eastern California, USA have evenly spaced erosional columns. These columns are more resistant to erosion due to the precipitation of the low-temperature zeolite (120-200 ºC), mordenite, which is not found in the surrounding tuff. Similar features observed in the Bandelier Tuff were hypothesized to form when cold water from above infiltrated into the still-hot tuff interior. This water would become gravitationally unstable and produced convection with steam upwellings and liquid water downwellings. These downwellings became cemented with mordenite while the upwellings were too dry for chemical reactions. We use two methods to quantitatively assess this hypothesis. First, scaling that ignores the effects of latent heat and mineral precipitation suggests the Rayleigh number (Ra, a measure of convective vigor) for this system is ~103 well above the critical Ra of 4π2. Second, to account for the effect of multiphase flow and latent heat, we use two-dimensional numerical models in the finite difference code HYDROTHERM. We find that the geometry of flow is consistent with field observations and confirm that geometry is sensitive to permeability and topography. These tests suggest a few things about low-pressure hydrothermal systems. 1) The geometry of at least some convection appears to be broadly captured by linear stability theory that ignores reactive transport, heterogeneity of host rock, and the effects of latent heat. 2) Topographic flow sets the wavelength of convection meaning that these columns formed somewhere without topography—probably a lake. Finally, these observations imply a wet paleoclimate in the Eastern Sierra namely that, in the aftermath of the Long Valley eruption, either rain or snow was able to pool in the caldera before the tuff cooled on the order of a hundred years after the eruption.

Zeolites with continuously tuneable porosity

OpenAIRE

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; Cejka, Jiří; Morris, Russell E

2014-01-01

Czech Science Foundation. Grant Number: P106/12/G015 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 tuneabl...

Positron annihilation in modified zeolites LTA and 13X

Energy Technology Data Exchange (ETDEWEB)

Cabral-Prieto, A.; Garcia-Sosa, I.; Jimenez-Becerril, J. [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, Col. Escandon, Del. M. Hidalgo, Mexico D. F., c. p. 11801 (Mexico); Lopez-Castanares, R.; Olea-Cardoso, O. [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Paseo Tollocan esquina paseo Tollocan, esquina paseo Colon, Toluca, c. p. 50120, Estado de Mexico (Mexico)

2007-07-01

The pick-off annihilation lifetimes of o -Ps, {tau}{sub po}, in dehydrated Co{sup 2+} and Mn{sup 2+} exchanged zeolites LTA, in dehydrated Co{sup 2+} exchanged zeolite 13X, and in dehydrated Na{sup +} zeolites LTA and 13X, are estimated. Although {tau}{sub po} can be estimated from the lifetime spectra of the cation exchanged zeolites LTA and 13X, this lifetime can not be estimated from those spectra of Na{sup +} zeolite LTA unambiguously. The estimated pick-off lifetimes due to the annihilation of o-Ps in the internal walls of the zeolites are systematically lower than the average lifetime of p-Ps and o-Ps in vacuum {tau}{sub a}=0.5 ns. Since the pick-off process of o-Ps occurs particularly on the internal cavity walls of dehydrated zeolites, the replacement of {tau}{sub a} by {tau}{sub po} within the classical model of Tao-Eldrup to calculate cavity radius should provide more realistic cavity radii of these porous materials than when using {l_brace}{tau}{sub a}{r_brace}. This suggestion is supported by previous and present results. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

The isolation of water-soluble radionuclides from deteriorating spent nuclear fuel in zeolite cartridge

International Nuclear Information System (INIS)

Hassan, N.M.; Thompson, M.C.

1996-01-01

A method of isolating water-soluble radionuclides leaching from deteriorating spent nuclear fuel by ion-exchange in zeolite cartridges has been studied. Design calculations of two zeolite cartridges to be incorporated in typical spent fuel storage bundle have been provided. Equilibrium exchange data obtained at several temperatures have shown that the maximum exchange capacity of total cesium in sodium titanium aluminosilicate was 114 mg/g zeolite and the capacity at 95% exchange for radioactive isotope Cs-137 was calculated as 55.2 mg/g zeolite. The kinetic data suggest that the rate of exchange of Cs + in sodium titanium aluminosilicate zeolite takes place by a fast initial exchange step followed by slow diffusion of cesium cations. Design calculations based on the equilibrium exchange data show that water-soluble radionuclides leaching from Mk 31 slugs can be isolated using two zeolite cartridges, each 3.7 inches in inside diameter and 2.5 inches in length. The cartridges are designed to isolate 95% of the Cs + leaching from the spent fuel storage bundle. The results from the thermal induced convective flow tests indicate that the system will provide necessary cooling to the spent fuel by convective currents while isolating the Cs + leaching from spent fuel storage bundle in the cartridges

Application of l-cystine modified zeolite for preconcentration and determination of ultra-trace levels of cadmium by flame atomic absorption spectrometry.

Science.gov (United States)

Rezvani, Seyyed Ahmad; Soleymanpour, Ahmad

2016-03-04

A very convenient, sensitive and precise solid phase extraction (SPE) system was developed for enrichment and determination of ultra-trace of cadmium ion in water and plant samples. This method was based on the retention of cadmium(II) ions by l-cystine adsorbed in Y-zeolite and carry out in a packed mini-column. The retained cadmium ions then were eluted and determined by flame atomic absorption spectrometry. The scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) spectroscopy techniques were applied for the characterization of cystine modified zeolite (CMZ). Some experimental conditions affecting the analytical performance such as pH, eluent type, concentration of sample, eluent flow rate and also the presence of interfering ions were investigated. The calibration graph was linear within the range of 0.1-7.5ngmL(-1) and limit of detection was obtained 0.04ngmL(-1) with the preconcentration factor of 400. The relative standard deviation (RSD) was obtained 1.4%, indicating the excellent reproducibility of this method. The proposed method was successfully applied for the extraction and determination of cadmium(II) ion in black tea, cigarette's tobacco and also various water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

29Si MAS NMR for the zeolite Y - gallium oxide system

International Nuclear Information System (INIS)

Sulikowski, B.; Derewinski, M.; Olejniczak, Z.; Segnowski, S.

1994-01-01

Wide-pore zeolites modified by gallium oxide has been prepared for catalytic use. Its physico-chemical and catalytic properties have been studied. The structure changes of the catalyst have been investigated by means of MAS NMR spectroscopy. Spectra of 29 Si has been described and discussed

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.

Synthesis and catalytic applications of combined zeolitic/mesoporous materials

Directory of Open Access Journals (Sweden)

Jarian Vernimmen

2011-11-01

Full Text Available In the last decade, research concerning nanoporous siliceous materials has been focused on mesoporous materials with intrinsic zeolitic features. These materials are thought to be superior, because they are able to combine (i the enhanced diffusion and accessibility for larger molecules and viscous fluids typical of mesoporous materials with (ii the remarkable stability, catalytic activity and selectivity of zeolites. This review gives an overview of the state of the art concerning combined zeolitic/mesoporous materials. Focus is put on the synthesis and the applications of the combined zeolitic/mesoporous materials. The different synthesis approaches and formation mechanisms leading to these materials are comprehensively discussed and compared. Moreover, Ti-containing nanoporous materials as redox catalysts are discussed to illustrate a potential implementation of combined zeolitic/mesoporous materials.

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.

Studies of adsorption and desorption of zinc ions on zeolites by means of 65Zn

International Nuclear Information System (INIS)

Foeldesova, M.; Dillinger, P.; Lukac, P.

2001-01-01

The uptake of different metals by natural and chemically modified ion-exchangers, including zeolites, were studied in order to minimize the contamination of environment with metals in ionic form. In recent years considerable attention has been devoted to the studies of chemically modified zeolites their properties and applications. The used zeolite originated from the deposit Nizny Hrabovec, eastern Slovakia (NH) and from deposit of Ukraine (U). The zeolite from Slovakia is a clinoptilolite /40 -70%/ type, the zeolite from Ukraine is a mixed mordenite /75%/ and clinoptilolite /25%/ type. A fraction of 1.5 -2.5 mm was separated from the grained zeolite by sieving. The sedimentary zeolites, being the siliceous zeolites, should exhibit substantial non-selectivity for the divalent cations having a high hydration enthalpy , including zinc ( -2026 kJ/g). Zinc is an essential trace element in all-living systems from bacteria to humans. The toxicity of zinc and most of zinc compounds is generally low, however, sometimes industrial and household wastes contain zinc in concentrations, which can be harmful to the environment. The zinc-accompanying impurities, such as cadmium and lead, are of much greater danger .The main source of zinc are waste waters and continuous emission from the production and processing of zinc, other nonferrous smelters, from coal power plants and fossil combustion. The static radio-exchange method using model radioactive solutions was utilized for the determination of the sorption of Zn by the mentioned above zeolitic materials. For this purpose the aqueous solution of 5 · 10 -2 mol dm -3 ZnCl 2 labelled with 65 Zn was used. The areas of application of natural zeolites have been well defined. However, their use can become more efficient after chemical modification. The zeolites acquire new valuable properties, while retaining their original ones. The obtained results make these materials excellent candidates for their potential use for waste water

Removal of radiocesium from low level radioactive effluents by hexacyanoferrate loaded synthetic zeolite. Laboratory to pilot plant scale demonstration

Energy Technology Data Exchange (ETDEWEB)

Banerjee, Dayamoy; Rao, Manjula A.; Khot, Shantinath A.; Shah, Jayesh G.; Banerjee, Kalyan [Bhabha Atomic Research Centre, Mumbai (India). Nuclear Recycle Group; Pawaskar, Chandrahas S.; Gangadharan, Anand; Rao, Shankar N.; Jain, Savita [Bhabha Atomic Research Centre, Mumbai (India)

2017-06-01

Present paper reports removal of radiocesium from low level waste using a modified sorbent (13X-CFC) prepared by in-situ precipitation of potassium copper hexacyanoferrate(II) inside the macropores of a synthetic zeolite. The Cs exchange isotherm of the sorbent is established and it found to follow Fruendlich absorption isotherm equation. It is varified that presence of hexacyanoferrate on zeolite facilitates rapid Cs uptake performance. This is further confirmed in laboratory scale column tests, wherein excellent Cs removal performance from low level waste simulant was observed even at higher flow rates (40 bed volumes per hour). The utility of the sorbent is established through successful demonstration in a pilot scale (50 L) trial with almost complete removal of {sup 137}Cs from more than 14,000 bed volumes of actual low level waste. The sorbent, owing to its low cost and excellent {sup 137}Cs removal performance, is expected to find application in treatment of very low active waste streams.

Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

Science.gov (United States)

Dieu, Bjorn; Roeffaers, Maarten B.J.; Hofkens, Johan

2016-01-01

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film. PMID:27911397

Applications of natural zeolites on agriculture and food production.

Science.gov (United States)

Eroglu, Nazife; Emekci, Mevlut; Athanassiou, Christos G

2017-08-01

Zeolites are crystalline hydrated aluminosilicates with remarkable physical and chemical properties, which include losing and receiving water in a reverse way, adsorbing molecules that act as molecular sieves, and replacing their constituent cations without structural change. The commercial production of natural zeolites has accelerated during the last 50 years. The Structure Commission of the International Zeolite Association recorded more than 200 zeolites, which currently include more than 40 naturally occurring zeolites. Recent findings have supported their role in stored-pest management as inert dust applications, pesticide and fertilizer carriers, soil amendments, animal feed additives, mycotoxin binders and food packaging materials. There are many advantages of inert dust application, including low cost, non-neurotoxic action, low mammalian toxicity and safety for human consumption. The latest consumer trends and government protocols have shifted toward organic origin materials to replace synthetic chemical products. In the present review, we summarize most of the main uses of zeolites in food and agruculture, along with the with specific paradigms that illustrate their important role. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

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

Application of Zeolitic Additives in the Fluid Catalytic Cracking (FCC

Directory of Open Access Journals (Sweden)

A. Nemati Kharat

2013-06-01

Full Text Available Current article describes application of zeolites in fluid catalytic cracking (FCC. The use of several zeolitic additives for the production light olefins and reduction of pollutants is described. Application of zeolites as fluid catalytic cracking (FCC catalysts and additives due to the presence of active acid sites in the zeolite framework  increase the formation of desired cracking products (i.e., olefin and branched products  in the FCC unit.

Effect of alkali-treatment on the characteristics of natural zeolites with different compositions.

Science.gov (United States)

Ates, Ayten

2018-08-01

A series of natural zeolites with different compositions were modified by post-synthesis modification with sodium hydroxide (NaOH) solution. Natural and modified zeolites were characterized by XRD, SEM, nitrogen adsorption, FTIR, zeta potential and temperature programmed desorption of ammonia (NH 3 -TPD). The adsorption capacities of these samples were evaluated by the adsorption of manganese from aqueous solution. The treatment with NaOH led to a decrease in the surface area and microporosity of all natural zeolites as well as partly damage of the zeolite structure depending on zeolite composition. In addition, the amount of weak, medium and strong acid sites in the zeolites was changed significantly by NaOH treatment depending on zeolite composition. The NaOH treatment resulted in a four-fold improvement in adsorption capacity of natural zeolite originated from Bigadic and a twofold decrease in that of the natural zeolite originated from Manisa-Gordes. Although the improved adsorption capacity might be mainly due to modification of porosity in the zeolites and formation of hydroxysodalite, the reduced adsorption capacity of the zeolite might be mainly due to a significant deformation of the zeolite structure. The pseudo-second-order kinetic model for the adsorption of manganese on all natural and modified zeolites fits well. Copyright © 2018 Elsevier Inc. All rights reserved.

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

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.

Effect of IX column maintenance on carbon-14 concentration in moderator systems

International Nuclear Information System (INIS)

Gallagher, C.L.; Tripple, A.W.

2006-01-01

The radionuclide 14 C is produced in CANDU reactors primarily by the (n,α) reaction with 17 O. Because of high neutron fluxes in the core, the majority of the 14 C (94.5%) is produced in the moderator. In the moderator system, 14 C is present mainly as CO 2 in the cover gas in dynamic equilibrium with dissolved carbonates, bicarbonates and CO 2 in the moderator water. Emissions of 14 C from reactors occur through venting or leakage of the cover gas. By controlling the dissolved carbonates in the moderator water with an ion exchange (IX) purification system, the amount of 14 C in the cover gas is minimized and thus the emissions of 14 C can be reduced. A study was conducted to measure the 14 C concentrations in the moderator system at Gentilly 2 in order to determine the effectiveness of the purification system in removing 14 C. Moderator water samples were obtained from the inlet and outlet of the purification system from 2004 January 14 to July 12, covering the operation of two IX columns (IX-1 and IX-3). The moderator water samples contained high levels of tritium (∼2 TBq·L -1 ). As both tritium and 14 C are β-radiation emitters, direct counting of moderator water for 14 C is impossible as the signal due to tritium dominates over that of other β-emitters. Therefore, a procedure developed by Caron et al. was used in this study, which involved acidifying the sample to release the dissolved 14 CO 2 as gas and collecting the 14 CO 2 in a base (NaOH), which could then be measured by liquid scintillation counting to determine the 14 C concentration. Both of the IX columns started with 14 C removal efficiencies of about 95%. The efficiency began to decrease almost immediately with the IX-1 column dropping to 80% efficiency after ∼1115 hours. This drop in efficiency also led to an increase in the inlet concentration over time. IX-1 column was removed from service after ∼1745 hours with a 14 C removal efficiency of ∼31%. IX-3 column was then placed in service

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)

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

Ion-exchange properties of cesium and strontium into zeolites from sodium salt solutions

International Nuclear Information System (INIS)

Kanno, Takuji; Hashimoto, Hiroyuki; Ohtani, Tozo.

1978-01-01

The ion-exchange properties of cesium and strontium into zeolite from sodium salt solution has been studied in zeolite A, zeolite X, zeolite Y, mordenite and clinoptilolite. The distribution of cesium into mordenite from about 1 -- 2 M sodium chloride and sodium hydroxide solutions is considerably larger than that into zeolite A. The distribution coefficient for 2 M solution of sodium salts was about 300. Therefore, the separation of cesium from sodium salt solution is possible by using mordenite. The distribution of strontium into zeolites form 1 -- 2 M solutions of sodium chloride and sodium nitrate were in the order of zeolite A>zeolite X>zeolite Y asymptoticaly equals mordenite. The distribution coefficient of 230 was obtained for 1 M solutions of sodium salts. The anion in solutions had no effect on the distribution of cesium and strontium into zeolite from sodium salt solution. (author)

Application of zeolite-based catalyst to hydrocracking of coal-derived liquids

Energy Technology Data Exchange (ETDEWEB)

Shimada, H.; Sato, T.; Yoshimura, Y.; Hinata, A.; Yoshitomi, S.; Castillo Mares, A.; Nishijima, A. (National Chemical Laboratory for Industry, Tsukuba (Japan))

1990-06-01

Y-zeolite supported catalysts were applied to the hydrocracking of coal-derived liquids. By the introduction of two-stage upgrading consisting of hydrotreating and hydrocracking, Wandoan coal-derived middle distillate was hydrocracked over Ni-Mo/Y-zeolite, producing a high gasoline fraction yield. Zeolite supported catalysts gave little hydrocracked compounds in the hydroprocessing of coal-derived heavy oils, even after hydrotreatment. The reaction inhibitors which seriously poison the active sites of zeolites were found to be small nitrogen-containing molecules. In the hydroprocessing of coal-derived heavy oils, zeolite supported catalysts were inferior to alumina supported catalysts. This is due to the high hydrocracking but low hydrogenation activity of zeolite supported catalysts. 22 refs., 5 figs., 11 tabs.

Zeolite from fly ash: synthesis and characterization

Indian Academy of Sciences (India)

Coal fly ash was used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. The synthesized zeolite was characterized using various techniques such as X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, BET method for surface area measurement etc.

