ZnO/Mg–Al layered double hydroxides as strongly adsorptive photocatalysts

Nanocomposites of magnesium aluminium layered double hydroxides with carbonate anions (Mg–Al–CO₃-LDHs) and ZnO nanorods were prepared by a homogeneous precipitation process. The ZnO nanorods give the calcined Mg–Al–CO₃-LDHs, strong adsorbents of anionic dyes, photocatalytic activity. The nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of the nanocomposites was investigated by degradation of acid red G in aqueous solution, and the nanocomposite with the ZnO-to-Mg–Al–CO₃-LDHs mass ratio of 1:1 had the highest photocatalytic activity in this photocatalytic reaction.     

稀土络合催化苯乙炔直接成膜聚合 Ⅴ.苯乙炔在钕、铁混合络合催化体系中的直接成膜聚合

乙酰丙酮(AA)、苯酰丙酮(BA)为配体的钕(Nd)、铁(Fe)混合催化剂与三异丁基铝[Al(i-Bu)_3]组成络合催化体系,能使苯乙炔在甲苯/己烷混合溶剂中直接聚合成膜。研究了其聚合反应规律及动力学行为,并对聚苯乙炔膜进行了全面表征,揭示了钕、铁两组分催化剂具有协同催化效应。     

Selective adsorption of phosphate from seawater and wastewater by amorphous zirconium hydroxide

Phosphate adsorption from single electrolyte (NaH2PO4), phosphate-enriched seawater, and model wastewater was studied using amorphous zirconium hydroxide, ZrO(OH)2(Na2O)0.05 1.5H2O, as an adsorbent. Batch experiments were carried out to investigate the adsorption of phosphate. The effect of pH on phosphate adsorption from seawater showed that the uptake of phosphate increased with an increase in pH up to 6, and then decreased sharply with a further increase in pH of the solution. The equilibrium data of phosphate adsorption were followed with a Freundlich isotherm. The uptake of phosphate at the adsorbent/solution ratio 0.05 g/2 L was 10 and 17 mg-P/g for the phosphate-enriched seawater and the model wastewater, respectively. A much higher adsorptivity toward phosphate ions in seawater was observed on ZrO(OH)2(Na2O)0.05 1.5H(2)O than on other representative adsorbents based on layered double hydroxides of Mg(II)-Al(III), Mg(II)-Fe(III), and Ni(II)-Fe(III). The effective desorption of phosphate ions on ZrO(OH)2(Na2O)0.05 1.5H2O could be achieved using a 0.1 M NaOH solution. The usefulness of experimental data for practical applications in removing phosphate in seawater and wastewater is discussed.     

稀土络合催化苯乙炔直接成膜聚合 Ⅴ.苯乙炔在钕、铁混合络合催化体系中的直接成膜聚合

 乙酰丙酮(AA)、苯酰丙酮(BA)为配体的钕(Nd)、铁(Fe)混合催化剂与三异丁基铝[Al(i-Bu)₃]组成络合催化体系,能使苯乙炔在甲苯/己烷混合溶剂中直接聚合成膜。研究了其聚合反应规律及动力学行为,并对聚苯乙炔膜进行了全面表征,揭示了钕、铁两组分催化剂具有协同催化效应。     

硝酸镁在γ-Al2O3上的热分解及MgO/γ-Al2O3

研究了不同载量时Mg(NO     

硝酸镁在γ-Al2O3上的热分解及MgO/γ-Al2O3的碱性

研究了不同载量时Mg(NO3)2 在γ Al2O3 上存在状态和热分解行为差异.考察了Mg含量不同时MgO/γ Al2O3 的碱性变化情况 ,并与水滑石焙烧产物Mg(Al)O的碱性进行了对比.结果表明,Mg(NO3)2 可单层分散于γ Al2O3 表面 ,Mg(NO3)2 的分散决定了MgO的分散阈值 ;单层态的Mg(NO3)2 比晶态的分解温度低 ;MgO/γ Al2O3 在阈值附近具有单位表面最高碱量 ,碱位分布与Mg(Al)O相似 ,单位表面碱量高于Mg(Al)O.由于γ Al2O3 的织构可以方便地调节 ,且MgO/γ Al2O3很容易制备 ,MgO/γ Al2O3 是一个很有应用前景的固体碱.     

