Microfluidic-oriented synthesis of enriched iridium nanodots/carbon architecture for robust electrocatalytic nitrogen fixation

Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-products.However,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic efficiency.Herein,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon architecture.Owing to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption capacity.As a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73 μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH solution.Moreover,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.30%are also achieved in H_(2)SO_(4) solution.The microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field.

Micro-nano-fabrication of green functional materials by multiphase microfluidics for environmental and energy applications

Multiphase microfluidic has emerged as a powerful platform to produce novel materials with tailor-designed functionalities,as microfluidic fabrication provides precise controls over the size,component,and structure of resultant materials.Recently,functional materials with well-defined micro-/nanostructures fabricated by microfluidics find important applications as environmental and energy materials.This review first illustrated in detail how different structures or shapes of droplet and jet templates are formed by typical configurations of microfluidic channel networks and multiphase flow systems.Subsequently,recent progresses on several representative energy and environmental applications,such as water purification,water collecting and energy storage,were overviewed.Finally,it is envisioned that integrating microfluidics and other novel materials will play increasing important role in contributing environmental remediation and energy storage in near future.

心功能标志物在认知障碍患者中的作用

目的:近年来,心脏功能在认知功能障碍中的作用成为研究热点,认为心功能下降与认知障碍有关。因此,我们研究了代表心功能的标志物,如每搏输出量(SV)、左室射血分数(LVEF)、N末端B型脑钠肽(NTpro-BNP)等与认知障碍的关联,并试图解释心功能指标在认知障碍患者中的作用及可能机制。方法:纳入认知障碍患者61例以及年龄、性别和文化水平相匹配的认知正常对照组50例,收集一般临床资料,并完成血生化如血脂、同型半胱氨酸(Hcy)、N端-B型钠尿肽前体(NT-proBNP)、游离三碘甲状腺原氨酸(FT3)、游离四碘甲状腺原氨酸(FT4)、三碘甲状腺原氨酸(T3)、甲状腺素(T4)、促甲状腺激素(TSH)、D-二聚体等指标检测,并完成血清NT-proBNP检测。两组患者均完成超声心动图,测量LVEF%、SV、每分搏出量(CO)等指标。结果:认知障碍组患者SV、CO明显低于健康对照组,NT-proBNP水平高于健康对照组,差异有统计学意义(P <0.05),而两组间LVEF%水平差异无统计学意义(P> 0.05);在多变量Logistic回归分析中,校正了体重指数、血管危险因素等影响因素后发现,SV与认知障碍独立相关(OR=0.918,P=0.022)。结论:心功能下降与认知障碍存在相关性,认知障碍患者更易合并有心功能下降,SV下降可能是认知障碍发生的独立危险因素。

Green microfluidics in microchemical engineering for carbon neutrality

The concept of“carbon neutrality”poses a huge challenge for chemical engineering and brings great opportunities for boosting the development of novel technologies to realize carbon offsetting and reduce carbon emissions.Developing high-efficient,low-cost,energy-efficient and eco-friendly microfluidicbased microchemical engineering is of great significance.Such kind of“green microfluidics”can reduce carbon emissions from the source of raw materials and facilitate controllable and intensified microchemical engineering processes,which represents the new power for the transformation and upgrading of chemical engineering industry.Here,a brief review of green microfluidics for achieving carbon neutral microchemical engineering is presented,with specific discussions about the characteristics and feasibility of applying green microfluidics in realizing carbon neutrality.Development of green microfluidic systems are categorized and reviewed,including the construction of microfluidic devices by bio-based substrate materials and by low carbon fabrication methods,and the use of more biocompatible and nondestructive fluidic systems such as aqueous two-phase systems(ATPSs).Moreover,low carbon applications benefit from green microfluidics are summarized,ranging from separation and purification of biomolecules,high-throughput screening of chemicals and drugs,rapid and cost-effective detections,to synthesis of fine chemicals and novel materials.Finally,challenges and perspectives for further advancing green microfluidics in microchemical engineering for carbon neutrality are proposed and discussed.

