CERAMICS INTERNATIONAL
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2022
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IF 5.532
Wei Liu,Jianwei Liang,Chong Fu,Baobao Zeng,Meipeng Huang,Gao Yang,Xudong Luo,Di An,Sai Wei,Zhipeng Xie,Guangzhou Xu
The coal fly ash (CFA) produced from coal-fired power generation is classified as a common solid waste; thus, improving the recovery and utilization rate of CFA is highly desirable. In this study, a novel strategy using CFA and Al 2 O 3 as raw materials, to prepare hierarchically porous ceramic composites that serve as potential candidates for future building materials is developed. In this process, the well-developed self-assembly method in which an anionic modifier is used to prepare hydrophobic powders that form an attractive oil/water network via electrostatic interactions , thereby yielding honeycomb-like structures. In order to explore the mechanism of preparation, five samples with different mixture ratios of alumina and CFA were prepared according to 1: 0, 2: 1, 1: 1, 1: 2, and 0: 1 (Alumina: CFA). Compared with the sample prepared with pure CFA, the as-prepared CFA/Al 2 O 3 composite exhibited both superior porosity and high mechanical property. When the porosity is as high as 73 ± 0.17%, the compressive strength is as high as 80.9 ± 3.4mpa (alumina: CFA = 1:1). As the porosity decreases to 49.3 ± 0.7%, the compressive strength reaches 159.33 ± 36.89mpa (alumina: CFA = 1:2). Moreover, this work obtains the highest compressive strength-porosity related B-value in comparison to previously reported CFA-based composites and provides a new insight into the effective recycling of CFA and offers a novel approach to prepare CFA/Al 2 O 3 composite with excellent overall mechanical properties .
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CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Xiao Liang,Jiyizhe Zhang,Min Li,Kai Wang,Guangsheng Luo
Surfactant adsorption plays an important role in the microfluidic droplet formation process, which manifested as dynamic interfacial tension phenomenon. Due to rapid droplet expansion and convection flow around the droplet, traditional methods of interfacial tension measurement are difficult to investigate the surfactant adsorption kinetics in microfluidic process. We thus developed a differential pressure based microfluidic platform and proposed an in-situ method to determine time-evolving interfacial tension during microfluidic droplet formation according to Young-Laplace equation in this research. Four classical nonionic surfactants: Triton X-100, Tween 20, Brij 56, and Brij 58 were tested with classical n -octant/water as the working system. The concentrations of these surfactants at interface were further determined from the measured interfacial tension based on Frumkin adsorption model. The adsorption rates of surfactant showed that increasing surfactant concentration in the bulk solution and flow rate of continuous phase both promoted surfactant adsorption in the cases of Tween 20, Brij 56, and Brij 58, indicating the mass transfer-controlled mechanism of adsorption kinetics. The average thickness of mass transfer boundary layer ranged from 0.1 to 5 μm was determined from the mass transfer rate and a correlation equation was proposed to predict the thickness. However, the adsorption mechanism of Triton X-100 turned to be kinetics-controlled for its high critical micelle concentration, which helped to determine the adsorption and desorption rate constants.
