Synthesis of reusable macroporous St/BMA copolymer resin and its absorbency to organic solvent and oil

In this paper, a reusable macroporous high oil absorption resin for oil spills was synthesized successfully by suspension copolymerization with styrene and butyl methacrylate as monomers. In the process of suspension copolymerization, a porogenic agent was introduced into the reaction system. Structure and surface morphology of the macroporous resin were characterized by Fourier transform infrared spectrometry, X‐ray photoelectron spectroscopy, and scanning electron microscopy. In addition, effects of different reaction factors on density and particle size of macroporous resins and effects of various factors on the oil absorbency of macroporous resins were discussed. Furthermore, oil absorption kinetics and repeatability of resin and the absorbency of the macroporous resin in various oils were also studied. Compared with the resin without macroporous structure, the maximum oil absorbency of the macroporous resin to the carbon tetrachloride (CCl₄) was 28.28 g/g, which increased by 61.42%. Meanwhile, the saturated oil absorption time of resin also decreased significantly from 7.5 to 2 hr. The macroporous high oil absorption resin presents predominant performance of reuse and regeneration. Moreover, the macroporous resin had certain absorbency (8.7 g/g) to crude oil, which makes it useful for marine oil spill. Copyright © 2015 John Wiley & Sons, Ltd.     

Preparation and Characterization of Epoxy/Inorganic Anti‐electrostatic Nanocomposites Using Submicrometer Al(OH)3 and Colloid Al2O3

New organic‐inorganic hybrid materials and their anti‐electrostatic hybrid membranes are prepared via sol‐gel process. The polycondensation of epoxy oligomers and AEAPS/Al₂O₃ complexes which are organically surface modified submicrometer aluminum trihydroxide inorganic fillers with an active aminoterminal silane coupling agent, N‐(2‐aminoethyl)‐3‐aminopropyltrimethoxysilane (AEAPS), are performed. AEAPS enhances the interfacial interactions between the inorganic fillers and epoxy polymers. Meanwhile, this coupling agent maintains well dispersion of fillers in these composites. To improve the mechanical strength and thermal stability, pyromellitic dianhydride (PMDA) is used as curing agent. These hybrid films prepared from this method have excellent physical properties, such as UV‐shielding, high transmission in visible resign (> 85%), high hardness (7～8H) , high adhesive force (7～8) and low relative surface resistance (9.71 × 10¹¹～1.26 × 10¹⁰ Ω/cm²) with anti‐electrostatic characters. For thermal resistance, the best Td value of epoxy/PMDA/AEAPS/Al₂O₃ is 378.6 °C which is 85.4 °C higher than that of neat epoxy resin. Physical properties of these materials are almost the same as those of the nanocomposites prepared from expensive colloid Al₂O₃. Evidences from TEM micrograph show that the inorganic additives are dispersed evenly in organic matrix with nanometer scale.     

Adsorption desulfurization performance and mechanism over nanocrystalline NiO/Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-1 adsorbent

Desulfurization performance was evaluated by an adsorption model or real oil (diesel and kerosene) at low temperature using nanocrystalline NiO/Al₂O₃-1 adsorbent in static equipment. The properties of the NiO/Al₂O₃ adsorbent samples were characterized by BET surface areas, transmission electron microscopy, FTIR spectra, and TG-DTG curves. Desulfurization experimental results indicated that the desulfurization efficiency for kerosene is much higher than that for diesel due to the π-electronic interaction and S–M bonds with NiO/Al₂O₃-1 adsorbent. Also, a performance of adsorbent regeneration was kept well for multiple cycles.     

