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Colloidosomes have been extensively studied in recent years because of their potential applications in various fields, such as food, cosmetics, or pharmaceutical industries. Herein, we present a si...

We report the process of intensified preparation of ultrasmall and monodisperse selenium-doped carbon dots (Se-CDs) by using an internal circulation rotating packed bed (IC-RPB) as the reactor, in ...

The work herein employed COMSOL Multiphysics simulation and experiment to study the temperature distribution of water in a specially designed cylindrical microwave (MW) reactor with two magnetrons....

As a family of important inorganic layered materials, layered double hydroxides (LDHs) have attracted considerable attentions owing to their potential applications in wide areas. Generally, the size, shape, uniformity and dispersity of LDHs have great effects on their application properties. Herein, we report an efficient approach to prepare surfactant-free transparent dispersions of monodispersed CO32- intercalated MgAl-LDH nanoparticles using a high-gravity-assisted intensified co-precipitation method in a rotating packed bed (RPB) reactor, followed by hydrothermal treatment. After a rapid co-precipitation in the RPB reactor, monodispersed MgAl-LDH nanoparticles with an average particle size of about 31 nm can be obtained. As compared to that in a stirred tank reactor (STR), the product from the RPB has much smaller particle size, narrower size distribution and higher optical transparency. More importantly, the reaction time can be significantly reduced from 20 min to 20 s, realizing an efficient contin...

An Al2O3-coated stainless steel wire mesh packing was prepared, aiming to serve as the monolithic catalyst support applied in a rotating packed bed (RPB) reactor. Before the application, the wetting behavior and gas–liquid mass transfer performance of Al2O3-coated wire mesh packing were investigated in this work. The results showed that the Al2O3-coated stainless steel fiber had on average 18.8% longer liquid spreading length compared with the uncoated stainless steel fiber. The gas–liquid effective interfacial area (ae) and the volumetric liquid-side mass transfer coefficient (kLae) of the RPB with Al2O3-coated wire mesh packing were on average 25.9 and 45.7% higher than those with uncoated wire mesh packing, respectively. The Al2O3-coated wire mesh packing has great prospects for the catalytic reactions in the RPB reactor by providing double functions of mass transfer intensification and the monolithic catalyst support.

We reported the process intensified synthesis of β-NaYF4 nanorods based on the traditional hydrothermal methods. A high-gravity rotating packed bed (RPB) reactor was used to intensify the mass tran...

Rotating packed beds (RPBs) have attracted widespread attention due to their high mass transfer efficiency. In this paper, gas flow characteristics in a rotating spherical packing bed (RSPB) were i...

Monolith catalysts fabricated with the immersion-pyrolysis technique suffer the uncontrollable morphology of active component, leading to low conversion and reaction rates. Herein, we propose a str...

Regeneration of spent caustic from liquefied petroleum gas sweetening in refineries is significant to save resources and reduce solid waste emissions. Conventional regeneration technologies have been widely used, but these technologies usually have a reactor and a separator in series which occupies a large space. In this work, simultaneous reaction and separation processes were proposed to be conducted in a rotating packed bed (RPB), aiming for the process intensification of spent caustic regeneration. Experimental results of laboratory tests show that the regeneration processes of mercaptide oxidation and disulfide separation were efficiently enhanced in the RPB. The side-line test, treating the actual spent caustic from a refinery, could achieve good performance for a long-time running. An artificial neural network model was applied for parameters analysis and prediction of the regeneration performance. This work demonstrated the feasibility of spent caustic regeneration in only one RPB unit, which disp...

Plasma discharge in contact with water is a promising technology for disinfection. Developing efficient gas–liquid nonthermal plasma reactors for disinfection is very urgent. In this work, a plasma...

Applying a HiGee reactor for H2S removal with solid sulfur generation by a chelated iron solution offers an economical way to exploit offshore natural gas. However, the high H2S removal efficiency ...

