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采用分光光度法测定水热合成条件下大同塔山电厂粉煤灰中硅、铝溶出量,据此调配粉煤灰水热合成沸石凝胶体系的硅铝比,在研究优化室温陈化时间、晶化温度和晶化时间等工艺参数的基础上,定向制备出X型沸石;采用氮气吸附仪、X射线衍射仪、醋酸铵法等表征沸石的比表面积、物相组成及阳离子交换容量.结果表明:水热合成条件下大同煤粉煤灰中硅、铝溶出量随时间延长先增大后减小,在14~16 min达到峰值,此时硅、铝溶出率分别为16.9%、9.1%,凝胶体系硅铝比为3.9,适宜制备X型沸石;室温陈化24 h、100℃晶化8h工艺条件下制备的沸石性能较好,比表面积为97.5 m2/g,阳离子交换容量为214.2 cmol/kg,产物主要为NaX型沸石. 相似文献
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粉煤灰分步溶出硅铝制备纯沸石分子筛的研究 总被引:1,自引:0,他引:1
研究了一种由粉煤灰合成纯沸石分子筛的新工艺,粉煤灰与碳酸钠混合焙烧生成硅酸钠和硅铝酸钠,用少量水浸取其中的硅酸钠,含硅铝酸钠的残余物用碱液浸取.实验发现,在碱溶过程中溶液中的硅铝存在过饱和现象,在过饱和期内实现固液分离,可提取粉煤灰中的硅铝用于合成X型、A型、P型纯沸石产品.1 kg粉煤灰合成310~560 g纯沸石.晶化导向剂和晶种对沸石晶型和晶化时间有很大影响.经仪器和化学分析方法对沸石产品从矿物组成和阳离子交换容量进行表征,制得产品的阳离子交换容量可达3.2~ 4.7meq/g,纯度较高. 相似文献
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粉煤灰合成沸石及其处理焦化废水A/O出水的试验 总被引:3,自引:0,他引:3
以NaOH作碱源,采用水热晶化法将粉煤灰转化成沸石.通过改变灼烧温度、NaOH浓度、液固比、晶化时间,考察合成条件对合成沸石阳离子交换容量的影响,并应用于焦化废水A/O出水的处理.结果表明:在灼烧温度为700℃、NaOH浓度为1 mol/L、液固比为5:1 mL/g、晶化时间为36 h条件下,合成沸石的阳离子交换容量最高为167 mmol/100g,是原粉煤灰的12.8倍,高于天然沸石的160 mmol/100 g;合成沸石处理焦化废水A/O出水的最佳条件是反应时间为1 h,沸石投加量为2g/100mL,pH值为6.0~9.0,此时NH3-N、COD去除率及出水质量浓度分别为46.7%、17.6%和62.6、197.8 mg/L,合成沸石对NH广N的吸附符合Freundlich吸附等温式. 相似文献
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本文研究了温度、碱度、液固比(L/S)及反应时间对粉煤灰水热法合成沸石过程中其溶解性的影响,结果表明在溶解阶段.反应时间、温度、碱度及液固比与粉煤灰的溶解性成正相关,而随着反应进入到结晶阶段,溶解的si和Al逐渐组合成沸石.在温度为95℃、L/S为6 mL/g、碱浓度(NaOH)为2 mol/L的条件下,Na-Pl沸石的合成在96h时产量最高,同时其阳离子交换容量(CEC)为206.7 cmol/kg,比表面积(SSA)为37.7 m<'2>/g,分别是原样粉煤灰的125倍和34倍,在水环境污染物吸附方面具有较大的应用潜能. 相似文献
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胡兵 《精细化工原料及中间体》2014,(6)
正专利披露了甲醇和醋酸甲酯与沸石催化剂接触生产醋酸和二甲醚的过程。沸石催化剂有2-尺寸的通道系统,系统包含至少一个有10-节环的通道和它的阳离子交换能力的至少5%由一个或多个碱金属阳离子所占据。Clark Thoms Edward(GB);ect.WO2013124423(A1) 相似文献
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Masato Tsujiguchi Tadashi Kobashi Yasuhiko Utsumi Nobuaki Kakimori Atsushi Nakahira 《Journal of the American Ceramic Society》2014,97(1):114-119
Synthesis of zeolite A from aluminoborosilicate glass used in liquid crystal display (LCD) panel glass substrate was attempted. Mixture of aluminoborosilicate glass and sodium aluminate was hydrothermally treated with sodium hydroxide solution for 10.8–345.6 ks at 368–423 K. Aluminoborosilicate glass was also acid treated with nitric acid before hydrothermal treatment. Obtained samples were characterized by X‐ray diffraction and scanning electron microscope observation. Zeolite A, hydroxysodalite, and zeolite P were synthesized, and with the specific conditions of hydrothermal treatment, a single phase of zeolite A was successfully obtained. Acid treatment was effective for synthesis of a single phase of zeolite A, because the components of aluminoborosilicate other than SiO2 preferentially eluted for acid solution and during following hydrothermal treatment SiO2 was supposed to elute for alkaline solution. Cation‐exchange capacities (CECs) were investigated for these products. It was clarified that CEC of the product with a single phase of zeolite A obtained from aluminoborosilicae glass was 4.2 mol/kg. CEC of the product consisted of zeolite A and hydroxysodalite was 3.9 mol/kg, and the one consisted of zeolite A, hydroxysodalite, and zeolite P was 2.6 mol/kg. This results shows that aluminoborosilicate glass could be expected to be recycled in zeolite A with good CEC by the appropriate process. 相似文献
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Yixin Zhang Lu Zhou Liqing Chen Yang Guo Fanhui Guo Jianjun Wu Baiqian Dai 《Frontiers of Chemical Science and Engineering》2021,15(3):518
The coal fly ash produced by gasification is estimated to be over 80 million ton per year in China by 2021. It has mainly been disposed as solid waste by landfill. There is lack of study focused on its utilization. In this paper, the coal fly ash produced by gasification was at first analyzed and then applied to synthesize zeolite as an adsorbent. The effects of synthesis conditions on the cation exchange capacity (CEC) of zeolite were investigated. The results from X-ray diffraction and scanning electron microscope indicated that the crystallinity of the synthesized zeolite is the most important factor to affect the CEC. When the synthesized zeolite with the highest CEC (275.5 meq/100 g) was used for the adsorption of Cr(VI) from aqueous solution, the maximum adsorption capacity for Cr(VI) was found to be 17.924 mg/g. The effects of pH, contact time and initial concentration on the adsorption of Cr(VI) were also investigated. The adsorption kinetics and isotherms can be well described by the pseudo-second-order model and Langmuir isotherm model, respectively. 相似文献