A kinetic study of ozone decomposition on illuminated oxide surfaces

The heterogeneous chemistry and photochemistry of ozone on oxide components of mineral dust aerosol, including α-Fe(2)O(3), TiO(2), and α-Al(2)O(3), at different relative humidities have been investigated using an environmental aerosol chamber. The rate and extent of ozone decomposition on these oxide surfaces are found to be a function of the nature of the surface as well as the presence of light and relative humidity. Under dark and dry conditions, only α-Fe(2)O(3) exhibits catalytic decomposition toward ozone, whereas the reactivity of TiO(2) and α-Al(2)O(3) is rapidly quenched upon ozone exposure. However, upon irradiation, TiO(2) is active toward O(3) decomposition and α-Al(2)O(3) remains inactive. In the presence of relative humidity, ozone decay on α-Fe(2)O(3) subject to irradiation or under dark conditions is found to decrease. In contrast, ozone decomposition is enhanced for irradiated TiO(2) as relative humidity initially increases but then begins to decrease at higher relative humidity levels. A kinetic model was used to obtain heterogeneous reaction rates for different homogeneous and heterogeneous reaction pathways taking place in the environmental aerosol chamber. The atmospheric implications of these results are discussed.     

Sensing Properties of NH2-MIL-101 Series for Specific Amino Acids via Turn-On Fluorescence

Metal–organic frameworks (MOFs) have been demonstrated to be desired candidates for sensing definite species owing to their tunable composition, framework structure and functionality. In this work, the NH₂-MIL-101 series was utilized for sensing specific amino acids. The results show that cysteine (Cys) can significantly enhance the fluorescence emission of NH₂-MIL-101-Fe suspended in water, while NH₂-MIL-101-Al exhibits the ability to sense lysine (Lys), arginine (Arg) and histidine (His) in aqueous media via turn-on fluorescence emission. Titration experiments ensure that NH₂-MIL-101-Fe and NH₂-MIL-101-Al can selectively and quantitatively detect these amino acids. The sensing mechanism was examined and discussed. The results of this study show that the metal centers in MOFs are crucial for sensing specific amino acids.     

Enhanced photochemical activity of α-Fe2O3 films supported on SrTiO3 substrates under visible light illumination

The visible light photochemical reactivity of a 50 nm thick α-Fe(2)O(3)(0001) (hematite) film on a SrTiO(3)(111) substrate is compared to the reactivities of bulk hematite and the same film supported by α-Al(2)O(3)(0001). The hematite film supported by SrTiO(3)(111) is far more reactive then the other two cases.     

α-Fe2O3、γ-Al2O3、SiO2混合体系的表面配位反应

运用自动电位滴定技术分别研究了纳米α-Fe₂O₃、γ-Al₂O₃、SiO₂单一体系及三组分混合体系中氧化物表面的酸碱性质和对重金属离子Cu²⁺、Pb²⁺、Zn²⁺的吸附行为. 依据表面配位理论恒电容模式(CCM), 计算了相应的表面酸碱配位常数. 结果表明: α-Fe₂O₃/γ-Al₂O₃/SiO₂三组分混合体系的表面化学反应并非是单一体系的简单叠加, 而是存在着不同矿物表面间复杂的交互作用. 三组分表面酸碱反应平衡式和相应的酸碱反应平衡常数分别为: ≡XOH₂⁺?≡XOH+H⁺ (lgK_a1=-4.23), ≡XOH?≡XO^-+H⁺(lgK_a2=-8.41). 根据重金属离子Cu²⁺、Pb²⁺、Zn²⁺在α-Fe₂O₃/γ-Al₂O₃/SiO₂混合体系表面的吸附行为, 计算得到Cu²⁺、Pb²⁺、Zn²⁺在混合体系表面配位反应及其平衡常数如下: ≡XOH＋M²⁺?≡XOM⁺+H⁺; lgK=-2.20, -1.90, -3.20 (M=Cu, Pb, Zn).     