Absorption of carbon dioxide into sodium hydroxide solution has been extensively used for mass transfer investigation in gas–liquid contacting reactors. To obtain a reliable value of effective mass transfer area (A), the selection of fundamental parameters, such as reaction rate constant, diffusion coefficient, and solubility data, is significant for data processing, and very little literature has been reported on the selection of these parameters. Therefore, an evaluation of the sources of fundamental parameters needs to be given. In this work, six parameter sources, including classic literature and newly published papers, were evaluated for effective mass transfer area measurement in a rotating packed bed. Quantitative comparisons demonstrated that using different reaction kinetics models will cause a large deviation in the values of the effective mass transfer area. Further, the inconsistency between the sources of kinetics models and physical properties can also cause a large deviation, which should b...

This study employed a rotating packed bed (RPB) to enhance the absorption process of NOx and SO2 into Na2SO3 solution with the preoxidation by ozone. The absorption performance of NOx and SO2 was e...

The outer cavity zone, having numerous moving liquids, is an important mass transfer zone in a rotating packed bed (RPB) reactor. However, investigation of the liquid flow in the outer cavity zone is scarce. In this work, liquid flow in the outer cavity zone of the RPB reactor with nickel foam packing was studied by computational fluid dynamics (CFD) simulation and then verified by high-speed photography technology. Large eddy simulation and volume of fluid model were adopted to predict the liquid flow pattern, average diameter, and velocity of liquid droplets in the outer cavity zone. A high-speed photography method, called “Sudoku”, with eight shooting windows was employed to capture the liquid flow of different zones in imaging experiments. Simulation results of liquid droplet velocity agreed well with the experimental results within a deviation of ±10%. This CFD simulation assisted with Sudoku photography was helpful to comprehensively understand the liquid flow in the outer cavity zone of the RPB rea...

Electrochemical oxidation is considered as a promising technology for wastewater treatment. In this work, a novel rotating multielectrodes reactor (RMER) has been developed to intensify the electro...

An efficient method of coating alumina (Al2O3) on stainless steel has been investigated by matching the rough surface of the substrate with different sizes of Al2O3 particles. An empirical correlation was established based upon the data of a controllable and measured pore size of the substrate surface by varying etching conditions. The correlation agreed fairly well with experimental results (deviations of ±20%). The Al2O3 coatings prepared by powders with average particle size of 324 nm had an optimal adhesion performance, and the minimum of coating weight loss on the inner surface of tubule after ultrasonic vibration was 1.7 wt %. The developed method of Al2O3 coating has potential prospects for the preparation of monolithic catalyst support.

As an important personal protective item against the COVID-19 pandemic, masks have recently attracted much attention in both academic and industrial contexts We established a modified numerical model for investigating the dominant factors on the performance of masks, including the thickness and fill rate of melt-blown fibers for a filtering layer, as well as the diameters and surface charge density of the fibers It is found that increasing the surface charge of melt-blown fibers can improve the filtration efficiency of the melt-blown layer with a low respiratory pressure drop The relationship between the filtered particle diameter and filtration efficiency of respirators is also investigated, which demonstrated that particles with a diameter of 0 1-0 2 μm are the most difficult to filter out Combined with molecular dynamics simulations and experimental verifications, the effect of hydrophobicity on the droplet adhesion and the water blocking performance was revealed The knowledge obtained in this work provides reference for the design of high-performance masks ©

A novel rotating packed bed (RPB) reactor is first adopted to intensify the reaction of isobutane alkylation with 2-butene catalyzed by H2SO4. This work investigated reaction performance, and reaction conditions were optimized. Under the optimal conditions, the research octane number (RON) reached 98.85. Meanwhile, the yields of C8 and trimethylpentanes were 90.65% and 85.47%, respectively. The reaction efficiency was tremendously improved by using RPB due to its high efficiencies of mass transfer and micromixing. More importantly, the inner mole ratio of isobutane to 2-butene was dramatically decreased in RPB, which means the energy cost of material cycling in the alkylation process could be extremely reduced. Moreover, an empirical correlation model was proposed to predict the multiproduct yields and RON with a deviation within ±10%. In conclusion, RPB reactor is a highly promising industrial platform for the process of H2SO4 alkylation.

