ATR-FTIR and XPS study on the structure of complexes formed upon the adsorption of simple organic acids on aluminum hydroxide

Information on the binding of organic ligands to metal （hydr）oxide surfaces is useful for understanding the adsorption behaviour of natural organic matter on metal （hydr）oxide. In this study, benzoate and salicylate were employed as the model organic ligands and aluminum hydroxide as the metal hydroxide. The attenuated total reflectance Fourier transform infrared （ATR-FTIR） spectra revealed that the ligands benzoate and salicylate do coordinate directly with the surface of hydrous aluminum hydroxide, thereby forming innersphere surface complexes. It is concluded that when the initial pH is acidic or neutral, monodentate and bridging complexes are to be formed between benzoate and aluminum hydroxide while bridging complexes predominate when the initial pH is alkalic. Monodentate and bridging complexes can be formed at pH 5 while precipitate and bridging complexes are formed at pH 7 when salicylate anions are adsorbed on aluminum hydroxide. The X-ray photoelectron （XP） spectra demonstrated the variation of C 1 s binding energy in the salicyate and phenolic groups before and after adsorption. It implied that the benzoate ligands are adsorbed through the complexation between carboxylate moieties and the aluminum hydroxide surface, while both carboxylate group and phenolic group are involved in the complexation reaction when salicylate is adsorbed onto aluminum hydroxide. The information offered by the XPS confirmed the findings obtained with ATR-FTIR.

Thermal Stability,Thermal Decomposition and Mechanism Analysis of Cycloaliphatic Epoxy/4,4'-dihydroxydiphenylsulfone/Aluminum Complexes Latent Resin Systems

The thermal stability of latent resin systems, cycloaliphatic epoxy/4,4＇- dihydroxydiphenylsulfone/aluminum complexes, was investigated by dynamic differential scanning calorimetry （DSC） analysis. Experiments were conducted under non-isothermal condition in a nitrogen atmosphere at the heating rate of 10, 20, 30 and 40 ℃/min, respectively. TG curves showed that, in the temperature range of 25 to 600 ℃, the stability of the resin systems could be enhanced by increasing the length of the aliphatic chain in the initiator. Both the Kissinger method and the Ozawa-Flyrm-Wall method were employed to calculate activation energies of the decomposition reaction, and the values obtained from the two methods were compared. Moreover, the corresponding reaction mechanism was identified by the Achar differential method and the Coats- Redfem integral method. The experimental results showed that these four methods were reliable and effective to study the kinetics of the thermal decomposition reaction; and the most probable thermal decomposition mechanism of the resin systems we proposed was found to comply with Mampel power law （m=1）.

Crystal structure evolution of complex metal aluminum hydrides upon hydrogen release

Complex aluminum hydrides have been widely studied as potential hydrogen storage materials but also,for some time now, for electrochemical applications. This review summarizes the crystal structures of alkali and alkaline earth aluminum hydrides and correlates structure properties with physical and chemical properties of the hydride compounds. The crystal structures of the alkali metal aluminum hydrides change significantly during the stepwise dehydrogenation. The general pathway follows a transformation of structures built of isolated [AlH4]- tetrahedra to structures built of isolated [Al H6]3- octahedra.The crystal structure relations in the group of alkaline earth metal aluminum hydrides are much more complicated than those of the alkali metal aluminum hydrides. The structures of the alkaline earth metal aluminum hydrides consist of isolated tetrahedra but the intermediate structures exhibit chains of cornershared octahedra. The coordination numbers within the alkali metal group increase with cation sizes which goes along with an increase of the decomposition temperatures of the primary hydrides. Alkaline earth metal hydrides have higher coordination numbers but decompose at slightly lower temperatures than their alkali metal counterparts. The decomposition pathways of alkaline metal aluminum hydrides have not been studied in all cases and require future research.

Characterization of Aluminum(III) Complexes in Coal Organic Matter

For geochemical purposes, complex aluminum compounds in coal organic matter in different types of coal were identified by solid state nuclear magnetic resonance measurements of 27Al. Low ash samples of anthracites, bituminous coals and altered coals from the Czech Republic, Russia, Ukraine, China and Australia were tested;further, low ash lignite and xylite from the Czech Republic and gagatite from Poland were analyzed. In acquired 27Al MAS NMR spectra, two significant peaks at chemical shifts were recorded, at 3.5 - 4 and 13.5 - 15 ppm. It was found that the significant peak at chemical shift at 3.5 - 4 ppm in spectra of bituminous coals, lignite, gagatite and a thermally weakly altered coal corresponds to that obtained for triaquo-hydroxo-diphenoxido-Aluminum(III) complex. The existence of triaquo-triphenoxido-Aluminum(III) complex in the spec- tra of anthracites, some bituminous coals and another thermally altered coal can be approved by the chemical shift at 13.5 - 15 ppm. These findings indicate that at least two different Al complexes were identified in coal organic matter. Further it was found that these complexes are concentrated in vitrinite fraction (alicyclic-aromatic part of coal), notably in collotelinite (gelified and homogenous vitrinite constituent). Ways of Al complexes formation in coal are suggested and their thermal stability is discussed.

