Ni-Co/Mg-Al catalyst derived from hydrotalcite-like compound prepared by plasma for dry reforming of methane

Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was investigated with dry reforming of methane.Experimental results showed that the hydrotalcite-like precursors could be completely decomposed and partly reduced by cold plasma jet,and the Nicontained catalysts exhibited much higher activity than the catalyst without Ni.Especially,the catalyst with Ni/Co ratio of 8/2 achieved not only the highest conversions of 80.3%and 69.3%for CH4 and CO2,respectively,but also the best stability in 100 h testing.The catalysts were characterized by XRD,XPS,TEM and N2 adsorption techniques,and the results showed that the better performance of the 8Ni2Co bimetallic catalyst was attributed to its higher metal dispersion,smaller metal particle size,as well as the interaction effect between Ni and Co,which were brought by the special catalyst preparation method.

Studies on the Synthesis and the Structure of Ferric Aluminum Magnesium Hydrotalcite-like Compounds

The particles of ferric aluminum magnesium hydrotalcite-like compounds (Fe-Al-Mg_HTlc) were synthesized by co-precipitation method. It was found that when n(Fe)/n(Al+Mg+Fe)<0.30 and n(Al)/n(Al+Mg+Fe)<0.30, pure HTlc can be formed; when the molar ratio of Al/ (Fe+Al+Mg)>0.30, Al(OH)3 will emerge; when the molar ratio of Fe/(Fe+Al+Mg) >0.30, the amorphous composition will appear. Hence Fe3+ and Al3+ have no concentration superposition effect on the crystal structure of the samples.

The Isoelectric Point and the Points of Zero Charge of Fe-Al-Mg Hydrotalcite-like Compounds

The relation of the isoelectric point (IEP) and the point of zero net charge (PZNC) of the hydrotalcite-like compounds was discussed. It was found that the IEP does not equal to the PZNC and the IEP is higher than the PZNC. The structural positive charges existing in the HTlc, which cause the difference between the IEP and the PZNC. The effects of the structural positive charges of the HTlc on its IEP and PZNC are the same as the specific adsorption of metal cations.

CoMnMgAl Hydrotalcite-like Compounds and their Complex Oxides: Facile Synthesis and FCC SO_x Removal

The X-CoMnMgAl hydrotalcite-like precursors(X-LDHs) were first synthesized by the coprecipitation method using Cl-, CO32-, NO3- and SO42- as the corresponding guest anions, which were further used to prepare X-CoMnMgAl complex oxides(X-LDOs) through calcination. The structure and the surface morphology of the as-prepared samples were characterized by FT–IR, XRD, N2 adsorption-desorption and SEM. These as-prepared X-LDOs could act as sulfur-transfer catalysts for desulfurization. The activity of SOx adsorption and regeneration was evaluated via a self-assembled fixed-bed reactor simulating the conditions found in the fluid catalytic cracking units. These four types of sulfur-transfer catalysts with the same phase but different structure displayed the following order of desulfurization efficiency: CO3-LDO >Cl-LDO >NO3-LDO > SO4-LDO.

N2O Decomposition over K-Ce Promoted Co-M-AI Mixed Oxide Catalysts Prepared from Hydrotalcite-like Precursors

A series of mixed oxide catalysts with different composition of Co-M-Al and Co-M-Ce- Al （M=Zn, Ni, Cu） were prepared by co-precipitation method from hydrotalcite-like compounds. The experimental results revealed the catalytic activity of Co-Ni-Al is slightly higher than that of Co-Zn-Al and much higher than that of Co-Cu-Al for direct decomposition of N2O. Moreover, addition of small amounts of Ce02 improved the catalytic activity signif- icantly and made the decomposition temperatures at which the N2O conversion was 50% and 90% （T50 and Tgo） both decreased 80 ℃ than those of Co-M-Al catalysts without CeO2 added. Further, potassium-load also promoted the catalytic activity, and the decomposi- tion temperatures of T50 and T90 both decreased approximately 50 ℃. It is significant for decomposing N2O from industries and reducing carbon emission from atmosphere.