Investigation of macro-/mesoporous Re<Subscript>2</Subscript>O<Subscript>7</Subscript>/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalysts prepared by a particle-template method for butylene metathesis

Macro-/mesoporous Al₂O₃ supports were prepared by using monodisperse polystyrene (PS) microspheres as a template. The pore volume and BET surface area of the Al₂O₃ supports increased considerably with increasing amounts of the PS microspheres; further investigation showed that PS template only increased the volume of macro-pores but did not change the volume of meso-pores or micro-pores. Macro-/mesoporous Re₂O₇/Al₂O₃ metathesis catalysts were prepared through loading Re₂O₇ onto the as-prepared macro-/mesoporous Al₂O₃ supports, and their catalytic performance was tested in a fixed-bed tubular reactor using the metathesis of normal butylenes as a probe reaction. The results showed that the prepared macro-/mesoporous Re₂O₇/Al₂O₃ catalyst had high activity with consistent selectivity; propylene and pentene accounted for more than 90 wt% of the metathesis products, while the amount of ethylene plus hexane was less than 10 wt%, the majority of which was hexane. These Re₂O₇/Al₂O₃ catalysts had not only higher activity, but also longer working life span and higher tolerance to carbon residues than conventional Re₂O₇/Al₂O₃ catalysts.     

Enhanced tribology properties of ZnO/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> composite nanoparticles as liquid lubricating additives

Monodispersed and hydrophobic ZnO/Al₂O₃ composite nanoparticles are prepared by a nonhydrolytic sol–gel method. ZnCl₂ and AlCl₃ are dissolved in acetone and used as precursors. Oleic acid is adopted as an oxygen donor. The tribology properties of the prepared ZnO/Al₂O₃ composite nanoparticles are studied by the four-ball friction and thrust ring friction test. It is demonstrated that the average friction coefficient and the wear scar diameter are reduced by 37.5 and 26.2%, respectively, in comparison with pure lubricating oil. Moreover, the ZnO/Al₂O₃ composite nanoparticles bear the merits of ZnO and Al₂O₃ when used as lubricant additives, exhibiting both excellent antifriction and antiwear behaviors simultaneously. The ZnO/Al₂O₃ composite nanoparticles improve the lubrication effect not only by turning the sliding friction into rolling friction, but also forming a hard Al₂O₃ protective film onto the thrust-ring surface containing ZnO/Al₂O₃ nanoparticles, which have much potentiality in industrial applications.     

Hierarchical Fe3O4@TiO2 Yolk–Shell Microspheres with Enhanced Microwave‐Absorption Properties

A facile and efficient strategy for the synthesis of hierarchical yolk–shell microspheres with magnetic Fe₃O₄ cores and dielectric TiO₂ shells has been developed. Various Fe₃O₄@TiO₂ yolk–shell microspheres with different core sizes, interstitial void volumes, and shell thicknesses have been successfully synthesized by controlling the synthetic parameters. Moreover, the microwave absorption properties of these yolk–shell microspheres, such as the complex permittivity and permeability, were investigated. The electromagnetic data demonstrate that the as‐synthesized Fe₃O₄@TiO₂ yolk–shell microspheres exhibit significantly enhanced microwave absorption properties compared with pure Fe₃O₄ and our previously reported Fe₃O₄@TiO₂ core–shell microspheres, which may result from the unique yolk–shell structure with a large surface area and high porosity, as well as synergistic effects between the functional Fe₃O₄ cores and TiO₂ shells.     

Magnetic phenolic resin core-shell structure derived carbon microspheres for ultrafast magnetic solid-phase extraction of triazine herbicides

In this study, monodisperse magnetic carbon microspheres were successfully synthesized through the carbonization of phenolic resin encapsulated Fe₃O₄ core-shell structures. The magnetic carbon microspheres showed high performance in ultrafast extraction and separation of trace triazine herbicides from environmental water samples. Under optimized conditions, both the adsorption and desorption processes could be achieved in 2 min, and the maximum adsorption capacity for simazine and prometryn were 387.6 and 448.5 μg/g. Coupled with high-performance liquid chromatography-ultraviolet detection technology, the detection limit of triazine herbicides was in the range of 0.30–0.41 ng/mL. The mean recoveries ranged from 81.44 to 91.03% with relative standard deviations lower than 7.47%. The excellent magnetic solid-phase extraction performance indicates that magnetic carbon microspheres are promising candidate adsorbents for the fast analysis of environmental contaminants.     