Exfoliation of two-dimensional zeolites in liquid polybutadienes

KAUST Repository

Sabnis, Sanket; Tanna, Vijesh A.; Li, Chao; Zhu, Jiaxin; Vattipalli, Vivek; Nonnenmann, Stephen S.; Sheng, Guan; Lai, Zhiping; Winter, H. Henning; Fan, Wei

2017-01-01

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

Morpho-chemical characterization and surface properties of carcinogenic zeolite fibers

International Nuclear Information System (INIS)

Mattioli, Michele; Giordani, Matteo; Dogan, Meral; Cangiotti, Michela; Avella, Giuseppe; Giorgi, Rodorico; Dogan, A. Umran; Ottaviani, Maria Francesca

2016-01-01

Highlights: • Differently carcinogenic zeolite fibers were investigated combining physico-chemical methods. • For the first time, zeolite fibers were studied by means of the EPR technique using different spin probes. • The structural properties and the adsorption capability are function of different types and distributions of adsorption sites. • The interacting ability of erionite is higher than that of other fibrous zeolites. • The surface interacting properties may be related with the carcinogenicity of the zeolite fibers. - Abstract: Erionite belonging to the zeolite family is a human health-hazard, since it was demonstrated to be carcinogenic. Conversely, offretite family zeolites were suspected carcinogenic. Mineralogical, morphological, chemical, and surface characterizations were performed on two erionites (GF1, MD8) and one offretite (BV12) fibrous samples and, for comparison, one scolecite (SC1) sample. The specific surface area analysis indicated a larger availability of surface sites for the adsorption onto GF1, while SC1 shows the lowest one and the presence of large pores in the poorly fibrous zeolite aggregates. Selected spin probes revealed a high adsorption capacity of GF1 compared to the other zeolites, but the polar/charged interacting sites were well distributed, intercalated by less polar sites (Si–O–Si). MD8 surface is less homogeneous and the polar/charged sites are more interacting and closer to each other compared to GF1. The interacting ability of BV12 surface is much lower than that found for GF1 and MD8 and the probes are trapped in small pores into the fibrous aggregates. In comparison with the other zeolites, the non-carcinogenic SC1 shows a poor interacting ability and a lower surface polarity. These results helped to clarify the chemical properties and the surface interacting ability of these zeolite fibers which may be related to their carcinogenicity.

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

High pressure synthesis of zeolite/polymer nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Haines, Julien; Thibaud, Jean-Marc; Rouquette, Jerome; Cambon, Olivier; Di Renzo, Francesco, E-mail: julien.haines@univ-montp2.fr [Institut Charles Gerhardt Montpellier (France); Lee, Arie van der [Institut Europeen des Membranes, Montpellier (France); Scelta, Demetrio; Ceppatelli, Matteo; Dziubek, Kamil; Gorelli, Federico; Bini, Roberto; Santoro, Mario [European Laboratory for Non Linear Spectroscopy, Firenze (Italy)

2016-07-01

Full text: Polymerization of simple organic molecules under high pressure in the subnanometric pores of pure SiO{sub 2} zeolites can be used to produce novel nanocomposite materials, which can be recovered at ambient P and have remarkable mechanical, electrical or optical properties. Polymerization of ethylene in silicalite was studied in situ at high pressure by IR and results in a nanocomposite with isolated chains of non-conducting polyethylene strongly confined in the pores based on single crystal x-ray diffraction data. The nanocomposite is much less compressible than silicalite and has a positive rather than a negative thermal expansion coefficient. In order to target novel electrical and optical properties, isolated chains of conducting polymers can also be prepared in the pores of zeolite hosts at high pressure, such as polyacetylene, which was polymerized under pressure in the pores of the 1-D zeolite TON. The structure of this nanocomposite was determined by synchrotron x-ray powder diffraction data with complete pore filling corresponding to one planar polymer chain confined in each pore with a zig-zag configuration in the yz plane. This very strong confinement can be expected to strongly modify the electrical properties of polyacetylene. In this nanocomposite, our theoretical calculations indicate that the electronic density of states of polyacetylene exhibit van Hove singularities related to quantum 1D confinement, which could lead to future technological applications. This new material is susceptible to have applications in nanoelectronics, nanophotonics and energy and light harvesting. Completely novel nanocomposites were prepared by the polymerization of carbon monoxide CO in silicalite and TON. In these materials, isolated, ideal polycarbonyl chains are obtained in contrast to the non-stoichiometric, branched bulk polymers obtained by high pressure polymerization of this simple system. These poly CO/zeolite composites could be interesting energetic

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)

Inhibition of palm oil oxidation by zeolite nanocrystals.

Science.gov (United States)

Tan, Kok-Hou; Awala, Hussein; Mukti, Rino R; Wong, Ka-Lun; Rigaud, Baptiste; Ling, Tau Chuan; Aleksandrov, Hristiyan A; Koleva, Iskra Z; Vayssilov, Georgi N; Mintova, Svetlana; Ng, Eng-Poh

2015-05-13

The efficiency of zeolite X nanocrystals (FAU-type framework structure) containing different extra-framework cations (Li(+), Na(+), K(+), and Ca(2+)) in slowing the thermal oxidation of palm oil is reported. The oxidation study of palm oil is conducted in the presence of zeolite nanocrystals (0.5 wt %) at 150 °C. Several characterization techniques such as visual analysis, colorimetry, rheometry, total acid number (TAN), FT-IR spectroscopy, (1)H NMR spectroscopy, and Karl Fischer analyses are applied to follow the oxidative evolution of the oil. It was found that zeolite nanocrystals decelerate the oxidation of palm oil through stabilization of hydroperoxides, which are the primary oxidation product, and concurrently via adsorption of the secondary oxidation products (alcohols, aldehydes, ketones, carboxylic acids, and esters). In addition to the experimental results, periodic density functional theory (DFT) calculations are performed to elucidate further the oxidation process of the palm oil in the presence of zeolite nanocrystals. The DFT calculations show that the metal complexes formed with peroxides are more stable than the complexes with alkenes with the same ions. The peroxides captured in the zeolite X nanocrystals consequently decelerate further oxidation toward formation of acids. Unlike the monovalent alkali metal cations in the zeolite X nanocrystals (K(+), Na(+), and Li(+)), Ca(2+) reduced the acidity of the oil by neutralizing the acidic carboxylate compounds to COO(-)(Ca(2+))1/2 species.

Structure sensitive reactions over Co, Fe and mixed metal clusters in zeolites

Energy Technology Data Exchange (ETDEWEB)

Suib, S.L.

1992-08-01

Transient and steady state kinetic studies of structure sensitive reactions of cyclopropane (c-C{sub 3}H{sub 6}) and hydrogen over zeolites is the first area of this studied. Low level impurity Fe{sup 3+} ions in zeolites complicate interpretation of spectroscopic and catalytic studies of these systems. We focused our efforts on selectively substituting Fe{sup 3+} ions in the frameworks of various zeolites to understand their role in catalytic reactions such as with c-C{sub 3}H{sub 6} and H{sub 2}. These studies led to isomorphous substitution of other ions like B{sup 3+} and their use in isomerization of n-butenes to isobutylene. The third area of research involves the synthesis, characterization and catalysis of a new class of molecular sieve manganese oxide tunnel structure materials.

Mixing of zeolite powders and molten salt

International Nuclear Information System (INIS)

Pereira, C.; Zyryanov, V.N.; Lewis, M.A.; Ackerman, J.P.

1996-01-01

Transuranics and fission products in a molten salt can be incorporated into zeolite A by an ion exchange process and by a batch mixing or blending process. The zeolite is then mixed with glass and consolidated into a monolithic waste form for geologic disposal. Both processes require mixing of zeolite powders with molten salt at elevated temperatures (>700 K). Complete occlusion of salt and a uniform distribution of chloride and fission products are desired for incorporation of the powders into the final waste form. The relative effectiveness of the blending process was studied over a series of temperature, time, and composition profiles. The major criteria for determining the effectiveness of the mixing operations were the level and uniformity of residual free salt in the mixtures. High operating temperatures (>775 K) improved salt occlusion. Reducing the chloride levels in the mixture to below 80% of the full salt capacity of the zeolite significantly reduced the free salt level in the final product

Detergent zeolite complex "Alusil", Zvornik

OpenAIRE

Stanković Mirjana S.; Pezo Lato L.

2003-01-01

The IGPC Engineering Department designed the basis technological and machine projects for a detergent zeolite complex, on the basis of which a pilot plant with an initial capacity of 5,000 t/y was constructed in 1983 within Birač-Zvornik production complex. Additional projects were done afterwards and the starting capacity increased to 200,000 t/y in 1988. This plant became the biggest producer of detergent zeolite in the world. These projects were manufactured on the basis of specific techno...

Preliminary study of zeolite-pva composite application in removal of SR-90

International Nuclear Information System (INIS)

Las, Thamzil; Zamroni, Huzen; Sugiarto; Darsono

1998-01-01

Zeolite-PAN composite was prepared by contacting the purified Bayah and Lampung zeolites with poly-vinyl alcohol binder and cured by using Gamma-ray of Co-60 at various doses, i.e., 10, 20, 30 dan 40 kGray with dose rates 7.5 kGy/hour. Zeolite-PAN composites were treated with solution containing Sr-90 up to 5 days and the Sr sorption was measured by Liquid Scintillation Counter for determination of their sorption efficiencies. The result obtained that, zeolite-PAN composites were shown high sorption efficiencies on the composites zeolite-PVA which was formulated from 20% zeolite, irradiated by 40 kGy and obtained the sorption efficiency of 94% with the Kd values similar to the purified zeolites. (author)

Utilization of Zeolites in environmentally protection

Energy Technology Data Exchange (ETDEWEB)

Kallo, D. [Hungarian Academy of Sciences, Chemical Research Center, Institute of Chemistry, Budapest (Hungary)

2000-07-01

It has been attempted to present the most important fields of natural zeolite applications in environmental protection. Realized and approved utilizations were demonstrated inciting the reader to take these materials into consideration for solution of similar problems. The outlined properties can be used for other purposes not discussed in this review. They can be applied, e.g., in fish farming, transportation of living fishes when simultaneous ammonium and carbon dioxide removals is required: ammonium is exchanged for calcium present in the zeolite and CO{sub 2} is then precipitated in the form of CaCO{sub 3}; in treatment of diluted manure when undesired organics can be fixed and bactericide effects can be attained. Natural zeolites are used, therefore, as deodorant of litter of dogs or cats. Small amounts of metal cations, e.g., Cu{sup 2+}, Ag{sup +} or Zn{sup 2+}, introduced by ion exchange may disinfect contacting water. Due to water adsorption and desorption capability natural zeolite as construction materials exert some conditioning effect without any mechanical accessory. It seems likely the human ingenuity will continue to discover new applications in the future.

