CARBOHYDRATE RESEARCH
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2021
·
IF 2.104
Shuai Wu,Dengwen Ning,Dezhong Xu,Yanan Cheng,Ajoy Kanti Mondal,Qiuxia Zou,Hongyi Zhu,Fang Huang
First time aerogels composite with super hydrophobic properties were developed by using tunicate cellulose nanocrystals (TCNC), which expanded the application scope of animal cellulose resources. In this study, the TCNC was firstly cross-linked with silica and methyltrimethylsilane (MTMS), further coated with fluorodopa to form an aerogel with super hydrophobic properties. The aerogel was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR), and X-ray photoelectron spectroscopy (XPS). Results indicated that the contact angle of aerogel was 158.7°, which showed good hydrophobicity . The composite aerogel has superior stability in wide pH range, after 72 h immersion in pH = 0 and 12 solutions, the contact angle was still greater than 150°. The aerogel shows excellent oil-water separation ability and it can be repeatedly used more than 10 times. The separation efficiency can all reach more than 90% for different water-oil mixtures. This synthesized super hydrophobic aerogels derived from tunicate cellulose has greatly extended the application of marine animal celluloses.
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FUEL
·
2021
·
IF 6.609
Tao Pan,Sida Ge,Mengnan Yu,Yana Ju,Ran Zhang,Pei Wu,Kuanyu Zhou,Zhijie Wu
Zn modified ZSM-5 zeolite supported Ni bifunctional catalysts were prepared by in-situ hydrothermal synthesis (Zn-Ni-ZSM-5), co-impregnation method (Zn-Ni/ZSM-5) as well as combining in-situ hydrothermal synthesis of Zn-ZSM-5 and sequential impregnation of Ni (Ni/Zn-ZSM-5) and used for the selective converting olefin to aromatics applicable for FCC gasoline hydro-upgrading. The Lewis (L) acid sites generated by ZnOH + species and hydrogenation active sites from Ni 0 species were varied with preparation method, in which their locations at the external surface or micropores of zeolite changed the acid properties of catalysts. Comparing to the Zn-Ni/ZSM-5 from the co-impregnation method, direct in-situ hydrothermal method could incorporate Zn and Ni species within zeolite, which makes the strong interaction between the metal species and the framework Al to form medium-strong L acids (ZnOH + /NiOH + ). This leads to the decrease of ratio of Brønsted acid sites to L acid sites (B/L) from 0.40 to 0.12 and the difficulty in reducing of Ni cations to Ni 0 from 57% to 30% Ni 0 percent. Ni/Zn-ZSM-5 sample prepared by incorporating Zn species into micropores and sequential depositing Ni species at the external surface of zeolite possesses a low B/L ratio similar to Zn-Ni-ZSM-5 (0.20 versus 0.12) but a much higher Ni 0 percent (52% versus 30%). Zn-Ni-ZSM-5 shows closer intimacy between Zn and Ni species comparing to Zn-Ni/ZSM-5 and Ni/Zn-ZSM-5. For the 1-hexene aromatization, the formed iso -alkene at acid sites was quickly saturated to iso -alkanes by the adjacent Ni 0 particles over Ni-Zn-ZSM-5 catalyst in hydrogen steam. However, the location of aromatization active sites (ZnOH + , L acid sites) in micropores and hydrogenation active sites (Ni 0 species) on external surface of Ni/Zn-ZSM-5 makes the tandem conversion of n-alkene → iso -alkene → aromatics, rather than the n-alkene → iso -alkene → iso -alkane. Thus, Zn-Ni-ZSM-5 with close intimacy of ZnOH + and Ni 0 particles shows a high iso -alkane selectivity (27.9% iC 4 + ), while Ni/Zn-ZSM-5 exhibits a high aromatics selectivity (39.6 %) in the conversion of 1-hexene in hydrogen steam. Similar results have also found in the conversion of n-heptane. Here, the control of the intimacy of Zn and Ni in ZSM-5 zeolites has been realized to be a good protocol to adjust the selective conversion of olefins/alkanes to aromatics versus iso -alkanes.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Shuyao Ye,Jincheng Dai,Wei Li,Yao Yang,Zhengliang Huang,Jingdai Wang,Yongrong Yang
