Aluminum Isopropoxide Research Articles

Ultrasound Promoted Expulsion of Lead Ions from Wastewater using Ionic Liquid Modified Aluminium Isopropoxide

In the present investigation Methyltrioctylammonium Chloride modified Aluminium isopropoxide was prepared under ultrasonicator. The IL-Aluminium isopropoxide was characterized using FTIR and X-ray diffractometer (XRD). The Prepared IL-Aluminium isopropoxide was tested for the adsorption of Pb2+ from aqueous solution and isotherms were determined. The Pb2+ adsorption performance of the prepared samples was studied by Atomic Adsorption Spectroscopy (AAS) method. Adsorption of Pb2+ on the chemically modified Aluminium isopropoxide was correlated well with the Langmuir model. Correlation coefficients (R2) of Langmuir adsorption isotherms was 0.9994. Efficient synthesis strategy and high adsorption efficiency of IL-Aluminium isopropoxide showed a best ability to remove Pb2+ metal ions from water.

Investigation of microstructure, morphology and properties of monolayer and multilayer coating T6-HSS by the sol–gel route

ABSTRACT The coating’s purpose is to enhance the tribological conditions at the tool-workpiece and chip–tool interfaces. In comparison to commercial coatings, the current work offers a coating for high-speed steel (HSS) equipment that is thinner and less expensive. A single-point AISI T6 high-speed steel tool having a square cross-section was used to prepare the cutting inserts for turning purpose. The best conditions for coating the HSS insert with ceramic oxides using the sol–gel process were determined. These precursor conditions involved: viscosity, PH, dispersion materials, and the ageing period. The deposition conditions were the number of coating cycles, the immersion time, the calcination temperature, and dry temperature that affects the layer thickness, adhesion, surface roughness, and homogeneity for coating layer. Titanium tetra-isopropoxide (TTIP), a catalyst HCl, and a dispersion material (triethanolamine) were employed to prepare the precursor (titanium hydroxide). The PH, the viscosity, and the ageing time, of the produced precursor were 6.46 and 8.74 cP, and 6 h, respectively. After the dip coating of the cutting inserts for 5 sec immersion time and two number of coating cycle in titania precursor, the inserts were dried at 355℃ for 1 hour. Then, to form the alumina coating film, the inserts were dipped in the alumina hydroxide sol, which was made by combining aluminium isopropoxide IPA, deionised water H2O, and nitric acid (HNO3). The produced precursor had a PH of 5.83, viscosity of 8.11 cP, with an ageing time of 12 h. The immersion time and number of coating cycles in the alumina precursor were 25 sec, and two, respectively. The inserts were dried at 355℃ for 1 hour, then calcinated at 500°C for 2 h to achieve the appropriate film thickness for the machining test. The study investigates the thermal and tribological properties of coated with single and multiple layers as well as uncoated cutting inserts. The results indicated that the hardness is 1393.3 HV with a thickness of 6 µm for multilayer. X-ray diffraction-phase analysis confirms the presence of phases originating from the coatings and substrate. EDS analysis of the chemical composition of the studied coatings indicates the presence of titanium and aluminium, as well as oxygen. Atomic force microscopy (AFM) was used to examine the surface morphologies of coated surfaces. Scratch hardness is measured in GPa and differs between monolayers (alumina) and multilayers (titania/alumina). Monolayer alumina has a value of 0.374 GPa, whereas multilayer alumina/titania has a value of 1.010 GPa. Multilayer coated inserts, on the other hand, have a lower wear rate than monolayer coated and uncoated inserts. The thermal expansion coefficient of the titania layer is often relatively near to the thermal expansion coefficient of the bulk HSS (11 × 10−6, 13 × 10−6 1/K) that reduces mismatch between substrate HSS and top coating layer (alumina).

SAPO-11 Molecular Sieves Synthesized from Aluminum Isopropoxide and SiO2 with Various Dispersions

SAPO-11 Molecular Sieves Synthesized from Aluminum Isopropoxide and SiO2 with Various Dispersions

Alumina deposited by metal-organic chemical vapour deposition process on NiCoCrAlYTa superalloy

Alumina deposit was produced by metalorganic chemical vapour deposition process on a NiCoCrAlY superalloy substrate. Low frequency injection in the range 5–10 Hz was used to feed the Aluminium Tri-isopropoxide precursor into a deposit chamber holding at 400 °C of temperature. Both scanning electron microscopy and X-ray diffraction analysis were accomplished to characterize the deposited alumina. Topographic images show an alumina deposit roughness of Ra 35 nm measured by atomic force microscopy. An X-photon spectroscopy analysis of the alumina deposit was performed to identify both Al species and chemical analysis. Thermo-gravimetric analysis was conducted to assess the effect of deposited alumina on the superalloy.