A novel approach to study the interactions between polymeric stabilized micron-sized oil droplets by optical tweezers

The well understanding of interaction forces between single dispersed droplets is crucial to the understanding of emulsion stabilization mechanism.Recently,many studies have reported the direct quantitative measurements of interaction forces between 20-200μm single droplet coated polymers by atomic force microscope(AFM).These studies have revealed many important results about the relationship of the interaction forces and the droplet deformation.However,these studies of the quantitative relationship between the measured interaction forces and the separation distance of the front end of the droplet have rarely been reported.Optical tweezer instrument can make it possible to establish the quantitative relationship between the measured force and the separation distance of the front end of the droplet,which will make better understanding of the interaction mechanisms between droplets.Due to the differences of the measuring mechanism between atomic force microscopy(AFM)and optical tweezers,the theory model of AFM measurements cannot be fitted with the force measurement by optical tweezers.We have made an exhaustive comparison of the measuring differences between AFM and optical tweezer instrument in this work.Moreover,we built a numerical model to derive the repulsive pressure through the measured force curve in order to quantify the measured force of two micron-sized oil droplet coated polymers by optical tweezers.Furthermore,the novel method can be extended to other micron-sized emulsion systems,and these findings will be a vital progress on quantitative force measurements between micron-sized droplets.

Efficient fixation of CO_(2) into propylene carbonate with [BMIM]Br in a continuous-flow microreaction system

Utilization of carbon dioxide(CO_(2)) is of great significance in the development of CO_(2) absorption and the solution of greenhouse gas effect.Highly efficient conversion of CO_(2) into cyclic carbonate with green catalysts is essential for the more sustainable expansion of CO_(2) fixation.Traditional batch reactor is limited by low efficiency, high cost and low security. Meanwhile, continuous flow system showcased a myriad of virtues, including shortening the residence time from hours to seconds, and decreasing reaction temperature, and possessing the nature of easy industrial scale-up. In this paper, a continuous-flow microreaction system was developed to synthesis propylene carbonate(PC) from propylene oxide(PO) and CO_(2) using 1-butyl-3-methylimidazolium bromide([BMIM]Br) as catalyst. By observing the flow patterns inside microreaction system, the effects of reaction temperature, molar fraction of catalyst, operating pressure, residence time, molar ratio of CO_(2)/PO as well as recycling performance of catalyst on the overall performances were comprehensively evaluated into details. Under different reaction conditions,the flow patterns were set to vary between slug flow and annular flow. The results showed that the yield of propylene carbonate(PC) can reach99.7% at 140℃ and 3.0 MPa with the residence time of 166 s, while the recycling performance of the designed system greatly conforms the future trend of green chemistry.

Microfluidic technology for multiphase emulsions morphology adjustment and functional materials preparation

Multiphase emulsions could be used as templates in considerable fields such as coating, optical materials, stan- dard particles and biomedicine. Among various emulsion forming methods, microfluidic technology, with good monodispersity, high controllability and operation simplicity, has been widely used in the preparation of multi- phase emulsions with different systems. This review would focus on the basic principles of forming multiphase emulsions, the recent progress in controlling multiphase flow in microfluidics, and preparation of functional ma- terials with microfluidics mainly by the authors＇ research group. We believe that the review will contribute to the readers in this prospective area very well. ~ 2016 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.

