Search

The colloidosome, as a kind of Pickering microcapsule, offers a highly functionalizable approach for encapsulation, but current studies mainly focus on shells that lack real‐time modulated permeability. Herein, a scalable spray drying method was employed to fabricate temperature/near‐infrared (NIR)/magnetic multi‐stimuli responsive colloidosomes with adjustable permeability, facilitating intelligent transmembrane transport of molecules. The colloidosomes assembled with SiO2/polydopamine/poly (N‐isopropyl acrylamide) nanoparticles can be heated from 25°C to 50°C within 5 min upon NIR exposure. The permeability of shells regulated by temperature and NIR allows for real‐time remote control. Yeast cells, as an example, are encapsulated within colloidosomes. The decomposition rate of H2O2 varies with temperature (25–45°C) and NIR intensity (0.5–1 W cm−2), which can attain a more than sixfold increase in the rate constant of pseudo‐first‐order kinetic model. Furthermore, the strategy was expanded by encapsulating doxorubicin/UiO‐66 particles, highlighting its great potential in realms of multi‐stimuli responsive colloidosomes applications. [ABSTRACT FROM AUTHOR]

Process intensified synthetic approach for synthesizing gadolinium and cerium co‐doped yttrium aluminum garnet (GdYAG:Ce) phosphors in white light‐emitting diodes (wLED) is developed. By using a high‐gravity rotating packed bed (RPB) reactor for preparation of sol–gel precursors, the significantly enhanced molecular mixing allows precise control and tuning of dry gel with designed structure to obtain nanosized particles of GdYAG:Ce precursors, which are prone to low temperature quick sintering process and therefore reduce the energy consumption of the electric furnace 76% compared to solid phase method. By analyzing the effect of cycling times and high gravity levels of RPB reactor on sintering and crystallization, sintering condition for emission spectrum adjustable GdYAG:Ce phosphors is optimized. Prototype devices based on blue chips and GdYAG:Ce phosphors exhibit high color rendering index of 83.8 and low correlation color temperature of 5357 K that are beneficial for creating a healthy and comfortable lighting environment. [ABSTRACT FROM AUTHOR]

Zr‐based metal‐organic framework (Zr‐MOF) nanoparticles (NPs) have attracted extensive research thanks to their outstanding thermal and chemical stability, but their efficient synthesis is still challenging. Here, high‐quality Zr‐MOF NPs with tunable and uniform particle sizes can be successfully fabricated within 30 min by high‐gravity technology with high yields. Significantly, the rapidly milder preparation of UiO‐66 NPs can also be achieved at 90 or 70°C. This strategy has been extended to the synthesis of other Zr‐MOF NPs. Furthermore, the water vapor adsorption properties of obtained UiO‐66 NPs display a size‐dependent effect. The 70 nm UiO‐66 NPs have the highest adsorption capacity of 625 mg g−1 among unmodified UiO‐66 reported so far, and manifest 2.0–2.8 times faster water adsorption rate than the micron ones. This study provides a feasible method for the efficient and mild preparation of MOFs nanoparticles, which may promote the synthesis and applications of nano‐sized MOFs. [ABSTRACT FROM AUTHOR]

Selectively separating CH4 from N2 in natural gas purification is extremely important, but challenging. Herein, a copper‐based metal–organic framework (MOF) NKMOF‐8‐Me with inert pore environment was reported for efficient CH4/N2 separation. Adsorption results show that this material owns the highest CH4 uptake (1.76 mmol/g) and initial adsorption heat (Qst0) of CH4 (28.0 kJ/mol) as well as difference in Qst0 (9.1 kJ/mol) among all materials with good water stability. Breakthrough experiments confirm that this MOF can completely separate the CH4/N2 mixture with the highest CH4/N2 breakthrough selectivity (7.8) reported so far. Theoretical calculations reveal the separation mechanism is the short average distance between CH4 and pore wall, resulting in a stronger adsorption affinity for CH4. In addition, this MOF exhibits highly structural stability and regeneration. These results guarantee this MOF as a promising adsorbent for the recovery of CH4 from coalbed methane. [ABSTRACT FROM AUTHOR]