The reduction in the entangled state of the nascent ultrahigh-molecular-weight polyethylene (UHMWPE) is of fundamental importance to enhance its processability and mechanical properties. However, it remains a challenge to retard the formation of entanglements during polymerization above 60 °C because the chain propagation rate is notably higher than the chain crystallization rate. Herein, we present a feasible method for synthesizing the weakly entangled polyethylene via nitrogen microbubble-assisted polymerization. The mass transfer of ethylene inside the growing polyethylene particles is found to dominate the chain propagation process, which is influenced by the nitrogen bubble size. The contact/interval time (10–3 s) between the microbubbles and the particles, observed by a high-speed camera, appears several orders less than the chain propagation time. Consequently, such frequent contact/separation instantly blocks/recovers the reactant transfer on the solvent–particle interphase, causing an intermittent “dormancy effect” to retard the chain propagation and facilitate the chain crystallization. Therefore, the less entangled polyethylene is synthesized at a relatively high activity.
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Molecular Catalysis
·
2023
·
IF 4.6
Bowen Wu,Yixi Chen,Mingtai Liu,Yi Tang,Gengfeng Zheng,Linping Qian
The surface properties of CoMg/Al 2 O 3 were evaluated in the aerobic oxidation of p -cresol. The surface interaction is enhanced greatly after Co and Mg impregnation with the mole ratio of Co/Mg from 2 : 1 and 2 : 3. The strongest interaction for the nonpolarity and benzene ring was found on CoMg/Al 2 O 3 with Co/Mg of 2 : 3. But for the interaction with p -π group bonding with negative anion, the highest value appears on the catalyst with the Co/Mg of 2 : 2. In aerobic oxidation of p -cresol, the conversion is significantly increased with Co addition and reaches around 60 % after 24 h' reaction at 338 K. The highest selectivity of p -hydroxybenzaldehyde of 99 % is achieved on Al 2 O 3 with the co-impregnation mole ratio of Co/Mg of 2 : 2. It is suggested that medium adsorption of the reactants and strong stabilization of the intermediates facilitate the aerobic oxidation of p -cresol to p -hydroxybenzaldehyde.
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Catalysis Science & Technology
·
2023
·Vol. 14
·期 2
·334-342
·
IF 5
Zhou Yang,Ru Wang,Hongji Liu,Zhou Chen,Xiaoli Hu,Limin Sun,Weikun Lai,Yunyun Dong,Weiping Fang,Xiaodong Yi
Selective hydrogenation is a significantly important catalytic process in many industrial processes, where Pd-based catalysts are the most commonly used. Herein, the surface properties of γ-Al2O3 were modified by the layered flower-like architectures of alkaline MgO using a simple hydrothermal method. Then, a series of Pd/Al2O3–MgO catalysts were prepared by an incipient wetness impregnation method for the selective hydrogenation of isoprene. The results showed that the Pd/Al2O3–0.12MgO catalyst exhibited superior catalytic performance with a high activity (93%) and high selectivity (99%) for the semi-hydrogenation products. Systematic studies have demonstrated that the support effect plays an important role in dispersing and stabilizing palladium particles. The reasons for the improved catalytic performance were attributed to the high dispersion of Pd nanoparticles, the changed electronic structure of Pd, and the strong interaction between Pd nanoparticles and supports. This work opens a simple route to regulate the electronic properties of active metal sites via support modification for selective hydrogenation reactions.
