Antiferromagnetic Phase Transition of K-Rb Alloy Nanoclusters Incorporated in Sodalite

Takehito Nakano,Yuko Ishida,Atsufumi Hanazawa,Yasuo Nozue 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12

We prepared Rb-rich K-Rb alloy nanoclusters arrayed in the regular nanospace of aluminosilicatesodalite which has a bcc arrangement of cages. The average chemical formula of the cluster is(K1.5Rb2.5)3+, where one unpaired s-electron is shared by four alkali cations and is confined in acage. The magnetic susceptibility and the electron spin resonance clearly show an antiferromagneticphase transition at a N´eel temperature TN of approximately 90 - 100 K. The observed TNis higher than that in K3+4 (TN = 72 K) and (K3Rb)3+ clusters (TN = 80 K) in sodalites. Thisresult indicates a systematic enhancement of the antiferromagnetic exchange coupling between theadjacent nanoclusters by substituting Rb atoms for K ones. The size and the spatial distributionof the s-electron wave function in the nanocluster play a key role in the exchange coupling.

소다라이트(sodalite)의 합성 및 수소흡착

이공희 ( Lee Gong Hui ),박찬교 ( Park Chan Gyo ) 한국공업화학회 2003 공업화학 Vol.14 No.8

포자자이트(faujasite)계통의 제올라이트-A, 및 소다라이트(sodalite)를 합성하였으며 이의 흡착특성을 조사하였다. β-케이지만으로 구성된 소다라이트가 α 및 β-케이지로 이루어진 제올라이트에 비해 우수한 흡착특성을 보였다. 실험결과 소다라이트의 경우에 수소저장매체로서의 이용가능성이 높은 반면에 제올라이트의 경우에는 기공에 대한 적당한 조절기구가 확립되어야 이용가능성을 보였다. From the known chemical compositions and structures, the zeolite and sodalite which belong to the faujasite type have been synthesized and their absorption properties have been investigated by using hydrogen gas. The results suggest that the sodalite containing only P-cages in their structures possess the higher degree of absorbate gas. Accordingly, sodalite cages are particularly suitable for hydrogen storage, white zeolites could be used for storage after manipulating the window with any bulky cations.

물유리에서 소달라이트의 합성: 합성모액 조성이 결정화도와 입자 크기에 미치는 영향

배송은 ( Song Eun Bae ),서곤 ( Gon Seo ),송미경 ( Mee Kyung Song ),노경태 ( Kyoung Tai No ) 한국화학공학회 2009 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.47 No.4

Development of a novel method for the removal of diazinon pesticide from aqueous solution and modeling by artificial neural networks (ANN)

Hossein Esfandian,Abdolraouf Samadi-Maybodi,Mehdi Parvini,Behnam Khoshandam 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.35 No.-

In this study, perlite was used as a low-cost source of Si and Al to synthesize the sodalite zeolite viahydrothermal synthesis method. Cu2O nanoparticles (30–60 nm) were coated on a bed of sodalitezeolite. Toward this aim, a series of batch adsorption experiments was carried out and the sorption ofdiazinon from aqueous solutions on acid treated zeolite (ATZ) with dilute H2SO4 solutions and modifiedzeolite by Cu2O nanoparticles (MZ) were also determined. Results showed that Cu2O nanoparticles havea significant effect on the diazinon removal processing from aqueous solution. Maximum adsorptionrates were 98.2% (with 0.2, 20, 6 of adsorbent dose, contact time and pH, respectively, for MZ) and 63.4%(with 0.3, 80, 6 of adsorbent dose, contact time and pH, respectively, for ATZ). Three equations, i.e.,Morris–Weber, Lagergren (pseudo first order) and pseudo second order have been applied to study thekinetics of removal process. The diazinon sorption process was well described by the pseudo secondorder (type 2) kinetic model. The Langmuir, Freundlich, Temkin and Dubnin–Randkovich (D–R) modelswere tested on sorption data to estimate the sorption capacity, intensity and energy. Langmuir (type 1)isotherm provided the best fit to the equilibrium data with maximum adsorption capacity of 61.73 and15.10 mg/g for MZ and ATZ, respectively. The thermodynamic parameters DH, DS and DG wereevaluated. Thermodynamic parameters showed that the sorption of diazinon onto zeolite was feasible,spontaneous and exothermic under studied conditions. Artificial neural network (ANN) model was alsoapplied for modeling of diazinon removal from aqueous solution by ATZ and MZ. There was a goodagreement between the experimental and predicted values with seven neurons in hidden layer.