Removal of Methylene Blue Dye from Waste Water Using Ionic Liquid Modified Aluminium Isopropoxide under Ultrasonic Irradiations

In this paper, Methyltrioctylammonium Chloride modified Aluminiumisopropoxide researched asadsorbent for the removal of Methylene Blue (MB) dye from waste water through a novel and efficientadsorption process under ultrasonication. Ultrasonic irradiations remarkably boosted the adsorption ratecomparative to conventional shaking while maintaining the same adsorption capacity. In addition, theeffects of initial MB concentration, Adsorbent dosage, pH, reaction time and temperature on the adsorptionwere studied. It was found that the isotherm data had a good correlation with the Langmuir isothermthrough analysing the experimental data by various models. The results showed thatMethyltrioctylammonium chloride modified Aluminiumisopropoxide was four times effective for theadsorption of MB dye under ultrasonication.

Continuous aluminum oxide-mullite-hafnium oxide composite ceramic fibers with high strength and thermal stability by melt-spinning from polymer precursor

Continuous aluminum oxide-mullite-hafnium oxide (AMH) composite ceramic fibers were obtained by melt-spinning and calcination from polymer precursor that synthesized by hydrolysis of the aluminum isopropoxide, dimethoxydimethylsilane and hafnium alkoxide. Due to the fine diameter of 8–9 µm, small grain size of less than 50 nm and the composite crystal texture, the highest tensile strength of AMH ceramic fibers was 2.01 GPa. And the AMH ceramic fibers presented good thermal stability. The tensile strength retention was 75.48% and 71.49% after heat treatment at 1100 °C and 1200 °C for 0.5 h respectively, and was 61.57% after heat treatment at 1100 °C for 5 h. And the grain size of AMH ceramic fibers after heat treatment was much smaller than that of commercial alumina fibers even when the heat treatment temperature was elevated to 1500 °C, benefited by the grain size inhibition of monoclinic-HfO2 (m-HfO2) grains distributed on the boundary of alumina and mullite grains.

Synthesis of Silico-Phospho-Aluminum Nanosheets by Adding Amino Acid and its Catalysis in the Conversion of Furfuryl Alcohol to Fuel Additives.

Self-assembled spheres of silico-phospho-aluminum nanosheets were synthesized with the addition of l-arginine and evaluated as catalysts for the valorization of furfuryl alcohol to fuel additives. Adding the amino acid, a bio-derived additive, contributed to higher external specific surface area and more active sites, featuring a simple, environmentally friendly, and feasible strategy to regulate the growth of nanosheets. Herein, in the reaction of furfuryl alcohol with ethanol, the performance of silico-phospho-aluminum nanosheets was significantly improved compared with typical silicon phosphorus aluminum catalyst SAPO-34. The yield of ethyl levulinate with the use of silico-phospho-aluminum nanosheets was 7.8 times higher than for SAPO-34, and meanwhile the amount of undesirable byproduct diethyl ether was decreased by two orders of magnitude and negligibly produced compared with SAPO-34. Moreover, replacing part of aluminum isopropoxide with aluminum sulfate as aluminum source could introduce sulfate in situ in the process of catalyst synthesis and increase the amount of acid sites on the catalyst.

Surface passivated LixSi with improved storage stability as a prelithiation reagent in anodes

In recent years, lots of efforts have been applied to improve the initial Coulombic efficiency (ICE) of lithium-ion batteries (LIBs), among which prelithiation is considered to be one of the most promising schemes. Here we report a modified LixSi with high lithium reserves and great environmental adaptability as the prelithiation reagent, which can make up for the capacity loss of the negative electrode in the first cycle. Through the chemical reaction between aluminum isopropoxide and LixSi, a protective layer consisting of LixAlySiOz/Li2O is formed on the surface of LixSi particles. This synthesized material provides a new idea for the actual industrial production of prelithiation.

A novel approach for in-situ preparation of copper/graphene composite with high hardness and high electrical conductivity

A bulk Cu/graphene-Al2O3 composite with high electrical conductivity (96.95% IACS) and high hardness (87.21 HV) was successfully fabricated through vacuum hot pressing sintering by introducing aluminum isopropoxide as the carbon source. The in-situ formed graphene with high-quality distributes along the grain boundary, the nano sized Al2O3 particles generated near the interface. Both graphene and Al2O3 nano particles greatly refine the microstructure of the Cu/graphene composite and strengthen the matrix. The cold rolled Cu/graphene-Al2O3 sheet presents high electrical conductivity and high strength. The coexistence of graphene and Al2O3 nano particles blocks the movement of grain boundaries, delays the recovery and recrystallization process of the Cu matrix and makes the composite possess excellent softening resistance. The work provides a new idea for large-scale preparation of high-performance Cu/graphene composites.

