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Efficient Removal of Phosphate from Aqueous Solutions Using Corundum-hollow-spheres Supported Caclined Hydrotalcite Porous Thin Films
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作者 刘云才 ZHU Chen 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期44-49,共6页
Phosphate was removed from aqueous environment by corundum-hollow-spheres supported caclined hydrotalcite (cHT) thin films. Mg-Al-CO3 hydrotalcite (HT) thin films were deposited on corundumhollow-sphere substrates by ... Phosphate was removed from aqueous environment by corundum-hollow-spheres supported caclined hydrotalcite (cHT) thin films. Mg-Al-CO3 hydrotalcite (HT) thin films were deposited on corundumhollow-sphere substrates by hydrothermal homogeneous precipitation at 120℃for 30-240 min and cHT thin films were obtained by annealing of the HT thin films at 500℃for 180 min. Their crystal phase, morphology and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).The results show that homogeneous, well-crystallized and hierarchical flower-like thin films were deposited firmly on the surface of the corundum. The mechanism of nucleation and growth of the HT thin films was fitted well with the anion coordination polyhedron growth unit model. To determine the absorption of phosphate by this adsorbent, different bed depth (10-30 cm) and flow rate (1.0-3.0 m L/min) were examined by column experiments. The highest removal efficiency of phosphate amounted to 98.5%under optimum condition (pH=7.2). The adsorption capacity increased as the bed depth increased and decreased as the flow rate increased. 展开更多
关键词 adsorption PHOSPHATE hydrotalcite corundum-hollow-sphere hydrothermal homogeneous precipitation thermal anneal
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Effect and Mechanism of Rare Earth Hydrotalcite Inhibiting Coal Spontaneous Combustion
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作者 张小娟 LIU Bo +1 位作者 罗振敏 SUN Lu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期50-59,共10页
A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition... A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%. 展开更多
关键词 rare earth hydrotalcite coal spontaneous combustion MECHANISM
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热处理对选区激光熔化Co-Cr合金微观组织与力学性能的影响
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作者 张波 刘艺 夏书标 《有色金属科学与工程》 CAS 北大核心 2024年第2期265-273,共9页
热处理不仅可以消除激光增材制造材过程中的热应力,还可以调控材料组织结构和力学性能。本文研究了选区激光熔化Co-Cr合金微观组织在不同热处理条件下的变化及其相应的力学性能。研究发现,打印态下合金组织为γ奥氏体,基体中存在大量层... 热处理不仅可以消除激光增材制造材过程中的热应力,还可以调控材料组织结构和力学性能。本文研究了选区激光熔化Co-Cr合金微观组织在不同热处理条件下的变化及其相应的力学性能。研究发现,打印态下合金组织为γ奥氏体,基体中存在大量层错和亚晶界组织,以及少量四方σ-CoCr沉淀相;在1150℃下保温1 h,发生γ-ε转变,ε马氏体含量为10.4%(V/V),同时沉淀相由四方σ相转变为六方Co_(3)W(Mo)_(2)Si相;再经过800℃处理2 h后,马氏体含量进一步增加至15.5%(V/V),同时沉淀相数量增加且尺寸增大。热处理后的沉淀相对力学性能影响显著,材料的硬度从31 HRC提高至38 HRC,屈服强度从848 MPa提高至1119 MPa。本研究可以为研究激光选区熔化Co基合金组织与性能调控提供参考。 展开更多
关键词 选区激光熔化 co-cr合金 热处理 沉淀相 力学性能
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Graphene oxide/hydrotalcite modified polyethersulfone nanohybrid membrane for the treatment of lead ion from battery industrial effluent
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作者 Sinu Poolachira Sivasubramanian Velmurugan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第8期253-261,共9页
In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcom... In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcome the irreversible agglomeration behavior of GO at a high concentration which affects the performance of the membranes. In particular, the shedding of HT in formamide provides a two-dimensional nanosheet with a higher positive charge density to prevent the restacking of GO nanosheets. Here, exfoliated GO and HT with different combinations(1:1, 1:2 and 1:3) were infused in the membrane matrix to treat lead-acid battery effluent effectively. Finally, the hybrid membranes