ZnMgAl-HTlc催化酯化高酸原油脱酸

在ZnMgAl类水滑石催化剂的作用下,辽河高酸原油中的环烷酸与乙醇反应生成环烷酸乙酯,可有效地降低原油的酸值,并降低其对设备的腐蚀性。实验结果表明,ZnMgAl类水滑石是一种有效的酯化脱酸催化剂,催化酯化反应后其结构基本未变。在醇/油质量比0.02、反应温度250℃、反应时间60 min、原油与ZnMgAl类水滑石催化剂质量比为100的条件下,催化酯化反应可使辽河高酸原油的酸值由3.61 mg KOH/g降至0.15 mg KOH/g,能够满足炼油厂在不进行材质升级条件下加工高酸原油的需求。

NiZnAl-HTLcs类水滑石化合物的制备和表征

以硝酸镍、硝酸锌和硝酸铝为原料 ,氢氧化钠为沉淀剂 ,采用变化pH值沉淀法 ,合成了NiZnAl HTLcs三元类水滑石化合物 ,从测定不同比例混盐的NaOH滴定曲线着手 ,利用XRD对滴定过程中不同pH值段合成物相进行鉴定 ,探讨了原料配比 ,水热处理温度和时间 ,合成温度和合成方式等因素对合成HTLcs的影响。借助FT IR ,ICP对其物化性质进行表征 ,筛选出合成HTLcs的最佳条件 ,并对合成的HTLcs随焙烧温度变化的结构进行初步研究。结果表明 ,制备HTLcs主要取决于pH值 ,原料配比 。

电解质对Mg-Al HTlc溶胶聚集动力学行为的影响

采用动态光散射法研究了电解质对Mg Al类水滑石 (HTlc)溶胶聚集动力学行为的影响 ,发现随惰性电解质 (NaCl ,NaNO3 )浓度的增大 ,Mg AlHTlc溶胶经历稳定、慢速聚集和快速聚集三个区域 ,而特性吸附电解质 (NaOH )在所研究的浓度范围 ( 0～ 4mmol/L)内未观察到快速聚集 .NaCl和NaNO3 的临界聚沉浓度分别为 12 7和 180mmol/L ,慢速聚集区稳定比与NaCl,NaNO3 和NaOH浓度间的关系式分别为 :logW =10 18-4 44logC ,logW =11 98-4 79logC ,logW =1 92 -0 74logC .

Synthesis of HTLcs modified by K_(3)PO_(4) for side chain alkylation of toluene with methanol

A series of calcined HTLcs catalysts were prepared and modified with potassium phosphate by impregnation method to clarify the influence of catalyst alkalinity on the side chain alkylation of toluene with methanol for synthesis of ethylbenzene and styrene.The catalysts were characterized by X-ray diffraction(XRD),N_(2)physical adsorption-desorption,Fourier-transform infrared spectroscopy(FT-IR),Scanning electron microscopy(SEM),X-ray photoelectron spectrometry(XPS),NH_(3)temperature-programmed desorption(NH_(3)-TPD)and CO_(2)temperature-programmed desorption(CO_(2)-TPD).It was found that the selectivity of styrene was highest(39.25%)when the K_(3)PO_(4)loading was 7.5 wt%.And the total yield of styrene and ethylbenzene could reach 65.08%with 10 wt%K_(3)PO_(4)loading.This might due to the fact that the addition of K_(3)PO_(4)could adjust the acid and basic sites of catalysts.In addition,appropriate strength and amount of basic sites were favorable to producing more styrene.

Preparation and characterization of a novel strong-fluorescent hydrotalcite-like compound (Al-HTLc)

A novel strong-fluorescent hydrotalcite-like compound (Al-HTLc) was synthesized by coprecipitation. In the sample, the content of aluminum(III) in the layers was decreased to a proper value. The Al3+ ions coordinated with 8-hydroxyquinolines (8-HQ) which were dispersed into the anions in the interlayer region. The sample was characterized by XRD, XPS, FT-IR, TG-DSC, UV-Vis, and fluorescence spec- troscopy; its composition and structure were also determined. The results indicate that the sample can emit fluorescence (487 nm) with a strong fluorescence intensity (4.9×105 (a.u.)). The fluorescent lifetime and fluorescence quantum yield of Al-HTLc were measured to be 21.24 ns and 67%, respectively, higher than those of pure 8-hydroxyquinoline aluminum (Alq3). The result of TG-DSC measurement clearly shows the enhanced thermal stability of Al-HTLc compared with that of MgAl-LDH and pure Alq3. Al-HTLc may be used as a novel luminescent functional material.

