MOLECULES
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2023
·Vol. 28
·期 15
·5683
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IF 4.6
Yan Xiao,Nannan Zhan,Jie Li,Yuan Tan,Yunjie Ding
The catalytic upgrading of ethanol into butanol through the Guerbet coupling reaction has received increasing attention recently due to the sufficient supply of bioethanol and the versatile applications of butanol. In this work, four different supported Cu catalysts, i.e., Cu/Al2O3, Cu/NiO, Cu/Ni3AlOx, and Cu/Ni1AlOx(Ni2+/Al3+molar ratios of 3 and 1), were applied to investigate the catalytic performances for ethanol conversion. From the results, Ni-containing catalysts exhibit better reactivity; Al-containing catalysts exhibit better stability; but in terms of ethanol conversion, butanol selectivity, and catalyst stability, a corporative effect between Ni–Al catalytic systems can be clearly observed. Combined characterizations such as XRD, TEM, XPS, H2-TPR, and CO2/NH3-TPD were applied to analyze the properties of different catalysts. Based on the results, Cu species provide the active sites for ethanol dehydrogenation/hydrogenation, and the support derived from Ni–Al–LDH supplies appropriate acid–base sites for the aldol condensation, contributing to the high butanol selectivity. In addition, catalysts with strong reducibility (i.e., Cu/NiO) may be easily deconstructed during catalysis, leading to fast deactivation of the catalysts in the Guerbet coupling process.Keywords:copper catalyst;hydrotalcite;stability;ethanol;butanol
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高影响因子
FUEL
·
2023
·
IF 7.4
Linjie Guan,Meiyu Liu,Honghai Liu,Li Zhang,Yiming Zhang,Yucai Qin,Binbin He,Yi Mei,Yun Zu
The regulation of the engineering regionally spatial framework aluminum (Al F ) distribution in MFI channels has been considered as an effective way for the production of light olefins by targeted fluid catalytic cracking (TCO) technology. In this work, ZSM-5 zeolites with controlled Al F distributions are facilely synthesized by tuning the combinations of pentaerythritol (PET), tetrapropylammonium (TPA) and Na cations. The Al F atoms in the prepared HZ5-[PET + Na] and HZ5-[TPA] samples are enriched in the straight channels and intersection channels, respectively, which are favorable to the n-butane monomolecular reaction pathway, promoting the propylene production. Whereas the Al F atoms in the HZ5-[TPA + Na] sample are simultaneously distributed in both the straight and intersection channels, the n-butane molecules preferentially take place monomolecular reaction in the straight channels to generate carbonium ions (e.g., C 2 H 5 + , C 3 H 7 + and C 4 H 9 + ). Subsequently, all of them enter into the intersection channels to induce the occurrence of bimolecular reaction. Such a process is conducive to the formation of ethylene. These insights can help to clarify the catalytic behavior of regional framework acid sites in ZSM-5 channels and then provide an effective approach to design efficient TCO catalysts.
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Journal of Environmental Chemical Engineering
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2023
·
IF 7.7
Yi Liu,Dengjie Zhong,Yunlan Xu,Haixing Chang,Lin Dong,Zhuofan Han,Jun Li,Nianbing Zhong
The limited metal sites of monometallic MOFs and the high influence of pH limit their adsorption capacity. To solve these problems, La/Al bimetallic MOFs/chitosan composite was prepared by hydrothermal synthesis and impregnation methods and then characterized by XRD, FTIR, SEM, BET and XPS techniques. The doping of La has no obvious effect on the structure of Al-MOFs, but chitosan has greatly changed the structure of La/Al bimetallic MOFs. The phosphate adsorption of the composite was affected by La/Al molar ratio, chitosan/bimetallic MOFs mass ratio, temperature, phosphate initial concentration, adsorbent dosage, pH, and coexisting ions. The optimum molar ratio of La/Al and mass ratio of chitosan/bimetallic MOFs are 0.5:1 and 5.0%, respectively. The addition of La and chitosan can provide additional adsorption active sites, inhibit metal leaching, and enhance the phosphate adsorption performance, stability, and acid-alkali resistance of the composite. Its maximum adsorption capacity was 264.48 mg·g −1 . Its phosphate removal efficiency is above 90% at pH= 3.0–9.0. The actual phosphorus-containing wastewater with 7.064 mg·L −1 PO 4 3- and initial pH 7.4 can be treated to meet Chinese first-class effluent quality standard. La, Al, amino groups, and hydroxyl groups play an important role in the adsorption process of phosphate. When pH < pH pzc (4.99), phosphate is adsorbed by electrostatic gravitation between it and protonated positively charged amino and hydroxyl groups on La and Al, while when pH > pH pzc , phosphate is removed by ligand exchange between it and hydroxyl groups on La and Al. A stable, low-cost, and efficient bimetallic MOFs-based phosphate adsorbent was designed and prepared in this paper, and the results can provide reference for researchers in environmental chemical engineering .