Practical application of versatile nanomaterials to food engineering is desirable. In this study, highly encapsulated curcumin‐loaded shellac (Cur@Lac) nanoparticles are efficiently prepared via a rotating packed bed (RPB). In this modified co‐precipitation process, the morphology of Cur@Lac nanoparticles is systematically investigated under experimental parameters involving the high‐gravity level, the volume of antisolvent and the concentration of shellac. By virtue of the highly structured polymeric ester matrices of shellac and adequate supersaturation brought from RPB on a microscale, the obtained Cur@Lac nanoparticles with uniform size exhibit high encapsulation efficiency of over 96%. After 2 months of storage at room temperature, the aqueous Cur@Lac nanodispersions exhibit long‐term stability with no agglomeration or sedimentation, and the final retention rate of curcumin was over 85%. Colored drinks of fruit syrup (pH = 4.0), fruit soda (pH = 6.0), and soda water (pH = 8.3) are prepared by using the Cur@Lac as the colorant, which possessed orange‐yellow color. The nanocomposites of alkali‐sensitive indicators based on cellulose paper and gelatin film demonstrated in the work show promising application value for sensing of alkaline solution and gas of perishable food. [ABSTRACT FROM AUTHOR]

This review presents the different combination methods of 3D printing and electrospinning processes and discusses the advantages of each method. Also, the applications of products of the hybrid process in the biomedical field, including tissue engineering and regenerative medicine, are thoroughly discussed. 3D printing and electrospinning are separate approaches for generating structured materials in a variety of biomedical applications. However, some shortfalls, such as the low resolution of 3D printing and uncontrollable shape of electrospun products, limits their application performances. Therefore, new ideas that combine 3D printing and electrospinning methods are proposed to give full play to their strengths and mitigate their weaknesses, which provide an effective and powerful platform for fabricating novel structural materials. Finally, a future vision regarding challenges and perspectives in the combination of 3D printing and electrospinning techniques is proposed. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have attracted much attention owing to their tailored pore environment and surface functionality. However, most of the currently reported MOFs are confined to small pore sizes (<5 nm), limiting their practical applications. Here, a facile and versatile strategy for rapid construction of hierarchically porous MOFs (HP‐MOFs) by spray‐drying is reported, in which presynthesized nanosized MOFs (N‐MOFs) can be assembled to form MOF microspheres with meso/macropores resulting from the interspace among closely arranged N‐MOFs. This strategy enables the construction of multicomponent HP‐MOFs with various functions. As a proof of concept, we show that the adsorption for tannic acid (TA) can be significantly enhanced using HP‐MIL‐101(Cr). Particularly, HP‐MIL‐101‐30 (30 represents the primary nanoparticle size) exhibits a record‐high adsorption capacity (1175 mg g−1), and the adsorption rate of HP‐MIL‐101‐30 is increased by 50% compared to that of N‐MIL‐101‐30. These findings have important implications for the rapid construction of HP‐MOFs, which is beneficial for the adsorption of large molecules. [ABSTRACT FROM AUTHOR]

Sustainable solutions on fabricating and using a face mask to block the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) spread during this coronavirus pandemic of 2019 (COVID‐19) are required as society is directed by the World Health Organization (WHO) toward wearing it, resulting in an increasingly huge demand with over 4 000 000 000 masks used per day globally. Herein, various new mask technologies and advanced materials are reviewed to deal with critical shortages, cross‐infection, and secondary transmission risk of masks. A number of countries have used cloth masks and 3D‐printed masks as substitutes, whose filtration efficiencies can be improved by using nanofibers or mixing other polymers into them. Since 2020, researchers continue to improve the performance of masks by adding various functionalities, for example using metal nanoparticles and herbal extracts to inactivate pathogens, using graphene to make masks photothermal and superhydrophobic, and using triboelectric nanogenerator (TENG) to prolong mask lifetime. The recent advances in material technology have led to the development of antimicrobial coatings, which are introduced in this review. When incorporated into masks, these advanced materials and technologies can aid in the prevention of secondary transmission of the virus. [ABSTRACT FROM AUTHOR]