Enhancing energetic performance of metal-organic complex-based metastable energetic nanocomposites by spray crystallization

Energetic metal-organic complexes have been involved in nanothermites as novel oxidants.However,the existing preparation methods often lead to mixing inhomogeneity and small contact area of ingredients,the reactivity and functionality of the novel energetic nanocomposites are still limited.In this work,spray crystallization(SC)method was used to prepare novel energetic nanocomposites,the high-energy metal-organic complex[Ni(CHZ)_(3)](ClO_(4))_(2)(CHZ=1,3-diaminourea)was composited with nanoaluminum(n-Al).Results showed that n-Al/[Ni(CH_(2))_(3)](ClO_(4))_(2)energetic nanocomposites prepared by SC method increased heat release to 2977.6 J/g and peak pressure to 3.91 MPa with higher pressurization rate(1324.06 MPa/s),decreased sensitivity thresholds(>100 mJ)to electrostatic discharge(ESD)and enhanced detonation ability compared with[Ni(CHZ)_(3)](ClO_(4))_(2)alone and physically mixed(PM)n-Al/[Ni(CHZ)_(3)](ClO_(4))_(2).These results proved that it is significant to introduce energetic metal-organic complexes with inherent high energy in new-concept n-Al/energetic metal-organic complexes nanocomposites through SC method for a better performance of its application.

氯化镁-氯化铝-EMImBF_(4)/有机醚可充镁电池电解液

可充镁电池(RMBs)是下一代最具潜力的储能体系之一,电解液对RMBs的性能具有重要影响.本文通过将1-乙基-3-甲基咪唑鎓四氟硼酸盐(EMImBF_(4))添加到MgCl_(2)+AlCl_(3)电解液(MACC)中,构建了一种MACC-EMImBF_(4)/有机醚(MACCE)可充镁电池电解液体系;采用循环伏安(CV)、线性扫描伏安(LSV)、电化学交流阻抗谱(EIS)和恒流充放电曲线(GCD)等方法测试了MACCE电解液的电化学性能及全电池性能;并通过场发射扫描电子显微镜(FESEM)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)对循环后的电极表面进行了分析.结果表明,EMImBF_(4)的添加有效改善了电解液的性能,MgCl_(2)-AlCl_(3)与EMImBF_(4)的最佳摩尔比为5∶1.MACCE电解液的离子电导率为3.94 mS/cm,Mg^(2+)沉积-溶出过电位为59 mV,库仑效率达97.5%以上,氧化稳定电位可达2.8 V(vs.Mg/Mg^(2+))且循环时间超过500 h.MACCE电解液在循环过程中可在Mg负极表面形成一层纳米颗粒层,有助于改善循环稳定性.MACCE电解液与正极材料Mo6S8的兼容性好,Mo6S8|MACCE|Mg全电池的放电平均比容量可达64.4mA∙h/g(12.88mA/g,0.1C),100次循环后比容量保持率可达73.2%.

Simulation of temperature and stress in 6061 aluminum alloy during online quenching process

The cooling curves of 6061 aluminum alloy were acquired through water quenching experiment. The heat transfer coefficient was accurately calculated based on the cooling curves and the law of cooling. The online quenching process of complex cross-section profile was dynamically simulated by the ABAQUS software. The results suggest that the heat transfer coefficient changes during online quenching process. Different parts of the profile have different cooling velocity, and it was verified by water quenching experiment. The maximum residual stress of the profile was predicted using FEM simulation based on ABAQUS software The relations between the temperature and stress were presented by analyzing the data of key points.