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LANGMUIR
·
2023
·
IF 3.9
Xiaoxia Ye,Zhihong Zheng,Ruiyang Chi,Juan Liu,Jie Chen,Wei Luo
Cationic surfactant-stabilized oil-in-water emulsions pose a significant challenge in separation due to the presence of surfactants. Herein, we develop a collagen-fiber-based CFM–PMDA–TiO2 membrane with unique infiltration properties capable of efficiently separating cationic surfactant-stabilized oil-in-water emulsions by exploiting the charge-demulsification effect. The membrane exhibits superhydrophilic and submerged superoleophobic properties, making it highly suitable for separating a wide range of commercially available cationic surfactant-stabilized oil-in-water microemulsions and nanoemulsions, which demonstrates an exceptional separation efficiency as high as 99.86% and an impressive flux of up to 1436.40 L m–2 h–1. Furthermore, even after a strong subjecting of the membrane to sandpaper abrasion and a full 15 time use, the separation efficacy of oil-in-water emulsions is retained, highlighting the durability, reusability, and economic viability. We propose that these features are enabled by the electrostatic interactions triggered from pyromellitic dianhydride (PMDA) and superhydrophilic–superoleophobic membrane intensified by the TiO2 on the unique collagen fiber membrane. Outcomes emphasize the versatility and potential of our membrane in addressing emulsified oily wastewater hurdles.
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CHEMICAL ENGINEERING JOURNAL
·
2026
·
IF 12.5
Weizhen Zhang,Wenqian He,Qian Yan,Lele Zhang,Nan Ni,Shaorui Song,Shuhua Tu,Jie Feng
Surfactant-free interfacial synthesis of hollow Al 2 O 3 via kinetic modulation • Chelation enables precursor transition from hydrophobic to amphiphilic states. • Simple room-temperature strategy bypasses harsh energy-intensive methods. • PDRC coatings deliver 97.6% solar reflectance and 0.976 mid-IR emissivity. • The scalable coatings realize a remarkable sub-ambient cooling of 9.66 °C. Hollow γ-Al 2 O 3 architectures are highly attractive for passive daytime radiative cooling (PDRC) owing to their low density and unique optical characteristics. However, their fabrication typically relies on sacrificial templates, hydrothermal treatments, or high-temperature processing, while the intrinsically ultrafast hydrolysis of aluminum alkoxides has long prevented their use in hollow-structure engineering. Here, we report a surfactant-free, chelation-enabled interfacial synthesis strategy that overcomes this limitation through kinetic regulation of aluminum sec-butoxide. The coordination process gradually transforms the precursor from hydrophobic to amphiphilic, enabling spontaneous self-emulsification and controlled interfacial assembly. As a result, hierarchical hollow γ-AlO(OH) microspheres are obtained at room temperature and subsequently converted into hollow γ-Al 2 O 3 microspheres by calcination. The resulting hollow γ-Al 2 O 3 microspheres exhibit tunable diameters (3.3–15.8 μm), uniform nanoscale shells (162 ± 60 nm), and an ultralow density of 0.083 g·cm −3 . The process is readily scalable using an industrial homogenizer. When incorporated into coatings, the hollow microspheres provide abundant dielectric interfaces that enhance solar reflection and thermal emission, delivering a solar reflectance of 97.6%, an atmospheric window emissivity of 0.976, and a sub-ambient cooling of 9.66 °C under a solar irradiance of 454.5 W·m −2 . This work provides a scalable and energy-efficient manufacturing strategy for hollow γ-Al 2 O 3 architectures, offering significant potential for large-area radiative cooling coatings and thermal management applications. Download: Download high-res image (108KB) Download: Download full-size image
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Gels
·
2023
·Vol. 9
·期 11
·902
·
IF 4.6
Jian Li,Yaning Li,Wei Xiao,Jingyan Wang,Boliang Wang
