共查询到20条相似文献,搜索用时 31 毫秒
1.
Masashi Miyakawa Kiyoshi Kobayashi Takashi Taniguchi 《Journal of the American Ceramic Society》2017,100(4):1285-1289
Solid solutions of 12CaO·7Al2O3 (C12A7) and 12SrO·7Al2O3 (S12A7) crystals were synthesized under high pressure. X‐ray diffraction patterns revealed that the lattice constants of the synthesized samples depend linearly on the compositional ratio of C12A7 and S12A7. Electron‐probe X‐ray microanalyses show that the chemical compositions of the crystals are represented by xC12A7·(1?x)S12A7 (0<x<1). These results indicate that the variation in the lattice constants is originated from a difference in the ionic radii of Ca2+ and Sr2+ ions. From impedance measurements, it was found that S12A7 has the highest conductivity (~1 × 10?3 Scm?1 at 550°C) among the solid solutions in the C12A7–S12A7 system. 相似文献
2.
《Ceramics International》2022,48(21):31614-31626
The utilization of rare earth resources, especially secondary resources (e.g., RE-oxide system slag), has been limited by the lack of thermodynamic information. In order to supplement and improve the thermodynamic data related to rare earth, the equilibrium experiments of SiO2–Ce2O3–CaO-25 wt %Al2O3 system phase diagram was carried out at 1673 K and 1773 K by the high-temperature isothermal equilibration/quenching technique in current paper. The composition of seven phase regions were determined by FE-SEM, XRD, EPMA and XRF analysis on the samples obtained by high temperature equilibrium technology at 1673 K and 1773 K, including the primary crystal regions of three compounds (C2AS, 2CaO·SiO2, CaO·2Ce2O3·3SiO2) and three three-phase coexistence regions (L + C2AS + 2CaO·SiO2, L + C2AS + CaO·2Ce2O3·3SiO2, L + CaO·2Ce2O3·3SiO2+CeAl11O18) and a liquid region. The phase relations and isotherms of SiO2–Ce2O3–CaO-25 wt %Al2O3 system obtained in current work are beneficial to the recycling of rare earth resources containing cerium. 相似文献
3.
《Journal of the European Ceramic Society》2014,34(2):533-539
Equilibrium phase relations in the system CaO·SiO2Na2O·SiO2Na2O·Al2O3·6SiO2 at 40–80 wt% Na2O·Al2O3·6SiO2 composition range have been experimentally studied at temperatures between 800 °C and 1200 °C. The liquidus temperature was determined with differential scanning calorimetry. The equilibrated samples were quenched with pressurized nitrogen, and examined with electron probe X-ray microanalysis and X-ray diffraction for identification of microstructure and phase relations. Five primary phase fields, CaO·SiO2, Na2O·SiO2, Na2O·2CaO·3SiO2, 2Na2O·CaO·3SiO2 and Na2O·Al2O3·6SiO2 were established. The ternary eutectic point of CaO·SiO2, Na2O·2CaO·3SiO2 and Na2O·Al2O3·6SiO2 was determined to be at 1030 °C with the composition of 29.0 wt% CaO·SiO2, 12.0 wt% Na2O·SiO2 and 59.0 wt% Na2O·Al2O3·6SiO2. Peritectic reaction of Na2O·2CaO·3SiO2, 2Na2O·CaO·3SiO2 and Na2O·Al2O3·6SiO2 occurred at 930 °C with the composition of 13.0 wt% CaO·SiO2, 29.0 wt% Na2O·SiO2 and 58.0 wt% Na2O·Al2O3·6SiO2. The liquidus surface projection of the ternary system has been constructed in the composition region important for the bottom ash application. 相似文献
4.
Isabel F. Sáez del Bosque Manuel Martín‐Pastor Sagrario Martínez‐Ramírez María Teresa Blanco‐Varela 《Journal of the American Ceramic Society》2013,96(3):957-965
This study aimed to monitor the effect of temperature and the addition of nanosilica on the nanostructure of the C–S–H gel forming during tricalcium silicate (C3S) hydration. Two types of paste were prepared from a synthesized T1 C3S. The first consisted of a blend of deionized water and C3S at a water/solid ratio of 0.425. In the second, a 90 wt% C3S + 10 wt% of nanosilica blend was mixed with water at a water/solid ratio of 0.7. The pastes were stored in closed containers at 100% RH and 25°C, 40°C, or 65°C. The hydration reaction was detained after 1, 14, 28, or 62 d with acetone, and then pastes were studied by 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR).The main conclusion was that adding nSA expedites C3S hydration at any age or temperature and modifies the structure of the C–S–H gel formed, two types of C–S–H gel appear. At 25°C and 40°C, more orderly, longer chain gels are initially (1 d) obtained as a result of the pozzolanic reaction between nSA and portlandite (CH) (C–S–HII gel formation). Subsequently, ongoing C3S hydration and the concomitant flow of dimers shorten the mean chain length in the gel. 相似文献
5.