Exploitation of Unique Properties of Zeolites in the Development of Gas Sensors

Directory of Open Access Journals (Sweden)

Prabir K. Dutta

2012-04-01

Full Text Available The unique properties of microporous zeolites, including ion-exchange properties, adsorption, molecular sieving, catalysis, conductivity have been exploited in improving the performance of gas sensors. Zeolites have been employed as physical and chemical filters to improve the sensitivity and selectivity of gas sensors. In addition, direct interaction of gas molecules with the extraframework cations in the nanoconfined space of zeolites has been explored as a basis for developing new impedance-type gas/vapor sensors. In this review, we summarize how these properties of zeolites have been used to develop new sensing paradigms. There is a considerable breadth of transduction processes that have been used for zeolite incorporated sensors, including frequency measurements, optical and the entire gamut of electrochemical measurements. It is clear from the published literature that zeolites provide a route to enhance sensor performance, and it is expected that commercial manifestation of some of the approaches discussed here will take place. The future of zeolite-based sensors will continue to exploit its unique properties and use of other microporous frameworks, including metal organic frameworks. Zeolite composites with electronic materials, including metals will lead to new paradigms in sensing. Use of nano-sized zeolite crystals and zeolite membranes will enhance sensor properties and make possible new routes of miniaturized sensors.

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)

Zeolites as catalyzer to environmental control. Nitric oxide removal

International Nuclear Information System (INIS)

Montes, C.; Zapata N, M; Villa H, A.L.

1995-01-01

Zeolites and the microporous materials related to them are a class of environmental catalysts, it which are used to remove the produced gases in combustion process (as mobile sources). In this work the importance that has catalysis for environment improvement is emphasized. A review of recent progress in the use of certain zeolitic material as catalysts for nitric oxide elimination of combustion systems is presented. More used nitric oxide removal methods are presented, as well as its advantages and disadvantages. Furthermore, it is emphasized on the need of accomplishing more investigation projects on the development of an active catalyst for the decomposition of the nitric oxide in its elements (N and O)

Dealuminization treatment effect of krypton gas adsorption on zeolite

International Nuclear Information System (INIS)

Shin, J. M.; Shin, S. W.; Park, J. J.; Lee, H. H.; Yang, M. S.

2003-01-01

During the OREOX process of DUPIC fuel fabrication, krypton is released as a noble fission gas. In order to treat Kr safely, adsorption method on solids havs been selected. In order to determine the optimum extraction conditions of zeolite for Kr adsorption, the preliminary experiments for the concentration of hydrochloric acid were conducted. It was found that zeolite treated with 2N hydrochloric acid solution is superior to the zeolite untreated with HCl solution. When the zeolite was treated with 2N hydrochloric acid, it was found that the surface area was decreased. The micropores and the pore volume were increased and the adsorption amount of Kr gas was increased

Regeneration of zeolite catalysts of isobutane alkylation with butenes

Energy Technology Data Exchange (ETDEWEB)

Manza, I.A.; Tsupryk, I.N.; Bartyshevskii, V.A.; Gaponenko, O.I.; Petrilyak, K.I.

1986-12-10

The industrial adoption of alkylation of isoalkanes with alkenes is held back by the rapid and irreversible deactivation of the zeolite catalysts appropriate to the process. This paper is aimed specifically at the restoration of the catalytic activity and increase in the service life of zeolite alkylation catalysts. The catalyst chosen for the investigation was HLaCaNaX zeolite both unmodified and modified with various multivalence cations. The thermochemical and oxidative regeneration process as well as the equipment utilized are described. Both the advantages and the drawbacks of the method are given; explanations for the possibly irreversible losses of the catalytic properties in the regenerated zeolites are also put forward.

Study of the influence of the silica source on the synthesis of the zeolite precursor MCM-22

International Nuclear Information System (INIS)

Barbosa, A.S.; Santos, E.R.F. dos; Leite, R.C.N.; Rodrigues, M.G.F.

2012-01-01

Zeolite MCM-22 precursors were synthesized under hydrothermal conditions in systems with hexamethyleneimine HMI as bulking agent (driver). Synthesis parameter, such as sources of silica (aerosil® and quartz) was modified to investigate the effects on the morphology and crystallization in precursor MCM-22 zeolite. The products were characterized by X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDX) and Scanning Electron Microscopy (SEM). According to, the X-ray diffraction showed the same characteristic peaks of zeolite MCM-22. It was found that the parameter in this work of synthesis, silica source, affects the hydrothermal synthesis of zeolite MCM-22 precursor. This can be evidenced by the different morphologies found using the different sources of silica. (author)

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.

The Effect of Zeolite Composition and Grain Size on Gas Sensing Properties of SnO2/Zeolite Sensor

Directory of Open Access Journals (Sweden)

Yanhui Sun

2018-01-01

Full Text Available In order to improve the sensing properties of tin dioxide gas sensor, four kinds of different SiO2/Al2O3 ratio, different particle size of MFI type zeolites (ZSM-5 were coated on the SnO2 to prepared zeolite modified gas sensors, and the gas sensing properties were tested. The measurement results showed that the response values of ZSM-5 zeolite (SiO2/Al2O3 = 70, grain size 300 nm coated SnO2 gas sensors to formaldehyde vapor were increased, and the response to acetone decreased compared with that of SnO2 gas sensor, indicating an improved selectivity property. The other three ZSM-5 zeolites with SiO2/Al2O3 70, 150 and 470, respectively, and grain sizes all around 1 μm coated SnO2 sensors did not show much difference with SnO2 sensor for the response properties to both formaldehyde and acetone. The sensing mechanism of ZSM-5 modified sensors was briefly analyzed.

CO hydrogenation on zeolite-supported Ru: Effect of neutralizing cations

International Nuclear Information System (INIS)

Oukaci, R.; Wu, J.C.S.; Goodwin, J.G. Jr.

1986-01-01

Previous results for zeolite-supported Ru prepared by ion exchange suggested a possible effect of the nature and concentration of the neutralizing cations in the zeolite on the catalytic properties of the metal. However, the interpretation of these results was complicated by the fact that a series of zeolites with different Si/Al ratios was used. The present study was undertaken to investigate systematically the influence of the nature of alkali neutralizing cations on CO hydrogenation over ion-exchanged Y-zeolite-supported ruthenium catalysts

Ammonium ion interaction with conditioned natural zeolite with silver and its effect on the disinfection of polluted water in front of a consortium of gram (+) and gram (-) microorganisms; Interaccion del ion amonio con zeolita natural acondicionada con plata y su efecto sobre la desinfeccion de agua contaminada frente a un consorcio de microorganismos gram (+) y gram (-)

Energy Technology Data Exchange (ETDEWEB)

Gonzaga G, V. E.

2013-07-01

Clinoptilolite zeolite material is a relative abundance in Mexico, which has ion exchange properties, therefore, has the ability to retain metal ions giving it an application in the process of disinfecting of water contaminated with pathogenic microorganisms. In this research, we conducted a study of disinfection of water contaminated with a microbial consortium, from a zeolite rock clinoptilolite from a deposit located in the State of Guerrero. Initially, the zeolite prepared by the grinding and sieving, for conditioning with NaCl and subsequently with AgNO{sub 3}, finally to be characterized using the techniques of scanning electron microscopy and X-ray diffraction. Tests using columns packed with zeolite material, the effect of zeolite bactericidal conditioned with silver (ZGAg) against a microbial consortium consisting of Escherichia coli and Sthapyloccocus aureus in aqueous solution in the presence of ammonium ions used to increase the ion exchange with zeolite fitted with silver. To describe curves disinfecting a continuous flow system is adapted Gu pta model, which describes the kinetics and equilibrium adsorption process, considering the microorganisms as the adsorbate and the sanitizing agent (conditioned with silver zeolite) as the adsorbent. Characterization results show that in the scanning electron microscopy (Sem), no changes were obtained on the morphology of typical clinoptilolite crystals before and after that was modified with sodium and then with silver, it is worth mentioning however that fitted with silver zeolite (ZGAg), small particles are seen on the zeolite material which when analyzed by energy dispersive spectroscopy (EDS), we found a high concentration of Ag +. The disinfection period is increased as the concentration increased ammonium ions, this behavior is attributed to the ion exchange that occurs between the ammonium ions and silver ions. A lower percentage of inactivation is due, therefore, to a lesser amount of money available to

Utilization of Natural Zeolite from Ponorogo and Purworejo for Naphthol Substance Adsorption

Science.gov (United States)

Imandiani, Sundus; Indira, Christine; Johan, Anthony; Budiyono

2018-02-01

Indonesia has many zeolite producing areas yet untapped. Researchers developed the utilization of natural zeolites useful for the adsorption of naphthol dyes commonly found in batik waste. In this study researchers used natural zeolites from Purworejo and Ponorogo that are activated using hydrochloric acid that is used for adsorption. The purpose of this research is to know the effect of natural zeolite activation from Ponorogo and Purworejo on the effectiveness of adsorption of naphthol dyes widely used in batik industry. Natural zeolite was activated using HCl concentration of 1.3N; 1.8N; 3.2N; and 3.9N for 60 minutes. The methods are preparation of natural zeolite from Purworejo and Ponorogo, dealumination using hydrochloric acid, adsorption process of naphthol dyes using activated zeolite, and test of adsorption result with uv-vis spectrophotometry. The test results showed that the higher HCl concentration will increase adsorption capacity. This can be known from the concentration of naphthol dye which decreased both using natural zeolite Ponorogo and Purworejo. While the effectiveness of adsorption shows natural zeolite Purworejo has a greater adsorption capacity than Ponorogo with optimum conditions of dealumination using concentration HCl 3,9N.