A spinning disk reactor (SDR) is one of the important process intensification devices. Previous studies primarily focused on the dependence of the liquid flow in a SDR on the operational conditions and liquid properties. However, the effect of hydrophobicity of the disk’s surface on the liquid flow in a SDR is rarely reported. In this work, the disk with a hydrophobic surface was prepared, and the effects of surface hydrophobicity, liquid flow rate, rotational speed, and liquid viscosity on the liquid flow patterns as well as the average diameter of a liquid droplet (davg) were investigated by a visualization method. An empirical correlation of davg was suggested, and the deviations were within ±15% when the calculated values of davg were compared with the experimental data.

To ensure steady operation of gas transmission lines and meet the utilization specification of downstream processes, gas dehydration is employed in offshore natural gas production, where urgent demands for space and size exist. In this work, a rotating packed bed (RPB) was used to intensify the triethylene glycol (TEG) dehydration process and the effects of operating variables on the overall volumetric mass transfer coefficient (Kya) and height of mass transfer unit (HTU) were investigated. The value of HTU in a RPB was measured to be 4.3–7.9 mm, which was at least an order of magnitude lower than that in conventional columns, indicating the significant reduction in the size of the dehydration apparatus. The predicted Kya matches well with the experimental data, and the mean relative error (MRE) is only 6.68%.

In this work, the gas-side mass transfer was investigated in a rotating packed bed (RPB) with structured nickel foam packings, with different surface properties, either a nonmodified nickel foam packing (NNP) or a hydrophobic surface-modified nickel foam packing (SNP). Effects on gas-side volumetric mass-transfer coefficient (kGae) of rotational speed, liquid flow rate, and gas flow rate were experimentally studied in the RPB with NNP and SNP. It can be found that the RPB loaded with SNP has a higher mass-transfer efficiency, compared with that loaded with NNP. Based on the experimental data, correlation of kGae in a RPB with structured nickel foam packing was proposed, which can hence provide a fast calculation of mass-transfer coefficients for the RPB design with structured nickel foam packing.

A novel route was proposed for the synthesis of transparent dispersions of monodispersed zinc oxide (ZnO) nanoparticles via a high-gravity reactive precipitation combined with “inorganic–organic successive layer coating” method. The as-prepared nanodispersion had a uniform particle size of about 4 nm, high stability of over 12 months, and still remained transparent at ultrahigh solid content of 60 wt %. Highly transparent polylactide (PLA)/ZnO and PLA/ZnO/cesium doped tungsten oxide CsxWO3 nanocomposite films were further fabricated by a simple solution mixing method. Because of the uniform dispersion of nanoparticles, PLA/ZnO films could maintain the same visible transmittance as pure PLA film even when ZnO content reached 60 parts per hundred of PLA resin by weight (phr). Furthermore, the films could shield almost 100% ultraviolet radiation at ZnO content of up to 5 phr, thereby realizing good antiaging property. Besides their excellent transparency and UV-shielding property, PLA/ZnO/CsxWO3 films could ...

It is well-known that Cs+Re is an efficient dual-promoter in the Ag catalyzed ethylene epoxidation, but it is still necessary to develop more efficient dual-promoters to gain higher selectivity to ethylene oxide (EO). In this work, we investigate the ethylene epoxidation catalyzed by Cs+Re, Cu+Re and Cs+Cu dual-promoted Ag (111) and (110) surfaces by using density functional theory (DFT) calculations. The predicted selectivity of pure and dual-promoted Ag (111) surfaces for EO follows the order of pure Ag < Cs+Cu < Cs+Re < Cu+Re. In contrast, the order of pure Ag < Cs+Re < Cs+Cu < Cu+Re is predicted for the selectivity of pure and dual-promoted Ag (110) surfaces for EO. Our results show that Cu+Re dual-promoted Ag (111) and (110) surfaces could achieve a higher selectivity to EO, indicating that Cu and Re dual-promoted Ag catalysts could be potential and high-efficient for catalyzing the ethylene epoxidation reaction.