Investigating the structural evolution of particulate gels is a very challenging task due to their vulnerability and true flow characteristics. In this work, deeper insight into the rheological properties of gel fuels filled with fumed silica (FS) and aluminum microparticles (Al MPs) was gained by changing shear procedures. Firstly, the flow curves were found to no longer follow the monotonic power law and exhibited subtle thixotropic responses. As the shear rate increased, the gel structure underwent a transition from local shear to bulk shear in the nonlinear region after yielding. This finding reveals the prevalence of nonideal local shear in industry. Secondly, the time-dependent rheological responses demonstrated that the strength spectrum of gel fuels depends on the applied shear rate, with stress relaxation more easily observed at lower shear rates. Those results involved the structural disruption, recovery, and equilibrium of particulate gels from two scales of shear rate and shear time.Keywords:gel fuels;microstructure;solid–liquid transition;thixotropy;local shear;shear history
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Journal of Cleaner Production
·
2023
·
IF 11.1
Teng Lu,Zhaomin Li,Liping Du
With declining conventional reserves, tapping heavy oils generates substantial emissions yet is essential to meet energy demands. This study pioneers an integrated approach using silica aerogels to develop thermally stable flue gas foams for enhanced CO 2 sequestration and heavy oil recovery. Microfluidic experiments and molecular dynamics simulations revealed a 5-fold decrease in gas diffusion rates for aerogel-stabilized versus pure surfactant foams at 95 °C due to the ultralow thermal conductivity of the nanoparticle coating layer . The thermally stable nanoengineered foams demonstrated a remarkable 81.23% CO 2 trapping efficiency in heterogeneous cores, surpassing conventional flue gas foam. Additionally, three-dimensional simulations in an oil reservoir model showed improved vertical conformance and oil recovery with aerogel-stabilized foam. The exceptional insulating properties redirected heat downward to enhance sweep efficiency. This novel concept transforms flue gas emissions into value-added foams for concurrent environmental and productivity benefits during heavy oil development.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2023
·
IF 4.4
Shiyi Chen,Mengli Ma,Juan Peng,Xiaogang He,Qian Wang,Ganghui Chu
Candida rugosa lipase (CRL, EC3.1.1.3) is one of the main enzymes synthesizing esters, and ZIF-8 was chosen as an immobilization carrier for lipase. Enzyme activity testing often requires expensive reagents as substrates, and the experiment processes are time-consuming and inconvenient. As a result, a novel approach based on near-infrared spectroscopy (NIRs) was developed for predicting CRL/ZIF-8 enzyme activity. The absorbance of the immobilized enzyme catalytic system was evaluated using UV–Vis spectroscopy to investigate the amount of CRL/ZIF-8 enzyme activity. The powdered samples' near-infrared spectra were obtained. The sample’s enzyme activity data were linked with each sample’s original NIR spectra to establish the NIR model. A partial least squares (PLS) model of immobilized enzyme activity was developed by coupling spectral preprocessing with a variable screening technique. The experiments were completed within 48 h to eliminate inaccuracies between the reduction in enzyme activity with increasing laying-aside time throughout the test and the NIRs modeling. The root-mean-square error of cross-validation (RMSECV), the correlation coefficient of validation set (R) value, and the ratio of prediction to deviation (RPD) value were employed as assessment model indicators. The near-infrared spectrum model was developed by merging the best 2nd derivative spectral preprocessing with the Competitive Adaptive Reweighted Sampling (CARS) variable screening method. This model's root-mean-square error of cross-validation (RMSECV) was 0.368 U/g, the correlation coefficient of calibration set (R_cv) value was 0.943, the root-mean-square error of prediction (RMSEP) set was 0.414 U/g, the correlation coefficient of validation set (R) value was 0.952, and the ratio of prediction to deviation (RPD) was 3.0. The model demonstrates that the fitting relationship between the predicted and the reference enzyme activity value of the NIRs is satisfactory. The findings revealed a strong relationship between NIRs and CRL/ZIF-8 enzyme activity. As a result, the established model could be implemented to quantify the enzyme activity of CRL/ZIF-8 quickly by including more variations of natural samples. The prediction method is simple, rapid, and adaptable to be the theoretical and practical basis for further studying other interdisciplinary research work in enzymology and spectroscopy.