Location of MTBE and toluene in the channel system of the zeolite mordenite: Adsorption and host-guest interactions

Energy Technology Data Exchange (ETDEWEB)

Arletti, Rossella, E-mail: rossella.arletti@unito.it [Department of Earth Sciences, University of Torino Via Valperga Caluso 35, I-10125, Torino (Italy); Martucci, Annalisa; Alberti, Alberto [Department of Earth Sciences, University of Ferrara, Via G. Saragat 1, I-44100, Ferrara (Italy); Pasti, Luisa; Nassi, Marianna [Department of Chemistry, University of Ferrara, Via L. Borsari 26, I-44100 Ferrara (Italy); Bagatin, Roberto [Research Centre for Non-Conventional Energy-Istituto ENI Donegani, Environmental Technologies, Via Fauser 4, I-28100 Novara (Italy)

2012-10-15

This paper reports a study of the location of Methyl Tertiary Butyl Ether (MTBE) and toluene molecules adsorbed in the pores of the organophylic zeolite mordenite from an aqueous solution. The presence of these organic molecules in the zeolite channels was revealed by structure refinement performed by the Rietveld method. About 3 molecules of MTBE and 3.6 molecules of toluene per unit cell were incorporated into the cavities of mordenite, representing 75% and 80% of the total absorption capacity of this zeolite. In both cases a water molecule was localized inside the side pocket of mordenite. The saturation capacity determined by the adsorption isotherms, obtained by batch experiments, and the weight loss given by thermogravimetric (TG) analyses were in very good agreement with these values. The interatomic distances obtained after the structural refinements suggest MTBE could be connected to the framework through a water molecule, while toluene could be bonded to framework oxygen atoms. The rapid and high adsorption of these hydrocarbons into the organophylic mordenite zeolite makes this cheap and environmental friendly material a suitable candidate for the removal of these pollutants from water. - graphical abstract: Location of MTBE (a) and toluene (b) in mordenite channels (projection along the [001] direction). Highlights: Black-Right-Pointing-Pointer We investigated the MTBE and toluene adsorption process into an organophilic zeolite mordenite. Black-Right-Pointing-Pointer The presence of MTBE and toluene in mordenite was determined by X-ray diffraction studies. Black-Right-Pointing-Pointer About 3 molecules of MTBE and 3.6 molecules of toluene per unit cell were incorporated into the zeolite cavities. Black-Right-Pointing-Pointer MTBE is connected to the framework through a water molecule. Black-Right-Pointing-Pointer Toluene is directly bonded to framework oxygen atoms.

Generalized synthesis of mesoporous shells on zeolite crystals

KAUST Repository

Han, Yu; Pitukmanorom, Pemakorn; Zhao, L. J.; Ying, Jackie

2010-01-01

A simple and generalized synthetic approach is developed for creating mesoporous shells on zeolite crystals. This method allows for the tailoring of thickness, pore size, and composition of the mesoporous shell, and can be applied to zeolites

Preparation of hierarchical micro-mesoporous aluminosilicate composites by simple Y zeolite/MCM-48 silica assembly

Energy Technology Data Exchange (ETDEWEB)

Enterría, Marina, E-mail: marina@incar.csic.es; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M.D.

2014-01-15

Highlights: • Hierarchical micro-mesoporous aluminosilicates were synthesized. • Y zeolite core/MCM-48 silica shell structures were obtained. • Y zeolite favors the formation of the mesostructure. • Porosity and structure can be varied by modifying the preparation variables. • Duration of the hydrothermal step has a great effect on the materials properties. -- Abstract: A simple procedure to obtain hierarchical micro-mesoporous aluminosilicate composites was developed by growing MCM-48 silica over commercial Y zeolite. The obtained hierarchical composites have a microporous core and a mesoporous shell. The process consists in assembling dispersed Y zeolite with a mesoporous silica phase that is formed “in situ” by “soft-templating” with cetryltrimethylammonium bromide (CTAB) as surfactant. The Y zeolite/MCM-48 silica ratio and aging time were varied to study their effects on the final porosity and structure of the hierarchical composites. The pore textural and structural characteristics of the composites did not match those of the corresponding Y zeolite/MCM-48 silica physical mixtures. This implies that the synthesized composites integrate micropores and mesopores in the same bulk. The obtained composites exhibited micropore and mesopore volumes ranging between 0.15–0.31 and 0.30–0.51 cm{sup 3}/g, respectively. X-ray diffraction and N{sub 2} adsorption results revealed that the presence of zeolite in the reaction medium favors the formation of mesopores in the obtained materials, especially for short hydrothermal treatments. TEM results showed that the obtained adsorbents are constituted by an integrated micro-mesoporous bimodal system in which Y zeolite is surrounded by a thin cover of MCM-48 silica.

Preparation of hierarchical micro-mesoporous aluminosilicate composites by simple Y zeolite/MCM-48 silica assembly

International Nuclear Information System (INIS)

Enterría, Marina; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M.D.

2014-01-01

Highlights: • Hierarchical micro-mesoporous aluminosilicates were synthesized. • Y zeolite core/MCM-48 silica shell structures were obtained. • Y zeolite favors the formation of the mesostructure. • Porosity and structure can be varied by modifying the preparation variables. • Duration of the hydrothermal step has a great effect on the materials properties. -- Abstract: A simple procedure to obtain hierarchical micro-mesoporous aluminosilicate composites was developed by growing MCM-48 silica over commercial Y zeolite. The obtained hierarchical composites have a microporous core and a mesoporous shell. The process consists in assembling dispersed Y zeolite with a mesoporous silica phase that is formed “in situ” by “soft-templating” with cetryltrimethylammonium bromide (CTAB) as surfactant. The Y zeolite/MCM-48 silica ratio and aging time were varied to study their effects on the final porosity and structure of the hierarchical composites. The pore textural and structural characteristics of the composites did not match those of the corresponding Y zeolite/MCM-48 silica physical mixtures. This implies that the synthesized composites integrate micropores and mesopores in the same bulk. The obtained composites exhibited micropore and mesopore volumes ranging between 0.15–0.31 and 0.30–0.51 cm 3 /g, respectively. X-ray diffraction and N 2 adsorption results revealed that the presence of zeolite in the reaction medium favors the formation of mesopores in the obtained materials, especially for short hydrothermal treatments. TEM results showed that the obtained adsorbents are constituted by an integrated micro-mesoporous bimodal system in which Y zeolite is surrounded by a thin cover of MCM-48 silica

Zeolite Formation and Weathering Processes in Dry Valleys of Antartica: Martian Analogs

Science.gov (United States)

Gibson, E. K., Jr.; Wentworth, S. J.; McKay, D. S.; Socki, R. A.

2004-01-01

Terrestrial weathering processes in cold-desert climates such as the Dry Valleys of Antarctica may provide an excellent analog to chemical weathering and diagenesis of soils on Mars. Detailed studies of soil development and the chemical and mineralogical alterations occurring within soil columns in Wright Valley, Antarctica show incredible complexity in the upper meter of soil. Previous workers noted the ice-free Dry Valleys are the best terrestrial approximations to contemporary Mars. Images returned from the Pathfinder and Spirit landers show similarities to surfaces observed within the Dry Valleys. Similarities to Mars that exist in these valleys are: mean temperatures always below freezing (-20 C), no rainfall, sparse snowfall-rapidly removed by sublimation, desiccating winds, diurnal freeze-thaw cycles (even during daylight hours), low humidity, oxidative environment, relatively high solar radiation and low magnetic fields . The Dry Valley soils contain irregular distributions and low abundances of soil microorganisms that are somewhat unusual on Earth. Physical processes-such as sand abrasion-are dominant mechanisms of rock weathering in Antarctica. However, chemical weathering is also an important process even in such extreme climates. For example, ionic migration occurs even in frozen soils along liquid films on individual soil particles. It has also been shown that water with liquid-like properties is present in soils at temperatures on the order of approx.-80 C and it has been observed that the percentage of oxidized iron increases with increasing soil age and enrichments in oxidized iron occurs toward the surface. The presence of evaporates is evident and appear similar to "evaporite sites" within the Pathfinder and Spirit sites. Evaporites indicate ionic migration and chemical activity even in the permanently frozen zone. The presence of evaporates indicates that chemical weathering of rocks and possibly soils has been active. Authogenic zeolites have

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.