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Hiromichi Aono Kazumasa Tamura Erni Johan Toru Yamamoto Naoto Matsue Teruo Henmi 《Journal of the American Ceramic Society》2013,96(10):3218-3222
The Na‐P1‐type zeolite having a high cation‐exchange capacity (CEC) was obtained using the waste coal fly ash from thermal power stations and a 2M NaOH solution at 100°C. The Na‐P1‐type zeolite was formed with the reaction time of 6 h at 100°C, and its CEC value increased with an increase in the reaction time. The addition of a suitable amount of NaAlO2 to the fly ash was also effective for improving the CEC value. A new composite material consisting of the Na‐P1‐type zeolite and magnetite was synthesized from the fly ash and iron chlorides because the magnetic collection was possible using this composite material after radioactive Cs+ ion adsorption. The existence of nanosized magnetites in the polycrystalline zeolite (several micrometers) was confirmed by TEM observations. The CEC and magnetic property of these composite materials were characterized. 相似文献
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Izabela Majchrzak-Kucęba 《Journal of Porous Materials》2013,20(2):407-415
The thermogravimetry was used for the evaluation of degree of conversion of fly ash into zeolite material alongside the CEC and XRD methods being currently proposed for this purpose. The present work proposes the calculation of the thermogravimetric fly ash-to-zeolite conversion factor, CFTGA, based on the comparison of the mass loss of the commercial zeolite (standard) occurred during dehydration with that of the fly ash-derived zeolite. This mass loss is characteristic of a specific zeolite type, and the corresponding zeolite water content in the sample of zeolites indicates their degree of crystallinity and zeolite phase content. The use of the TGA method for the indirect determination of the fly ash-to-zeolite conversion factor would be preferable owing to its “speed” compared to other methods proposed for this purpose, as well as the capability to use a consistent procedure. Because of its short CFTGA determination procedure, the thermogravimetric method can be used for the control and determination of the quality of fly ash-derived zeolite in an industrial plant. 相似文献
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Takaaki Wajima Tomoe Shimizu Yasuyuki Ikegami 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(6):921-927
BACKGROUND: This study aimed to investigate the synthesis of zeolites from paper sludge ash (PSA) with added diatomite to remove both NH4+ and PO43? for water purification. The PSA had low Si and significant Ca contents. Four types of diatomite: white (T‐W) and brown (T‐B) from deposits of marine origin in Takanosu, and white (S‐W) and gray (S‐G) from lacustrine deposits in Shonai, were added to NaOH solution to increase the Si content and thereby synthesize zeolites with high cation exchange capacity (CEC). RESULTS: The order of the amounts of Si extracted from the diatomite to the alkali solution was S‐W > T‐W = T‐B > S‐G, which correlates with the amorphous SiO2 content of diatomite. The original ash without addition of diatomite yielded hydroxysodalite with CEC of about 1.0 mmol g?1. For all samples, the addition of diatomite to the solution yielded zeolite‐P with a higher CEC, but the addition of excess Si inhibited the synthesis of zeolite‐P, and the CEC of the product was low. A product with high CEC including zeolite‐P was obtained in a solution with around 500 mmol L?1 of Si concentration, and had the ability to remove both NH4+ and PO43?. CONCLUSION: Diatomite has the potential for used as an additive for the synthesis of high CEC zeolite from PSA. The product with zeolite‐P exhibited relatively high CEC, capacity for NH4+ uptake, and the ability to remove PO43? by precipitation, which is preferable for water purification applications. Copyright © 2008 Society of Chemical Industry 相似文献