Preparation of ultrafine flexible alumina fiber for heat insulation by the electrospinning method

In this work, aluminum isopropoxide is used as the aluminum source, and acetylacetone (Hacac) is used as the ligand to synthesize a precursor, which can be used to prepare ultrafine Al2O3 fibers. Fiber with excellent flexibility is obtained by electrospinning and subsequent heat treatment processes. The uniform diameter of the fiber is approximately 300–400 nm, and it has a compact structure and no surface defects, such as cracks and holes, the lack of which can prevent it from being damaged in the process of flexible behavior, such as folding in half. By analyzing the crystallization transformation process of the Al2O3 precursor fibers, it is found that the precursor begins to transform from amorphous to γ-Al2O3 at approximately 700 °C. After heat treatment at 1000 °C, it completely changed to α-Al2O3, which is 100–200 °C lower than the results reported in previous literature. Even after heat treatment at 1200 °C, the fiber still has good flexibility, which ensures its functional performance. In addition, the thermal conductivity of the prepared Al2O3 fibers was only 0.318 W/m·K at 1000 °C, which can be used as a thermal insulation material in aerospace, high-temperature industries and other fields.

Kinetics, mechanism, and simulation of hydrogen transfer reaction of α, β‐unsaturated aldehydes to allylic alcohols

AbstractHomogeneous hydrogen transfer reactions of methacrolein (MAL) and isopropanol to methallyl alcohol (MAA) were investigated in batch reactor (Conv. 89%, Select 93.1%) and tubular reactor (Conv. 88.1%, Select 95%) using aluminum isopropoxide (Al(OPri)3) as catalyst. Kinetic experiments on hydrogen transfer reactions and reaction order were investigated in batch reactor and tubular reactor. Response surface methodology was applied to optimize the optimum reaction conditions of hydrogen transfer reaction. Purification process of MAA from product mixture after hydrogen transfer reaction was simulated with Aspen Plus software; theoretical stages, reflux ratio, and feed stage of distillation tower were optimized. Density functional theory was used to investigate viable reaction pathway and to probe the catalytic mechanism between reactants and catalyst, including dehydrogenation, coupling, and hydrogenation reaction. Microscopic mechanisms of hydrogen transfer reaction from MAA to MAL were acquired in detail and could be easily extended to other series of hydrogen transfer reaction.

Relation between Morphology and Porous Structure of SAPO-11 Molecular Sieves and Chemical and Phase Composition of Silicoaluminophosphate Gels.

The formation of silicoaluminophosphate gels using boehmite, Al isopropoxide, and di-n-propylamine as a template of silicoaluminophosphate gels as well as their subsequent crystallization into SAPO-11 molecular sieves was studied in detail using X-ray fluorescence spectroscopy (XRF), powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2 adsorption–desorption methods. The effect of the chemical and phase composition of silicoaluminophosphate gels on the physicochemical properties of SAPO-11 molecular sieves was shown. The secondary structural units that the AEL lattice is composed of were found to be formed at the initial stage of preparation involving aluminum isopropoxide. Several approaches to control their morphology and secondary porous structure are also proposed.

Micro-Nanometer Particle Composition and Functional Design of Surface Nano-Structured Ammonium Polyphosphate and Its Application in Intumescent Flame-Retardant Polypropylene.

A novel composite and functional micro-nanometer particle is designed by the hydrolysis of aluminium isopropoxide on the surface of ammonium polyphosphate (APP) to prepare surface nanostructured ammonium polyphosphate (NSAPP). NSAPP is characterised by XPS, XRF, SEM, water solubility tests, and TGA. Results indicate that nanosized aluminium hydroxide is deposited on the surface of NSAPP, which enhanced its water resistance and thermostability. Then, APP and NSAPP coupled with dipentaerythritol (DPER) is used for the flame retardant of polypropylene (PP). The limiting oxygen index (LOI) value of the PP/DPER/NSAPP composite is higher than that of PP/DPER/APP. Besides, the UL 94 vertical burning test of PP/DPER/NSAPP composites can reach the V-0 rating easily. According to the study of the combustion behaviour of FR-PP composites, NSAPP contributes to form a dense and multi-layered char in the combustion process. Thus, such an intumescent char with a ceramic-like, continuous, and dense structure over the PP matrix protects the underlying matrix and enhances the thermal stability of the condensed phase, thereby improving the flame retardant performance of FR-PP.