PREPARATION, CHARACTERIZATIONS AND MODIFICATION OF Ni-Pd/NATURAL ZEOLITE CATALYSTS

Directory of Open Access Journals (Sweden)

Wega Trisunaryanti

2010-06-01

Full Text Available Preparation, and modification of Ni-Pd/natural zeolite as well as their characterizations had been carried out. The aim of this research for the fututure is to prepare the best characters catalyst for the conversion of waste plastics fraction to gasoline fraction (C5-C12 hydrocarbons. The preparation of catalysts was performed by reacting a natural zeolite with the precursor of Ni(NO32. 9H2O and PdCl2 in an ammonia solution (25%. The modifications were performed by varying the rasio of Ni/Pd loaded to the zeolite, whereas the Pd was previously loaded and total metal content was 1 wt.% based on the zeolite. The characterization of catalysts included determination of acidity gravimetrically by adsorption of ammonia or pyridine vapour  base method, metal content by Atomic Adsorption Spectrophotometer (AAS and X-ray Fluoresence (XRF and crystallinity by X-ray Diffraction (XRD. The treatment of catalysts using Etilene Diamine Tetra Acetic acid  (EDTA was performed to study the metal distribution on the outer or inner surface of the zeolite. The characterization results showed that the loading of metals to the zeolite increased its acidity and decreased its spesific surface area, however, did not defect its crystallnity.  The metals loaded on the zeolite were distributed inside the pore and at outer surface of the zeolite. For all catalyst samples, the acidities determined using ammonia were higher than those of pyridine, and the acidities determined before the EDTA treatment was lower than those after the treatment.  Metal contents of the zeolite before the EDTA treatment were higher than those after the treatment. The EDTA treatment enhanced the crystallinity of the sampel. The relationship between the metal rasio towards the acidity of the catalyst samples were in variation. Catalyst samples produced in this research have good characters, thus promisingly can be used for conversion process of waste plastics to gasoline fraction.    Keywords

Zeolite-catalyzed biomass conversion to fuels and chemicals

DEFF Research Database (Denmark)

Taarning, Esben; Osmundsen, Christian Mårup; Yang, Xiaobo

2011-01-01

Heterogeneous catalysts have been a central element in the efficient conversion of fossil resources to fuels and chemicals, but their role in biomass utilization is more ambiguous. Zeolites constitute a promising class of heterogeneous catalysts and developments in recent years have demonstrated...... their potential to find broad use in the conversion of biomass. In this perspective we review and discuss the developments that have taken place in the field of biomass conversion using zeolites. Emphasis is put on the conversion of lignocellulosic material to fuels using conventional zeolites as well...

Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

DEFF Research Database (Denmark)

Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng

2014-01-01

With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite-1 is reported and their high...... zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2-3nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50% conversion of ethanol with 98...

Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

DEFF Research Database (Denmark)

Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng

2014-01-01

With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite‐1 is reported and their high...... zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2–3 nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50 % conversion of ethanol with 98...

FUNDAMENTALS AND APPLICATIONS OF PERVAPORATION THROUGH ZEOLITE MEMBRANES

Science.gov (United States)

Zeolite membranes are well suited for separating liquid-phase mixtures by pervaporation because of their molecular-sized pores and their hydrophilic/hydrophobic nature, and the first commercial application of zeolite membranes has been for dehydrating organics [1]. Because of ...

Biomechanical analysis of the fixation systems for anterior column and posterior hemi-transverse acetabular fractures.

Science.gov (United States)

Lei, Jianyin; Dong, Pengfei; Li, Zhiqiang; Zhu, Feng; Wang, Zhihua; Cai, Xianhua

2017-05-01

The aim of this study was to evaluate the biomechanical properties of common fixation systems for complex acetabular fractures. A finite element (FE) pelvic model with anterior column and posterior hemi-transverse acetabular fractures was created. Three common fixation systems were used to fix the posterior wall acetabular fractures: 1. Anterior column plate combined with posterior column screws (group I), 2. Anterior column plate combined with quadrilateral area screws (group II) and 3. Double-column plates (group III). And 600 N, representing the body weight, was loaded on the upper surface of the sacrum to simulate the double-limb stance. The amounts of total and relative displacements were compared between the groups. The total amount of displacement was 2.76 mm in group II, 2.81 mm in group III, and 2.83 mm in group I. The amount of relative displacement was 0.0078 mm in group II, 0.0093 mm in group III and 0.014 mm in group I. Our results suggested that all fixation systems enhance biomechanical stability significantly. Anterior column plate combined with quadrilateral area screws has quite comparable results to double column plates, they were superior to anterior column plate combined with posterior screws. Copyright © 2017 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

Physical and mechanical properties of sand stabilized by cement and natural zeolite

Science.gov (United States)

Salamatpoor, Sina; Jafarian, Yaser; Hajiannia, Alborz

2018-05-01

Loose sands are prone to lose their shear strength when being subjected to static or cyclic loads. To this end, there exist several methods to improve the mechanical properties of sands, but the most crucial and viable approach is the one with the lowest harmful environmental impact both in production and recycling processes. In this regard, zeolite as a natural pozzolanic additive offers an eco-friendly improvement in strength parameters of cemented sandy soils. Thereby, in this study, a series of unconfined compressive strength (UCS) tests are conducted to evaluate the mechanical parameters of the zeolite-cemented sand. The results demonstrate a meaningful increase in the UCS of the treated sand samples for replacement of cement by zeolite at an optimum proportion of 40% in specimens with 14 and 28 days curing time. The effectiveness of the improvement process is demonstrated by the strength improvement ratio which was up to be 128% to 209% for the samples with 14 and 28 days curing time, respectively. With regard to the above results, zeolite can be introduced as a promising cement substitute in stabilization of sandy ground including backfills, roadbed, embankments, and other structural filling systems.

Efficiency of fly ash belite cement and zeolite matrices for immobilizing cesium

International Nuclear Information System (INIS)

Goni, S.; Guerrero, A.; Lorenzo, M.P.

2006-01-01

The efficiency of innovative matrices for immobilizing cesium is presented in this work. The matrix formulation included the use of fly ash belite cement (FABC-2-W) and gismondine-type Na-P1 zeolite, both of which are synthesized from fly ash of coal combustion. The efficiency for immobilizing cesium is evaluated from the leaching test ANSI/ANS 16.1-1986 at the temperature of 40 deg. C, from which the apparent diffusion coefficient of cesium is obtained. Matrices with 100% of FABC-2-W are used as a reference. The integrity of matrices is evaluated by porosity and pore-size distribution from mercury intrusion porosimetry, X-ray diffraction and nitrogen adsorption analyses. Both matrices can be classified as good solidify systems for cesium, specially the FABC-2-W/zeolite matrix in which the replacement of 50% of belite cement by the gismondine-type Na-P1 zeolite caused a decrease of two orders of magnitude of cesium mean Effective Diffusion Coefficient (D e ) (2.8e-09 cm 2 /s versus 2.2e-07 cm 2 /s, for FABC-2-W/zeolite and FABC-2-W matrices, respectively)

Microwave preparation of Li-zeolite directly from alumatrane and silatrane

International Nuclear Information System (INIS)

Sathupunya, Mathavee; Gulari, Erdogan; Wongkasemjit, Sujitra

2004-01-01

Li-zeolites were successfully synthesized in a one-step sol-gel process and microwave technique using silatrane and alumatrane as precursors and lithium hydroxide as the hydrolytic agent. Many types of Li-zeolites were obtained by controlling synthesis parameters. Perfect crystalline zeolite, EDI type zeolite, was obtained at 90 deg. C after heating for 60 min while ABW type zeolite was produced after heating for 300 min at 110 deg. C. With increasing temperature, a higher packing density product was generated. Changing Si/Al loading ratio highly influenced the morphology of the synthesized product. With increasing Al loading, more irregular morphology products were obtained. Changing Li 2 O/SiO 2 ratio, led to changes in the unit cell structure and crystal morphology. Lowering the Li 2 O/SiO 2 ratio to one produced FAU type zeolite at 110 deg. C for 240 min. The thermal stability of EDI and ABW were very low while that of FAU was higher which might come from the effect of low ring strain construction of FAU

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.

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.

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.

Adsorption methods for hydrogen isotope storage on zeolite sieves

International Nuclear Information System (INIS)

Cristescu, Ioana; Cristescu, Ion; Vasut, Felicia; Brad, Sebastian; Lazar, Alin

2001-01-01

Adsorption molecular sieves and activated carbon were used for hydrogen isotopes. The adsorption process proceeds at liquid nitrogen and liquid hydrogen temperatures. The synthetic zeolites have similar properties as natural zeolites, but they have a regular pore structure and affinity for molecules of different size with defined shapes. Experimental results obtained at liquid nitrogen and liquid hydrogen temperatures evidenced the efficient behavior of the activated carbon and zeolite sieves for hydrogen isotope temporary storage. (authors)

Evaluation of natural zeolite clinoptilolite efficiency for the removal of ammonium and nitrate from aquatic solutions

Directory of Open Access Journals (Sweden)

Mozhdeh Murkani

2015-01-01

Full Text Available Background: Surface water and groundwater pollution with various forms of nitrogen such as ammonium and nitrate ions is one of the main environmental risks. The major objectives of this study were to evaluate the capacity of natural zeolite (clinoptilolite to remove NO3– and NH4+ from polluted water under both batch and column conditions. Methods: The laboratory batch and column experiments were conducted to investigate the feasibility of clinoptilolite as the adsorbent for removal of nitrate (NO3– and ammonium (NH4+ ions from aqueous solution. The effects of pH, clinoptilolite dosage, contact time, and initial metal ion concentration on NO3– and NH4+ removal were investigated in a batch system. Results: Equilibrium time for NO3– and NH4+ ions exchange was 60 minutes and the optimum adsorbent dosage for their removal was 1 and 2.5 g/L, respectively. The adsorption isotherm of reaction (r> 0.9 and optimum entered concentration of ammonium and nitrate (30 and 6.5 mg/L, respectively were in accordance with Freundlich isotherm model. The ammonium removal rate increased by 98% after increasing the contact time. Conclusion: Our findings confirmed that natural Clinoptilolite can be used as one of effective, suitable, and low-costing adsorbent for removing ammonium from polluted waters.