《Journal of the European Ceramic Society》2006,26(4-5):803-807
Substitution characteristics of the halide ions F− Cl− for the OH− ions in the crystal lattice of 12CaO·7Al2O3 solid solution were investigated. Single phases of composition 11CaO·7Al2O3·CaF2 and 11CaO·7Al2O3·CaCl2 were formed at 900 °C or above. The OH− ions in 12CaO·7Al2O3 solid solution, i.e. 11CaO·7Al2O3·Ca(OH)2, could be replaced wholly or partially by F− or Cl− ions from the corresponding calcium halide, forming 11CaO·7Al2O3·Ca(OH,F)2 and 11CaO·7Al2O3·Ca(OH,Cl)2 solid solutions above 500 °C and above 700 °C, respectively. Lattice constants of 12CaO·7Al2O3 solid solution changed continuously with the proportion of F− ions or Cl− ions. The F− ions in 11CaO·7Al2O3·CaF2 could be wholly or partially substituted by Cl− ions from CaCl2 at 900 °C or more, forming the solid solution 11CaO·7Al2O3·Ca(F,Cl)2. The Cl− ions in 11CaO·7Al2O3·CaCl2 could be partially replaced F− ions from CaF2 at 1000 °C or above, apparently due to slow chloride loss by evaporation. 相似文献
6.
Lidia K. Kazantseva Sergey V. Rashchenko 《Journal of the American Ceramic Society》2014,97(6):1743-1749
Lightweight glass‐ceramic material similar to foam glass was obtained at 700°C–800°C directly from alkali‐activated silica clay and zeolitized tuff without preliminary glass preparation. It was characterized by low bulk density of 100–250 kg/m3 and high pore size homogeneity. Chemical processes occurring in alkali‐activated silica clay and zeolitized tuff were studied using X‐ray diffraction, thermal gravimetry, IR‐spectroscopy, and scanning electron microscopy. Pore formation in both compositions is caused by dehydration of hydrated sodium polysilicates (Na2O·mSiO2·nH2O), formed during alkali activation. Additional pore‐forming gas source in alkali‐activated zeolitized tuff is trona, Na3(CO3)(HCO3)·2H2O, formed during interaction between unbound NaOH and CO2 and H2O from air. Influence of mechanical activation of raw materials on chemical processes occurring in alkaline compositions was also studied. 相似文献
7.
《Applied Catalysis A: General》2007,316(2):134-141
Ni–W hydrodesulfurization (HDS) catalysts supported on MCM-41 synthesized from two different silica sources (sodium silicate hydrate and tetraethylorthosilicate) as well as on Na+ or K+ ion exchanged MCM-41 were prepared. These catalysts were used to investigate the influence of the surface properties of MCM-41 on the performance of HDS catalysts with DBT as the model molecule. The XRD and N2 adsorption results indicated that the MCM-41 prepared from tetraethylorthosilicate (MCM-41(T)) exhibited the best structural properties. The mesostructure of MCM-41 synthesized from sodium silicate (MCM-41(S)) remained after ion exchange with Na2C2O2 and K2C2O2. Both pyridine FT-IR and Hammett indicators showed that only MCM-41(S) possessed some Brönsted and Lewis acid sites. Ni–W/MCM-41(S) showed the highest HDS and hydrogenation activities. The introduction of Na+ and K+ strongly inhibited the hydrogenation activity of Ni–W/MCM-41(S) but enhanced its hydrogenolysis activity. UV–vis and TPR studies indicated that the introduction of Na+ and K+ into MCM-41(S) may lead to the segregation of surface Ni species and may hinder the reducibility of the supported Ni–W oxides. Spillover hydrogen, which is “trapped” by Na+ and K+, may play an important role in the HDS activity and selectivity of Ni–W catalysts. 相似文献
8.