A circular microreaction method to the safe and efficient synthesis of 3-methylpyridine-N-oxide

3-Methylpyridine-N-oxide is an essential intermediate in the preparation of 2-chloro-5-methylpyridine,which can be used to synthesize nicotine insecticides such as imidacloprid and acetamiprid.The traditional method of production of 3-methylpyridine-N-oxide is catalytic oxidation of 3-methylpyridine in semi-batch reactors.Due to strong exothermic reaction and explosive property of 3-methylpyridine,the reaction efficiency and safety is low using batch technology.Therefore,the development of a safer and efficient 3-methylpyridine-N-oxide production process is very necessary in industrial production.In this paper,microreaction systems were introduced into the preparation of 3-methylpyridine-N-oxide.The comparison of three different methods(traditional semibatch method,co-current microreaction method,and circular microreaction method)showed that the circular microreaction method was the most applicable,with relative higher product yield(~90%),less side reaction and better reaction control.

A CO_(2)/N_(2)-Responsive Pickering Emulsion Stabilized by Novel Switchable Surface-Active Alumina Nanoparticles

This article reports the development of a novel switchable Pickering emulsion with rapid CO_(2)/N_(2) respon-siveness,which is stabilized using alumina nanoparticles hydrophobized in situ with a trace amount of a switchable superamphiphile via electrostatic interactions.With the introduction of CO_(2) for 30 s,the Pickering emulsion can be spontaneously demulsified with complete phase separation;the emulsion can then be reconstructed in response to N_(2) purging for 10 min followed by homogenization.Moreover,the stable Pickering emulsion can be stored for more than 60 days at room temperature with-out any visible change.The CO_(2)/N_(2)-responsive behavior of the switchable Pickering emulsion is attribu-ted to the reversible desorption/adsorption of the switchable surfactants on the surfaces of the alumina nanoparticles upon the alternative bubbling of CO_(2)or N_(2).Thanks to the simple fabrication of the surfac-tant and the hydrophobization of the alumina nanoparticles,this research has developed an extremely facile and cost-efficient method for preparing a rapidly CO_(2)/N_(2)-responsive switchable Pickering emul-sion.The dosage of the switchable surfactants has been significantly reduced by nearly 1500 times(from 150 to 0.1 mmol·L^(-1))as compared with the dosage used in previous studies.Moreover,the as-prepared CO_(2)/N_(2)-responsive switchable Pickering emulsion is environmentally friendly,mild,and nontoxic;thus,it holds great potential for practical applications with considerable economic and environmental benefits,such as oil transport,fossil fuel production,environmental gases detection,and the encapsulation and release of active ingredients.

Equilibrium morphology of gas–liquid Janus droplets: A numerical analysis of buoyancy effect

In this article, a theoretical model for predicting the equilibrium morphology of gas–liquid Janus droplets was built. Based on this model, the effects of bubble radius and volume ratio on morphology change was systematically studied. The increase of bubble radius causes the two parts(bubble and oil drop) in Janus droplets tend to merge while the impact of volume ratio is complicated. When volume ratio increases, these two parts firstly tend to merge, then gradually separate. The accuracy of this model was verified by experimental results.

Solvent extraction of lanthanum and cerium ions from hydrochloric acidic aqueous solutions using partly saponified 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester

In order to clarify the extraction process with saponified extractant, the solvent extraction experiments of rare earth elements(REEs), lanthanum and cerium, by using partly saponified 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester(EHEHPA, HL) from hydrochloric acidic solutions have been performed. The concentration of initial aqueous rare earth ion was in a range of 0.0010–0.1000 mol·L^(-1); EHEHPA in a range of 0.2877–0.8631 mol·L^(-1) with saponification rate of 0.3(mole fraction), and the initial aqueous p H in a range of 1.00–4.00. Firstly, the extracted species were determined by the saturation extraction capacity method. Secondly, according to the equilibrium aqueous pH values, the extraction processes were divided into three different categories: extraction with saponified EHEHPA, extraction with un-saponified EHEHPA, and hydrolysis process. Finally, for the first two processes, in order to predict the distribution ratio, two semi-empirical calculation models were developed with.The calculation results are in good agreement well with the experimental data.