Mild Mechanochemical Synthesis of Nanodispersed Composites Magnetite@M(II)-Fe Layered Double Hydroxides (M = Mg,Ni)

Russian Journal of Applied Chemistry - The possibility of synthesis of nanodispersed composites Fe3O4@M(II)-Fe layered double hydroxides (M = Mg, Ni) is shown by mechanical processing a mixture of...     

SYNTHESIS AND CHARACTERIZATION OF FeZSM 48 IN A NON AQUEOUS SYSTEM

FeZSM-48 molecular sieve has been synthesized for the first time in a non aqueous system of Na 2O-SiO2-Al2O3-Fe2O3-H2N(CH2)6NH2-(C2H5)3N. Its X ray diffraction pattern and scanning electron micrograph show that it has ZSM-48 topological structure. Framework IR spectra and TG/DTA analysis provide evidences for the incorporation of Fe(III) ions into the skeleton. The signal g =4.3 in ESR spectra indicates that tetrahedral coordination of Fe(III) presents in the framework.     

CF4在Al2O3基金属氧化物上的分解反应

考察了在无水条件下γ-Al2O3基金属氧化物M-Al2O3(M=Mg、La、Ba、Ce、Ni、P)与CF4反应转化为金属氟化物的反应. 结果表明, 在所筛选的金属氧化物中, γ-Al2O3的初活性较高, 但由于CF4分解时产生的强放热效应使未反应的γ-Al2O3发生了α相变, 致使CF4转化率急剧下降, 反应温度越高, γ-Al2O3的α相变越快, 活性下降就越快. CF4在MgO-Al2O3上分解时, Mg物种比Al优先氟化生成了MgF2, Mg物种的氟化反应及其产生的强放热效应使MgAl2O4结构发生了解体. 在Al2O3表面负载助剂P、Ni,提高了其热稳定性, 抑制了CF4高温分解时未反应的Al2O3发生α相变, 使更多的γ-Al2O3参与了CF4分解反应.     

添加碱土金属对负载型铂锡催化剂长链烷烃脱氢反应性能的影响

用微型催化反应装置结合吡啶吸附 红外光谱、热重、氢化学吸附和程序升温等还原手段,研究了添加碱土金属离子助剂对负载型PtSn/γ-Al2O3催化剂长链烷烃(C10~13)脱氢反应性能的影响。结果表明,碱土金属助剂的引入可以降低催化剂积炭量、提高催化剂铂金属表面裸露度,从而提高催化剂脱氢反应稳定性。但强碱性的碱土金属助剂如Ba2+的引入增强了锡与载体之间的相互作用,减弱了锡与铂之间的相互作用, 导致反应后催化剂铂金属表面裸露度下降,故PtSnBa/γ-Al2O3催化剂脱氢活性较低。     

Synthesis and UV absorption properties of 5-sulfosalicylate-intercalated Zn-Al layered double hydroxides

5-sulfosalicylic acid (SSA) anions have been intercalated into layered double hydroxides (LDHs) by an anion-exchange reaction using ZnAl-NO₃-LDHs as a precursor. The samples were characterized by XRD, FT-IR, TG-DTA/MS and UV-visible spectroscopy. The results show that the NO₃⁻ anions in the precursor have been completely replaced by SSA anions to give ZnAl-SSA-LDHs having a high degree of crystallinity. Detailed studies reveal the existence of a supramolecular structure in ZnAl-SSA-LDHs involving electrostatic attraction between opposite charges, hydrogen bonding and other weak chemical bonding interactions between host layers and SSA anions. The thermal stability of ZnAl-SSA-LDHs is considerably enhanced compared with that of a mixture of ZnAl-NO₃-LDHs and SSA. After addition of 2.0 wt% ZnAl-SSA-LDHs to polypropylene (PP), the resistance of the polymer to UV degradation is significantly improved.     