Pulanchiyodan Abhilash Dhanesh Thomas Kuzhichalil P. Surendran Mailadil T. Sebastian 《Journal of the American Ceramic Society》2013,96(5):1533-1537
The 10 mol% ZnO–2 mol% B2O3–8 mol% P2O5–80 mol% TeO2 (ZBPT) glass was prepared by quenching as well as slowly cooling the melt. The ZBPT glass prepared by both methods show similar microwave dielectric properties. ZBPT glass has an εr of 22.5 (at 7 GHz), Qu × f of 1500 GHz, and τf of ?100 ppm/°C. The ceramic‐glass composites of Sr2ZnTeO6 (SZT) and ZBPT is prepared through two convenient methods: (a) conventional way of co‐firing the ceramic with ZBPT glass powder and (b) a nonconventional facile route by co‐firing the ceramic with precursor oxide mixture of ZBPT glass at 950°C. In the former route, SZT + 5 wt% ZBPT composite sintered at 950°C showed moderately good microwave dielectric properties (εr = 13.4, Qu × f = 4500 GHz and τf = ?52 ppm/°C). Although the SZT + 5 wt% ZBPT composite prepared through the nonconventional method also showed similar microwave dielectric properties (εr = 13.8, Qu × f = 5300 GHz and τf = ?50 ppm/°C), the synthesis procedure is much simplified in the latter case. The composites are found to be chemically compatible with Ag. The composite containing 5 wt% ZBPT prepared through conventional and nonconventional ways shows linear coefficients of thermal expansion of 7.0 ppm/°C and 7.1 ppm/°C, respectively. Both the composites have a room‐temperature thermal conductivity of 2.1 Wm?1 K?1. 相似文献
9.
This study explores the beneficial effects of Na2CO3 as an additive for microstructural and strength improvements in a Ca(OH)2-activated fly ash system. NaOH-activated fly ash samples were also tested to compare the effect of Na2CO3. Compressive strength testing, XRD, SEM/BSE/EDS, 29Si/27Al MAS-NMR, MIP and TGA were performed. The testing results indicate that the use of Na2CO3 for Ca(OH)2-activation led to a noticeable improvement in strength and microstructure, primarily due to (1) more dissolution of raw fly ash at an early age, (2) more formation of C–S–H [or C–S–H(I)], (3) porosity reduction, and (4) pore-size refinement. We also found that (1) an early high alkalinity from the NaOH formation was not a major cause of strength, (2) geopolymer was not formed despite the early NaOH formation, and (3) no visible pore-filling action of CaCO3 was observed. However, Na2CO3 did not produce any improvement in strength for NaOH-activated fly ash. 相似文献
10.
Ganyu Zhu Huiquan Li Xingrui Wang Shaopeng Li Xinjuan Hou Wenfen Wu Qing Tang 《Journal of the American Ceramic Society》2016,99(8):2778-2785
Synthesis of calcium silicate hydrate (C‐S‐H) was conducted over the range of 50°C–90°C and C/S ratio of 0.86–2.14 in the highly alkaline Na2O–CaO–SiO2–H2O system for silicon utilization in high alumina fly ash. Structural change in C‐S‐H formed in the highly alkaline system was investigated using XRD and 29Si MAS NMR spectra. X‐ray photoelectron spectroscopy was used to confirm the amount of sodium ions in C‐S‐H. Conversion of Si may reach 99% under optimum conditions. A higher degree of polymerization of silicate was obtained at lower temperature and C/S ratio. Na+ was confirmed to exist as Na–OSi and Na–OH. The amount of Na+ is the least at C/S ratio of 1.43, which conform to the prediction of topological constraint theory. High Ca/Si ratio leads to the increasing in Na+ combined in the interlayer. Increasing in the Na+ concentration in the system also increases the amount of Na+ combined in the interlayer and reduces the polymerization. Ion exchange was proven to be an effective way to remove Na+ combined in the interlayer of C‐S‐H. 相似文献
11.