were characterized for hydrophilicity, mechanical strength and pure water flux. In combination with the superior properties of GO and HT, the prepared hybrid membranes can be used as effectively to improve the separation and permeation performance. The phase inversion process eliminated the leaching of nanoparticles from the membrane matrix. The reusability of the hybrid membrane was achieved using0.1 mol·L^(-1)NaOH solution and reused without significant reduction in lead removal efficiency. The cost analysis of the membrane was also estimated from the lab study. Therefore, the present study suggested the selective and sustainable treatment of lead from a real-life effluent. 展开更多
关键词 Nanohybrid membrane POLYETHERSULFONE Graphene oxide hydrotalcite Lead battery effluent REUSABILITY Cost analysis
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Corrosion resistance of in-situ Mg-Al hydrotalcite conversion film on AZ31 magnesium alloy by one-step formation 被引量:15
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作者 曾荣昌 刘振国 +4 位作者 张芬 李硕琦 赫庆坤 崔洪芝 韩恩厚 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第6期1917-1925,共9页
In situ growth of nano-sized layered double hydroxides (LDH) conversion film on AZ31 alloy was synthesized by a urea hydrolysis method. The formation mechanism of the film was proposed. Firstly, the dissolved Mg2+ ... In situ growth of nano-sized layered double hydroxides (LDH) conversion film on AZ31 alloy was synthesized by a urea hydrolysis method. The formation mechanism of the film was proposed. Firstly, the dissolved Mg2+ ions deposited into a precursor film consisted of MgCO3 and Mgs(CO3)4(OH)2·4H2O; secondly, the precursor translated into the crystalline Mg(OH)2 in alkaline conditions; finally, the Mg2+ ions in Mg(OH)z were replaced by A13+ ions, Mg(OH)2 translated into the more stable LDH structure, simultaneously, the OH- ions in the interlayer were exchanged by CO32-, thus led to the formation of the LDH (Mg6Alz(OHh6CO3·4H2O) film. The results indicated that the LDH film characterized by interlocking plate-like nanostructures and ion-exchange ability significantly improved the corrosion resistance of the AZ31 Mg alloy. 展开更多
关键词 magnesium alloy hydrotalcite conversion film corrosion resistance ion-exchange
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Hydrotalcite的合成与应用
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作者 张冬珍 《河北化工》 2010年第4期16-17,21,共3页
介绍了以碱式碳酸镁、铝酸碱金属盐为原料合成Hydrotalcite的方法,并论述了其作为制酸剂和抗胃脘剂、聚烯烃树脂的中和剂、PVC热稳定剂的应用。
关键词 hydrotalcite 合成 热稳定剂 中和剂
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Adsorption removal of thiocyanate from aqueous solution by calcined hydrotalcite 被引量:15
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作者 LI Yu-jiang YANG Min +5 位作者 ZHANG Xiao-jin WU Tao CAO Nan WEI Na BI Yan-jun WANG Jing 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2006年第1期23-28,共6页
A hydrotalcite with Mg/AI molar ratio 2 was prepared by co-precipitation method and was characterized by XRD, TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500℃, with the dehydration f... A hydrotalcite with Mg/AI molar ratio 2 was prepared by co-precipitation method and was characterized by XRD, TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500℃, with the dehydration from interlayer, the dehydroxilation from the brucite-like layer and the decomposition of carbonate successively, transformed into the mixed oxide type. The removal of thiocyanate from aqueous solution by using the original hydrotalcite and calcined hydrotalcite (HTC-500) was investigated. The results showed that the thiocyanate adsorption capacity of calcined hydrotalcite was much higher than that of the original form. Calcined hydrotalcite was particularly effective at removing thiocyanate, and that the effective range of pH for the thiocyanate removal are between 5.5-10.0. The experimental data of thiocyanate removal fit nicely with Langmuir isotherm, and the saturated adsorption uptake was 96.2 mg SCN-/g HTC-500. The adsorption of thiocyanate by calcined hydrotalcite follows first-order kinetics. And the intercalation to the structure recovery for calcined hydrotalcite. But the presence of additional anions could affect the adsorption behavior of thiocyanate. 展开更多