Ultrasmall metal–organic frameworks (MOFs) may generate unique properties to expand the scope of applications. However, the synthesis is still a great challenge. Herein, we propose a strategy to synthesize ultrasmall MOFs by high gravity technology. With the aid of tremendous intensification of molecular mixing and mass transfer in high‐gravity field, six typical MOFs were obtained instantaneously in a continuous way. These samples are monodispersed with sub‐5 nm in size, smaller than the previously reported values and even close to the length of one crystal unit cell. As a proof‐of‐concept, catalytic activity for Knoevenagel reaction can be significantly enhanced using ultrasmall ZIF‐8. Conversion time of benzaldehyde was decreased by 94 % or 75 % compared to those using conventional or hierarchically porous ZIF‐8. More importantly, this approach is readily scalable with the highest space‐time yield for nano‐MOFs, which may promote the convenient synthesis and practical applications of ultrasmall MOFs in large‐scale. [ABSTRACT FROM AUTHOR]

Luminescent thermometry is a noninvasive method of temperature detection with high sensitivity and response speed. The present study demonstrated the process‐intensified synthesis of ytterbium and erbium codoped calcium molybdate phosphors (CaMoO4:Yb3+/Er3+). The experiment involved the initial premixing of the precursors using a high‐gravity rotating packed bed (RPB) reactor and subsequent calcination processing. The pronounced mass transfer and micromixing of the reactants in the RPB facilitated the scalable and controllable synthesis of CaMoO4:Yb3+/Er3+ particles with submicron sizes and regular morphologies. The CaMoO4:Yb3+/Er3+ particles exhibited a bright‐green emission with temperature‐dependent luminescence characteristics under 980 nm laser irradiation. Furthermore, the maximum absolute sensitivity was determined to be 0.02837 K−1. These results indicated that the synthesized product was a suitable candidate for application in upconversion luminescent thermometers capable of temperature sensing at the microscale. [ABSTRACT FROM AUTHOR]

Ultraviolet‐curable polyurethane acrylate (PUA) materials can be used in a number of important applications spanning from microfluidics, surface patterning to wearable technology. For the first time, the potential of encapsulation of modified zirconia (ZrO2) nanoparticles is reported in PUA‐based hybrid films aimed to facilitate profoundly enhanced hardness and refractive index. By successfully manipulating the interfacial reaction conditions between ZrO2 nanoparticles and PUA film, the PUA‐based nanocomposites exhibit an ultrahigh hardness of 9 and superior refractive index of 1.64 (589.3 nm). The outcomes obtained pave the way for seamless application of nanozirconia/PUA as a potent encapsulating material that provides structurally morphable, water resistant, and optically transparent light emitting diodes toward wearables devices in healthcare. [ABSTRACT FROM AUTHOR]

Disperse dyes are poorly water‐soluble and difficult to stably disperse in an aqueous medium, which greatly limits their application in dyeing synthetic fibers. Micronization can solve this problem. Herein, a facile way to prepare stable aqueous nanodispersions of disperse dye (C.I. disperse yellow 54) is presented by combining high‐gravity antisolvent precipitation in a rotating packed bed (RPB) with spray drying. The as‐prepared product had an average particle size of 120 nm, which could be readily redispersed in water. Compared with raw dye, the wettability and dispersibility of disperse dye nanoparticles were remarkably improved. Furthermore, the dyeing properties of the nanodispersions were obviously better than those of the commercial dye, which was micronized by ball milling. [ABSTRACT FROM AUTHOR]

Perovskite nanocrystals are embedded into metal–organic frameworks (MOFs) to create composites with high light absorption coefficients, tunable electronic properties, high specific surface area, and metal atom tunability for enhanced photocatalytic carban dioxide (CO2) reduction. However, existing perovskite‐MOF structures with a large particle size are achieved based on Pb source adsorption into the pores of MOFs, which can significantly break down the porous structure, thereby resulting in a decreased specific surface area and impacting CO2 adsorption. Herein, a novel perovskite‐MOF structure based on the synthesis of bimetallic Pb‐containing MOFs and post‐processing to convert Pb to CsPbBr3 nanocrystals (NCs) is proposed. It is discovered that the additional Pb is not introduced by adsorption, but instead engages in coordination and generates Pb‐N. The produced ZIF‐8@CsPbBr3 NCs are ≈40 nm and have an ultra‐high specific surface area of 1325.08 m2g−1, and excellent photovoltaic characteristics, which are beneficial for photocatalytic CO2 reduction. The electronic conversion rate of composites is 450 mol g−1h−1, which is more than three times that of pure perovskites. Additionally, the superior reduction capacity is sustained after undergoing four cycles. Density Functional Thoery (DFT) simulations are used to explore the 3D charge density at the ZIF‐8@CsPbBr3 NCs interface to better understand the electrical structure. [ABSTRACT FROM AUTHOR]