Lithium aluminate (α‐/β‐LiAlO2) particles were fabricated using three methods. The first method used organic glycerin and triethylene glycol which functioned as a catalyst for fabrication of α‐LiAlO2 particles with Al(OH)3 and LiOH·H2O as the starting materials. As a result of the heat‐treatment of the starting materials, α‐/β‐LiAlO2 particles could be obtained. The amount of α‐LiAlO2 particles in α‐/β‐LiAlO2 increased slightly as more organics were added. Additionally, when synthesised α‐/β‐LiAlO2 particles were heat‐treated in a CO2 gas flow, β‐LiAlO2 was partially transformed to α‐LiAlO2. In the second method, molten salts (Li2/Na2/K2CO3) were used as a catalyst to fabricate α‐LiAlO2 as a major phase, however, this method requires a washing process which can produce unexpected impurities. In the third method, pure α‐LiAlO2 was obtained by heat‐treatment of cheap sources such as Li2CO3 and Al(OH)3 at 600–800 °C. The mean particle size (604 nm–11.85 μm) and the specific surface area (3.22–11.4 m2 g–1) of α‐LiAlO2 were suitable for reinforcing the matrix and tape casting. Lastly, this study examined the effect of CO2 for the synthesising of α‐LiAlO2 particles. 相似文献
12.
A highly ionic conductive solid‐gel membrane based on polyacrylamide hydrogels with a K2CO3 additive was investigated. The polymer‐based gel was prepared by adding ionic species K2CO3 to a monomer solution followed by polymerization. After polymerization, the ionic species was embedded in the polymer‐based gel, where it remained. The ionic species behaved like a liquid electrolyte, whereas the polymer‐based solid‐gel membrane provided a smooth impenetrable surface that allowed for the exchange of ions. The gel membranes were obtained in the form of thin films of reasonable mechanical strength. Their ambient temperature conductivities were in the range 10?2 to 10?1 S/cm. The effect of K2CO3 concentration on the conductivity of the gels prepared was examined in the temperature range from 0 to 100°C. The microstructure and chemical composition of the gels studied were characterized by environmental scanning electron microscopy and FTIR, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2076–2081, 2004 相似文献
13.
Christophe Chlique David Lambertin Pascal Antonucci Fabien Frizon Philippe Deniard 《Journal of the American Ceramic Society》2015,98(4):1308-1313
The purpose of this work was to study the role of cesium in sodium‐based geopolymer and its thermal stability for nuclear waste management. A series of mixed sodium and cesium geopolymer samples (Na1?x Cs x )2O·Al2O3·SiO2·12H2O (referred to as (Na1? x Cs x )‐GP, where x = 0, 0.08, 0.15, 0.42, 1) have been prepared. All geopolymer samples were heated at 1100°C for 24 h. Pollucite (CsAlSi2O6) and feldspathoid (CsAlSiO4) were crystallized from Cs‐GP. Nepheline (NaAlSiO4) and a small amount of crystallized silica were obtained from Na‐GP. The other geopolymers (Na1? x Cs x )‐GP (x = 0.08, 0.15, 0.42) led to pollucite and nepheline main phases. Amorphous silica phase was observed in all the geopolymer samples with various amounts. Phase quantification and scanning electron microscope revealed that higher Cs concentrations in Na‐GP tend to decrease the amorphous phase while improving pollucite and nepheline phase quantification. The amorphous geopolymers have also been studied by pair distribution function analysis. Tetrahedral chains formed by T–O bonding (with T = Si, Al) were shown to be more tighten around Cs+ than around Na+. It led to shorter Cs–T bond than Na–T bond matching the higher solvation property of Na+. Furthermore, thermal study analysis pointed out the fact that geopolymer samples (Na1? x Cs x )‐GP, can be considered as solid solutions. 相似文献
14.
A novel method has been developed to modify the natural polymer chitosan. The process utilizes a monomer prepared by employing a Morita–Baylis–Hillman (MBH) reaction. Specifically, the vinyl monomer 2‐[hydroxy(pyridin‐3‐yl)methyl]acrylonitrile (HPA) was synthesized using a high‐yielding MBH reaction of acrylonitrile with pyridine‐3‐carboxaldehyde in the presence of 1,4‐diazabicyclo[2.2.2]octane. Conversion of HPA to 2‐cyano‐1‐(pyridin‐3‐yl)allyl acrylate (CPA) was then carried out by reaction of acryloyl chloride. The highly functionalized monomer CPA was grafted onto chitosan through a reaction in 2% acetic acid containing a persulfate and a sulfite (K2S2O8/Na2SO3) as redox promoter. An optimal grafting percentage of 123% is obtained when the grafting process is conducted at 60 °C for 4 h employing a 1:0.5 ratio of K2S2O8 and Na2SO3 at a concentration of 2.5 × 10?3 mol L?1. Chitosan‐graft‐poly[2‐cyano‐1‐(pyridin‐3‐yl)allyl acrylate] graft copolymers, having various grafting percentages, were characterized using Fourier transform infrared, 1H NMR and 13C NMR spectroscopies, X‐ray diffraction, thermogravimetric analysis and scanning electron microscopy. Finally, the results of studies probing the antimicrobial activities of the polymers against selected microorganisms show that the graft copolymers display higher growth inhibition activities against bacteria and fungi than does chitosan. © 2014 Society of Chemical Industry 相似文献
15.