关键词 magnesium aluminum mixed oxide hydrotalcite ADSORPTION THIOCYANATE
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Aqueous-phase catalytic hydrogenation of furfural to cyclopentanol over Cu-Mg-Al hydrotalcites derived catalysts:Model reaction for upgrading of bio-oil 被引量:9
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作者 Minghao Zhou Zuo Zeng +2 位作者 Hongyan Zhu Guomin Xiao Rui Xiao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2014年第1期91-96,共6页
A series of Cu-Mg-Al hydrotalcites derived oxides with a(Cu+Mg)/Al mole ratio of 3 and varied Cu/Mg mole ratio(from 0.07 to 0.30) were prepared by co-precipitation and calcination methods, then they were introduced to... A series of Cu-Mg-Al hydrotalcites derived oxides with a(Cu+Mg)/Al mole ratio of 3 and varied Cu/Mg mole ratio(from 0.07 to 0.30) were prepared by co-precipitation and calcination methods, then they were introduced to the hydrogenation of furfural in aqueous-phase. Effects of Cu/Mg mole ratio, reaction temperature, initial hydrogen pressure, reaction time and catalyst amount on the conversion rate of furfural as well as the selectivity toward desired product cyclopentanol were systematically investigated. The conversion of furfural over calcined hydrotalcite catalyst with a Cu/Mg mole ratio of 0.2 was up to 98.5% when the reaction was carried out under 140 ?C and the initial hydrogen pressure of 4 MPa for 10 h, while the selectivity toward cyclopentanol was up to 94.8%. The catalysts were characterized by XRD and SEM. XRD diffraction of all the samples showed characteristic pattern of hydrotalcite with varied peak intensity as a result of different Cu content. The catalytic activity was improved gradually with the increase of Cu component in the hydrotalcite. 展开更多
关键词 hydrotalcite hydrogenation FURFURAL CYCLOPENTANOL CYCLOPENTANONE BIO-OIL UPGRADING
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Effects of hydrotalcite combined with esomeprazole on gastric ulcer healing quality: A clinical observation study 被引量:19
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作者 Rui-Qi Yang Hua Mao +2 位作者 Li-Yun Huang Pei-Zhu Su Min Lu 《World Journal of Gastroenterology》 SCIE CAS 2017年第7期1268-1277,共10页
AIM To evaluate the effects of hydrotalcite combined with esomeprazole on gastric ulcer healing quality. METHODS Forty-eight patients diagnosed with gastric ulcer between June 2014 and February 2016 were randomly allo... AIM To evaluate the effects of hydrotalcite combined with esomeprazole on gastric ulcer healing quality. METHODS Forty-eight patients diagnosed with gastric ulcer between June 2014 and February 2016 were randomly allocated to the combination therapy group or monotherapy group. The former received hydrotalcite combined with esomeprazole, and the latter received esomeprazole alone, for 8 wk. Twenty-four healthy volunteers were recruited and acted as the healthy control group. Endoscopic ulcer healing was observed using white light endoscopy and narrow band imaging magnifying endoscopy. The composition of collagen fibers, amount of collagen deposition, expression of factor. and TGF-beta 1, and hydroxyproline content were analyzed by Masson staining, immunohistochemistry, immunofluorescent imaging and ELISA. RESULTS Following treatment, changes in the gastric microvascular network were statistically different between the combination therapy group and the monotherapy group (P < 0.05). There were significant differences (P < 0.05) in collagen