Green Cycle: Sulfate Sorption from Natural Water on Anionic Clay Compound Obtained from Industry Wastewater

In this paper we are describing a green cycle process. The first step was a novel hydrotalcite-like compound (HTLC) synthesized by a co-precipitating method, under standard ambient temperature and pressure, using chemical industry wastewater rich in divalent and trivalent cations, activated by a thermal treatment and finally characterized by scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDS) and thermogravimetric analysis (TGA). The second step was a series of batch sorption tests performed with this activated HTLC and untreated underground sulfurous water from the state of Puebla, México. The HTLC calcined at 500°C/3 h exhibited the best sorption ability for ions, demonstrated a decrease of the hardness and sulfate ions to below the regional legal standards for drinking water. Once inactive after being used in water treatment, the sorbed ions were removed by ion exchange in a carbonate-containing solution, resulting in an 80% recycling of the material which upon activation demonstrated a retained capacity for water treatment. This recyclability suggests the exciting possibility of this novel compound as an efficient “green” technology in water treatment processes.

Synthesis and characterization of a strong-fluorescent Eu-containing hydrotalcite-like compound

A novel strong-fluorescent Eu-containing hydrotalcite-like compound (Eu-HTlc) was synthesized using the coprecipitation method,in which aluminum(III) was partially substituted by Europium (III) in the hydrotalcite-like layers,and thenoyltrifluoroacetone,1,10-phenanthroline were dispersed into the anions in the interlayer region.The sample was characterized by XRD,XPS,FT-IR,ICP,TG-DSC,TEM and fluorescence spectra,and its composition and structure were determined.The results indicated that the sample exhibited a characteristic red light (614 nm).The fluorescent lifetime and fluorescence quantum yield of Eu-HTlc were measured to be respectively 893 -s and 66.44%,higher than those of Eu(III)-thenoyltrifluoroacetone1,10-phenanthroline complex [Eu(TTA)3phen].The result of TG-DSC measurement showed the enhanced thermal stability of Eu-HTlc compared with that of MgAl-LDHs and Eu(TTA)3phen.With excellent photoluminescent property and thermal stability,low contents of rare earth ions and ligands,the Eu-HTlc may become one of the novel fluorescent materials with potential applications.

Removal of Cu（Ⅱ） from CuSO4 Aqueous Solution by Mg-Al Hydrotalcite-like Compounds

Hydrotalcite-like compound （HTlc） with a Mg/AI molar ratio of 2 ： 1 was synthesized by using a coprecipitation method and the sorption removal of Cu（Ⅱ） by the Mg-AI HTlc sample from CuSO4 solution was investigated. It was found that the Mg-AI HTlc showed a good sorption ability for Cu（Ⅱ） from CuSO4 solution, indicating that the use of hydrotalcite-like compounds as promising inorganic sorbents for the removal of heavy metal ions from water is possible. The sorption kinetics and the sorption isotherm of Cu（Ⅱ） on the HTlc obeyed the pseudo-second order kinetic model and Langmuir equation, respectively. The percent removal of Cu（Ⅱ） by the HT1c was strongly dependent on the initial pH of bulk solution. It increased sharply with the increase of initial pH value in the range of 5-7, and was relatively small in the initial pH range of 4-5, while it reached about 100% after initial pH was higher than 7. The presence of AlCl3 might obviously lower the equilibrium sorption amount （qc） of Cu（Ⅱ） on the HTlc. However, the presences of NaCI and MgCl2 might increase the qe. The presences of ligands （citric acid and EDTA） in the studied concentration range might obviously decrease the qe of Cu（Ⅱ） on the HT1c. The removal mechanism of Cu（Ⅱ） cations by HTlc in the presence of SO4^2- anions may be attributed to the surface-induced precipitation of Cu（Ⅱ） hydroxides and the surface complex adsorption by the linking effect of SO4^2- between the HTlc and Cu（Ⅱ） cations, and the removal ability arising from the surface-induced precipitation is much higher than that from the linking effect of SO4^2-.

Thixotropy of Aqueous Suspensions Containing Mg-AI Hydrotalcite-like Compound and Low-substituted Cationic Starch： Comparison between Oscillatory Shear and Thixotropic Loop Measurements

The rheological properties of aqueous suspensions consisting of positively charged aluminum magnesium hydrotalcite-like compound （HTlc） and low-substituted cationic starch （LCS） were investigated. Special emphasis was placed on the thixotropic phenomenon. Thixotropic behavior was investigated by two thixotropic methods： thixotropic loop and oscillatory shear measurements. LCS molecules could be adsorbed onto HTlc particles due to the hydrogen bonding between ether groups or hydroxyl groups of LCS and hydroxyl groups of HTlc. The elastic dynamic response of the HTlc/LCS suspension increased with increasing mass ratio （R） of HTlc and a three-dimensional network structure could be formed in the suspension with higher R value. The thixotropic type of the HTlc/LCS suspension transformed from negative to positive and then to complex thixotropy when R changed from 0 to 0.5. By comparing between the thixotropic results obtained by thixotropic loop and oscillatory shear measurements, it was validated that the thixotropic loop for the suspension showing complex thixotropy had a crossover point.