Abstract
A novel precipitation/digestion route has been developed to synthesize crystalline cerium hydroxy carbonate (CHC: Ce(OH)CO3) by using an equimolar quantity of cerium nitrate (Ce(NO3)3·6H2O) and mixed precipitants (KOH + K2CO3) at room temperature. Nano-sized CeO2 supports could be prepared by the pre-calcination of CHC at 400 °C for 4 h. A highly active water gas shift (WGS) catalyst, 1 wt.% Pt/CeO2 catalyst showed almost equilibrium CO conversion with 100% CO2 selectivity at 320 °C even at the gas hourly space velocity (GHSV) of 45,625 h−1. 相似文献16.
Soo Chool Lee Ho Jin Chae Bo Yun Choi Suk Yong Jung Chun Yong Ryu Jung Je Park Jeom-In Baek Chong Kul Ryu Jae Chang Kim 《Korean Journal of Chemical Engineering》2011,28(2):480-486
Potassium-based sorbent was prepared by impregnation with potassium carbonate on activated carbon. The role of water and its
effects on pretreatment and CO2 absorption was investigated in a fixed bed reactor. K2CO3 could be easily converted into K2CO3·1.5H2O working as an active species by the absorption of water vapor as the following reaction: K2CO3+3/2 H2O→K2CO3·1.5H2O. One mole of K2CO3·1.5H2O absorbed one mole of CO2 as the following reaction: K2CO3·1.5H2O+CO2ai2KHCO3+0.5 H2O. The K2CO3·1.5H2O phase, however, was easily transformed to the K2CO3 phase by thermal desorption even at low temperature under low relative humidity. To enhance CO2 capture capacity and CO2 absorption rate, it is very important to maintain the K2CO3·1.5H2O phase worked as an active species, as well as to convert the entire K2CO3 to the K2CO3·1.5H2O phase during CO2 absorption at a temperature range between 50 °C and 70 °C. As a result, the relative humidity plays a very important role
in preventing the transformation from K2CO3·1.5H2O to the original phase (K2CO3) as well as in producing the K2CO3·1.5H2O from K2CO3, during CO2 absorption between 50 °C and 70 °C. 相似文献
17.
Ying Li Na Jiang Kwok Ho Lam Yongquan Guo Qiaoji Zheng Qiang Li Wei Zhou Yang Wan Dunmin Lin 《Journal of the American Ceramic Society》2014,97(11):3602-3608
Lead‐free multiferroic ceramics of BiFeO3‐BaTiO3‐Bi0.5Na0.5TiO3 have been prepared by a conventional ceramic technique. The microstructure, multiferroic, and piezoelectric properties of the ceramics have been studied. The ceramics sintered at 1000°C for 2 h possess a pure perovskite structure and a morphotropic phase boundary of rhombohedral and tetragonal phases is formed at x = 0.02. After the addition of Bi0.5Na0.5TiO3, two dielectric anomalies are observed at high temperatures (Tm ~ 510°C–570°C and T2 ~ 720°C). The phase transition around Tm becomes wider gradually with increasing x. The ferroelectricity, piezoelectricity, and ferromagnetism of the ceramics are significantly improved after the addition of Bi0.5Na0.5TiO3. High resistivity (~1.3 × 109 Ω·cm), strong ferroelectricity (Pr = 27.4 μC/cm2), good piezoelectricity (d33 =140 pC/N, kp = 31.4%), and weak magnetic properties (Mr =0.19 emu/g) are observed. 相似文献
18.