deposition, expression level of Factor. and TGF-beta 1, and hydroxyproline content in the two treatment groups compared with the healthy control group. These parameters in the combination therapy group were significantly higher than in the monotherapy group (P < 0.05). The ratio of collagen. to collagen. was statistically different among the three groups, and was significantly higher in the combination therapy group than in the monotherapy group (P < 0.05). CONCLUSION Hydrotalcite combined with esomeprazole is superior to esomeprazole alone in improving gastric ulcer healing quality in terms of improving microvascular morphology, degree of structure maturity and function of regenerated mucosa. 展开更多
关键词 hydrotalcite ESOMEPRAZOLE Gastric ulcer Quality of ulcer healing
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Unique catalysis of Ni-Al hydrotalcite derived catalyst in CO_2 methanation: cooperative effect between Ni nanoparticles and a basic support 被引量:7
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作者 Lei He Qingquan Lin +1 位作者 Yu Liu Yanqiang Huang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2014年第5期587-592,共6页
Ni-Al hydrotalcite derived catalyst (Ni-Al2O3-HT) exhibited a narrow Ni particle-size distribution with an average particle size of 4.0 nm. Methanation of CO2 over this catalyst initiated at 225℃ and reached 82.5% ... Ni-Al hydrotalcite derived catalyst (Ni-Al2O3-HT) exhibited a narrow Ni particle-size distribution with an average particle size of 4.0 nm. Methanation of CO2 over this catalyst initiated at 225℃ and reached 82.5% CO2 conversion with 99.5% CH4 selectivity at 350℃, which was much better than its impregnated counterpart. Characterizations by means of CO2 microcalorimetry and 27 Al NMR indicated that large amount of strong basic sites existed on Ni-Al2O3-HT, originated from the formation of Ni-O-Al structure. The existence of strong basic sites facilitated the activation of CO2 and consequently promoted the activity. The combination of highly dispersed Ni with strong basic support led to its unique and high efficiency for this reaction. Keywords 展开更多
关键词 CO2 methanation hydrotalcite NiJA1203 basic support Ni-O-Al
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Catalytic depolymerization of calcium lignosulfonate by NiMgFeO_x derived from sub-micron sized NiMgFe hydrotalcite prepared by introducing hydroxyl compounds 被引量:3
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作者 Hongjing Han Jinxin Li +5 位作者 Haiying Wang Feng Xue Yanguang Chen Yanan Zhang Yizhen Wang Mei Zhang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第8期1933-1938,共6页
A new method for regulating the synthesis of Ni Mg Fe hydrotalcites(NMF LDHs) with the addition of hydroxyl compounds was proposed. A series of NMF LDHs were prepared by the above method, and then were calcined to obt... A new method for regulating the synthesis of Ni Mg Fe hydrotalcites(NMF LDHs) with the addition of hydroxyl compounds was proposed. A series of NMF LDHs were prepared by the above method, and then were calcined to obtain the Ni Mg FeOx(NMFOx) samples. The NMFOxsamples were characterized by XRD,SEM, TG-DTG, XPS and CO2-TPD, respectively. The catalytic performance of NMFOxfor depolymerizing calcium lignosulfonate(CLS) was evaluated by hydrothermal reaction. The results showed that the addition of hydroxyl compounds favored reducing the particle sizes of NMF LDHs. For the depolymerization of CSL, the yield of liquid product increased from 45% to 75.8% with the addition of NMFOx-ethanol(NMFOxET). The liquid products were mainly phenolics, aromatics, ketones and esters. The total selectivity of oxy-containing compounds was over 90.6%, among them, the phenolics were approximately 35.2%. The valence of Ni and Fe, crystalline phase and basicity almost remained unchanged. The NMFOx-ET samples were recycled for the depolymerization of CLS, moreover, the NMFOx-ET samples had high activity and stability after 4 cycles. 展开更多