长期施钾红壤中铁铝氧化物调控有机无机复合体钾素分布

【目的】探究长期施用钾肥如何调控有机无机复合体中速效钾的分布及作用机制,为红壤钾库健康培育提供理论依据。【方法】旱地红壤长期定位试验始于1986年,2022年玉米收获后采集不施肥(CK)、化学氮磷肥配施(NP)、化学氮磷钾肥配施(NPK)3个处理的土样,通过干筛法获得各处理大团聚体(>2 mm)、小团聚体(0.25~2 mm)和微团聚体(<0.25 mm)土样,结合虹吸法进一步分离得到各级团聚体下的有机无机复合体(<2、2~10、10~50和>50μm)样品,分析各粒级有机无机复合体颗粒组成、速效钾和铁铝氧化物含量与分布,探究铁铝氧化物与速效钾之间的相互关系。【结果】1)与CK和NP处理相比,NPK处理大团聚体中<2μm粒级复合体含量占比分别提高20.5%和149.0%,10~50μm粒级复合体含量占比分别提高18.6%和降低31.0%。2)在0~50μm粒级复合体范围内,大、小和微团聚体中10~50μm粒级复合体速效钾含量均为最低水平。土壤速效钾主要存在于<2μm粒级复合体中,占比为54.6%~85.9%。与CK和NP处理相比,NPK处理大团聚体中<2μm粒级复合体速效钾含量占比分别提高44.6%和23.0%。3)与NP处理相比,NPK处理大团聚体<2μm粒级复合体游离铁、铝氧化物含量分别提高30.0%、467.0%,无定形态铁、铝氧化物含量分别降低79.7%、59.3%。与NP处理相比,NPK处理大团聚体<2μm粒级复合体有机络合态铝氧化物含量提高9.8%;10~50μm粒级复合体有机络合态铝氧化物含量降低33.2%。4)在<2μm粒级复合体中,游离态铁铝氧化物、无定形态铝氧化物和有机络合态铝氧化物与速效钾之间存在极显著的正相关关系。无定形态和有机络合态铝氧化物对速效钾含量分布解释度较高,分别为11.2%和11.0%。【结论】长期施用钾肥显著提高红壤旱地土壤大团聚体<2μm粒级复合体速效钾含量占比和游离态铁铝氧化物含量,降低无定形态铝氧化物含量。且无定形态、有机络合态铝氧化物对<2μm粒级复合体速效钾具有正向调控作用,有助于增加土壤钾库。

改性三氯化铝催化剂研究进展

对于傅-克烷基化或酰基化反应,金属卤化物(Lewis酸)是最重要和最有效的一类催化剂,其中无水三氯化铝以其优异的催化性能和廉价易得应用最广泛,但其自身有很多缺点,如有腐蚀性。将三氯化铝(AlCl_(3))改性是扩大其应用范围,提高其使用性能的有效途径。AlCl_(3)催化剂改性的主要途径有:一是固载化,固载化的载体有γ-Al_(2)O_(3)、聚苯乙烯树脂、聚氯乙烯树脂、阳离子交换树脂、HY分子筛、SBA-15分子筛、Al及膨润土等,其中以γ-Al_(2)O_(3)为载体的固载化催化剂最有希望实现产业化;AlCl_(3)固载化的方法有真空气相固载、有机溶剂固载;AlCl_(3)负载催化剂改性的难点在于无水处理,其关键在于提高负载量,其核心在于增强AlCl_(3)与载体的结合度。二是络合化,将AlCl_(3)与溶剂形成络合物,或与酰胺形成AlCl_(3)-酰胺络合物催化剂。

6063铝合金CMP中络合剂构效关系研究

6063铝合金因其独特的性能,在各个行业有着广泛的应用。化学机械抛光(CMP)作为一种超精密加工技术可以实现平面全局平坦化,得到超光滑的镜面效果。为了提高6063铝合金的抛光效率,研究了不同基团(氨基、羧基)络合剂对铝合金抛光速率、表面粗糙度的影响及作用机理,利用电化学工作站及X射线光电子能谱仪(XPS)分析了不同基团络合剂对6063铝合金CMP加工影响机制。研究发现:在含双氧水的抛光液体系中,羧酸类络合剂对6063铝合金抛光性能的提高程度要大于胺类及氨基酸类络合剂,同时随着羧酸类和胺类络合剂的碳链增长,材料去除速率和表面质量均得到提高;氨基酸类络合剂表现出不同于羧酸类和胺类络合剂的规律,即随着碳链的增长,材料去除速率呈现下降的趋势。由XPS和电化学分析可知,两种不同基团络合剂的加入会在铝合金表面形成吸附层,保护铝合金表面,且长碳链的羧酸类及胺类络合剂有助于铝合金表面的腐蚀溶解,进而提高抛光速率。

Semi-solid moulding:Competition to cast and machine from forging in making automotive complex components

The very latest technique for impeller manufacture is called semi-solid moulding(SSM).Cummins Turbo Technologies Limited,together with Aluminum Complex Components Inc,developed SSM compressor wheels as a way of achieving cost and durability performance somewhere between that of cast and machined from solid(MFS) aluminium alloy wheels.Experimental results show SSM material has a superior microstructure and mechanical properties over cast and comparable to MFS materials.Component testing including durability testing,using accelerated speed cycle tests,proves SSM compressor wheels emerge as being significantly more durable than cast equivalents and approaching that of MFS impellers.Further challenges for semi-solid processing in manufacture of other complex components and other materials in automotive industry in terms of both cost and durability are also discussed.