This work presents a novel process of nano-Ni preparation by liquid reduction method without surfactant in a combined reactor of a rotating packed bed (RPB) and a stirred tank reactor (STR). The reaction mechanism of this process was studied, and the effects of different operating conditions including rotation speed, NaBH4 concentration, liquid volumetric flow rate, and liquid circulation time on the characteristics of the nano-Ni were systematically investigated in the RPB to control the morphology and average particle size of the prepared nano-Ni. The average particle size of the prepared nano-Ni can be adjusted from 42 to 130 nm by changing operating conditions, and the prepared nano-Ni with a face centered cubic (FCC) structure, an average particle size of 42 nm, and a particle size distribution of 30–60 nm was obtained under the optimal operating conditions. This research provides a novel pathway and theoretical basis for controllable preparation production of nano-Ni.

The development of green synthetic approaches is one of the key materials challenges in moving toward semiconductor quantum dots (QDs) for large-scale production and commercial applications. This article presents a comprehensive overview on the synthesis of colloidal QDs prepared via chemical approaches in solution phase, with emphasis on green routes which possess the advantages of environment-friendly raw materials, simple operation process, and robust mass-scale production. The approaches for the synthesis of QDs in batch reactors are summarized, including hot-injection organometallic synthesis, noninjection organometallic synthesis, aqueous synthesis and biosynthesis approaches, with some of the concerns on their limitations for scale-up, followed by some continuous synthetic methods aiming for reproducible and large-scale production. Current advances in continuous synthesis of QDs by microfluidic devices, high-gravity reactors, and spray-based techniques are briefly introduced. We also provide some i...

Nucleation is the initial step of the crystallization process and is the significant step to prepare nanometer-sized crystalline materials. In this work, we systematically investigated the nucleation kinetics of poorly water-soluble drug sorafenib when precipitated by liquid antisolvent precipitation in high-gravity rotating packed bed. We found that high-gravity field tremendously promoted the nucleation rate, and the nucleation rate was increased by 2–3 orders of magnitude over that in the stirred tank reactor. Moreover, polymer excipients have a significant impact on nucleation; especially, poly(vinylpyrrolidone) (PVP) could increase the nucleation rate by 3 orders of magnitude over that without excipient. Finally, stable amorphous sorafenib nanoparticulate formulation with a particle size of 80 nm was obtained by controlling nucleation in RPB. Compared to the coarse drug, the nanoparticulate formulation performed faster drug release and had much better cytotoxicity. In vivo pharmacokinetics of the nan...

High efficiency and compact design of the desulfurization technology is necessary to meet the strict emission requirement of the marine environment. A rotating packed bed (RPB), having the high mass transfer efficiency and small size, is an excellent choice for SO2 removal from the flue gas in ships or warships. In this work, SO2 removal in a laboratory and a pilot RPB with sodium sulfite solution was investigated. Experimental results show that the SO2 concentration at the gas outlet of the RPB can meet the emission requirement and it has no obvious scale up effect. A correlation of the mass transfer coefficient (Kya) was proposed and the predicted Kya agrees with the experimental data with a deviation within ±12%. Compared with the spray tower, the RPB has a higher SO2 removal efficiency and a quarter volume, which displays a bright future for the offshore application of SO2 removal.

A novel multiliquid-inlet rotating packed bed (MLI-RPB), compared to the conventional RPB, was demonstrated to result in higher gas–liquid mass-transfer in our previous studies (Chu et al., Ind. En...