关键词 hydrotalcite CALCIUM LIGNOSULFONATE DEPOLYMERIZATION Oxy-containing compounds
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Influence of the preparation method on the catalytic activity of Mg-Al hydrotalcites as solid base catalysts 被引量:4
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作者 Sungjae Park Dahye Kwon +1 位作者 Ji Yeon Kang Ji Chul Jung 《Green Energy & Environment》 SCIE CSCD 2019年第3期287-292,共6页
Mg-Al hydrotalcites were synthesized using different preparation methods(a co-precipitation method, a urea method, and a simple one) to analyze their effect on the catalytic activity of these solid base catalysts. The... Mg-Al hydrotalcites were synthesized using different preparation methods(a co-precipitation method, a urea method, and a simple one) to analyze their effect on the catalytic activity of these solid base catalysts. The method strongly affected the structure of their layers(e.g., the growth and stacking of the layers, and the type of intercalated anions) and, accordingly, their catalytic activity. The Mg-Al hydrotalcite prepared by co-precipitation showed the best catalytic performance in the isomerization of glucose into fructose, due to the small crystallite size and sand rose morphology enhancing the exposure of surface active sites to reactants. 展开更多
关键词 MG-AL hydrotalcite Preparation method Base catalyst GLUCOSE ISOMERIZATION FRUCTOSE
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Preparation,Characterization and Application of ZnAlLa-Hydrotalcite-Like Compounds 被引量:3
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作者 Xianmei Xie, Xia An, Xiulan Wang , Zhizhong WangCollege of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan 030024, China 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2003年第4期259-263,共5页
The preparation of ZnAlLa-hydrotalcite-like compounds [ZnAlLa-HTLcs] wasstudied. ZnAlLa-HTLcs were synthesized by a method of variable pH with the raw materials ofZn(NO_3)_2, Al(NO_3)_3, La(NO_3)_3, and NaOH. The eS&#... The preparation of ZnAlLa-hydrotalcite-like compounds [ZnAlLa-HTLcs] wasstudied. ZnAlLa-HTLcs were synthesized by a method of variable pH with the raw materials ofZn(NO_3)_2, Al(NO_3)_3, La(NO_3)_3, and NaOH. The eS'ccts of some factors (i.e. pH values, the moleratio of Al^(3+) to La^(3+), temperature and the period of hydrothermal treatment) on thepreparation of HTLcs were discussed systematically. XRD, TG-DTA, FT-IR spectroscopy, and ICP wereperformed to characterize ZnAlLa-HTLcs samples, and the thermal stability of HTLcs was alsodiscussed. It was shown that unique ZnAlLa-HTLcs with high crystallinity can be prepared, under theconditions of pH = 5.5-6.5, n(Zn^(2+))/n(Al^(3+) + La^(3+))=2 and the atomic ratio of La^(3+) toAl^(3+) ranging from 0.07 to 2, hydrothermal treatment at 120 ℃ for 5 h. When the calcination ofthe HTLcs is performed at temperatures above 200 ℃, ZnO phase is detected with Al_2O_3 and La_2O_3spreading on its top. The complex metal oxides derived from ZnAlLa-HTLcs at 500 ℃ have highercatalytic activity and selectivity than those from ZnAl-HTLcs for the esterification of acetic acidwith n-butanol under the same reaction conditions. 展开更多
关键词 layered compound double hydroxide anionic clay hydrotalcite ZnAlLa PREPARATION CHARACTERIZATION APPLICATION
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Preparation, Characterization of Hydrotalcites and the Catalytic Properties in Synthesis of o-Phenylphenol over Pt/CHT 被引量:3
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作者 YANGPiao-ping WANGZhen-lü YUJian-feng LIUQing-sheng XUEBin ZHANGZuo-wang WUTong-hao 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2005年第1期83-87,共5页