공업용 물유리를 출발물질로 한 흡수용 제올라이트 제조 공정 연구

임형미 ( Hyung Mi Lim ),정상진 ( Sang Jin Jung ),안병길 ( Byeng Gil Ahn ),최병현 ( Byung Hyun Choi ),이명영 ( Myung Young Lee ) 한국공업화학회 2003 공업화학 Vol.14 No.1

본 연구는 공업용 물유리와 액상 알루민산나트룸을 출발물질로 하여, A형 제올라이트를 합성할 때 합성 변수에 따른 결정형과 그 특성에 대한 것으로, 출발물질의 몰비, 반응온도, 숙성 조건, 결정화 조건 및 가열 속도에 따른 생성물의 결정형, 결정화도, 입자 형성, 입도, 양이온 교환능, 흡습량의 변화를 관찰하였다. 일반적으로는 숙성한 조건에서 생성된 입자가 더 작고 균일한 크기의 입자를 얻었다. 숙성과정을 거치지 않은 경우, 가열속도가 빠르면 경쟁상으로 알려진 소달라이트상이 일부 관찰되기도 한였다. 합성된 제올라이트는 주사전자현미경, X선 분말 회절 및 FT-IR 분광기를 이용해 분석하였다. 실온 고습 조건에서 흡습량을 확인한 결과 A형 제올라이트의 경우 초기 흡습 속도는시간당 0.3~0.4wt%이나 소달라이트는 시간당 0.07wt% 정도로 작고 15일 방치 후 최대 흡습량은 A형 제올라이트의 경우 26wt% 소달라이트는 14wt% 정도이다. In the synthesis of zeolite with industrial water glass and sodium aluminate, the synthesis condition and water adsorption characteristics of zeolite were studied. It was found that type of zeolite, crystallinity, morphology, cation exchange capacity, water adsorption capacity depended on molar ratio of starting material, reaction temperature, aging condition, crystallization condition, and heating rate. In general, aging led to production of zeolite particles with smaller and more uniform in size. Without aging, simultaneous formation of sodalite phase was apparent when the heating rate was fast. The products were analyzed by scanning electron microscopy, X-ray powder diffractometry, and FT-IR spectrometry. The initial water adsorption rate was 0.3~0.4wt%/h and 0.07wt%/h and the maximum water adsorption capacity was 26wt% and 14wt% for NaA and sodalite, respectively, in the humid chamber at room temperature.

Effect of theTEOS /Al(i-pro)3 mol ratio in the composition on the crystal morphology of zeolites

김익진,Wei Zhao,Xiaoou Fan,Jeong Ho Chang,Ludwig J. Gauckler 한양대학교 세라믹연구소 2010 Journal of Ceramic Processing Research Vol.11 No.2

The interest is focused on the control of crystal morphology of single phase zeolite nanocrystals from cube, LTA to octahedron,Faujasite by the mol ratio of TEOS /Al(i-pro)3 in the mother solution, a Al(i-pro)3 : 2.2 TEOS: 2.4-5.7 TMAOH: 0.3 NaOH :200 H2O compositions. Well- controlled single nanocrystals of a high quality zeolite LTA with a size of 264 nm and sodalite with a size of 30-50 nm were synthesized by the compositions having a TEOS /Al(i-pro)3 : 2.2 and 5.2, respectively. The synthesized crystals were characterized by scanning electron microscopy (SEM). high resolution transmission electron microscopy(HRTEM), X-ray powder diffraction(XRD), and dynamic light scattering (DLS).

Pyroprocess Experiments at ENEA Laboratories

Giorgio DE ANGELIS,Elio BAICCHI,Mauro CAPONE,Carlo FEDELI,Massimo SEPIELLI,Giuliano TIRANTI,Mirko DA ROS,Francesca GIACOBBO,Marco GIOLA,Elena MACERATA,Mario MARIANI 한국방사성폐기물학회 2015 방사성폐기물학회지 Vol.13 No.S