x-氧化铝的添加对纯的和修饰的y-氧化铝上H_2S氧化反应性能的影响（英文）

考察了y-Al_2O_3,(y+x)-Al_2O_3和α-Al_2O_3的结构性质和酸性对其催化H_2S直接氧化反应性能(活性、选择性和稳定性)的影响.采用红外光谱(FTIR)与氨-程序升温脱附(NH3-TPD)方法对氧化铝作用下H_2S转化为S的反应性能与其酸性进行了比较.结果显示,H_2S吸附主要发生在弱Lewis酸位.含有x相和/或Mg~(2+)修饰的y-Al_2O_3样品具有更高浓度的弱Lewis酸位,并表现出更高的催化活性.当氧化铝样品用硫酸溶液处理后,表现出强Lewis酸位性质,且Lewis酸位点数量显著下降.而当用HCl对氧化铝进行修饰时,其对Lewis酸位强度的影响很小,保持着弱Lewis酸位的性质,且其Lewis酸位数量与未修饰的样品相比增加了二倍,但处理过的样品中含有Al–Cl键.用硫酸盐和氯离子修饰过的氧化铝样品在H_2S氧化反应中的催化性能均较低.     

＂Intelligent＂ reforming catalysts： Trace noble metal-doped Ni/Mg（A1）O derived from hydrotalcites

Trace amounts of noble metal-doped Ni/Mg(Al)O catalysts were prepared 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 ofmethane. 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 Ni0 assisted by hydrogen spillover from Pt (or Pt-Ni alloy). The self-regenerative activity was accomplished by self-redispersion of active Ni0 particles due to a reversible reductionoxidation movement of Ni between the outside and the inside of the Mg(Al)O periclase crystal; surface Ni0 was oxidized to Ni2+ by steam and incorporated into Mg(Ni2+,Al)O periclase, whereas the Ni2+ in the periclase was reduced to Ni0 by the hydrogen spillover and appeared as the fine Ni0 particles on the catalyst surface. Further a “green” preparation of the Pt/Ni/[Mg3.5Al]O catalysts was accomplished starting from commercial Mg3.5-Al HT by calcination, followed by sequential impregnation of Ni and Pt.     

Reforming of CH4 with CO2 over Co/Mγ-Al oxide catalyst

A series of Co/Mg–Al oxide samples,CoMgAl-x(x=(Mg+Co)/Al molar ratio of 1–5),were prepared by the self-combustion method followed by H2reduction.The catalytic performance and stability of the samples were studied in dry reforming of CH4.XRD and H2-TPR characterization results showed that the reduced CoMgAl-x samples mainly consisted of solid solution and spinel phases with cobalt particles.The spinel phases contained Co3O4 and Con Mg1-n Al2O4(0≦n≦1)varying with the(Mg+Co)/Al ratio.The effect of (Mg+Co)/Al molar ratio on the catalytic behavior was investigated in detail and CoMgAl-3 exhibited the highest catalytic activity and stability among the catalysts studied.     

Exploring the reactions of β-amyloid (Aβ) peptide 1-28 with Al(III) and Fe(III) ions

The reactions of human β-amyloid peptide 1-28 (Aβ28) with Al(III) and Fe(III) ions were investigated by (1)H NMR and electrospray ionization mass spectrometry (ESI-MS) under pH conditions close to physiological ones. (1)H NMR titrations, performed in the 5.3-8.0 pH range, revealed that no measurable amounts of Aβ28-Al(III) or Aβ28-Fe(III) adducts are formed; such metal adducts could not be obtained even by changing a number of experimental conditions, e.g., temperature, buffer, nature of the salt, etc. These observations were later confirmed by ESI-MS. It is thus demonstrated that Aβ28, at physiological pH, is not able to form binary complexes with Al(III) and Fe(III) ions of sufficient stability to compete with metal hydroxide precipitation. The biological implications of these findings are discussed in the frame of current literature.     

NiMgAl三元类水滑石的制备研究

在Ni(NO3) 2-Mg(NO3) 2-Al(NO3) 3-NaOH体系中，研究了共沉淀法制备NiMgAl三元类水滑石的合成规律。考察了pH值、Ni/Mg/Al比、沉淀生成温度及水热处理条件对合成NiMgAl-HTLcs的影响，借助XRD 、ICP、 FT-IR对合成样品进行表征。实验结果表明，合成NiMgAl-HTLcs的适宜pH范围为5.5～7.0，Ni/Mg=2.0～4.0，水热处理条件为100 ℃，7 h。通过对合成物热行为研究表明，NiMgAl-HTLcs结构开始破坏温度为300 ℃，经焙烧后可得Ni元素高度分散的复合氧化物。