Mg/Al mixed oxides with molar ratios of 2_6 of Mg to Al used as supports for platinum catalysts were obtained by the thermal decomposition method. The effect of the composition of the mixed oxides on the physicochemic... Mg/Al mixed oxides with molar ratios of 2_6 of Mg to Al used as supports for platinum catalysts were obtained by the thermal decomposition method. The effect of the composition of the mixed oxides on the physicochemical properties was studied by TPD, nitrogen sorption, XRD and TG-DTA characterization methods. The synthesis of o-phenylphenol(OPP) from a dimer(obtained from cyclohexanone condensation) was investigated over Pt/CHT catalysts and compared with those over Pt/MgO and Pt/Al 2O 3 catalysts. These catalysts show a high activity and selectivity for OPP, with a conversion reaching 93.8% and a selectivity reaching 87.9% in some experiments. For Pt/CHTx catalysts, the calcined hydrotalcites exhibited strong base sites, which were necessary to catalyze the synthesis of OPP. 展开更多
关键词 hydrotalcite CHT OPP Dimer dehydrogenation n(Mg)/n(Al) ratio
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Preparation and Characterization of Mg/Al/Fe Hydrotalcite with Superb Absorption Capacity toward Congo Red 被引量:2
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作者 YANG Kai DU Yi SHEN Jie 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第4期866-875,共10页
Mg/Al/Fe layered double hydroxide(MAF-LDH1) was prepared by solvothermal method with the sodium dodecyl sulfate as the template, and the ethanol system was benefit to growth of sample. The nature in the resulting MAF-... Mg/Al/Fe layered double hydroxide(MAF-LDH1) was prepared by solvothermal method with the sodium dodecyl sulfate as the template, and the ethanol system was benefit to growth of sample. The nature in the resulting MAF-LDH was investigated by X-ray diffraction, field emission scanning electron microscopy, Fourier transformed infrared spectra, thermogravimetric analysis, and N2 adsorption-desorption.The morphology of MAF-LDH1 is petal-like with the size of 400-500 nm and the thickness about 10-20 nm. The adsorption performance of the samples was evaluated by absorption of the Congo red(CR) solutions. Compared with Mg/Al layered double hydroxide(MA-LDH), the maximum adsorption capacities of the MAF-LDH1 samples were 943.4 mg/g which was greatly enhanced. Furthermore, after seven cycling tests, the adsorption performance was still up to 90%. Theoretical calculation results revealed that the adsorption process was spontaneous and followed the pseudo-second-order kinetic model and Freundlich model. This work provides a promising alternative strategy to enhance the adsorptive properties of hydrotalcite-like materials. 展开更多
关键词 adsorption Mg/Al/Fe hydrotalcite CONGO RED ETHANOL system
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The Adsorption of NO_X on Magnesium Aluminium Hydrotalcite 被引量:2
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作者 ZheMingNI WeiHuaYU +1 位作者 ShaoFenZHAO ZhongHuaGE 《Chinese Chemical Letters》 SCIE CAS CSCD 2004年第8期989-992,共4页
Magnesium aluminium hydrotalcite (Mg-Al-HT) with molar ratio of Mg-to-Al of 3 to l was prepared and characterized by X-ray diffraction (XRD) and infrared spectra (IR). The performances of Mg-Al-HT for the adsorption a... Magnesium aluminium hydrotalcite (Mg-Al-HT) with molar ratio of Mg-to-Al of 3 to l was prepared and characterized by X-ray diffraction (XRD) and infrared spectra (IR). The performances of Mg-Al-HT for the adsorption and desorption of NOx were studied. The results indicated that the adsorption capacity of the hydrotalcite for NOx was 1398.2 mg/g, and it was higher than the acticarbon's. The adsorption capacities depended on adsorption time and temperature. Mg-Al-HT could be regenerated by thermal decomposition, and the adsorption efficiency had not changed markedly after three cycles. 展开更多
关键词 Magnesium aluminium hydrotalcite NOx adsorption.