Controlled synthesis of graphene oxide/alumina nanocomposites using a new dry sol–gel method of synthesis

The present paper gives new insight into the problem of controlling the morphology of reduced graphene oxide/alumina (RGO/Al₂O₃) nanocomposites. The dry and simplified sol–gel methods of RGO/Al₂O₃ nanocomposite synthesis were compared and the influence of six key synthesis parameters on the morphology of the resulting nanocomposite powders was investigated to optimize the morphology of RGO/Al₂O₃ nanocomposites in terms of reducing the undesired agglomeration of RGO/Al₂O₃ nanocomposite flakes to a significant minority and obtaining the uniform coverage of RGO surface with Al₂O₃ nanoparticles. Our investigations indicate that, despite the high excess of Al₂O₃ used (95 wt%), the lowest RGO/Al₂O₃ flake agglomeration and the formation of a uniform layer composed of Al₂O₃ nanoparticles with the average size of 58 nm occurred only when 5 wt% of graphene oxide was used as a substrate for the deposition of Al₂O₃ nanoparticles together with triethyl aluminium as an Al₂O₃ precursor and dry hexane as the reaction environment. The resulting organic precursor was thermally decomposed at 280 °C for 3 h in air atmosphere (R4 reaction pathway). This was confirmed by the high BET-specific surface area (242.4 m²/g) and the high open porosity (0.7 cm³/g) of the obtained RGO(5 wt%)/Al₂O₃ nanocomposite. This is also the first study with a detailed discussion of the reactions expected to occur during the synthesis of an RGO/Al₂O₃ nanocomposite.     

Morphology,tensile properties,and fracture toughness of epoxy/Al2O3 nanocomposites

Epoxy/Al₂O₃ nanocomposites were prepared using an epoxy resin, diglycidyl ether of bisphenol A, and cured with a polyoxypropylene diamine (Jeffamine D‐400). Transmission electron microscopy and wide angle X‐ray diffraction were employed to reveal the morphology of epoxy/Al₂O₃ nanocomposites. Dynamic mechanical analysis results showed that the storage modulus and the glass transition temperature (T_g) of epoxy were improved. Tensile strength and Young's modulus also increased with increasing Al₂O₃ loading. Fracture toughness, as indicated by the stress intensity factor, K_Q, was determined using single edge notch bending method, and 40% increase in K_Q was observed with only 2 vol % Al₂O₃. Scanning electron microscopy study of fracture surface showed a rather smooth and flat morphology for neat epoxy. However, massive plastic deformation was observed for epoxy/Al₂O₃ nanocomposites, leading to the significant increase in fracture toughness. The influence of spherical Al₂O₃ nanoparticles on thermophysical properties of epoxy was discussed and compared with that of sheet‐like nanoclays. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1466–1473, 2006     

Enhanced epoxidation of soybean oil by novel Al2O3–ZrO2–TiO2 solid acid catalyst

This study aims to develop highly efficient, recyclable solid catalysts for the epoxidation of vegetable oils. An Al₂O₃–ZrO₂–TiO₂ solid acid catalyst was prepared by a co‐precipitation/impregnation method and characterised through scanning electron microscopy, energy‐dispersive spectroscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, Fourier‐transform infrared and nitrogen adsorption–desorption analyses. The solid acid catalyst with a high surface area and typical slit pore adsorption was successfully synthesised. Al₂O₃–ZrO₂–TiO₂ also exhibits high stability and improved catalytic efficiency in the epoxidation of soybean oil. An oil conversion rate of 86.6%, which is higher than that of conventional catalysts, was obtained with a catalyst loading of 0.8 wt% and was maintained at 76.6% even after recycling the catalyst three times. The performance of the solid catalyst was slightly superior to that of H₂SO₄. Therefore, this novel catalyst may potentially be applicable in catalysing soybean oil epoxidation.     