Kinetic study of CO_(2) fixation into propylene carbonate with water as efficient medium using microreaction system

Carbon dioxide(CO_(2))utilization and fixation have become one of the most important research areas nowadays due to the increase of global greenhouse effect.Cyclic carbonate,which is widely used in various fields,can be synthesized by fixation of CO_(2) with epoxide in industry.Moreover,the synthesis of cyclic carbonate is a 100%atom economical reaction,which makes it eco-friendly and promising.To enhance the reaction efficiency and safety,a microreaction system was used as the platform for cycloaddition reaction.In this work,tetrabutylammonium bromide(TBAB)was chosen as catalyst,and propylene oxide(PO)as a mode substrate.Interestingly,the addition of water can increase the propylene carbonate(PC)yield and decrease the activation energy considerably,proving water as catalyst promoter for PC synthesis.PC yield and selectivity could reach 91.6%and 99.8%,respectively.The Influence factors and kinetic equation for CO_(2) cycloaddition were obtained as well.

Experimental investigation of dynamic mass transfer during droplet formation using micro-LIF in a coaxial microchannel

The mass transfer of Rhodamine 6G from the droplet to the continuous phase in a coaxial micro-channel is studied using micro-LIF(Laser-Induced Fluorescence).The mass distribution inside droplet is measured and visualized.The experimental results affirm that there exists the internal circulation inside the droplet and it could enhance the convective mass transfer.The stagnant center of vortices is also observed.The extraction fraction could reach 40%80%.In order to establish the mass transfer model,different flow rates of the dispersed and continuous phase are adopted.The high continuous phase flow rate and low dispersed phase flow rate are both beneficial to enhance mass transfer by expediting the internal circulation.A modified mass transfer model is found to calculate the extraction fraction.A good agreement between the model and experiment in various conditions demonstrates that the mass transfer model in this work is reliable and feasible.

Continuous synthesis of few-layer MoS_(2) with highly electrocatalytic hydrogen evolution

As one of the most promising alternative fuels,hydrogen is expected with high hopes.The electrolysis of water is regarded as the cleanest and most efficient method of hydrogen production.Molybdenum disulfide(MoS_(2))is deemed as one of the most promising alternatives HER catalysts owing to its high catalytic activity and low cost.Its continuous production and efficient preparation become the key problems in future industrial production.In this work,we first developed a continuous micro-reaction approach with high heat and mass transfer rates to synthesize few-layer MoS_(2)nanoplates with abundant active sites.The defective MoS_(2)ultrathin nanoplates exhibit excellent HER performance with an overpotential of 260 m V at a current density of 10 m A cm^(-2),small Tafel slope(53.6 m V dec^(-1))and prominent durability,which are comparable to most reported MoS_(2)based catalysts.Considering the existence of continuous devices,it's suitable for the synthesis of MoS_(2)as highperformance electrocatalysts for the industrial water electrolysis.The novel preparation method may open up a new way to synthesize all two-dimension materials toward HER.

安宁地区住院患儿呼吸道病原体七联检阳性检测结果分析

目的分析安宁地区住院患儿呼吸道感染病毒病原体阳性检测结果。方法选择2019年9月至2022年2月安宁地区住院患儿1766例为研究对象,根据年龄分为<6月龄组、6月龄~4岁组、4~14岁组;根据新冠疫情防控,2019年9月至2020年2月前为公众防护前,2020年2月后公众防护后;采集所有患儿鼻咽拭子标本,采用直接免疫荧光法测定甲型流感病毒抗原、乙型流感病毒抗原、呼吸道合胞病毒抗原、腺病毒抗原、副流感病毒Ⅰ型抗原、副流感病毒Ⅱ型抗原、副流感病毒Ⅲ型抗原7种呼吸道病原体,统计分析患儿呼吸道病原体检出情况。结果1766例患儿呼吸道感染病毒病原学检出阳性584例,阳性率为33.07%,呼吸道病毒病原体中检出主要以呼吸道合胞病毒(316例/17.89%)、腺病毒(90例/5.10%)、副流感病毒Ⅲ型(82例/4.64%)为主;患儿呼吸道感染病毒病原体阳性主要集中在<6月龄组、6月龄~4岁组,检出阳性率分别为111例(34.69%)、327例(34.31%),不同年龄段呼吸道感染病原体检测阳性率,差异有统计学意义(χ^(2)=8.392,P=0.031);公众防护后甲型流感病毒检出阳性率0.29%低于公众防护前5.94%,差异有统计学意义(P<0.05);公众防护前后乙型流感病毒抗原、腺病毒抗原、副流感病毒Ⅰ型、副流感病毒Ⅱ型、副流感病毒Ⅱ型检出率差异无统计学意义(P>0.05)。结论安宁地区住院患儿呼吸道感染病毒病原学检出率较高,呼吸道合胞病毒是主要病原体,公众防护后甲型流感病毒检出阳性率明显下降,故继续做好公众防护对防范甲型流感亦有重要意义。