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Zeolite Y was selectively synthesised by treating Tarong fly ash in a hydrothermal system. The effects of ageing and seeding on the formation of the resultant phases, crystallisation kinetics, and gel chemistry of Si and Al were investigated. Most of the Si and Al components in the Tarong fly ash could be effectively transformed into zeolite Y in the presence of seeds but not the mineral phase, like mullite. The maximum crystallinity of zeolite Y obtained was 72%. The cation-exchange capacity (CEC) of the fly ash was 0.08 mmol/g but increased to 3.2 mmol/g after a proper treatment. Crystallisation of zeolite materials from fly ash is quite different from that of normal zeolite synthesis because the sources of Si and Al are relatively less reactive and other cation ions (e.g., K+, Mg2+) are present in fly ash. Zeolite P is a competitive phase present in the resulting products that could be eliminated by employing the seeding method. NMR study demonstrated that ageing plays an important role in enhancing the hydrothermal condition during which both Si and Al in fly ash dissolved into a basic solution and reacted to form ring-like structures, and further to zeolite materials. Seeding can selectively induce the formation of zeolite Y and eliminate the processes of induction and nucleation. 相似文献
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Giora Rytwo Hilla Varman Nir Bluvshtein Tom N. König Asaf Mendelovits Amir Sandler 《Applied Clay Science》2011,51(1-2):43-50
There is interest in studying interactions between organic modifiers and raw commercial clays aiming the production of low-cost “organoclays”. In this study we report the interaction between berberine — a monovalent organic cation — and three commercial bentonites and a Turkish zeolite. The Turkish zeolite exhibited adsorption at values of 5–10% of the cation exchange capacity (CEC) with no neutralization of the particles. Adsorption of the organo-cation on Egyptian bentonite, Volclay KWK and Pure-Flo B80, was above the CEC of the bentonites, yielding neutral and even slightly positively charged particles. Electron microscopy and X-ray diffraction results showed expansion of the basal spacing of the smectite. Such low-cost organo-bentonites might be suitable for environmental applications as removal of pollutants, drug and pesticides delivery, or water treatment. Application in turbidity reduction of industrial effluents is demonstrated. 相似文献
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Jamshid Behin Syed Salman Bukhari Vahid Dehnavi Hossein Kazemian Sohrab Rohani 《化学工程与技术》2014,37(9):1532-1540
The reuse of industrial wastes from a coal‐fired power plant and a plasma electrolytic oxidation process was attempted to realize a zero discharge. The batch composition was adjusted by adding sodium hydroxide and sodium aluminate. A single‐mode microwave oven equipped with reflux condenser was used for crystallization under atmospheric pressure. The synthesized samples were characterized by X‐ray diffraction, scanning electron microscopy, BET, thermogravimetric analysis, and cation‐exchange capacity (CEC) measurement. Analytical results indicated that Na‐A zeolite with a defined maximum crystallinity could be successfully synthesized by hydrothermal treatment of fly ash with wastewater. Due to the high CEC, the product can be applied for gas purification and soil remediation processes. 相似文献
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以污泥焚烧灰为原料,通过酸处理和加碱煅烧预处理后,采用水热法合成了NaSOD型沸石,并对其进行了表征和性能测定。结果表明:酸处理可显著提高焚烧灰中硅铝成分的含量,加碱煅烧能够有效激活存在于石英等晶体中的硅铝元素;酸预处理的最佳pH为1,此时SiO2和A1舢含量的百分比之和可达77.65%,比焚烧灰原料高出22.17%;最佳煅烧碱灰比为3:2,最佳煅烧温度为700℃。对合成样品的X射线衍射(XRD)、扫描电镜(SEM)以及傅里叶红外光谱(Fr—IR)表征结果显示,污泥焚烧灰经过预处理后合成的样品,其结构呈NaSOD型沸石,且结晶完整、晶型单一,晶体形貌为球形笼状结构,合成沸石中自由水的含量高。而未经预处理直接水热合成的样品,结晶度低,且存在大量未被活化的石英晶体。因此,预处理对污泥焚烧灰合成NaSOD型沸石起着至关重要的作用。性能测定的结果显示,经预处理合成的NaSOD型沸石,其阳离子交换容量(CEC)、比表面积和总孔容,相对于焚烧灰原料分别提高了40、78和24倍,而未经预处理直接水热合成的产物则分别只提高了14、30和12倍。这意味着经预处理的合成产物在离子交换、吸附和催化等方面的性能有了很大的提升。 相似文献