Efficient conversion of fructose to 5‐hydroxymethylfurfural by functionalized γ‐Al2O3 beads

Millimeter size γ‐Al₂O₃ beads were prepared by alginate assisted sol–gel method and grafting organic groups with propyl sulfonic acid and alkyl groups as functionalized γ‐Al₂O₃ bead catalysts for fructose dehydration to 5‐hydroxymethylfurfural (5‐HMF). Experiment results showed that the porous structure of γ‐Al₂O₃ beads was favorable to the loading and dispersion of active components, and had an obvious effect on the properties of the catalyst. The lower calcination temperature of γ‐Al₂O₃ beads increased the specific surface area, the hydrophobicity and the activity of catalysts. Competition between the reaction of alkyl groups and ‐SH groups with surface hydroxyl during the preparation process of the catalyst influenced greatly the acid site densities, hydrophobic properties and activity of the catalyst. With an increase in the alkyl group chain, the hydrophobicity of catalysts increased obviously and the activity of the catalyst was enhanced. The most hydrophobic catalyst C₁₆‐SO₃H‐γ‐Al₂O₃–650°C exhibited the highest yield of 5‐HMF (84%) under the following reaction conditions: reaction medium of dimethylsulfoxide/H₂O (V/V, 4:1), catalyst amount of 30 mg, temperature of 110°C and reaction time of 4 hr.     

Ni/Al2O3改性催化剂催化重整生物油模拟物制氢研究

制备了Ni/Al₂O₃、Ni-Cu/Al₂O₃、Ni-Co/Al₂O₃和Ni-Co-Cu/Al₂O₃催化剂,研究了Co和Cu对生物油水蒸气催化重整的影响。实验表明,Co 能促进水汽变换(WGS)反应,提高氢气的产率,Cu能抑制反应中焦炭的形成,提高催化剂的稳定性。对催化剂Ni-Co-Cu/Al₂O₃进行工艺条件考察,当900 ℃、水油比为6 g/g、质量空速(WHSV)为1 h^-1时,碳选择性达到87.5%,氢气产率达到84.2%,潜在氢气产率达到92.4%。     

Dearomatization, cetane improvement and deep desulfurization of diesel feedstock in a single-stage reactor

Hydrotreating of light cycle oil over CoMo/Al₂O₃, NiMo/Al₂O₃ and NiW/Al₂O₃ catalysts has shown that the type of catalyst has a critical influence on the composition and properties of the product. Divergent effects of aromatics content and molecular weight on the cetane index by these catalysts occurred. Data show that it was not possible to obtain a diesel product that meets stringent specifications using one type of catalyst in a single-stage reactor even under severe operating conditions.     

Hydrocracking of vacuum gas oil in the presence of catalysts NiMo/Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–amorphous aluminosilicates and NiW/Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–amorphous aluminosilicates

Supported nickel–molybdenum and nickel–tungsten hydrocracking catalysts prepared using a support that consists of 70% Al₂O₃ and 30% amorphous aluminosilicate were characterized by nitrogen and mercury porosimetry, IR spectroscopy of adsorbed CO, and high-resolution electron microscopy. The catalytic tests in hydrocracking of vacuum gas oil containing 3.39% sulfur showed that the nature of the hydrogenating component (NiMo or NiW) only slightly influences the vacuum gas oil conversion and the diesel fraction yield, but noticeable influences the properties of the diesel fraction obtained. The catalyst NiMo/Al₂O₃–amorphous aluminosilicates, compared to NiW/Al₂O₃–amorphous aluminosilicates, ensures lower sulfur content in the diesel fraction obtained, whereas the catalyst NiW/Al₂O₃–amorphous aluminosilicates allows obtaining a diesel fraction with lower content of polyaromatic compounds.     