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.

Water column separation in power plant circulating water systems

International Nuclear Information System (INIS)

Papadakis, C.N.

1977-01-01

Power plant circulating water system condensers operate with a siphon. Column separation is a common occurence in such condensers during low pressure transients. The assumptions that no gas evolves from solution leads to very conservative values of maximum pressures upon rejoining of separated column. A less conservative method led to the development of a macroscopic mathematical model including the presence of air and vapor in a cavity which forms at the top of the condenser. The method of characteristics is used to solve the equations. A case study is analyzed to illustrate the applicability of the developed mathematical model and to provide comparisons of the results obtained

Curbing the greenhouse effect by carbon dioxide adsorption with zeolite 13X

Energy Technology Data Exchange (ETDEWEB)

Konduru, N.; Lindner, P.; Assaf-Anad, N.M. [Manhattan College, Bronx, NY (USA). Dept. of Chemical Engineering

2007-12-15

The removal of carbon dioxide (CO{sub 2}) from industrial emissions has become essential in the fight against climate change. In this study, we employed Zeolite 13X for the capture and recovery of CO{sub 2} in a flow through system where the adsorbent was subjected to five adsorption-desorption cycles. The influent stream contained 1.5% CO{sub 2} at standard conditions. The adsorbent bed was 1 in. in length and 1 in.3/8 in dia., and was packed with 10 g of the zeolite. Temperature swing adsorption (TSA) was employed as the regeneration method through heating to approximately 135{sup o}C with helium as the purge gas. The adsorbent capacity at 90% saturation was found to decrease from 78 to 60g CO{sub 2}/kg{sub Zeolite13X} after the fifth cycle. The CO{sub 2} capture ratio or the mass of CO{sub 2} adsorbed to the total mass that entered the system decreased from 63% to only 61% after the fifth cycle. The CO{sub 2} recovery efficiency ranged from 82 to 93% during desorption, and the CO{sub 2} relative recovery, i.e., CO{sub 2} desorbed for the nth cycle to CO{sub 2} adsorbed for the first cycle, ranged from 88 to 68%. The service life of the adsorbent was determined to be equal to eleven cycles at a useful capacity of 40g CO{sub 2}/kg{sub Zeolite13X}.

Studies on the formation of hierarchical zeolite T aggregates with well-defined morphology in different template systems

Science.gov (United States)

Yin, Xiaoyan; Chu, Naibo; Lu, Xuewei; Li, Zhongfang; Guo, Hong

2016-01-01

In this paper, the disk-like and pumpkin-like hierarchical zeolite T aggregates consisted of primary nano-grains have been hydrothermally synthesized with and without the aid of the second template. The first template is used with tetramethylammonium hydroxide (TMAOH) and the second template is used with triethanolamine (TEA) or polyving akohol (PVA). A combination of characterization techniques, including XRD, SEM, TEM and N2 adsorption-desorption to examine the crystal crystallinity, morphology and surface properties of hierarchical zeolite T aggregates. In the single-template preparation process, the two-step varying-temperature treatment has been used to improve the meso-porosity of zeolite T aggregates. In the double-template preparation process, the amounts of PVA or TEA on the crystallinity, morphology and meso-porosity of zeolite T aggregates have been studied. It has been proved that the interstitial voids between the primary grains of aggregates are the origin of additional mesopores of samples. The micro- and meso-porosities of samples prepared with and without the second template have been contrasted in detail at last. In particular, the sample synthesized with the addition of PVA presents a hierarchical pore structure with the highest Sext value of 122 m2/g and Vmeso value of 0.255 cm3/g.

Detergent zeolite complex "Ceosil", Tallinn, Estonia

OpenAIRE

Stanković Mirjana S.; Pezo Lato L.

2003-01-01

The IGPC Engineering Department, together with the "Birac", Zvornik Engineering Department designed basic projects for detergent zeolite production, using waste flotation sand and hydrates. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, production plant in Tallinn, Estonia was constructed, with a capacity of 100,000 t/y from 1989. to 1993. This plant became the biggest producer of detergent zeolite in the world.Several goals we...

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.

Zeolite from fly ash: synthesis and characterization

Indian Academy of Sciences (India)

Unknown

to attempt making zeolite from fly ash (Höller and Wir- sching 1985; Henmi ... thermal treatment method to synthesize low silica NaX- type zeolite from .... catalytic applications. Mixture of ... amount of Fe2O3 and the oxides of Mg, Ca, P, Ti etc. The chemical ..... This work is partly supported by the Ministry of Human. Resource ...

Picosecond infrared activation of methanol in acid zeolites

NARCIS (Netherlands)

Bonn, Miacha; van Santen, Rutger A.; Lercher, J.A.; Kleyn, Aart W.; Bakker, H.J.; Bakker, Huib J.

1997-01-01

Highly porous, crystalline zeolite catalysts are used industrially to catalyze the conversion of methanol to gasoline. We have performed a picosecond spectroscopic study providing insights into both the structure and the dynamics of methanol adsorbed to acid zeolites. We reveal the adsorption

Defluorination of drinking water using surfactant modified zeolites ...

African Journals Online (AJOL)

This study focused on the removal of fluoridefrom groundwater by employing surfactant modified zeolites (SMZ) synthesized using locallyavailable kaolin material as precursor. The zeolite synthesis involved calcination of kaolin, alkaline fusion and hydrothermal treatment. The final product was modified with 5g/L ...

Calcining natural zeolites to improve their effect on cementitious mixture workability

International Nuclear Information System (INIS)

Seraj, Saamiya; Ferron, Raissa D.; Juenger, Maria C.G.

2016-01-01

Despite the benefits to long-term concrete durability, the use of natural zeolites as supplementary cementitious materials (SCMs) is uncommon due to their high water demand. The motivation of the research presented here was to better understand how the physical and chemical characteristics of natural zeolites influenced the workability of cementitious mixtures and whether those properties could be modified through calcination to mitigate the high water demand of natural zeolites. In this research, three different natural zeolites were characterized in their original and calcined states using x-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) surface area measurements. Rheology experiments were then conducted on cementitious pastes containing these natural zeolites, in their original and calcined states, to assess mixture viscosity and yield stress. Results showed that calcination destabilized the structure of the natural zeolites and reduced their surface area, which led to an improvement in mixture viscosity and yield stress.

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

Fly ash based zeolitic pigments for application in anticorrosive paints

International Nuclear Information System (INIS)

Shaw, Ruchi; Tiwari, Sangeeta

2016-01-01

The purpose of this work is to evaluate the utilization of waste fly ash in anticorrosive paints. Zeolite NaY was synthesized from waste fly ash and subsequently modified by exchanging its nominal cation Na + with Mg 2+ and Ca 2+ ions. The metal ion exchanged zeolite was then used as anticorrosive zeolitic pigments in paints. The prepared zeolite NaY was characterized using X-Ray diffraction technique and Scanning electron microscopy. The size, shape and density of the prepared fly ash based pigments were determined by various techniques. The paints were prepared by using fly ash based zeolitic pigments in epoxy resin and the percentages of pigments used in paints were 2% and 5%. These paints were applied to the mild steel panels and the anticorrosive properties of the pigments were assessed by the electrochemical spectroscopy technique (EIS).

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.

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

Synthesis of Zeolite-X from Bottom Ash for H2 Adsorption

Science.gov (United States)

Kurniawan, R. Y.; Romadiansyah, T. Q.; Tsamarah, A. D.; Widiastuti, N.

2018-01-01

Zeolite-X was synthesized from bottom ash power plant waste using fusion method on air atmosphere. The fused product dissolved in demineralized water and aluminate solution was added to adjust the SiO2/Al2O3 molar ratio gel prior hydrothermal process. The synthesis results were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Fourier Transform Infrared (FTIR). The results showed that the zeolite-X has a high crystallinity with octahedral particle. The pure-form zeolite-X then was characterized and tested for H2 gas adsorption by gravimetric method to determine the H2 gas adsorption capacity of zeolite-X from bottom ash and it was compared to synthetic zeolite-X.

Influence of zeolite nanofillers on properties of polymeric materials

OpenAIRE

Kopcová, M.; Ondrušová, D.; Krmela, J.; Průša, P.; Pajtášová, M.; Jankurová, Z.

2012-01-01

The present work deals with the preparation and study of modified polymeric materials with the replacement of carbon black by nanofillers on the basis of zeolite that is environmentally friendly. Natural zeolites from a group of aluminosilicate nanoporous materials have wide range of possibilities for applications that are environmentally friendly. Zeolites can be used in the role of fillers into the polymer materials too [1]. The given work deals with the preparation and study of modif...

A comparative evaluation of IONSIV reg-sign IE-911 and chabazite zeolite for the removal of radiostrontium and cesium from wastewater

International Nuclear Information System (INIS)

Bostick, D.T.; DePaoli, S.M.; Guo, B.