Bo Liang Guoda Wang Haiyang Shan Pingping Dong Liangliang Yu Changgui Lin Chengwei Gao Yongxing Liu Xiang Shen Qing Jiao 《Journal of the American Ceramic Society》2023,106(5):3199-3208
Solid Na-ion-conducting sulfides exhibited potential applications for commercial solid-state rechargeable batteries because of their low cost and good contact with the electrode. In the present work, a sulfide sodium-ion conductor 2Na3SbS4·Na2WS4 with a conductivity of 1.55 mS cm−1 was obtained, which was identified as superior to the 2Na3SbS4·Na4XS4 (X = Si, Ge, Sn) systems. Further exploration of the heat treatment to improve the crystallinity of the glass resulted in a high conductivity of 1.9 mS cm−1 and low activation energy of 0.24 eV for the 2Na3SbS4·Na2WS4 glass–ceramic electrolyte. The high crystallinity after heat treatment at 380°C facilitated the migration of Na+ together with large sodium vacancies formed by doping with W6+ in 2Na3SbS4·Na2WS4 glass–ceramic electrolyte, resulting in the improved electrochemical performance. In addition, the air stability of the 2Na3SbS4·Na2WS4 glass–ceramic electrolyte decreased monotonically with increase of the annealing temperature, and heat application at 380°C effectively improved the electrolyte tolerance to the air compared with pure Na3PS4 electrolyte. The origins of aliovalent ion doping and thermal effect on the electrochemical performance were discussed in detail. 相似文献
19.
Borate melt structure: Temperature‐dependent B–O bond lengths and coordination numbers from high‐energy X‐ray diffraction
下载免费PDF全文
![点击此处可从《Journal of the American Ceramic Society》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Oliver L. G. Alderman Chris J. Benmore Alex Lin Anthony Tamalonis J. K. Richard Weber 《Journal of the American Ceramic Society》2018,101(8):3357-3371
Borate melts containing <20 mol% Na2O have been studied using high‐energy synchrotron X‐ray diffraction. Temperature dependencies of the mean B–O bond lengths are shown to vary strongly with soda content, by comparison to previous measurements on liquid B2O3 and Na2B4O7. Whereas in liquid B2O3 linear thermal expansion of the BØ3 units is observed, with coefficient αBO = 3.7(2) × 10?6 K?1, this expansion is apparently slightly suppressed in melts containing <20 mol% Na2O, and is dramatically reversed at the diborate composition. These effects are interpreted in terms of changes in the mean B–O coordination number, where the reaction BØ4? + BØ3 ? BØ3 + BØ2O? shifts to the right with increasing temperature. The empirical bond‐valence relationship is used to convert measured bond lengths, rBO, to coordination numbers, nBO, including a correction for the expected thermal expansion. This method is more accurate and precise than direct determination of nBO from peak areas in the radial distribution functions. Gradients of ΔnBO/ΔT = ?3.4(3) × 10?4 K?1 close to the diborate composition, and ΔnBO/ΔT = ?0.3(1) × 10?4 K?1 for a 13(3) mol% Na2O melt are observed, in reasonable agreement with Raman spectroscopic observations and thermodynamic modeling, with some quantitative differences. These observations go toward explaining isothermal viscosity maxima and changes in fragility across the sodium borate system. 相似文献
20.
S. W. Park Y. H. Yun S. D. Kim S. T. Yang W. S. Ahn G. Seo W. J. Kim 《Journal of Porous Materials》2010,17(5):589-595
ETS-10 was ion exchanged by various alkali cations (Li+, Na+, K+, Rb+ and Cs+) and the BET surface area and pore volume was exactly consistent with cationic size; that is, in the order of Li+ > Na+ > K+ > Rb+ > Cs+. It was observed that a single point adsorption capacity was inversely proportional to cationic size. The largest CO2 capacity was observed for Li+-ETS-10 and it is attributed to greater cation–quadrupole interactions with CO2 than larger cation. The results also suggests that as the CO2 loading is increased, the accessibility of adsorbing CO2 to framework basic O− sites should have become difficult with the increase in cationic size due to the blocking effect by extra-framework CO2-M+. The slight decrease in the slope of adsorption capacity with temperature, especially beyond 373 K for Li+-ETS-10 and K+-ETS-10 suggests that the adsorption of CO2 on small alkali cation exchanged-ETS-10 at high temperature is somewhat associated with basic oxygen anion sites in framework
due to the existence of large pore. The CO2-TPD results show that the amount of desorbed CO2 at higher temperature was proportionally increased due to the increased basicity of oxygen anions in framework. It also shows
that the desorption temperature associated with alkali cations in extra-framework (corresponding to low temperature desorption
peak) has been lowered with the increase in cationic size, indicating weak cation–quadrupole interactions with CO2 for larger cations. 相似文献