Thin-film Al2O3 coating on low carbon steel obtained by the sol–gel method with different peptizing acids: Corrosion investigation

Thin alumina films were obtained on low carbon steel using boehmite gel prepared by the sol–gel method with aluminium isopropoxide and peptizers – nitric, acetic and maleic acids. The paper considers the acid nature effect on steel corrosion in the studied colloidal systems for obtaining film coatings. It shows that the substrate corrosion behaviour in these systems depends on two factors: medium acidity and complex formation from Fe(III) ions and anions of acid peptizers. Barrier type alumina films can be prepared in the presence of nitric acid as the latter increase boehmite peptization effectiveness. The thin-layer aluminium oxide coatings (prepared from alumina gel using HNO3 as a peptizing agent), can shift the electrode steady-state potential in a 3.5% NaCl by over 0.6 V and effectively slow down steel corrosion in this solution. The electrochemical impedance spectroscopy method was applied to study the kinetics of changes in the electrical parameters of the metal | alumina films | sodium chloride solution phase boundary.

Role of Al pairs on effective N2O decomposition over the ZSM-5 zeolite catalyst

Series of ZSM-5 zeolites with diverse contents and locations of Al pairs were synthesized, and Co2+ ions were subsequently anchored at the Al pairs of ZSM-5 zeolites by wet ion-exchange with H protons. The Co-ZSM-5 sample derived from the mixtures of AlCl3 and TEOS of Si/Al=30.3 showed the best deN2O performance. Analysis on Co (Ⅱ) ion exchange capacity demonstrated the content of Al pairs followed the sequence: AlCl3 (0.84) > Al(NO3)3 (0.73) > aluminum isopropoxide (0.65) and TEOS (0.84) > silicic acid (0.57). More Al pairs coordinated with protons or cobalt ions were essentially associated with better performances for N2O catalytic dissociation. Moreover, Si source had a significant effect on the location of Al pairs determined by UV–vis–DRS of bare Co (Ⅱ), Al pairs of ZSM-5 zeolite synthesized from TEOS were enriched in the sinusoidal channel (γ site), whereas those synthesized from silicic acid were concentrated in the channel intersections (6-MRs β site). The theoretical calculation revealed that the O2 desorption at γ-site Co2+ of ZSM-5 zeolite required to overcome less energy barrier (23.8 kcal/mol) than that at β-site one.

The effect of process parameters and catalyst support preparation methods on the catalytic efficiency in transesterification of sunflower oil over heterogeneous KI/Al2O3-based catalysts for biodiesel production

The essence of this study is synthesis of a newly developed and efficient heterogeneous catalyst based on aluminum oxide support promoted with potassium iodide (KI) as active dopant responsible for pronounced catalyst activity. Modified sol–gel, reflux and hydrothermal method were used for synthesis of aluminum-oxide support using aluminum isopropoxide as a precursor. The γ-Al2O3 support and KI/γ-Al2O3 catalyst samples were examined by various experimental techniques. Effects of several operational parameters were considered and those are: methanol to sunflower oil molar ratio, catalyst loadings, reaction time and reaction stirring rate. The obtained results indicated that modified sol–gel method for synthesis of γ-Al2O3 catalyst support is the most favorable for obtaining the catalyst with superior catalytic performances in transesterification of sunflower oil. A maximum conversion (triglycerides to methyl esters) of 99.99% was achieved using the SG-KI/γ-Al2O3-770 catalyst under following optimal process parameters: 15:1 methanol to sunflower oil molar ratio, 2.5 wt% catalysts loading, 600 rpm stirring rate and 4 h of the reaction run.

Activity and stability studies of H-transfer reduction reactions of aldehydes and ketones over aluminium isopropoxide heterogenised catalysts.

Aluminium isopropoxide Al(OiPr)3 immobilised on various mesoporous supports (SiO2, TiO2 and γ-Al2O3) was tested for H-transfer reductions of various aldehydes and ketones in the presence of 2-propanol as a sacrificial agent. The heterogenised catalysts were characterised by N2 physisorption, XRD, SEM-EDX, FTIR and ICP-OES. The characterisation results show a successful grafting of the homogeneous aluminium isopropoxide catalyst, covalently bound to the solid surface, with high dispersion over the mesoporous supports. The heterogenised catalysts show an excellent catalytic activity with high selectivity towards the desired alcohol product, with performances that are comparable with those of the homogeneous Al(OiPr)3 catalyst. Al(OiPr)3 grafted on SiO2 shows higher activity compared to γ-Al2O3 and TiO2 supported catalysts. The catalysts remain very active after 5 cycles of reuse and no leached Al(OiPr)3 was found in the reaction mixture, hence showing an excellent stability. The work reported here shows that it is possible to effectively immobilise catalytic functions, usually working in the homogeneous phase, over solid supports, with the resulting heterogenised catalysts keeping the same catalytic activity of the homogeneous counterpart and excellent stability, and with the advantage of being able to recycle and reuse them, without loss of catalytic materials.