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CHEMICAL ENGINEERING RESEARCH & DESIGN
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2023
·
IF 3.9
Honghui Xiong,Jinglei Liu,Yongjun Zhang,Hao Wang,Enhao Sun
To reduce the coke formation, a novel Al/Si/Cr/Ce composite ceramic coating was prepared on the surface of the Cr 25 Ni 35 Nb alloy substrate by pack cementation. The microstructure, phase composition, surface morphology and element distribution of substrate and coating were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results reveal that the outer layer of the coating forms a protective layer with a high proportion of AlN and Cr 3 Si and trace amounts of Ce. The inter-diffusion layer is mainly aluminide coating (AlNi and AlFe) and transition layer contains a small amount of AlN. The anti-coking performance of the coating was assessed using naphtha steam cracking. To study coking behavior, the morphology and microstructure of the coke layer were analyzed and characterized by SEM and Laser Micro-Raman Spectrometer. The coke layer on uncoated sample has a higher focal density and is more likely to spall and peel off when subjected to coking experiment. A large number of filamentous and granular cokes appear on the surface of the uncoated sample, whereas only less granular cokes appear on the surface of the coated sample, and the coke on the uncoated sample has a more disordered and amorphous carbon structure. The coating significantly inhibited the growth of filamentous coke and reduced coke accumulation.
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Materials
·
2023
·Vol. 16
·期 9
·3532
·
IF 3.4
Ruohan Xia,Bing Zhang,Kousuo Dong,Yao Yan,Zisheng Guan
Superhydrophobic coatings with excellent water-repellent properties imply a wide range of application areas. However, improvements are needed in terms of stability and complex processing procedures. In the present study, a superhydrophobic coating on Al sheets was prepared by mixing hexadecyltrimethoxysilane (HDTMS)-modified SiO2nanoparticles and acid-catalyzed silica sols (HD-SiO2/SiO2Sol) with polydimethylsiloxane (PDMS) binder. The HD-SiO2nanoparticles and acid-catalyzed silica sol (SiO2sol) form a binary graded micro-nanostructure, providing excellent superhydrophobicity (Water Contact Angle = 158.5°, Sliding angle = 0°). Superhydrophobic coatings with excellent water-repellent properties have potential for corrosion prevention. However the commonly used organic resins have poor chemical and mechanical properties. In the present study, the results of outdoor exposure for 30 days, immersion in acid and alkaline solutions for 24 h, grit abrasion, and water impact experiments, respectively, showed that the prepared superhydrophobic coating has good wear resistance. The integrated superhydrophobic coating on the Al sheets exhibited good corrosion inhibition with an efficiency (η) of 98.9%, which is much higher than that of the uncoated sheets. The present study provides a promising approach for producing stable superhydrophobic coatings at a low cost, with the potential to supplant conventional organic resin anti-corrosion coatings.Keywords:superhydrophobic;SiO2;surface modification;anti-corrosion
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COMBUSTION AND FLAME
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2021
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IF 4.185
Jie Ji,Li Liang,Heng Xu,Guifeng Xiang,Haozhe Li,Pingyun Li,Xiang Zhou,Xiaode Guo
Nanothermites with fluoropolymer are popular among researchers due to their excellent combustion performance. Polyvinylidene fluoride (PVDF) is a kind of typical fluoropolymer with excellent chemical stability. This paper applied the evaporation method by employing the cyclohexane to realize the preparation of the core-shell structured Al@PVDF particles. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and fourier transform infrared spectroscopy were employed to characterize the core-shell structure and elemental distribution of the samples. Desirable corrosion resistance could be obtained at different surroundings of water, acid and alkali, indicating that Al@PVDF particles with the core-shell structured possess the improved stability than Al nanoparticles . Constant volume pressure tests were performed to characterize the energy release property. The results are applied to prove that the Al@PVDF particles have the outstanding pressure output ability in the environment short of oxygen. In terms of the ignition delay time, the light intensity and the combustion flame propagation, the combustion performance of samples were examined in air by the device with optical sensor and the high-speed camera to be compared with the samples by traditional physical mixing method. Al@PVDF particles have outstanding pressure output ability as well as more excellent combustion performance. In addition, the preparation method needs much lower technical requirements so that it is more suitable to apply to industrial production.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2021