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Hierarchical Ni-Al hydrotalcite supported Pt catalyst for efficient catalytic oxidation of formaldehyde at room temperature 被引量:13
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作者 Zhaoxiong Yan Zhihua Xu +2 位作者 Lin Yue Ling Shi Linyong Huang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第12期1919-1928,共10页
Catalytic oxidation at room temperature is recognized as the most promising method for formaldehyde(HCHO)removal.Pt‐based catalysts are the optimal catalyst for HCHO decomposition at room temperature.Herein,flower‐l... Catalytic oxidation at room temperature is recognized as the most promising method for formaldehyde(HCHO)removal.Pt‐based catalysts are the optimal catalyst for HCHO decomposition at room temperature.Herein,flower‐like hierarchical Pt/NiAl‐LDHs catalysts with different[Ni2+]/[Al3+]molar ratios were synthesized via hydrothermal method followed by NaBH4 reduction of Pt precursor at room temperature.The flower‐like hierarchical Pt/NiAl‐LDHs were composed of interlaced nanoplates and metallic Pt nanoparticles(NPs)approximately 3–4 nm in diameter were loaded on the surface of the Pt/NiAl‐LDHs with high dispersion.The as‐prepared Pt/NiAl21 nanocomposite was highly efficient in catalyzing oxidation of HCHO into CO2 at room temperature.The high activity of the hierarchical Pt/NiAl21 nanocomposite was maintained after seven recycle tests,suggesting the high stability of the catalyst.Based on in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)studies,a reaction mechanism was put forward about HCHO decomposition at room temperature.This work provides new insights into designing and fabricating high‐performance catalysts for efficient indoor air purification. 展开更多
关键词 hydrotalcite NiAl‐layered double hydroxides Hierarchical structure Catalytic oxidation Formaldehyde removal
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Tuning the base properties of Mg–Al hydrotalcite catalysts using their memory effect 被引量:9
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作者 Dahye Kwon Ji Yeon Kang +2 位作者 Suna An Inchan Yang Ji Chul Jung 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第7期229-236,I0008,共9页
Herein,the relationship between the structure and base properties of Mg–Al hydrotalcite catalysts was comprehensively investigated in relation to heat treatment and rehydration processes,which are well known as memor... Herein,the relationship between the structure and base properties of Mg–Al hydrotalcite catalysts was comprehensively investigated in relation to heat treatment and rehydration processes,which are well known as memory effects of hydrotalcite.The structure of Mg–Al hydrotalcites changed from layered double hydroxide(LDH)to mixed metal oxide and subsequently to a spinel structure during heat treatment,and it was returned from mixed metal oxide to a LDH structure by rehydration.Based on various characterizations,we successfully proposed a detailed mechanism of memory effect.We also confirmed that the Mg–Al hydrotalcites had weak or strong base sites and that their base properties could be systematically tuned by heat treatment and rehydration.The prepared Mg–Al hydrotalcites were applied to a model reaction,isomerization of glucose to fructose,as base catalysts.Among the catalysts tested,the rehydrated Mg–Al hydrotalcite efficiently produced fructose due to its appropriate base and structure properties.We finally concluded that the base sites of Mg–Al hydrotalcites can be designed as desired by heat treatment and rehydration.Moreover,through systematic design of the base sites of Mg–Al hydrotalcites,these can be promising catalysts for various heterogeneous reactions over base catalysts,giving excellent catalytic performances. 展开更多
关键词 Mg–Al hydrotalcite Structure Base properties Heat treatment REHYDRATION
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Zn-Zr-Al oxides derived from hydrotalcite precursors for ethanol conversion to diethyl carbonate 被引量:6
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作者 Jian Zhang Tingting Yan +3 位作者 Yusen Yang Jialue Sun Yanjun Lin Min Wei 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第4期515-522,M0002,共9页