Synthesis and Characterization of High Surface Area Nano Titanium Dioxide

TiO2 and TiO2-Al2O3 nanoparticles were synthesized via sol-gel method using hydrolysis of Titanium tetraisopropoxide (TTIP) with ethanol and water mixture as titania source. TiO2-Al2O3 Nano-composite was successfully synthesized using the sol-gel technique. Tetraisopropoxide and aluminium isopropoxide were used to prepare TiO2-Al2O3. All prepared samples calcination were conducted at different temperature (400 to 700) oC. The synthesized TiO2 and TiO2-Al2O3 nanocomposites were then characterized by XRD, AFM, BET surface area, SEM, XRF. XRD, the analysis showed that the presence of alumina (Al2O3) in the TiO2 has an effect on crystal size, particles size, surface area, and crystal phases; The XRD result revealed that the prepared TiO2 nanoparticles were anatase phase at 400oC, and 500oC, and transformed to rutile from 600oC to 700oC, but after addition of alumina TiO2 was of anatase phase, without any rutile at all calcination temperatures, also, the addition of alumina leads to a significant decrease in the crystal size, particles size, especially at high temperatures while the surface area of pure titanium was increased, and this corresponds to the results of the AFM and SEM. The best-obtained surface area was 355.18 m2/ gm. with 34.98 nm of average particle size at 500oC in comparison with pure nano titanium dioxide

Sol–Gel Approach for Design of Pt/Al2O3-TiO2 System—Synthesis and Catalytic Tests

Al2O3-TiO2 systems with Ti:Al 0.1, 0.5 and 1.0 molar ratio obtained by the sol–gel method have been used as a platinum support. As a precursor of alumina gel, aluminum isopropoxide has been chosen. Titanium tert-butoxylate was applied to obtain titania gel and hexachloroplatinic acid was applied as a source of platinum. The systems have been characterized by the following methods: thermogravimetric analysis (TGA), Fourier transformation infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), low-temperature nitrogen adsorption–desorption isotherms (BET, BJH), temperature-programmed reduction with hydrogen (TPR-H2) and hydrogen chemisorption. Reactions of toluene to methylcyclohexane and selective o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN) hydrogenation were used as the tests of systems’ catalytic activity. The application of Al2O3-TiO2 as a support has enabled the obtaining of platinum catalysts showing high activities for hydrogenation of toluene and selective hydrogenation of o-chloronitrobenzene to o-chloroaniline in the liquid phase. The highest activity in both reactions has been found for Pt/Al2O3-0.5TiO2 catalyst and the highest selectivity for Pt/Al2O3-. The activity of Pt/Al2O3-TiO2 catalysts was higher than that of alumina-supported ones.

Synthesis and characterization of mesoporous gamma-alumina by glucose as soft-template for molybdenum-99 adsorption: high and low molar ratio of water to aluminium isopropoxide effect

The mesoporous gamma-alumina is a good material for metal adsorption. Its textural properties are excellent, mainly for molybdenum-99 radioisotopes adsorption as part of 99Mo/99mTc generator in nuclear medicine. In this work, we have prepared mesoporous gamma-alumina by sol-gel treatment in the presence of glucose as a soft template. The molar ratio of reactant (water: aluminium isopropoxide(AIP)) was applied in the high and low ratios (150:1 and 25:1). The resulted mesoporous gamma-alumina was investigated using characterization analysis of X-ray diffraction, Nitrogen adsorption-desorption, and FTIR. The results indicate that the mesoporous gamma-alumina in the high molar ratio of water to AIP had a higher surface area and better crystallinity than the low molar ratio of reactants. Furthermore, in the Mo adsorption test, the mesoporous gamma-alumina with the high molar ratio posed a higher Mo adsorption capacity up to 55.69 mg Mo g−1 adsorbent. In the future, the molar ratio of reactants should be tuned in the range of around 150:1 to obtain the optimal Mo adsorption capacities of the resulted mesoporous gamma-alumina using the glucose template.