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MOLECULES
·
2022
·Vol. 27
·期 9
·2782
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IF 4.927
Rui Song,Xueqin Zhang,Huihui Wang,Chuanfu Liu
Polyoxometalate (POM) presents great potential in oxidative desulfurization (ODS) reaction. However, the high dissolubility of POM in common solvents makes it difficult to recycle. Besides, the small specific surface area of POM also limits the interaction between them and the substrate. Depositing polyoxometalates onto three-dimensional (3D) network structured materials could largely expand the application of POM. Here, the surfaces of cellulose nanofibrils (CNFs) were modified with very few (3-Aminopropyl) trimethoxysilane (APTS) to endow positive charges on the surfaces of CNFs, and then phosphotungstic acid (PTA) was loaded to obtain the aerogel A-CNF/PTA as the ODS catalyst. FT-IR indicated the successful deposition of PTA onto aminosilane modified CNF surfaces. UV-VIS further suggested the stability of PTA in the aerogels. BET and SEM results suggested the increased specific surface area and the relatively uniform 3D network structure of the prepared aerogels. TGA analysis indicated that the thermal stability of the aerogel A-CNF/PTA50% was a little higher than that of the pure CNF aerogel. Most importantly, the aerogel A-CNF/PTA50% showed good catalytic performance for ODS. Catalysis results showed that the substrate conversion rate of the aerogel A-CNF/PTA50% reached 100% within 120 min at room temperature. Even after five cycles, the substrate conversion rate of the aerogel A-CNF/PTA50% still reached 91.2% during the dynamic catalytic process. This work provides a scalable and facile way to stably deposit POM onto 3D structured materials.Keywords:cellulose nanofibrils;phosphotungstic acid;oxidation desulfurization;catalyst
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JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
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2022
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IF 5.168
Han Jia,Daofan Wang,Qiuxia Wang,Jiajun Dai,Qiang Wang,Shijie Wen,Zhe Wang,Bowen Wang,Xincan Jiang,Xu Li,Kaihe Lv
Mixed nanoparticle stabilized Pickering emulsion is a novel research topic, which has been attracted more attention. In the present study, the novel amphiphilic GO-Janus SiO 2 -Cn nanoparticles (GOJS-Cn, n represents the number of carbon atoms in the modified alkyl chain) were successfully fabricated for the first time and investigated their ability in stabilizing Pickering emulsions for enhancing oil recovery. Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were employed to determine the successful fabrication of the GOJS-Cn. The optical microscopy was utilized to directly observe the GOJS-Cn (n = 0, 3, 8, and 12) stabilized emulsions and the static multiple light scattering was employed to further evaluate its stability quantitatively. It was found that the GOJS-C12 displayed the greatest ability to stabilize emulsions, even in high salinity (10 4 mg/L NaCl/MgCl 2 /CaCl 2 /AlCl 3 ) and temperature (90 °C). Then, the interfacial tension, water contact angle, and dilatational measurements were conducted to reveal the mechanism of the GOJS-C12 superior emulsifying ability. The amphiphilic GOJS-C12 with great amphiphilicity spontaneously adsorbed at oil-water interface to promote the formation of rigid interfacial film, which was essential for the long-term stability of emulsion . Moreover, the core flooding tests reflected the GOJS-C12 stabilized emulsion could significantly enhance oil recovery (∼14.8%), then based on microscopic visualization experiments the potential EOR mechanism was proposed.
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ACS Applied Materials & Interfaces
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2022
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IF 10.383
Cheng Chen,Tongtong Xuan,Yang Yang,Fan Huang,Tianliang Zhou,Le Wang,Rong-Jun Xie
Perovskite light-emitting diodes (PeLEDs) are promising candidates used for superthin emissive displays with high resolution, high brightness, and wide color gamut, but the CsPbI3 nanocrystal (NC) based ones usually have an external quantum efficiency (EQE) of less than 20%, which needs further enhancement to minimize the gap between their counterparts. Herein, we propose to improve optical properties of the CsPbI3:Sr emissive layer (EML) by inserting an additional potassium iodide (KI) passivation layer between the hole transport layer and EML to increase the film quality, photoluminescence quantum yield, and thermal stability of the EML. The KI layer can also increase the carrier mobility to balance the charge injection in PeLEDs, leading to a reduction in Auger recombination and Joule heating. An interesting deep-red-emitting PeLED (λem = 687 nm) with a record EQE of 21.8% and a lifetime T50 of 69 min is obtained by applying the additional KI passivation layer. Moreover, a flexible PeLED consisting of the KI layer is also demonstrated to have a record EQE of 12.7%. These results indicate that the use of a functional KI layer is a feasible way to develop high-performance electroluminescent devices.