·
IF 7.312
Yifan Guo,Changhui Xin,Linjuan Dai,Yiping Zhang,Xin Yu,Quanhui Guo
Preparation of high-performance composites photocatalysts for organic pollutants degradation is of great significance. In this work, elemental doping was employed to realize the visible-light harvesting and visible-light photocatalysis of the (Al,C)-Ta 2 O 5 mesocrystals following by introduction of CdS quantum dots (QDs) into layered and poriferous (Al,C)-Ta 2 O 5 nanosheets for fabrication of S-scheme charge transfer pathways. In this work, the higher temperatures treatment induced the successful transformation of (Al,C)-Ta 2 O 5 nanosheets from Ta 3 AlC 4 MAX. The experimental results also revealed that CdS QDs/(Al,C)-Ta 2 O 5 composites showed highly enhanced visible-light absorption and visible-light photocatalytic tetracycline degradation performance. The optimal photocatalytic reaction rate constant of the CdS QDs/(Al,C)-Ta 2 O 5 -30% composite reached as high as 0.1117 min −1 , which was approximately 27.24 times of the (Al,C)-Ta 2 O 5 nanosheets and 2.43 times of CdS QDs , far better than those of commercial Ta 2 O 5 and pristine Ta 3 AlC 4 . Meanwhile, the prepared CdS QDs/(Al,C)-Ta 2 O 5 composites were also employed for efficient photodegradation of norfloxacin. Besides, the effects of various experimental parameters, reactive species determination, and band structures were also investigated. The improved visible-light photocatalytic performance of the CdS QDs/(Al,C)-Ta 2 O 5 composites was mainly attributed to fabrication of S-scheme charge transfer pathways for efficient charge separation.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Gang Zhao,Peipei Xu,Gang Wei,Kezhen Zhang,Chunxue Yi,Shanyi Guang,Hongyao Xu
Intelligent materials are functional material systems with intelligent responses to external stimulation. With the continuous advances in science and technology, intelligent materials have surfaced as a research trend in material science and are providing a new direction for the systematic application of nanocomposite materials. In this study, an intelligent organic-inorganic nano-hybrid sensor or intelligent nanorobot, POSS-RHB-PEG, was developed by employing density functional theoretic calculations (DFT) under the Gaussian 03 program by a “Click Chemistry” based preparation strategy, in which RHB group can act as a recognizing ion in the cell under the action of intense coordination field and then as a function of coordinating ions. A low-chain PEG with good cell permeability functions as a machine wheel on account of the principle of osmotic pressure. The POSS-based nanorobotic molecular analytical device, with appropriate bio-compatibility, was designed and developed for the semiquantitative, intuitive, and sensitive detection and morphological analysis of Al 3+ ions in a real sample with a detection limit of 1.0×10 −8 M. Significant color evolutions from colorless to red were observed by the naked eye under the ultraviolet lamp, resulting in a semiquantitative visual detection. Compared to the organic sensing material RHB-Ac, the intelligent nanorobot POSS-RHB-PEG has high stability, selectivity (sulfhydryl group can self-screen Fe 3+ ions), and good biocompatibility. Furthermore, the nanohybrid nanorobot sensor successfully targeted HeLa cells, monitored cellular endogenous Al 3+ , and assessed cell stress in living cells. The nanohybrid nanorobot sensor POSS-RHB-PEG was also able to detect and image Al 3+ in living nude mice, indicating its exceptional detection potential in biological systems, it mainly involves the detection of metal ions in blood and the detection and treatment of heavy metal ions caused by clinical bone and joint replacement.
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Defence Technology
·
2023
·
IF 5.1
Jialu Yang,Jiaheng Hu,Yinghua Ye,Jianbing Xu,Yan Hu,Ruiqi Shen
Self-destructing chips have promising applications for securing data. This paper proposes a new concept of energetic diodes for the first time, which can be used for self-destructive chips. A simple two-step electrochemical deposition method is used to prepare ZnO/CuO/Al energetic diode, in which N-type ZnO and P-type CuO are constricted to a PN junction. This paper comprehensively discusses the material properties, morphology, semiconductor characteristics, and exploding performances of the energetic diode. Experimental results show that the energetic diode has typical rectification with a turn-on voltage of about 1.78 V and a reverse leakage current of about 3 × 10 −4 A. When a constant voltage of 70 V loads to the energetic diode in the forward direction for about 0.14 s or 55 V loads in the reverse direction for about 0.17 s, the loaded power can excite the energetic diode exploding and the current rises to about 100 A. Due to the unique performance of the energetic diode, it has a double function of rectification and explosion. The energetic diode can be used as a logic element in the normal chip to complete the regular operation, and it can release energy to destroy the chip accurately.