The rotating packed bed (RPB) has drawn wide attention owing to its outstanding advantage in process intensification. In the present study, gas flow characteristics in RPB were investigated by particle image velocimetry (PIV) measurement. The velocity and turbulent kinetic energy (TKE) in the packing zone were obtained and the effects of various parameters were analyzed. During rotation, gas rapidly acquired tangential velocity, which was dominant in resultant velocity. Mean gas velocity increased with the increase of rotational speed, but was almost independent of gas flow rate and packing size at lower rotational speed. Moreover, mean radial and tangential slip velocities were overall positively affected by gas flow rate and rotational speed, respectively. Higher TKE near the inner packing than those in the bulk zone revealed the existence of a gas end-effect zone in RPB. The results could provide a theoretical basis for further study on gas–solid catalytic reaction or the gas–liquid mass transfer proce...

As one of the important bone regeneration materials, α-calcium sulfate hemihydrate (α-CSH) has attracted widespread attention. In this study, a facile method was developed to prepare α-CSH with low aspect ratio via high-gravity continuously reactive precipitation of a calcium sulfate dihydrate (CSD) precursor, using ethanol as a morphology modifier in a rotating packed bed (RPB) reactor, combined with CaCl2 salt solution method under atmospheric pressure with the addition of citric acid with a low concentration (0.06 wt %). The precipitation time of CSD powders in the RPB was dramatically shortened from 30 min to 1 s, and the precursor exhibited more regular short rod shapes and much smaller size, compared to that obtained in a conventional stirring tank reactor (STR). Furthermore, calcium sulfate bone materials with high stability and good mechanical property were prepared by mixing α-CSH and normal saline with a liquid–solid ratio of 0.6. The RPB products had a higher compressive strength (2–3 times) th...

The development of metal-free catalysts for hydrogenation reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) has been of great increasing scientific and industrial importance. Herein, we reported the preparation of sulfurized graphene (SG) nanomaterials by a well-developed ball-milling method. The as-prepared SG nanomaterials were systematically characterized by scanning electron microscope, transmission electron microscope, Fourier transform infrared, and X-ray photoelectron spectroscopy. The SG exhibited flake-like morphology with average size of 100 nm, and the S doping (3.4 atom %) into the nanocarbon molecules results in asymmetry of electron density distribution, providing high catalytic performance for catalytic reduction of 4-NP to 4-AP by using NaBH4 as the reducer. The related catalytic mechanism and reaction path of the reduction were investigated. The effects of different initial 4-NP concentrations, initial reductant concentrations, catalyst dosages, and reaction temperatures were pres...

Optically transparent upconversion luminescent organic–inorganic nanocomposites are of great significance in many fields. The related key science problems are how to control size and uniformity of upconversion nanophosphors, as well as the dispersity of the upconversion nanophosphors in transparent polymer matrix. In this article, we reported a novel route to prepare Gd2O3:Yb3+/Er3+ nanophosphors by high gravity reactive precipitation along with post hydrothermal and calcination process. A rotating packed bed (RPB) reactor was used to create a high-gravity environment for intensified mixing during the precipitation process of particles. The as-prepared Gd2O3:Yb3+/Er3+ nanoparticles exhibited uniform particle size of

Rotating packed bed (RPB) reactors, with strong centrifugal acceleration up to several hundred times gravitational acceleration, can greatly intensify the gas–liquid mass transfer efficiency. With the improvement of high performance computer clusters and simulation models, a more precise and comprehensive simulation on the gas–liquid flows in RPBs has been achieved by a three-dimensional model. The volume of fluid (VOF) multiphase model, sliding model (SM), and different turbulence models were used to compute the velocity fields and capture the evolution of the gas–liquid interface in the RPB reactor. The liquid flow behavior, droplet size, liquid phase distribution, specific surface area, and mean residence time (MRT) of the liquid phase within the RPB were studied. Compared with two-dimensional simulations, the three-dimensional simulation model can not only describe the liquid breakage and coalescence processes within RPB reactors more clearly, but also obtain results in more satisfactory agreement wit...