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MOLECULES
·
2022
·Vol. 27
·期 7
·2191
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IF 4.927
Yingbiao Xu,Yefei Wang,Tingyi Wang,Lingyu Zhang,Mingming Xu,Han Jia
Various nanoparticles have been applied as chemical demulsifiers to separate the crude-oil-in-water emulsion in the petroleum industry, including graphene oxide (GO). In this study, the Janus amphiphilic graphene oxide (JGO) was prepared by asymmetrical chemical modification on one side of the GO surface with n-octylamine. The JGO structure was verified by Fourier-transform infrared spectra (FTIR), transmission electron microscopy (TEM), and contact angle measurements. Compared with GO, JGO showed a superior ability to break the heavy oil-in-water emulsion with a demulsification efficiency reaching up to 98.25% at the optimal concentration (40 mg/L). The effects of pH and temperature on the JGO’s demulsification efficiency were also investigated. Based on the results of interfacial dilatational rheology measurement and molecular dynamic simulation, it was speculated that the intensive interaction between JGO and asphaltenes should be responsible for the excellent demulsification performance of JGO. This work not only provided a potential high-performance demulsifier for the separation of crude-oil-in-water emulsion, but also proposed novel insights to the mechanism of GO-based demulsifiers.Keywords:heavy oil-in-water emulsion;demulsification;Janus graphene oxide;molecular dynamic simulation
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Journal of the American Chemical Society
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2022
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IF 16.383
Chuying Ye,Jiawei Jiang,Shaolan Zou,Wenbo Mi,Yin Xiao
We developed type-II core–shell nanocrystals (NCs) with a chiral low-dimensional perovskite shell and an achiral 3D MAPbBr3 core. The core–shell NCs exhibit spin-polarized luminescence at the first excitation band of the achiral core, which is due to the chiral-induced spin selectivity (CISS) effect-governed spin-dependent shell-to-core electron transportation and the subsequent electron–hole recombination in the core. The preferred spin state of the transferred electrons is determined by the handness of the chiral shell. For the core–shell NCs film, a photoluminescence quantum yield (PLQY) of 54% and a circularly polarized luminescence (CPL) with a maximum |glum| of 4.0 × 10–3 are obtained at room temperature. Finally, we achieved a spin-polarized light-emitting diode (spin-LED), affording a circularly polarized electroluminescence (CP-EL) with a |gCP-EL|of 6.0 × 10–3 under ambient conditions.
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CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Wei Liu,Meipeng Huang,Jianwei Liang,Xudong Luo,Gao Yang,Di An,Sai Wei,Zhipeng Xie
In this work, we present a preparation strategy for pH-responsive hierarchically porous bioinspired Al 2 O 3 ceramic membrane (pH-HPBA-CM). The pore size of the pH-HPBA-CM could be adjusted by altering the pH value. With the increase of the pH value, the porosity gradually decreases and the compressive strength of the pH-HPBA-CM is also affected by the pH value, which presents an increasing trend with the increase of the pH value. The variation of compressive stress versus displacement of the pH-HPBA-CMs (stress-strain relationship) prepared at different pH values was discussed. A mechanical simulation experiment was carried out to better analyze the reason why the honeycomb-like structure of the pH-HPBA-CM has excellent specific strength . In the simulation process, the small pore model (15 μm) can be regarded as part of the large pore model (35 μm). The simulation of the total deformation, equivalent stress, and equivalent elastic strain were obtained by setting the load pressure of 100 MPa. At this load pressure, the maximum deformation of the entire ceramic membrane is far lower than the theoretical limit value of its simulation, and all of them are distributed at the junction (connectional pores). This work provides a new insight into the effective preparation of pH-responsive hierarchically porous bioinspired ceramic membranes with high porosity, excellent mechanical performance, and tunable pore size.