Novel Co-Mg-Al-Ti-O catalyst derived from hydrotalcite-like compound for NO storage/decomposition

Catalysts of Co1.5Mg1.5/Al0.9Ti0.1O and Co1.5Mg1.5/AlO were successfully prepared by calcinations of corresponding hydrotalcite-like compounds at 800°C for 4 hr. The derived oxides were of spinel phase and a small quantity of Ti substitution did not change the crystal purity. Their catalytic performance for the NO storage/decomposition was investigated. Ti incorporation enhanced the NO decomposition activity while has an opposite effect on the storage capacity of catalyst. In situ FT-IR spectra of the catalysts showed that the final adsorption species on the catalysts was coordinated nitrates/nitrites. In addition, NO storage/decomposition mechanism has been discussed on the basis of these observations.

水滑石类化合物的性质及其催化应用

简述了水滑石类化合物的性质。基于水滑石类化合物的特性 ,对水滑石类化合物及以其为前驱体的焙烧产物分别被用作碱催化剂、多酸型催化剂。

柱撑阴离子粘土材料研究进展

水滑石类化合物是一类重要的阴离子粘土材料 ,在工业上有潜在的应用价值。论述了水滑石类化合物的结构 ,介绍了制备水滑石类化合物和柱撑水滑石类化合物的方法 ,概括了柱撑水滑石常用的表征方法 ,包括XRD、IR、Raman、固体MAS -NMR谱、ESR谱及差热分析等 ,并对它们的用途进行了简要的说明。对柱撑水滑石类化合物作为催化剂在石油炼制、石油化工、精细化工以及环境保护、材料科学等方面的应用现状及前景进行了分析。

类水滑石复合产物催化消除氮氧化物的研究进展

综述了国外多种类水滑石热分解复合产物M (Ⅱ )M (Ⅲ ) -HT [M(Ⅱ ) =Mg ,Co ,Ni,Cu ,Zn ,Pd ;M(Ⅲ ) =Al,Fe ,Cr,La,Rh]用于消除不同排放气氛中N2 O的催化分解活性及类水滑石中含不同二价离子和三价离子时对催化分解N2 O性能的影响。通过与其他类型催化剂如离子交换分子筛、金属氧化物比较 ,发现类水滑石热分解复合产物在低温下即有很高的反应活性。在实验模拟的多种排放气氛中考察时 ,发现它具有不易受其他组分如H2 O、O2 、SO2 等影响的稳定性能 ,其中CoAl-HT热分解复合产物催化剂在模拟含O2 和H2 O的尼龙 6 6生产排放气氛中稳定性可达 175h。通过对国内外多种类水滑石复合产物上催化消除NOx 的介绍 ,表明类水滑石热分解复合产物同样具有以上催化分解N2 O时所表现的各种优良催化性能 ,特别是具有很好的抗SO2

Mg-Al-Fe类水滑石及其焙烧产物对酸性橙Ⅱ脱色性能的实验研究

采用共沉淀法合成出一系列镁铝铁摩尔比不同的碳酸根型类水滑石(HTLCs),经500℃高温煅烧制备出镁铝铁复合氧化物HTLCs-500,并用X-射线、红外光谱对它们进行表征。考查了吸附剂投加量、反应时间、初始pH值等因素对二者处理阴离子染料酸性橙Ⅱ模拟废水效果的影响。实验结果表明:镁铝铁摩尔比为3/0.9/0.1制得的HTLCs对酸性橙Ⅱ的脱色效果最好;在最佳条件下,HTLCs及HTLCs-500对70mg.L-1的酸性橙Ⅱ模拟废水的脱色率分别可达99.88%和99.16%;HTLCs-500在脱色时投加量更少,吸附更迅速,适应的pH范围更广,脱色性能更好;四次再生后的HTLCs-500对酸性橙Ⅱ的脱色率仍可达90%以上。

类水滑石化合物的合成及催化应用

简述类水滑石化合物的合成方法 ,并对以类水滑石化合物为前驱体的柱撑水滑石及将其焙烧后的复合氧化物的性质和催化应用进行了综述。