As the main inorganic component of human hard tissue, hydroxyapatite (HAp) has attracted extensive interest in biomedical and clinical applications, especially for HAp nanoparticles. In this study, HAp nanorods with a controllable aspect ratio were successfully prepared using NH3·H2O and CO(NH2)2 as aspect ratio modifier by a high-gravity reactive precipitation in a rotating packed bed (RPB) combined with hydrothermal treatment. The influences of the molar ratio of NH3·H2O and CO(NH2)2 and the rotating speed on the average size and aspect ratio of HAp nanorods were systematically explored. The as-synthesized HAp nanorods were investigated with TEM, XRD, and FTIR. The results indicated that the average aspect ratio of HAp nanorods could be facilely controlled in the range 2.2–39. As compared to a traditional batch stirred tank reactor, the RPB reactor had HAp nanorods with a smaller particle width and a wider range of aspect ratio, and a much shorter reaction time from 20 min to 1 s. Further, the potential...

Graphene-based nanocomposites exhibiting excellent properties have been attracting tremendous interest for their extensive applications. In this work, we present an in situ high-gravitational strategy to synthesize silver/graphene oxide (AGO) nanocomposite in an ultrafast manner and propose a possible mechanism for the formation of silver nanoparticles (Ag-NPs) on graphene oxide (GO) sheets with high coverage density. The size of Ag-NPs can be controlled at ∼5 nm with a narrow size distribution. Transparent conductive films are further fabricated with AGO nanocomposite. The visible transmittance of the Ag/reduced graphene oxide (rGO) film with a sheet resistance of 1.12 kΩ/□ can reach 91%. The graphene-based nanocomposites prepared rapidly by the high-gravity technology, which is easy to realize in large-scale production, may provide extensive applications in electronics, catalysis, optics fields, etc.

Polytetrafluoroethylene (PTFE) material, which is well-known for its excellent anticorrosion properties, was used as wire mesh packing in a rotating packed bed (RPB). The effective interfacial area (ae) and the volumetric liquid-side mass-transfer coefficient (kLae) of the RPB with PTFE packing was studied experimentally by a NaOH–CO2 chemical absorption system and an oxygen–water physical desorption system, respectively. Experimental results showed that both ae and kLae increased with decreasing fiber diameter and pore size. As for material, mass-transfer performance of the PTFE packing was lower than that of the stainless steel wire mesh packing but is applicable in some high-corrosion and -viscosity environments. Moreover, correlations for ae and kLae were proposed.

In this work, external circulation rotating packed bed (EX-RPB) was combined with internal circulation rotating packed bed (IN-RPB) for the preparation of Y-type oxotitanium phthalocyanine nanocrystals (Y-TiOPc NCs) for the first time. The operating conditions in EX-RPB and in IN-RPB were investigated in detail. X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible (UV-vis) absorption spectroscopy analysis, and elemental analysis were performed, and xerographic properties were analyzed, to characterize the products. The experimental results indicated Y-TiOPc NCs with the average size of 6 nm were successfully prepared. The Q-band absorption peak of Y-TiOPc NCs centered at 782 nm, implying their potential application in the xerographic photoreceptors of laser printers. The photoreceptor fabricated with Y-TiOPc NCs exhibited an initial surface potential of 703.56 V, a photosensitivity of 0.166 μJ/cm2, a residual potential of 26.48 V, and a dark decay rate of 10.64 V/s. This wo...