A new facility, known as Pyrel III, has been installed at ENEA laboratories for pyrochemical process studies under inactive conditions. It is a pilot plant which allows electrorefining and electroreduction experiments to be conducted on simulated fuel. The main component of the plant is a zirconia crucible. The crucible is heated by a furnace which is supported in an externally water-cooled well under the floor of a steel glove-box, where an argon atmosphere is maintained by a continual purge of about 10 L·min-1. The vessel is loaded with LiCl-KCl eutectic salt (59-41 mol%) and is currently operated at 460 °C. Several improvements on Pyrel II (the previous operating plant) have been introduced into Pyrel III. They are described in detail, together with the results from the first experimental campaign which used lanthanum metal. Moreover, studies about the treatment of chloride salt wastes from pyroprocesses have been conducted in parallel. They follow two main routes: on one hand, a matrix termed sodalite, a naturally occurring mineral containing chlorine, has been synthesized from a mix of nepheline, simulated exhausted salts and glass frit; on the other hand, a novel method proposed by Korea Atomic Energy Research Institute (KAERI) is under assessment. The final waste forms have been fully characterized with the support of the Politechnique of Milan, by means of density measurements, thermal analysis, and stereomicroscopy observations, FTIR, XRD, and RAMAN spectra, as well as leach tests under static conditions.

Synthesis of mesoporous geopolymers containing zeolite phases by a hydrothermal treatment

Lee, N.K.,Khalid, H.R.,Lee, H.K. Elsevier 2016 Microporous and mesoporous materials Vol.229 No.-

<P>The present study investigates the synthesis of mesoporous geopolymers containing different nano crystalline zeolite phases. A hydrothermal treatment procedure was utilized to synthesize the mesoporous geopolymers using fly ash, slag and alkaline solution. The effects of slag addition and molar ratio of alkaline solution on the microstructure and mechanical strength of the geopolymers were investigated and evidenced by XRD analysis, compressive strength and nitrogen adsorption tests. The test results showed that the geopolymers incorporating fly ash and slag consisted of Na-P1 and Sodalite zeolite phases, and had the characteristic of mesoporous materials (2 nm < pore size < 50 nm) in which capillary condensation may occur. The highest compressive strength of the geopolymers was 16.57 MPa, and the desired mesoporous characteristics were met by adding 20% slag content to fly ash and adopting the hydrothermal process at a relatively low temperature. The highest BET surface area and single point adsorption pore volume of the mesoporous geopolymers were 114.16 m(2)/g and 0.2677 cm(3)/g, respectively. (C) 2016 Elsevier Inc. All rights reserved.</P>

Zeolitic Conversion of Gochang Loess

Lee, Sun Hee,Ahn, Byoung Joon,Chang, Wonghil,Kam, Sang-Kyu,Lee, Min-Gyu 한국공업화학회 2005 Journal of Industrial and Engineering Chemistry Vol.11 No.2

Zeolites were synthesized using Gochang loess, which is found abundantly in Gochang province, Korea. Because Gochang loess contains large amounts of silica and alumina, ca. 80 wt%, the zeolitic conversion of the loess was performed using hydrothermal synthesis in alkaline conditions. Experimental parameters, such as the reaction temperature, alkali concentration, and reaction time were controlled to determine the best zeolite synthesis conditions. Na-P1 zeolite, hydroxy sodalite, analcime, and cancrinite phases were identified under various experimental conditions. Na-P1 zeolite, which was observed under a limited temperature and alkali concentration range, exhibited a higher cation exchange capacity (CEC) and heavy metal removal selectivity than did the zeolite produced from coal fly ash. The results showed that the serpentine group, the major clay component of Gochang loess, could be easily converted into the zeolite phase.

Zeolitic Conversion of Cheju Scoria

Jeon, Byoung Eun,Ahn, Byoung Joon,Chang, Wonghil,Kam, Sang-Kyu,Lee, Min-Gyu 한국공업화학회 2004 Journal of Industrial and Engineering Chemistry Vol.10 No.4

Various zeolite-type materials have been synthesized using Cheju Scoria, which is widely distributed in Cheju Island, Korea. Cheju Scoria is composed mainly of plagioclase, pyroxene, hematite, and aluminosilicate glass. Since the plagioclase and glass components can be used as Si and Al sources, the zeolitic conversion of Scoria was examined using a conventional hydrothermal synthesis under alkaline conditions. Na-P1 zeolite, hydroxy sodalite, nepheline hydrate, analcime, and cancrinite were obtained by using different reaction temperatures and NaOH concentrations. Na-P1 was observed at 120℃ in 2 M NaOH over a long reaction period, while hydroxy sodalite was formed over a wide range of reaction temperatures, 100 to 150℃, in > 3 M NaOH.