Designing magnetic and superhydrophobic cellulose nanofibers based-aerogel for efficient oil water separation

In this work, we used cellulose nanofibers (CNF) as the skeleton, Fe₃O₄@ZnO composite particles as magnetic synergist particles, 3-(2-aminoethylamino) propyltrimethoxysilane (AS) and trimethoxy(octyl)silane (OTMS) as water-based hydrophobic modifiers to prepare magnetic and superhydrophobic cellulose nanofibers based-aerogel with low density and intricate three-dimensional structure. Fe₃O₄@ZnO confers magnetic properties (3.82 emu/g) and exceptional thermal stability (water contact angle of 150.1° at 200 °C) to the system, while the combination with OTMS/AS endows the system superhydrophobic (157.5°) and excellent mechanical properties (stress of 96.95 kPa at 80% strain). It is worth noting that in the process of modifying the system with OTMS/AS, no organic solvents and acidic substances are used in the solution. Benefiting from their synergies, the system demonstrates a notable oil absorption capacity (12.31–41.91 g/g) and outstanding oil selectivity (exceeding 90%), driven by gravity alone. Interestingly, this system, marked by its cost-effectiveness, simplicity, eco-friendliness, and heightened efficiency, holds promising prospects for diverse applications in different oil–water separation behavior and purifying industrial oil wastewater, as well as oil flooding incidents.     

Facile Fabrication of Porous Bi2O3 Microspheres by Thermal Treatment of Bi2O2CO3 Microspheres and its Photocatalysis Properties

β- and α-phase porous Bi₂O₃ microspheres with an average size of around 4 μm had been synthesized by thermal treatment of Bi₂O₂CO₃ microspheres at 350 and 400–500 °C respectively in an air atmosphere. The Bi₂O₂CO₃ microspheres had been synthesized at a temperature of 180 °C by a hydrothermal process using Bi(NO₃)₃ as the bismuth source with the assist of citric acid. By combining the results of X-ray powder diffraction, transmission electron microscope, scanning electron microscopy, and UV–Visible absorption spectra, the structural, morphological and optical properties characterization of the products were performed. The photocatalytic activity of the as-prepared α- and β-phase porous Bi₂O₃ microspheres have been tested by degradation of methylene orange under visible light, indicating that porous β-Bi₂O₃ microspheres showed enhanced photocatalytic performance compared to P25 and α-Bi₂O₃ microspheres.     

氧化铝载体和氧化钡助剂对钌基氨合成催化剂结构和性能的影响

采用不同来源γ-Al2O3(市售Al2O3-1,合成Al2O3-2)作为钌基氨合成催化剂载体,利用浸渍法制备了一系列添加不同BaO助剂含量的Ba-Ru/Al2O3催化剂.通过X射线衍射(XRD)、N2-低温物理吸附、X射线荧光光谱(XRF)、透射电镜(TEM)、H2程序升温还原(H2-TPR)、NH3程序升温脱附(NH3-TPD)和X射线光电子能谱(XPS)等方法研究了不同来源的Al2O3以及BaO助剂含量对负载型钌基催化剂的物相结构、织构性质、微观形貌、表面性质和催化剂的氨合成活性等方面的影响.结果表明,载体的物理化学性质对制备的钌基氨合成催化剂的结构以及活性有较大影响.BaO助剂对催化剂的影响主要表现在两个方面:添加量不同导致BaO与γ-Al2O3的作用力不同,从而进一步影响催化体系的比表面积和孔结构性质;BaO助剂会对体系的Ru物种还原性质以及催化剂表面酸碱性质进行调节,适量BaO的加入能够极大提高反应活性,而这种最佳量与载体性质密切相关.     