Micromixing in rotating-packed-bed (RPB) reactors is of great significance for their process-intensifying performance. On the basis of the iodide–iodate reaction system, a two-dimensional computational framework of RPB was developed to investigate the micromixing efficiency in a RPB. The volume-of-fluid multiphase model, laminar finite-rate model, and the Reynolds stress model were adopted to simulate the volumetric fraction of the liquid phase, the concentration distributions, and the effects of rotating speed and liquid flow velocity on the micromixing performance of a RPB. The computational fluid dynamics results showed that the micromixing and reaction processes occurred mainly in the inlet region of RPB packing, which further confirmed the end effect of the packing. An increase of the rotating speed and liquid flow velocity could remarkably enhance the micromixing efficiency in a RPB. On the basis of the incorporation model, the micromixing time in a RPB was estimated as 0.05−0.30 ms, indicating a re...

A transparent aqueous nanodispersion of magnesium hydroxide (MH) is first synthesized by using a rotating packed bed (RPB) reactor. Based on this nanodispersion, we further fabricate a transparent poly(vinyl alcohol) (PVA)/MH nanocomposite with enhanced flame-retardant property by a solution-mixing method. The PVA/MH nanocomposite can keep good transparency even at high MH contents. The limiting oxygen index (LOI) of PVA/MH nanocomposite with 50 phr MH is improved by 45% compared to pure PVA. The peak of heat release rate (pHRR) in the microscale combustion calorimetry (MCC) significantly reduces from 453 W/g for pure PVA to 332 W/g. Importantly, a smooth and compact residue layer for the PVA/MH nanocomposite is formed during combustion, which yields a barrier for the transfer of heat and oxygen. These results indicate that the PVA/MH is an excellent transparent flame-retardant material, which opens a door to manufacture transparent and fire-resistant polymer-based nanocomposites with environmental-friend...

A microimpinging stream reactor (MISR) at the size of 1 mm was built with a commercial T-junction and steel capillaries for the preparation of CuO/ZnO/Al2O3 catalysts. The coprecipitation of catalyst precursors in MISR was conducted under precisely controlled concentration, pH and volumetric flow rate (VA), followed by the conventional postprecipitation steps. TEM images showed that the coprecipitation in MISR would generate mostly round catalyst particles with a mean size of 8–10 nm; whereas slightly larger and irregular particles were produced in conventional batch route. In addition, the CuO/ZnO/Al2O3 catalysts prepared in MISR possessed larger BET surface area (SBET), specific copper surface area (SCu) and pore volume as well as better Cu/Zn dispersion when compared to those produced in batch route. It was also found that during the preparation of CuO/ZnO/Al2O3 catalysts in MISR, the reactant concentration (Cmn) and volumetric flow rates (VA) had great influences on the structures and properties of th...

To enhance the solubility and dissolution rate, and thus potentially improve the oral bioavailability of cefixime (CFX), amorphous CFX nanoparticles were prepared via high-gravity antisolvent precipitation (HGAP) without the aid of any pharmaceutical additives in a rotating packed bed (RPB). The effects of operating variables on particle size and distribution were investigated. Compared to raw CFX, the mean size of prepared nanoparticles decreased greatly from about 2.1 μm to 57 nm, and the saturation solubility increased tremendously from 0.289 to 0.951 mg/mL. CFX nanoparticles showed good stability and were capable of generating a maximum supersaturation level, reaching up to ∼22.8 times of raw CFX’s saturation solubility. Further, CFX nanoparticles achieved 100% drug dissolution within 2 min, while the raw drug did not dissolve completely after 45 min, suggesting that the solubility and dissolution properties of CFX nanoparticles were significantly improved. Since the drug recovery ratio achieved 99.9%...