1998-01-01

Natural chabazite zeolite was selected as the baseline treatment technology for the removal of fission products, namely 90 Sr and 137 Cs, from near-neutral-pH process wastewater and groundwater. The sorbent IONSIV reg-sign IE-911, a crystalline silicotitanate manufactured by UOP, was recently tested in this capacity and found to compare extremely well against the baseline material. This paper presents and compares the results of similar batch and column tests performed using both materials, and summarizes the physical and chemical characteristics of the sorbents

Study of the ortho-positron annihilation process in zeolite Y

International Nuclear Information System (INIS)

Alvarado D, M. E.

2010-01-01

For several years a great interest has existed for the study of the natural and synthetic zeolites due to its properties. The porosity, one of their main characteristics allows that these materials are used as molecular sieves, catalysts, gases drying, etc. In order to investigating the porosity and other zeolite properties one carries out the study of the process of positron annihilation lifetime spectroscopy (Pals). This is a technique that provides information about the size and the pores form since is highly sensitive to the free volume and the superficial area of those porous materials as the zeolites. The study began with the elaboration of zeolite Y tablets in a hydraulic press where different pressures (from 0 to 1.26 GPa) and masses (70, 80 and 100 mg) were proven to obtain the estimate porosity of each tablet. A graph was elaborated and the effect of the mass and pressure with regard to the zeolite porosity was analyzed. Later on, the powder and tablets of 70 mg were characterized by means of X-ray diffraction (the glass size, interplanar distance, length and the volume of the unitary cell); scanning electron microscopy (the particles size and morphology); thermo gravimetric analysis (dehydration temperature and the stability up to 700 C) and the Brunauer Emmett Teller method (specific area). After the zeolite Y tablets characterization was carried out the positron annihilation process by means of Pals where its free volume of zeolite Y was analyzed, which includes to the structural cavities and the interparticle volume. The powdered zeolite was analyzed to different experimental conditions (preparation of the sample and the Pals equipment) to obtain the optimal conditions (a window with a time of 400 ns and a enlarged energy window) of analysis. On the other hand, the tablets were analyzed under optimal conditions to obtain the four components of time and intensity (τ, Ι), result of the different ways of positrons annihilation in the zeolite. These

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

Theoretical determination of proton affinity differences in zeolites

NARCIS (Netherlands)

Kramer, G.J.; Santen, van R.A.

1993-01-01

An important factor in zeolite catalysis is the proton affinity, i.e., the energy required to remove a proton from the zeolite lattice. Differences in proton affinity are expected to influence the catalytic activity of acid sites, making the catalytically active sites inhomogeneous (within one

Dietary effects of Ca-zeolite supplementation on some blood and ...

African Journals Online (AJOL)

smyo

to the Al, Si, Zn, Na or K concentrations of zeolite, because these minerals have been ... The SiO2, Al2O3, H2O related to loss on ignition, and CaO are the essential ...... The effect of interaction between narasin and nicarbazin with zeolite ... Protective role of zeolite on short- and long-term lead toxicity in the teleost fish.

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%.

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.

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)

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)

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.)

Lithium modified zeolite synthesis for conversion of biodiesel-derived glycerol to polyglycerol

Energy Technology Data Exchange (ETDEWEB)

Ayoub, Muhammad, E-mail: muhammad.ayoub@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS, 31750, Tronoh, Perak, Malaysia and School of Chemical Engineering, Universiti Sains Malaysia, 43000, Pinang (Malaysia); Abdullah, Ahmad Zuhairi, E-mail: chzuhairi@usm.my [School of Chemical Engineering, Universiti Sains Malaysia, 43000, Pinang (Malaysia); Inayat, Abrar, E-mail: abrar.inayat@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS, 31750, Tronoh, Perak (Malaysia)

2014-10-24

Basic zeolite has received significant attention in the catalysis community. These zeolites modified with alkaline are the potential replacement for existing zeolite catalysts due to its unique features with added advantages. The present paper covers the preparation of lithium modified zeolite Y (Li-ZeY) and its activity for solvent free conversion of biodiesel-derived glycerol to polyglycerol via etherification process. The modified zeolite was well characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Nitrogen Adsorption. The SEM images showed that there was no change in morphology of modified zeolite structure after lithium modification. XRD patterns showed that the structure of zeolite was sustained after lithium modification. The surface properties of parent and modified zeolite was also observed N{sub 2} adsortion-desorption technique and found some changes in surface area and pore size. In addition, the basic strength of prepared materials was measured by Hammet indicators and found that basic strength of Li-ZeY was highly improved. This modified zeolite was found highly thermal stable and active heterogamous basic catalyst for conversion of solvent free glycerol to polyglycerol. This reaction was conducted at different temperatures and 260 °C was found most active temperature for this process for reaction time from 6 to 12 h over this basic catalyst in the absence of solvent.

Characterization of natural and modified zeolites using ion beam analysis techniques

Energy Technology Data Exchange (ETDEWEB)

Andrade, E. [Instituto de Fisica, Departamento de Fisica Experimental, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 (Mexico)], E-mail: andrade@fisica.unam.mx; Solis, C. [Instituto de Fisica, Departamento de Fisica Experimental, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 (Mexico); Aceves, J.M.; Miranda, R. [Facultad de Estudios Superiores Cuautitlan Itzcalli, Departamento de Quimica, Universidad Nacional Autonoma de Mexico, 1 de Mayo S/N, Cuatitlan Itzcalli, Edo. de Mexico, C.P. 74540 (Mexico); Cruz, J. [Instituto de Fisica, Departamento de Fisica Experimental, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 (Mexico); Rocha, M.F. [Escuela Superior de Ingenieria Mecanica y Electrica, Instituto Politecnico Nacional, U.P. ' Adolfo Lopez Mateos' , Zacatenco, Del. Gustavo A. Madero, Mexico D.F. 07738 (Mexico); Zavala, E.P. [Instituto de Fisica, Departamento de Fisica Experimental, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 (Mexico)

2008-05-15

Zeolites are very important materials in catalytic and industrial processes. Natural, modified and synthetic zeolites have a wide range of uses because of their good adsorption, ion exchange capacity and catalytic properties. Mexico is an import source of natural zeolites, however their utilization in the natural form is limited due to the presence of trace metallic impurities. For example, metals such as vanadium and chromium inhibit the elimination of sulfur in hydrocarbons. Therefore, it is important to know the precise composition of the zeolite material. In this work, we report the elemental characterization of zeolites using various IBA techniques. {sup 3}He{sup +} and {sup 2}H{sup +} beams were used to measure the major element concentrations (Si, Al, O, C) by RBS and NRA. PIXE and SEM-EDS were used to measure the total trace element content (V, Cr, Fe, Ni, Cu, Zn, Rb, Sr, Zr, Pb, etc). Additionally, XRD was used to study the zeolite crystal structure.

PEMANFAATAN ZEOLIT DARI ABU SEKAM PADI DENGAN AKTIVASI ASAM UNTUK PENURUNAN KESADAHAN AIR

Directory of Open Access Journals (Sweden)

VH Putranto

2016-04-01

Full Text Available Aktivasi menggunakan asam kuat dalam sintesis zeolit dikenal dapat meningkatkan kemampuan zeolit sebagai adsorben. Penelitian ini bertujuan untuk memanfaatkan abu sekam padi sebagai sumber silika yang diaktivasi dengan HCl 2 M pada sintesis zeolit secara hidrotermal dan memanfaatkan zeolit hasil sintesis untuk menurunkan tingkat kesadahan air sumur. Proses aktivasi dilakukan dengan menggunakan larutan HCl 2 M. Zeolit hasil sintesis diuji secara kualitatif menggunakan Spektrofotometer Inframerah (FTIR dan Difraksi Sinar-X (XRD kemudian dimanfaatkan untuk menurunkan kadar ion logam Ca2+ dan Mg2+ penyebab kesadahan air dengan variasi waktu kontak (0, 20, 30, 40, 50, 60, 90, dan 120 menit dilanjutkan variasi massa zeolit sintetis (0,05; 0,1; 0,125; 0,25; serta 0,5 gram per volume air sumur 25 ml. Hasil uji komposisi kimia dengan Fluoresensi Sinar-X menunjukkan abu sekam padi yang telah diaktivasi memiliki kadar silika (SiO2 yang lebih tinggi yakni mencapai 95,83%. Hasil penelitian menunjukkan bahwa zeolit sintetis yang dihasilkan merupakan zeolit tipe NaY (zeolite like dengan kristal cancrinite sebagai fasa dominan. Adsorbsi optimum ion logam Ca2+ dan Mg2+ dalam air sumur oleh zeolit hasil sintesis terjadi pada waktu 60 menit dengan penyerapan optimum sebesar 94,71% Ca2+ dan 84,55% Mg2+ serta pada massa adsorben optimum 0,125 gram dengan penyerapan optimum sebesar 93,02% Ca2+ dan 83,78% Mg2+.Activation using a strong acid in zeolite synthesis is known can enhance the ability of zeolite as adsorbent. This study aims to utilize rice husk ash as a source of silica, which is activated with 2 M HCl in zeolite synthesis hydrothermally and apply the zeolite to reduce the level of hardness in well water. The activation process is performed by using HCl 2 M solution. Zeolite product is analyzed qualitatively using infrared spectrometer (FTIR and X-ray Diffraction (XRD and then used to reduce the levels of metal ions Ca2+ and Mg2+ which cause water hardness

Catalytic Flash Pyrolysis of Biomass Using Different Types of Zeolite and Online Vapor Fractionation