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研究以氟硅酸和氨水为原料,通过沉淀反应、搅拌陈化、固液分离得滤液和滤渣,滤渣经酸化、水洗、喷雾干燥等工艺过程制备白炭黑,滤液经真空法制备氟化氢铵,所得氨水作为原料返回系统循环使用.实验考察了氟硅酸与氨水滴加的体积比、底液与氨水体积比、反应温度、陈化时间等因素对白炭黑DBP值的影响,获得制备白炭黑的最佳工艺条件:氟硅酸与氨水滴加的体积比为1∶6,底液与氨水体积比为0.6,反应温度为75℃,陈化时间为6h,此条件下得到的白炭黑DBP值为3.53 mL/g,并对其进行了FT-IR、XRD、TEM表征和粒径检测,证实产物为白炭黑,粒径(d50)235 nm.氟化氢铵经XRD和SEM表征,确定产物为氟化氢铵,纯度为98.7%. 相似文献
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采用共沉淀法制备SO42-/FeO3-Al2O3-TiO2固体超强酸.通过正交实验考察了3种金属最佳配比,陈化时间,硫酸浸渍浓度,浸渍时间,焙烧温度,焙烧时间等因素对酸强度的影响.研究表明,SO42-/Fe2O3-Al2O3-TiO2固体超强酸最佳制备条件是:n(Fe):n(AL):n(Ti)=1:2:2,陈化时间3h,浸渍H2SO4浓度1.0mol·L-1,浸渍用量15mL·g-1,浸渍时问20min,焙烧温度500℃,焙烧时间5h.此外,还利用红外光谱对催化剂进行了结构表征,利用酯化反应对其催化活性进行了初步研究. 相似文献
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以醋酸锌和草酸为原料,利用溶胶凝胶法制备纳米氧化锌晶体。用正交实验法考查了纳米氧化锌制备过程中醋酸锌浓度、草酸与醋酸锌摩尔比、溶剂用量V乙醇∶V水、柠檬酸三铵与醋酸锌质量比的影响,优化了制备过程中的搅拌温度及搅拌时间、反应温度及反应时间、真空干燥温度及真空干燥时间、煅烧温度及煅烧时间。采用X射线衍射、扫描电镜、红外光谱对样品的结构等性能进行了考查。结果表明:制备的纳米氧化锌具有六方晶体结构。研究发现,醋酸锌浓度为0.4 mol/L,草酸与醋酸锌摩尔比为1∶1,溶剂用量V乙醇∶V水为1∶1,柠檬酸三铵与醋酸锌质量比8%,搅拌温度为90℃,搅拌时间为1 h,反应温度为60℃,反应时间为0.5 h,真空干燥温度为60℃,真空干燥时间为2.5 h,煅烧温度为700℃,煅烧时间为2 h,所制备的纳米氧化锌纯度高,分散性好,晶型良好。 相似文献
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首先采用草酸络合法对NAY分子筛进行脱铝改性,得到Oxalate-NaY分子筛催化剂,使用FTIR、BET和NH3-TPD表征方法证明了催化剂的成功合成。然后以催化裂化餐厨废油反应为模型反应,分别考察了催化剂合成时草酸浓度、催化剂合成时间、催化剂合成温度对催化裂化产率的影响。结果表明,Oxalate-NaY分子筛催化剂形成了强酸中心,比表面积为560m2·g-1,催化剂制备的最佳条件为草酸浓度0.08 mol·L-1、反应温度40℃、反应时间40 min,此条件下得到的催化剂催化效果最佳。 相似文献
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《当代化工》2020,(8)
针对放射性含铯废水,运用河南某电厂粉煤灰为原材料,对粉煤灰进行酸化、碱熔等预处理后,调整硅铝比、陈化时间和温度,运用微波辅助-水热合成法合成NaA型沸石分子筛,缩短其合成时间。其最优合成条件为:微波反应温度90℃、反应时间30 min、硅铝比为1.5、碱度2 mol·L~(-1)、水热陈化温度为120℃、陈化时间8 h。对产物进行XRD、SEM等分析,其结晶良好。在pH8的条件下,平衡吸附时间为120 min,对1 g·L~(-1)的Cs~(2+)溶液中的铯离子的去除率为98.45%,沸石的选择吸附性顺序为Cs~(2+)Sr~(2+)Al~(3+)Ca~(2+)Cu~2。 相似文献
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Edwin Ntainjua Ndifor Tomas Garcia Benjamin Solsona Stuart H. Taylor 《Applied catalysis. B, Environmental》2007,76(3-4):248-256
Nano-crystalline ceria catalysts prepared by homogeneous precipitation with urea were tested for the total oxidation of naphthalene, a model polycyclic aromatic hydrocarbon (PAH). Systematic variation of preparation conditions, including calcination temperature, calcination time and aging time, resulted in differences in surface area, reducibility, morphology and crystallite size of the CeO2 catalyst and hence differences in catalytic performance. A combination of high surface area, small crystallite size and high oxygen defect concentration was found to favor the efficiency of the ceria catalysts for the total oxidation of naphthalene. Optimum preparation conditions for this study included: aging time of 12 h, calcination temperature of 500 °C and a calcination time of 6 h. 相似文献
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将超声波用于以硫酸亚铁铵、草酸为原料的直接沉淀法制备超细氧化铁。对氧化铁的前驱体——草酸亚铁的合成及焙烧工艺进行了详细研究。讨论了反应温度、物料浓度、超声沉淀反应时间以及焙烧温度、焙烧时间对氧化铁粒度的影响。结果发现,在一定的试验条件下,可获得粒度小于40nm的氧化铁。XRD实验表明,所合成的Fe2O3为α型,TEM的测试结果平均粒径为20nm,且分散性好。 相似文献