Recent advances in the microfluidic generation of shape-controllable hydrogel microparticles and their applications

Hydrogel microparticles,generally accepted as significant green materials,have been widely used in chemical,biological,and biomedical fields owing to their excellent biocompatibility,biodegradability,and noncytotoxicity.Among these,non-spherical hydrogel microparticles with diverse shape anisotropy have great potential in applications such as drug delivery,cellular interaction,micromotors,etc.Benefiting from their shapes,their functionalities in such fields cannot be satisfied by the typical spherical types.Recently,microfluidics with precise control and domination of fluids at microflow sizes has emerged as a powerful method for synthesizing shape-controllable hydrogel microparticles with good monodispersity and unique morphology.In this review,we tried to provide an overview of the production of non-spherical microparticles composed of green hydrogel materials,emphasizing the microfluidic approaches.Furthermore,a brief introduction to their current applications is also presented.

Microfluidic platform serves as controllable fabrication of binary Mo/Ir nanodots/carbon hetero-material for efficient electrocatalytic nitrogen reduction

Electrocatalytic nitrogen reduction reaction(NRR)is regarded as a potential routine to achieve environment-friendly ammonia production,because of its abundant nitrogen resources,clean energy utilization and flexible operation.However,it is hindered by low activity and selectivity,in which con-dition well-designed catalysts are urgently in need.In this work,a binary Mo/Ir nanodots/carbon(Mo/Ir/C)hetero-material is efficiently constructed via microfluidic strategy,of which the nanodots are ho-mogeneously distributed on the carbon skeleton and the average size is approximately 1 nm.Excellent performance for NRR is obtained in 1 mol L^(-1) KOH,of which the optimized ammonia yield and faradic efficiency are 7.27μg h^(-1) cm^(-2) and 2.31%respectively.Moreover,the optimized ammonia yield of 6.20μg h-1 cm-2 and faradic efficiency of 10.59%are also obtained in 0.005 mol L^(-1) H_(2)SO_(4).This work achieves the continuous-flow synthesis and controllable adjustment of hetero-materials for favorable morphologies,which provides an innovative pathway for catalyst design and further promotes the development of ammonia production field.

Perchlorate removal using granular activated carbon supported iron compounds: Synthesis, characterization and reactivity

Synthesis and use of the iron compounds supported on granular activated carbon （ICs/GAC） have shown significant environmental implications for perchlorate （ClO4^- ） removal. ICs/GAC was synthesized via hydrolyzing FeSO 4 ·7H2O on GAC, reduced by NaBH 4 solution in polyethylene glycol 6000 and ethanol solution, dried in vacuum condition and exposed to air. Synthesized ICs/GAC was characterized using transmission electron micrograph （TEM）, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy （XPS）. ICs/GAC was determined to be containing a large amount of FeOHSO 4 , Fe2O3 and a small amount of zero-valent iron （ZVI） nanoparticles according to TEM and XPS measurements. Batch static kinetic tests showed that 97% of ClO4^- was removed within 10 hr at 90°C and 86% of ClO4^- was removed within 12 hr at 25°C, at ICs/GAC dosage of 20 g/L. The experimental results also showed that FeOHSO 4 and Fe 2 O 3 nanoparticles have the function of perchlorate adsorption and play important roles in ClO4^- removal. The activation energy （E a ） was determined to be 9.56 kJ/mol.