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Junjie Qi,Jingkun Li,Yuqi Wan,Yu Li,Fuwei Pi
Antibiotic residues are becoming more and more concern due to the increasingly serious resistance from bacteria to organism. On-site and accurate evaluation on antibiotics is necessary and urgent to effectively solve such public issue. To provide point-of-care-test (POCT) ideas for antibiotic accurate evaluation, a fluorescence (FL)-surface-enhanced Raman scattering (SERS) dual-mode detection of tetracycline antibiotic (TCs) was realized for the first time. Based on the inner filter effect in Ag@NH 2 -MIL-101(Al) nanoprobe, the fluorescence quenching was induced and the SERS signal was swiftly turn on through π-π interaction and hydrogen bonding in the presence of TCs. This FL-SERS dual mode sensor displayed excellent detection limits (FL in ∼10 −3 ppm, SERS in ∼10 −5 ppm), and achieved a reliable detection of TCs in honey with a recovery rate of 84.45%−112.08%. This method combines the advantages of FL and SERS detection, meanwhile, two techniques verified against each other to achieve highly sensitive and specific FL-SERS dual-mode sensor for TCs. We believe that such antibody-or aptamer-independent FL and SERS complementary nanoprobe can be applied to fast, direct and multiple sensing in environment and food hazards.
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2023
·
IF 6.1
Yougan Xiao,Jiahui Lu,Shunjian Cheng,Zilong Wang,Antong Shi,Jyunhong Shen,Zhuwu Jiang
From a preliminary performance comparison of several layered double hydroxides (LDHs), magnetically separable Ni-M LDHs (M = Fe, Al) were synthesized and applied as efficient ozonation catalysts for degrading dye Rhodamine B (RhB). As proved by various characterizations, the micromorphology, nanostructure size, and porous feature of the synthesized Ni-M LDHs significantly varied with different metal components. Among them, Ni 3 -Fe LDH and Ni 2 -Al LDH possessed a relatively larger specific surface area to react with O 3 interfacially, thereby exhibiting excellent catalytic ozonation performance. The RhB was almost completely degraded within 60 min, and the removal efficiencies of COD and TOC reached above 70% and 50%, respectively. The effects of catalyst dosage, initial dye concentration, solution pH, and coexisting inorganic anions on RhB degradation were studied systematically. ESR measurements and radical quenching experiments indicated that OH , O 2 − , and 1 O 2 are primary reactive oxygen species (ROS), while 1 O 2 induced the most dominant degradation contribution. According to the variations of ROS formation and material properties during the catalytic ozonation process, the possible reaction mechanisms were proposed. Moreover, the differences involved in the redox of multivalent metals and the transformation of surface hydroxyls over Ni-Fe and Ni-Al LDHs were further revealed.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Zequan Liu,Tao Ou,Minhua Su,Hairong Peng,Gang Song,Lingjun Kong,Diyun Chen
Uranium and uranium-containing pollutants are excessively released into the environment, leading to serious water and soil contamination. Minerals such as alumina are naturally abundant and frequently affect the fate and migration behavior of uranium ions. A thorough understanding of the migration and immobilization behavior of uranium on Al-rich minerals (e.g., α-alumina [α-Al 2 O 3 ] and γ-alumina [γ-Al 2 O 3 )]) is essential for unraveling numerous environmental issues. We performed a systematic comparative analysis of U(VI) retention by α-/γ-alumina. The effects of coexisting ions and natural organic matter were explored. Solution pH contributed critically to the retention of U(VI) by α-/γ-alumina. The adsorption rate of γ-Al 2 O 3 for U(VI) removal was faster than that of α-Al 2 O 3 , reaching equilibrium within 15 min with a high removal efficiency of 94.43%. PO 4 3− ions significantly promoted U(VI) adsorption, especially for the case of α-Al 2 O 3 . The addition of phosphate resulted in a 15-fold enhancement in adsorption capacity. Humic acid promoted U(VI) removal by γ-Al 2 O 3 under acidic conditions while strong inhibition on both α-Al 2 O 3 and γ-Al 2 O 3 in basic conditions. The removal mechanism of U(VI) by alumina is mainly ascribable to electrostatic interaction and surface complexation from various oxygenated functional groups. The present findings are pivotal to the understanding of uranium migration and immobilization in the environment.
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