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为实现不锈钢老化着色液杂质离子的分离与回收,采用预还原-草酸沉淀法对老化液中铁、镍、锰沉淀除杂过程进行研究。通过溶液化学计算及条件优化实验,考察铁、镍、锰离子沉淀效率,并使用X射线衍射仪、扫描电子显微镜、X射线光电子能谱仪对草酸沉淀物进行物相及形貌结构的表征。结果表明,通过控制溶液pH及草酸用量可有效实现溶液中铁离子、锰离子、镍离子与草酸根络合,形成草酸盐沉淀,实现杂质离子与溶液铬离子分离,杂质离子沉淀顺序依次为锰离子、镍离子、铁离子。老化液预还原后,在草酸过量系数为1.2、溶液pH为2、反应温度为25℃的条件下沉淀反应2 h,铁、锰、镍离子沉淀率分别可达98.12%、99.35%、87.26%,沉淀物主要为二水草酸亚铁及少量草酸镍、草酸锰。 相似文献
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Sonalika Vaidya Tokeer Ahmad Suman Agarwal Ashok K. Ganguli 《Journal of the American Ceramic Society》2007,90(3):863-869
The oxalate and carbonate precursors of cerium and zirconium have been prepared using reverse micelles as nanoreactors. Cerium oxalate precursor on thermal decomposition leads to a mixture of nanorods and nanoparticles of cerium oxide (nanoparticles of 10 nm and nanorods with 7 nm diameter and 30 nm length). Cerium oxide with crystallite size of 10 nm was obtained from cerium carbonate precursor. Monodispersed nanoparticles of zirconia with an average size of 3–5 and 12 nm were obtained from the oxalate and carbonate precursor, respectively. Detailed dielectric properties of sintered discs of nanocrystalline ceria and zirconia have been studied with variation of frequency and temperature. 相似文献
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Jungseung KimRebecca J. Desch Stephen W. Thiel Vadim V. GuliantsNeville G. Pinto 《Microporous and mesoporous materials》2012,149(1):60-68
Mesostructured cellular foam (MCF) silica was synthesized using a non-ionic surfactant template-directed method without ammonium fluoride; the acid concentration and aging time were varied to determine the effects of these parameters on the final material. Increasing the acid concentration and aging time resulted in larger window size, which is critical in gating of biomolecule access to the interior of the MCF silica. In particular, when the acid concentration was changed from 1.6 to 3.5 M the window pore dimension approximately doubled, although the pore size distribution was broader. In this study, the optimal synthesis conditions to produce large, narrowly distributed window pores are 3.5 M HCl with an aging time of 20 h. The loadings of l-tryptophan (Trp), lysozyme (LYS) and bovine serum albumin (BSA) on the MCF samples were measured using batch adsorption. Adsorption data followed a Type I isotherm. The monolayer adsorption capacity of Trp on acid-washed MCF was several times higher than that of LYS and BSA, because of the smaller size of Trp. Protein adsorption onto MCF silica showed minimal size exclusion until the window size of the silica was barely larger than the largest protein dimension. 相似文献
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采用微波辐射的方法提取胡萝卜中的果胶.实验考察了微波辐射时间、微波火力、草酸铵浓度、料液比及醇析中乙醇浓度对提取率的影响.实验确定微波条件下提取果胶的最佳工艺条件是:微波辐射时间2min,微波火力为中火,草酸铵浓度4g·L-1,料液比1:15 (g:mL),醇析中乙醇的浓度是70%,提取率可达6.907%. 相似文献