Facile and scalable synthesis of nanostructured Fe2O3 using ionic liquid-assisted ball milling for high-performance pseudocapacitors

In this study, we report that ionic liquid (IL)-assisted ball milling of iron precursors in the absence of any reagent resulted in the scalable production of IL/Fe₂O₃ hybrids with a favourable morphology (high surface area of 202 m²/g and pore size of 40nm) for supercapacitor applications. During ball milling process, ILs are played role as structure guiding templates for construction of rod-like pore containing Fe₂O₃ and surface functionalities for IL/Fe₂O₃ hybrids, resulting in good wettability and enhanced ion transfer. These attractive features of IL/Fe₂O₃ hybrids make them excellent candidate pseudocapacitive electrode materials that exhibit a high specific capacitance of 230 F/g at a current density of 1 A/g, fast and reversible charge/discharge rates (∼71% retention at 15 A/g), and excellent long-term cycle stability (∼100% retention over 10000 cycles).     

Facile and green methodology for surface‐grafted Al2O3 nanoparticles with biocompatible molecules: preparation of the poly(vinyl alcohol)@poly(vinyl pyrrolidone) nanocomposites

The present work describes preparation of modified alumina with biocompatible, water soluble, and treating agents such as citric acid and ascorbic acid. Also, the influence of the modified nanoparticles (NPs) into the blend of poly(vinyl alcohol)@poly(vinyl pyrrolidone) (50/50) matrix was studied. At first, citric acid and ascorbic acid as environmental friendly agents were grafted on the surface of Al₂O₃ NPs. Then, nanocomposites (NCs) with different amounts of modified Al₂O₃ NPs were prepared via a simple ultrasonic method. The characterizations of the molecular structure of the NCs specified that chemical and physical interactions happened between inorganic and organic counterparts. The mutual effect of modified NPs into the polymer matrix was investigated on the structural, interfacial interaction, thermal stability, and optical properties. The results from morphological characterization confirmed changes in morphology of poly(vinyl alcohol) and poly(vinyl pyrrolidone) after loading NPs. Uniform dispersion of modified spherical Al₂O₃ NPs powders into the matrix of 50/50 polymers was detected by field emission scanning electron microscopy and energy‐dispersive X‐ray. Adding M‐NPs into the polymer matrix expressively improved the thermal stability of NCs. Peaks in ultraviolet–visible spectra were shifted to the higher absorption. Copyright © 2017 John Wiley & Sons, Ltd.     

Physicochemical and Reactivity Studies on Polystyrene‐Cu/Al2O3 Catalysts: An Attempt to Control Copper Dispersion

The influence of coating of 5.0 (w/w%) Cu/γ‐Al₂O₃ catalyst by different ratios of polystyrene on the physicochemical and textural properties was studied. The physicochemical and textural properties of polystyrene‐`Cu/γ‐Al₂O₃ catalysts were investigated by N₂ adsorption, O₂ chemisorption, FTIR, XRD, TEM, and SEM. In addition, the kinetics of H₂O₂ decomposition as a model redox reaction over polymer coated and uncoated catalysts was investigated. The highest activity was achieved by 0.06 wt% polystyrene‐5.0Cu/γ‐Al₂O₃ catalyst. The parent 5.0Cu/γ‐Al₂O₃ catalyst showed auto‐catalytic first order mechanism, which was subjected to a pronounced modification to a simple first order one upon coating by polystyrene. This modification in the mechanism was accompanied with an increase in the apparent activation energy of the reaction. The observed high activity of 0.06 wt% polystyrene‐5.0Cu/γ‐Al₂O₃ catalyst was attributed to the role of polymer in enhancement of the degree of dispersion of the surface copper. However, the modification in kinetics of the reaction was attributed to the difference in the nature of Cu active sites namely, the polymer protected the metallic copper species on the surface of γ‐Al₂O₃ support against possible oxidation to copper sub‐oxides and/or that polymer might change the hydrophilic properties of the reaction media.