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Journal of Industrial Textiles
·
2023
·
IF 3.2
Jiahua Gu,Huiting Wang,Xinxin Dai,Yuqi Zhu,Dongqi Lin,Siyi Liu,Xu Han,Bin Lu,Yinsong Hu,Yinjiang Zhang
The contact layer of traditional medical dressing is easy to adhere to the new wound granulation tissue, which brings the deficiency of secondary wound injury. This work assumed that low-cost and soft mesh spunlace nonwoven was used as medical dressing contact layer. After micro-nano SiO2 modification, polydimethylsiloxane (PDMS)/n-heptane were uniformly sprayed on the surface of materials. PDMS modification was studied by using the three-factor three-level orthogonal experiment. The results showed that when the PDMS concentration was 1%, the heat treatment temperature and time were 120°C and 12 h respectively, material possessed the optimal hydrophobicity and its water contact angle (CA) was 151.0 ± 1.1°. Meanwhile, the hydrophobicity, microstructure, thermogravimetry, composition, tensile mechanics, adhesion resistance and durability of materials with/without treatment were compared. It was proved that PDMS was indeed grafted onto the material and could effectively improve the hydrophobicity in coordination with micro-nano SiO2 without affecting the mesh structure of material. The machine direction (MD) and cross-machine direction (CD) strength of material decreased but the elongation increased slightly. The MD and CD peeling energy was 129.7 ± 33.9 J/m2 and 98.1 ± 38.3 J/m2, respectively. Moreover, the water CA of material modified by micro-nano SiO2/PDMS was still 139.4 ± 1.4° after 10 friction stroke tests, indicating that the modified material possessed the great durability. Overall, this study can provide the research basis for the development of anti-adhesion medical dressing contact layer.
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COMBUSTION AND FLAME
·
2023
·
IF 4.4
Bingjie Chen,Peng Liu,Bingzhi Liu,Zhandong Wang,Xiang Gao,William L. Roberts
As a representative aromatic component of practical fuels, understanding the low temperature chemistry of 1,2,4-trimethylbenzene under the reaction environment of fuel mixtures is necessary to improve the ignition and combustion process . In this work, low temperature oxidation of 1,2,4-trimethylbenzene was examined in a jet stirred reactor with reactants of n-heptane and 1,2,4-trimethybenzene in a fuel mixture (1:1 in mole, 500–800 K, ϕ = 0.5, τ = 2.0 s, p = 1 bar). Chemical species and their mole fraction evolution with reaction temperatures were recorded by the time of flight molecular beam mass spectrometer using synchrotron vacuum ultraviolet radiation as photon ionization source. Molecular structures of 56 species were identified by comparing the species ionization energies and the photonionization efficiency curves. 25 chemical formula of monocyclic oxygenated aromatics and oxygenated polycyclic aromatic hydrocarbons (OPAH) are detected, and 12 of them are identified. Some of the OPAHs are more toxic than the polycyclic aromatic hydrocarbons, indicating the importance of revealing their formation pathways in low temperature oxidation of aromatics. Numerical simulations using the latest kinetic model from Lawrence Livermore National Laboratory well predict the mole fractions of the reactants and most intermediates, but many monocyclic oxygenated aromatics and OPAHs are missing. The detection and identification of key monocyclic oxygenated aromatics (e.g., peroxides, aldehydes, dialdehydes, and ketohydroperoxides of 1,2,4-trimethylbenzene) provide important clues to unravel the low temperature oxidation pathways of alkylated aromatics like 1,2,4-trimethylbenzene. For monocyclic oxygenated aromatics and OPAHs that are missing in the kinetic model, potential formation pathways were proposed based on the molecular structure information, which might be useful for future kinetic model development.
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