Owing to its strong reducibility capacity, nanoscale zero‐valent iron (nZVI) can be widely used in the treatment of wastewater. In this study, nZVI particles with an average size of 14 nm were continuously prepared using a rotating packed bed (RPB) reactor with stainless wire mesh packing. The effects of the surfactant type and the rotating speed of the RPB reactor on the particle size of nZVI were investigated. The results indicated that the average particle size could be notably reduced with the proper addition of PVP in the preparation process. Meanwhile, the particle size could be further decreased by increasing the rotating speed of the RPB. Compared to a stirred tank reactor (STR), the RPB reactor had nZVI with a smaller particle size and a much shorter reaction time. The as‐prepared nZVI was further employed to remove Cr(VI) in the simulated sewage. The results indicated that lower pH, higher nZVI dosage, and higher temperature were beneficial to the efficient removal of Cr(VI). The removal process of Cr(VI) well conformed to a pseudo‐first‐order kinetic model. Thermodynamic studies showed that the reduction of Cr(VI) by nZVI was a spontaneous endothermic reaction process with increased entropy. In addition, nZVI prepared in the RPB displayed higher removal efficiency than the counterpart in the STR, and the removal rate was greatly increased by 17.4 times. [ABSTRACT FROM AUTHOR]

The environmental transmission electron microscope (ETEM) is an effective tool for understanding the behaviour of materials at an atomic level. In the present work, we have characterized the dynamics of gas flow in ETEM using computational fluid dynamic (CFD) simulations. The gas pressure drop, pressure distribution, and gas flow of different inlet pressures for a gas chamber are investigated. Based on the detailed CFD simulations, the hydrodynamics for the gas‐heating holder are carried out. Also, an attempt has been made to optimize the structure, and it is proposed that the triangle shaped inlet tube is more suitable. The results presented are useful for understanding the dynamics of gas flow in a gas chamber and provide a basis for further structure optimizations. [ABSTRACT FROM AUTHOR]

We report the preparation of a porous 3D‐foam‐structured nitrogen‐doped graphene‐Ni (NG/NF) catalyst and the evaluation of its performance in the reduction of nitrobenzene (NB) through detailed studies of the kinetics. The NG/NF catalyst showed a significantly higher reaction rate than pure Ni foam (NF). Moreover, the separation of the 3D‐foam‐structured catalyst from the products was more convenient than that of NG powdered catalysts. The obtained kinetics data fit well to the Langmuir‐Hinshelwood model, with an error ratio below 10%. Density functional theory (DFT) calculations indicated that the adsorption of sodium borohydride (NaBH4) on the NG/NF surface was stronger than that of NB, which strongly agreed with the kinetic parameters determined from the Langmuir‐Hinshelwood model. The excellent catalytic efficiency of the 3D‐foam‐structured catalyst combined with the knowledge of the kinetics data make this catalyst promising for application in larger scale nitrobenzene reduction. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1330–1338, 2018 [ABSTRACT FROM AUTHOR]

The preparation of monodispersed inorganic nanoparticles is of great interest for many applications. In this article, transparent oil dispersion of monodispersed amorphous CaCO3 nanoparticles with high concentration and long-term stability were controllably prepared by a reverse microemulsion method. The effects of the addition amount of extra minute water and (NH4)2CO3 as novel assistant promoter, reaction temperature, Ca(OH)2/CaO mole ratio were explored. The optimum synthesis conditions were achieved. The as-prepared transparent oil nanodispersion had a good monodispersity, a uniform particle size of 8-10 nm, a high stability of over 12 months, a high solid content of 38 wt% (Ca content of about 15.5 wt%) and a high total base number of 416 mgKOH/g. The preparation process was further investigated by polarized optical microscope and Fourier transform infrared. This nanodispersion will find a promising applicability as an excellent nanodetergent in the fields of automobile and marine lubricants. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3663-3669, 2017 [ABSTRACT FROM AUTHOR]