Ethanol conversion to high-value-added products has attracted considerable attention in both academic research and industrial fields.In this study,we synthesized a series of tunable acid–base bifunctional Zn-Zr-Al me... Ethanol conversion to high-value-added products has attracted considerable attention in both academic research and industrial fields.In this study,we synthesized a series of tunable acid–base bifunctional Zn-Zr-Al metal oxides(represented as Zn2ZrxAl-MMO)in light of the structural topotactic transformation of Zn2ZrxAl-hydrotalcite precursors(Zn2ZrxAl-LDH).The resulting Zn2ZrxAl-MMO catalysts were employed in the conversion of ethanol to diethyl carbonate.The Zr^4+ ion content of the LDH precursor plays a key role in modulating the acid-base properties and determining catalytic performance:the Zn2Zr0.1Al-MMO sample exhibits the optimal catalytic behavior with a diethyl carbonate(DEC)yield of 42.1%,which is the highest reported for metal oxide catalysts.Structure-property correlation investigations revealed that the synergic catalysis between medium-strong basic sites and weak acid sites plays a predominant role in the catalytic behavior.Furthermore,in situ Fourier transform infrared measurements showed that the weak acidic site promotes activation adsorption of the reactant(urea)and the intermediate product(ethyl carbamate),while the medium-strong basic site accelerates ethanol activation.Moreover,the Zn2Zr0.1Al-MMO catalyst has the advantages of cost effectiveness,good stability,and reusability.Therefore,the acid-base bifunctional catalysts developed in this work can be employed as promising candidates in acid-base catalytic reactions such as ethanol conversion. 展开更多
关键词 hydrotalcite Metal oxides Acid-base catalytic reactions Ethanol conversion
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“Intelligent” reforming catalysts:Trace noble metal-doped Ni/Mg(Al)O derived from hydrotalcites 被引量:3
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作者 Katsuomi Takehira 《Journal of Natural Gas Chemistry》 CAS CSCD 2009年第3期237-259,共23页
Trace amounts of noble metal-doped Ni/Mg(AI)O catalysts were pre- pared starting from Mg-Al hydrotalcites (HTs) and tested in daily start-up and shut-down (DSS) operation of steam reforming (SR) of methane or ... Trace amounts of noble metal-doped Ni/Mg(AI)O catalysts were pre- pared starting from Mg-Al hydrotalcites (HTs) and tested in daily start-up and shut-down (DSS) operation of steam reforming (SR) of methane or partial oxidation (PO) of propane. Although Ni/Mg(Al)O catalysts prepared from Mg(Ni)-Al HT exhibited high and stable activity in stationary SR, PO and dry reforming of methane and propane, the Ni/Mg(Al)O catalysts were drastically deactivated due to Ni oxidation by steam as purge gas when they were applied in DSS SR of methane. Such deactivation was effectively suppressed by doping trace amounts of noble metal on the catalysts by using a "memory effect" of HTs. Moreover, the noble metal-doped Ni/Mg(Al)O catalysts exhibited "intelligent" catalytic behaviors, i.e., self-activation and self-regenerative activity, leading to high and sustainable activity during DSS operation. Pt was the most effective among noble metals tested. The self-activation occurred by the reduction of Ni2+ in Mg(Ni,Al)O periclase to Ni^0 assisted by hydrogen spillover from Pt (or Pt-Ni alloy). The self-regenerative activity was accomplished by self-redispersion of active Ni^0 particles due to a reversible reductionoxidation movement of Ni between the outside and the inside of the Mg(Al)O periclase crystal; surface Ni^0 was oxidized to Ni2+ by steam and incorporated into Mg(Ni2+,Al)O periclase, whereas the Ni2+ in the periclase was reduced to Ni^0 by the hydrogen spillover and appeared as the fine Ni^0 particles on the catalyst surface. Further a "green" preparation of the Pt/Ni/[Mg3.sAl]O catalysts was accomplished starting from commercial Mg3.5-AI HT by calcination, followed by sequential impregnation of Ni and Pt. 展开更多
关键词 hydrocarbon reforming Pt/Ni/Mg(Al)O catalysts hydrotalcite pre cursors SELF-ACTIVATION self-regenerative activity
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