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JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
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2022
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IF 2.042
Zhang Xuemei,Fu Feng,Gao Xiaoming,Hou Xiufang,Niu Fengxing
The pollution of water by oil is a global challenge. In this study, the design and fabrication of a superhydrophobic stainless steel mesh are reported. This was achieved through a sample “glue + fly ash” fabrication method. The fly ash was first modified by a stearic acid solution impregnation method. After the modification, the fly ash was then bonded to the surface of a stainless-steel mesh by an epoxy resin solution to obtain the superhydrophobic mesh. The introduction to the modified fly ash endows the mesh with excellent corrosion resistance and superhydrophobicity when compared with the original mesh. The as-prepared mesh could separate various oil and organic solvents from water with a separation efficiency exceeding 98%. Interestingly, the oil separation capacity of the as-prepared mesh still kept a high value after 30 cycles of reuse. The simplicity, eco-friendliness and low cost of this method turn it into a practical and realistic approach to the large-scale fabrication of superhydrophobic surfaces. These properties make the as-prepared mesh an ideal candidate for actual oily wastewater treatment.
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Nature Communications
·
2022
·Vol. 13
·期 1
·1-8
·
IF 17.694
Su Qiang,Chen Shuming
Up-conversion electroluminescence, in which the energy of a emitted photon is higher than that of the excitation electron, is observed in quantum-dot light-emitting diodes. Here, we study its mechanism by investigating the effect of thermal energy on the charge injection dynamic. Based on the results of temperature-dependent electroluminescence and theoretical analysis, we reveal that at sub-bandgap voltage, holes can be successfully injected into quantum-dots via thermal-assisted thermionic-emission mechanism, thereby enabling the sub-bandgap turn-on and up-conversion electroluminescence of the devices. Further theoretical deduction and experimental results confirm that thermal-assisted hole-injection is the universal mechanism responsible for the up-conversion electroluminescence. This work uncovers the charge injection process and unlocks the sub-bandgap turn-on mechanism, which paves the road for the development of up-conversion devices with power conversion efficiency over 100%.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2022
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IF 9.965
Xiao Liang,Min Li,Kai Wang,Guangsheng Luo
Surfactant adsorption plays an important role in microfluidics, which can be investigated by the dynamic evolution of interfacial tension. A differential pressure-based method is proposed to understand the basic laws of time-evolving interfacial tension and adsorption kinetics of ionic surfactants during the microfluidic droplet formation processes. Instantaneous flow rates and flow resistances are precisely analyzed based on auto-recognized microscopic images and the waveform of differential pressure, and the interfacial tension is determined from the Young-Laplace equation with a time resolution of 1/60 s. The concentration of surfactant at the liquid–liquid interface is obtained according to the Frumkin adsorption model, leading to an in-depth understanding of the adsorption rates and the apparent mass transfer rates of surfactants. The surfactant adsorption is demonstrated to obey the kinetic-controlled adsorption mechanism and therefore a measurement method for the adsorption rate constant is created to understand the kinetic characteristics of small-molecule ionic surfactants.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
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IF 9.965
Huan Wang,Guo Du,Shaohua Chen,Zhipeng Su,Pingchuan Sun,Tiehong Chen
As an important heterogeneous catalyst , Titanium Silicalite-1 (TS-1) zeolite has been widely applied in various catalytic processes. Here, hierarchical TS-1 single-crystals were successfully synthesized by a steam-assisted crystallization strategy using hierarchically porous titanium-containing silica (Ti-NKM-5) as a precursor. Due to the presence of large mesopores (10–40 nm), the microporous structure-directing agents penetrated the interstitial structure of silica particles, inducing the dissolution and crystallization process . During crystallization, the generated nanocrystals grew together to form a hierarchical structure. Titanium was fully incorporated into the zeolite framework, and no extra-framework anatase was formed. Compared with the traditional microporous TS-1 zeolite, the synthesized hierarchical TS-1 single-crystal exhibited superior catalytic performance in oxidative desulfurization (ODS) of dibenzothiophene (DBT) and 4, 6-dimethyl dibenzothiophene (4, 6-DMDBT) owing to the hierarchically porous and anatase-free structure. The recycling test revealed the durability of the obtained hierarchical TS-1 catalyst under moderate reaction conditions.
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