Ag/graphene nanocomposites have been demonstrated to be promising catalysts for hydrogenation reduction of p-nitrophenol ( p-NP) to p-aminophenol ( p-AP). Herein, we reported the synthesis of graphene-supported silver nanoparticles (Ag/G) using one-step and stabilizer-free process. The obtained Ag/G nanocomposites were demonstrated to be efficient catalysts for the reduction of p-NP to p-AP. The reaction kinetics of the catalytic reduction, including the effects of catalyst concentrations and temperatures are reported. These results are of significant values for the scale-up of using Ag/graphene catalysts for hydrogenation reduction. [ABSTRACT FROM AUTHOR]

NO gas emission has harmfully impacted human health and the environment. Absorption of NO gas into an aqueous solution is considered to be a promising approach for its removal. FeII(EDTA) solution has been demonstrated as an efficient option in the denitrification process. However, its absorption rate is strongly affected by mass transfer limitation of NO into FeII(EDTA) solution in traditional reactors. In this paper, the removal process of NO with FeII(EDTA) solution was studied in a microporous tube-in-tube microchannel reactor (MTMCR). The effects of design and operating parameters such as micropore size, annular channel width, liquid flow rate, gas flow rate, gas-liquid ratio, pH and concentration of absorbent, and absorption temperature on overall volumetric mass transfer coefficient ( KLa) and NO removal efficiency were explored. The results indicated that the MTMCR exhibited obvious advantages owing to continuous operation mode and higher NO removal efficiency of over 90 %, as compared to traditional reactors. Both KLa and NO removal efficiency increased with increases of absorbent concentration and liquid flow rate, as well as decreases of absorption temperature, micropore size, and annular channel width. In addition, KLa increased while NO removal efficiency decreased with increasing gas-liquid ratio and gas flow rate. The obtained results imply a great potential of the MTMCR in the removal of NO from post-combustion flue gas. [ABSTRACT FROM AUTHOR]

A novel mass-transfer intensified approach for CO2 capture with ionic liquids (ILs) using rotating packed bed (RPB) reactor was presented. This new approach combined the advantages of RPB as a high mass-transfer intensification device for viscous system and IL as a novel, environmentally benign CO2 capture media with high thermal stability and extremely low volatility. Amino-functionalized IL (2-hydroxyethyl)-trimethyl-ammonium (S)−2-pyrrolidinecarboxylic acid salt ([Choline][Pro]) was synthesized to perform experimental examination of CO2 capture by chemical absorption. In RPB, it took only 0.2 s to reach 0.2 mol CO2/mol IL at 293 K, indicating that RPB was kinetically favorable to absorption of CO2 in IL because of its efficient mass-transfer intensification. The effects of operation parameters on CO2 removal efficiency and IL absorbent capacity were studied. In addition, a model based on penetration theory was proposed to explore the mechanism of gas-liquid mass transfer of ILs system in RPB. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2957-2965, 2013 [ABSTRACT FROM AUTHOR]

Organic fluorescent dyes have attracted wide interest because of their high photoluminescence quantum efficiencies. However, there are several application limitations arising from their hydrophobicity, poor dispersity and large particle sizes. These problems can be improved by preparing nanoparticles with a small size. Herein, we present a continuous approach to efficiently prepare an aqueous nanodispersion of water‐insoluble organic fluorescent dye Nile red (NR) with monodispersed and uniform nanoparticles (35 nm) by high‐gravity antisolvent precipitation in a rotating packed bed (RPB). In contrast, NR nanodispersions prepared using a traditional batch stirred tank (ST) had a broad size distribution (20–150 nm). Due to its small size effect and good dispersity in water, the RPB nanodispersion displayed significantly increased saturation solubility and much stronger fluorescent intensity compared to raw NR, and was obviously superior to the ST counterpart. Furthermore, NR nanodispersions were mixed with ink to draw fluorescent patterns on paper for counterfeit labeling. [ABSTRACT FROM AUTHOR]