Micromixing, the mixing at the molecular scale, is believed to play a substantial role in many industrial processes. In this work, a novel surface-modified nickel foam packing (SNP) loaded in a rotating packed bed (RPB) reactor was first proposed to improve the micromixing efficiency studied by adopting the iodide–iodate reaction as a working system. Experimental results showed that the RPB reactor with the SNP presented better micromixing efficiency, compared to the RPB reactor with the nonmodified nickel foam packing (NNP) or traditional stainless steel wire mesh packing (SWP). It could be found that the segregation index (XS) decreased as the rotational speed and liquid flow rate each increased, while it increased with increasing acid concentration and volumetric ratio. Moreover, the micromixing time (tm) was calculated using an incorporation model based on the experimental data. Compared with NNP or SWP, the minimum tm value of SNP (tm = 3.28 ms) is less than that of NNP (tm = 5.68 ms) or SWP (tm = 8....

Transparent nanocrystal suspension exhibits many unique properties, and are thus attractive materials for numerous applications. However, the synthesis of transparent nanocrystal suspension of magnesium hydroxide (MH) with wide applications is yet to be realized. This paper presents a novel route of synthesizing transparent suspension of lamellar MH nanocrystals by using high-gravity reactive precipitation combined with successive surface modification. Reactive precipitation in ethanol phase instead of aqueous phase is conducted by introducing MgCl2·6H2O and NaOH ethanol solutions into a rotating packed bed (RPB) reactor with a rotating speed of 2500 rpm at 30 °C to form MH nanocrystal suspension, which is subsequently modified with KH570 (KH570/MH = 10 wt %) for an optimum time of 3 h and temperature of 70 °C to yield transparent suspension of lamellar MH nanocrystals with about 1 nm in thickness. The as-prepared transparent MH nanocrystal suspension is characterized by transmission electron microscopy (...

Porous manganese dioxide (MnO2) was synthesized via an ultrasound–microwave-intensified precipitation reaction with the soft template of triblock polymer P123. The MnO2 particles prepared by combining microwave heating and ultrasonic dispersing showed a loose sphere-network structure with tiny pores 4–5 nm in diameter inside the spheres, as well as architectural mesopores and macropores among the secondary particles. The loose network structure became more solid with bigger particles and less surface area if the microwave heating or ultrasonic dispersing was replaced by conventional hot plate heating or magnetic stirring. The electrochemical properties examined by cyclic voltammetry (CV) and galvanostatic charge/discharge methods illustrated that the MnO2 prepared with intensified precipitation had the highest discharge specific capacitance of ∼214 F/g and showed negligible capacitance decline after 1000 cycles and acceptable decline after 5000 cycles, which further confirmed the combined intensifying eff...

This study was conducted to investigate the effect of inorganic salts on the mass-transfer coefficient of O3 and decolorization of azo dye (Acid Red 14, AR14) solution through ozonation in a microporous tube-in-tube microchannel reactor (MTMCR). The overall volumetric mass-transfer coefficient (KGa) of O3 in the MTMCR was deduced by material balance. The effects of different salts on the KGa of O3 and decolorization efficiency of the AR14 solution were studied, and results show that both were significantly affected by the inorganic salts. Although the KGa of O3 and the decolorization efficiency of AR14 increased with increasing salt concentration and pH, the effect of NaNO3 was much weaker than that of NaCl, Na2SO4, Na2CO3, and NaHCO3. The enhanced KGa of O3 and decolorization could be due to the generation of species with high oxidizing ability in the presence of the salts.

End effect is a significant phenomenon in a rotating packed bed (RPB). The mass transfer accomplished in the end zone can be one magnitude higher than what is achieved in the bulk zone of the packing. In order to make full use of the end effect, a novel multiliquid-inlet rotating packed bed (MLI-RPB) was developed, which artificially created the extra end zones in the bulk zone along the radial direction of the rotor. The effective interfacial area (a) and liquid-side volumetric mass-transfer coefficient (kLa) of the MLI-RPB were measured using a system of CO2 chemisorption into NaOH solution. Mass-transfer experiments were also conducted in a traditional RPB with the same size as the MLI-RPB. Compared with the traditional RPB, higher values of a and kLa were obtained in the MLI-RPB, showing a great potential for the industrial applications.