Recent advances in carbon dioxide capture and utilization with amines and ionic liquids

Global warming and climate change due to anthropogenic carbon dioxide(CO_(2))have aroused significant concerns at the global scale due to rapid economic growth in industries and other fields.Therefore,CO_(2)capture,use,and storage have become particularly important.In this review,general background and methods for CO_(2)capture and separation,in particular,on ionic liquids(ILs)-based solvents and materials,are discussed.Comprehensive surveys of ILs for CO_(2)absorption are presented,which focused mainly on experimental researches,and then the concept is extended to functionalized absorbents and recent developments for CO_(2)capture.Major advantages and disadvantages of amines-based and ILs-based absorbents are discussed in this review.Solutions of traditional amines(MEA,MDEA,DEA,AMP,PZ,etc.)and ILs(conventional ILs,functionalized ILs,etc.)are summarized.Moreover,research progresses on CO_(2)separation are also introduced focusing mainly on amines and ILs-based membranes(e.g.supported amines membranes,SILMs).Futhermore,the fixation of CO_(2)into cyclic carbonates catalyzed by ILs(pure ILs,complex catalyst system with ILs,supported ILs,etc.)is summarized,clearly explaining the mechanism of CO_(2)fixation with ILs.Finally,exploration of some recent studies about CO_(2)capture and conversion by ILs and challenges for further progress are presented and related suggestions are put forward.

Efficient extraction and stripping of Nd(Ⅲ),Eu(Ⅲ) and Er(Ⅲ) by membrane dispersion micro-extractors

The extraction of low concentration rare earth elements at high phase ratio was investigated. The traditional extraction set-up, such as mixer-settler, have drawbacks of easy emulsification, difficult separation and low efficiency if operated at the above condition. Membrane dispersion micro-extractor,owing to its well-dispersed, high surface-to-volume ratio and fast mass transfer rate, was employed in our work. Nd（Ⅲ）,Eu（Ⅲ）,Er（Ⅲ） were chosen to represent light, medium,heavy rare earth elements（REEs）. The extraction process of REEs with 2-ethylhexyl phosphoric acid-2-ethylhexyl ester（P507） was investigated by membrane dispersion micro-extractors. Firstly, the extraction equilibrium of these three elements was explored in the stirred conical flasks, and it is indicated that the extraction efficiencies can be 0.95, 0.97 and 0.98, respectively within 40 min at phase ratio of 100：1. Then the effects of operational conditions such as the residence time, organic and aqueous flow rates on extraction efficiency were also explored in micro-extractors. The results indicate that the efficiency decreases and then increases if increasing aqueous phase flow rate, residence time and droplets＇ diameter are the key factors of this process. Increasing the phase ratio reduces the extraction efficiency significantly. When the REEs solution has an initial pH of 4.00, the flow rates of continuous and dispersed phase are 40 and 1.6 mL/min,respectively, and 90 mg/L Nd（Ⅲ）, Eu（Ⅲ） and Er（Ⅲ） is extracted by 1 mol/L P507 at the out-let length of8 m. The extraction efficiencies are 0.978,0.983 and 0.991, respectively. Finally the stripping process was also studied with the micro-extractor. The stripping efficiencies of Nd（Ⅲ）, Eu（Ⅲ） and Er（Ⅲ） can reach0.99, 0.96 and 0.91, respectively when the out-let length is 8 m and the concentration of hydrochloric acid is 1 mol/L. The developed approach offers a novel and simple strategy on the fast extraction and enrichment of low concentration rare earth elements from waste water.