Interaction of catechins with aluminum in vitro

Tea is one of the most popular beverages, consumed by over two thirds of the world’s population; but the aluminum accumulation property of tea plant is becoming the focus of many researches because of aluminum’s known adverse effect on human health. Investigation of the interactions of catechins with Al3+ showed that during the interaction of catechins with Al3+, the UV-vis spectrum of catechins was changed. Absorption of EGCG at 274 nm decreased and increased at 322 nm; EC and C’s at 278 nm changed little. The ratio of Al3+ to EGCG was 1:1 in pH 5.0 buffer solution; in pH 6.2 buffer solution, the ratio in the Al-EGCG complex was 1:1. Interestingly, while the ratio reached to over 2, after the complex of Al-EGCG started polymerization, the ratio in the polymer was 2:1. In pH 6.2 buffer solution, the complex behavior of C with Al3+ was the same as that of EGCG, with a little difference for EC. When the ratio of Al3+ to EC was <1, the complex in ratio was 1:2, but, the complex polymerized when the ratio of Al3+ to EC was >1. It was found that the ratio of Al3+ to EC in the polymer was 1:1. Polymerization of Al-catechin complexes might reduce aluminum absorption in the intestine. Kow value was also employed to study the properties of aluminum species in tea infusion (at gastric and intestine pH condition) and the effect of catechins and tea polyphenols on Kow in buffer solution. Results showed that Kow value rose much higher at the intestine pH than at the gastric pH. Tea polyphenols and catechins could greatly reduce aluminum Kow value in acetic buffer, indicating that these compounds may reduce aluminum absorption during tea intake.

Effects of Exposure to Aluminum on Long-term Potentiation and AMPA Receptor Subunits in Rats in vivo

Objective To explore the effects of exposure to aluminum （AI） on long-term potentiation （LTP） and AMPA receptor subunits in rats in vivo. Methods Different dosages of aluminum-maltolate complex [Al（mal）3] were given to rats via acute intracerebroventricular （i.c.v.） injection and subchronic intraperitoneal （i.p.） injection. Following AI exposure, the hippocampal LTP were recorded by field potentiation technique in vivo and the expression of AMPAR subunit proteins （GluR1 and GluR2） in both total and membrane-enriched extracts from the CA1 area of rat hippocampus were detected by Western blot assay. Results Acute AI treatment produced dose-dependent suppression of LTP in the rat hippocampus and dose-dependent decreases of GluRz and GluR2 in membrane extracts; however, no similar changes were found in the total cell extracts, which suggests decreased trafficking of AMPA receptor subunits from intracellular pools to synaptic sites in the hippocampus. The dose-dependent suppressive effects on LTP and the expression of AMPA receptor subunits both in the membrane and in total extracts were found after subchronic AI treatment, indicating a decrease in AMPA receptor subunit trafficking from intracellular pools to synaptic sites and an additional reduction in the expression of the subunits. Conclusion Al（mal）3 obviously and dose-dependently suppressed LTP in the rat hippocampal CA1 region in vivo, and this suppression may be related to both trafficking and decreases in the expression of AMPA receptor subunit proteins. However, the mechanisms underlying these observations need further investigation.

Determination of Boron Trifluoride in Boron Trifluoride Complex by Fluoride Ion Selective Electrode

A method was proposed to determine boron trifluoride in boron trifluoride complex using fluoride ion selective electrode(ISE). Hydroxide was chosen to mask aluminum for the determination of 0.01—0.1 mol/L of fluoride. The simulation indicated that the permissible aluminum masked at a certain p H value was limited and hardly related to F-concentration and boric acid. It is better to control p H value below 11.5 and the aluminum concentration within 0.025 mol/L to minimize the interference of hydroxide to the fluoride ISE. The decomposition conditions of boron trifluoride by aluminum chloride were investigated. It is found that the F-detection ratio will approach 1.0 if the Al/F molar ratio is 0.3—0.7 and aluminum concentration is no more than 0.02 mol/L when heated at 80 ℃ for 10 min. In one word, hydroxide is quite fit to mask aluminum for samples which contain high content of fluoride and aluminum and the BF3 content can be successfully determined by this method.

Species distribution of polymeric aluminium ferrum——timed complexation colorimetric analysis method of Al-Fe-Ferron

The effects of the calorimetric buffer solutions were investigated while the two colorimetric reactions of AI-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and the pH of the solutions were also investigated. A timed complexatian colorimetric analysis method of Al-Fe-ferron in view of the total concentration of {AI + Fe} was then established to determine the species distribution of polymeric Al-Fe. The testing wavelength was recommended at 362 net and the testing pH value was 5. With a comparison of the ratios of n(Al)/n(Fe), the standard adsorption curves of the polymeric Al-Fe solutions were derived from the experimental results. Furthermore, the solutions' composition were carious in both the molar n(Al)/n(Fe) ratios, i.e. 0/0, 5/5, 9/1 and 0/10, and the concentrations associated with the total ( Al + Fe which ranged from 10(-5) to 10(-4) mol/L..

Subsequent yield loci of 57540 aluminum alloy sheet

Complex loading paths were realized with cruciform specimens and biaxial loading testing machine. Experimental method for determining the subsequent yield locus of sheet metal was established. With this method,the subsequent yield loci of 5754O aluminum alloy sheet were obtained under complex loading paths. Theoretical subsequent yield loci based on Yld2000-2d yield criterion and three kinds of hardening modes were calculated and compared with the experimental results. The results show that the theoretical subsequent yield loci based on mixed hardening mode describe the experimental subsequent yield loci well,whereas isotropic hardening mode,which is widely used in sheet metal forming fields,predicts values larger than the experimental results. Kinematic hardening mode predicts values smaller than the experimental results and its errors are the largest.

Minimization of Residual Aluminum in Drinking Water by Using Nontoxic Polysilicate Coagulants

Two kinds of complex polysilicate coagulants-polysilicate iron PSI and polysilicate ferric aluminum PSFA were prepared. The polymerization processes of PSI and PSFA were investigated under various conditions. Experimental results show that the molecular weight(M.W.) of polysilicic acid PS and the molar ratio of Fe 3+ to SiO 2 are two of the most important factors for preparing high effective coagulants PSI and PSFA. It is shown that PSI and PSFA are not only high effective, nontoxic and cheap coagulants, but also effective for decreasing the dosage of aluminum salt. The mechanism of coagulation of PSI and PSFA is also discussed in this paper.

钻井液用抑制剂络合铝中铝离子含量的测定方法

采用双氧水热解酸化法处理可将偏铝酸根转变为铝离子,再用氟盐置换EDTA容量法滴定分析测定铝离子含量,从而可以计算出样品中偏铝酸根的含量。结果表明∶此种测定方法的加标回收率超过98%、重复性试验得到相对标准偏差小于0.3%,该方法可操作性强、适用范围广、结果可靠准确,是测定钻井液用抑制剂络合铝中铝离子含量的有效方法。该方法不仅有利于抑制剂络合铝产品的质量控制,还可对络合铝的现场应用提供技术指导。

轻质铝合金复杂异形构件的铣削数值模拟仿真与试验

轻质铝合金材料在加工中易产生弹塑性变形和黏刀现象,并且复杂异形构件的壁厚小、曲面多以及切削深度较大,使轻质铝合金复杂异形构件加工难度大。利用数值模拟对金属材料去除过程进行仿真模拟,探究切削参数对切削力和扭矩等的影响,并进行了试验验证。试验和仿真数据表明:仿真预测值与实测值间的误差在可接受范围内;在一定范围内,铣削温度随切削深度的变化较小,切削深度、切削速度对切削力、扭矩的变化影响较大,选择合适的切削深度和切削速度对金属切削的加工质量有显著影响,得到最优铣削参数组合为切削深度a_(p)=0.4mm,切削速度v_(c)=5.5mm/s。

铁尾矿制备高性能莫来石复相陶瓷的研究

以铁尾矿微粉、铝粉、氧化铝为主要原料,采用固相烧结法制备莫来石复相陶瓷材料。通过X射线衍射(XRD)、傅里叶红外光谱(FTIR)和扫描电镜(SEM)、万能试验机、阿基米德排水法等研究了配铝系数(0.90~2.10)、烧结温度(1100~1300℃)两个因素对莫来石复相陶瓷材料的微观组织、抗压强度、气孔率、体积密度的影响。结果表明,所制备的样品均为莫来石-石英复相陶瓷;配铝系数和烧结温度增加均可提高陶瓷材料中莫来石含量,且后者的影响较大;莫来石复相陶瓷试样的最佳制备工艺为烧结温度为1250℃,配铝系数为2.10,此条件下所制得的莫来石复相陶瓷材料的莫来石晶须更长且更完整,气孔率为13.40%,抗压强度为112.12 MPa。