Filtration of aerosol particles using non-woven fibrous media is a common practice for air cleaning. It has found wide applications in industries and our daily lives. This paper overviews some of these applications and provides an industrial perspective. It starts from discussing aerosol filtration theory,followed by a brief review on the advancement of filtration media. After that,filtration applications in respiratory protection,dust collection,and engine in-take air cleaning are elaborated. These are the areas that the author sees as the typical needed ones in China's fast pace economical development endeavor,where air filtration enables the protection of human health,environment and equipment for sustainability.

Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed.Influence of external diffusion,internal diffusion and heat transfer on the intrinsic reaction rate was investigated and the conditions free of internal and external diffusion resistance have been determined.In the experiments,in order to correctly evaluate the intrinsic kinetics parameters for reducing Fe₂O₃ to Fe₃O₄,the reaction temperatures were set between 440℃ and 490℃.However,in order to distinguish the reduction of Fe₃O₄ to FeO from that of FeO to Fe,the reaction temperature in the experiment was set to be greater than 570℃.Intrinsic kinetics of iron oxide reduction by hydrogen was established and the newly established kinetic models were validated by the experimental data.

This paper presents the experimental results of liquid-liquid microflows in a coaxial microfluidic device with mass transfer.Three working systems were n-butanol+phosphoric acid(PA)+water,methyl isobutyl ketone(MIBK)+PA+water,30% kerosene in tri-n-butylphosphate(TBP)+PA+water.The direction and intensity of mass transfer were adjusted by adding PA in one of two phases mutual saturated in advance.When PA transferred from the organic phase to the aqueous phase,tiny aqueous droplets may generate inside the organic phase by mass transfer inducement to form a new W/O/W flow pattern directly on some special cases.Once the PA concentration was very high,violent Marangoni effect could be observed to throw part of organic phase out of droplets as tail.The interphase transfer of PA could expand the jetting flow region,in particular for systems with low or medium interfacial tension and when the mass transfer direction was from the aqueous phase to the organic phase.

A new mixer-settler-mixer three chamber integrated extractor is proposed in this work for liquid-liquid-liquid three phase countercurrent and continuous extraction.Experiments revealed the influences of the structural design of the three-liquid-phase extractor and some key operational parameters on three-phase partition of two phenolic isomers,p-nitrophenol(p-NP) and o-nitrophenol(o-NP).The model three-liquid-phase extraction system used here is nonane(organic top-phase)-polyethylene glycol(PEG 2000)(polymer middle-phase)-(NH₄)₂SO₄ aqueous solution(aqueous bottom-phase).It is indicated that agitating speed and retention time in three-phase mixer are key parameters to extraction fraction of nitrophenol.Dispersion band behavior is related to agitating intensity,and its occurrence does not affect the extraction fraction of target compounds.The present work highlights the possibility of a feasible approach of scaling up of the proposed three-phase extraction apparatus for future industrial-aimed applications.

To study the characteristic of liquid-liquid extraction equilibrium of lithium from brine sources,the complexes formed from tributyl phosphate(TBP) and methyl isobutyl ketone(MIBK) with lithium were investigated using FeCl₃ as coextracting agent.Liquid-liquid extraction reaction mechanisms were proposed and the stoichiometry of tetrachloroferrate(Ⅲ) complex with lithium was obtained by regressing the experimental data.It is found that the stoichiometry of tetrachloroferrate(Ⅲ) to lithium in the complex is 1:1 with either TBP or MIBK as extractant in kerosene.The stoichiometry of the complex of TBP with Li was 1:1 and that of MIBK with Li was 2:1.The formed complexes of TBP and MIBK with lithium are determined to be LiFeCl₄·TBP and LiFeCl₄·2MIBK,respectively,according to the rule of neutralization.

A new kind of hydrophobic ionic liquids [1-alkyl-3-(1-carboxylpropyl)im][PF₆] has been synthesized,and their extraction properties for Y(Ⅲ) in the nitric acid medium was also investigated.The effects of extractant concentration,equilibrium pH of aqueous phase,salt concentration,temperature etc.were discussed.The results show that this kind of Task-Specific Ionic Liquid (TSIL) needs to be saponified before being used for the Y(Ⅲ) extraction,and the extraction is acid dependent,and the extraction efficiency increases with the aqueous phase acidity decreasing.Furthermore,the loaded organic phase is easy to be stripped;more than 95% Y(Ⅲ) could be stripped from the loaded organic phase when the stripping acidity is higher than 0.07 mol·L^-1.The slope analysis technique is used to investigate the extraction mechanism,and a possible cation-exchange extraction mechanism is proposed in the present extraction system.

Biodesulfurization(BDS) is a promising technology for deep desulfurization.In this work,Pseudomonas delafieldii R-8 cells are immobilized in calcium alginate beads and used for BDS of transportation fuels.It is found that thiophene and dibenzothiophene(DBT) can be simultaneously metabolized by immobilized R-8 cells.The initial sulfur content in the model oil is 300 mg·kg^-1(thiophene:DBT 1:1).After 10 h of treatment,the thiophene concentration is reduced by 40%,while DBT is reduced by 25%.The utilization rate of thiophene is faster than that of DBT.Moreover,the oil/water ratio of alginate immobilized cells is studied to reduce the water volume in desulfurization systems.Long-term recycling of BDS by alginate immobilized cells is carried out with oil/water ratio at 5:1.The immobilized cells are successfully reused over 15 batch cycles.In the last batch,the desulfurization activity remains at least 75% of the first batch.

The thermostability of three sulfur oxygenase reductases(SORs) was investigated from thermoacidophilic achaea Acidianus tengchongensis(SOR_AT) and Sulfolobus tokodaii(SOR_ST) as well as the moderately thermophilic bacterium Acidithiobacillus sp.SM-1(SOR_SB).The optimal temperatures for catalyzing sulfur oxidation were 80℃(SORAT),85℃(SORST),and 70(SOR_SB),respectively.The half-lives of the three SORs at their optimal catalytic conditions were 100 min(SORAT),58 min(SOR_ST),and 37 min(SOR_SB).In order to reveal the structural basis of the thermostability of these SORs,three-dimensional structural models of them were generated by homology modeling using the previously reported high-resolution X-ray structure of SORAA(from Acidianus ambivalens) as a template.The results suggest that thermostability was dependent on:(a) high number of the charged amino acid glutamic acid and the flexible amino acid proline,(b) low number of the thermolabile amino acid glutamine,(c) increased number of ion pairs,(d) decreased ratio of hydrophobic accessible solvent surface area(ASA) to charged ASA,and(e) increased volumes of the cavity.The number of cavities and the number of hydrogen bonds did not significantly affect the thermostability of SORs,whereas the cavity volumes increased as the thermal stability increased.

Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic-supported polymer composite pervaporation membranes.The separation materials of polymer/ceramic composite membranes presented here include hydrophobic polydimethylsiloxane(PDMS) and hydrophilic poly(vinyl alcohol)(PVA),chitosan(CS) and polyelectrolytes.The effects of ceramic support treatment,polymer solution properties,interfacial adhesion and incorporating or blending modification on the membrane structure and PV performance are discussed.Two in-situ characterization methods developed for polymer/ceramic composite membranes are also covered in the discussion.The applications of these composite membranes in pervaporation process are summarized as well,which contain the bio-fuels recovery,gasoline desulfuration and PV coupled process using PDMS/ceramic composite membrane,and dehydration of alcohols and esters using ceramic-supported PVA or PVA-CS composite membrane.Finally,a brief conclusion remark on polymer/ceramic composite membranes is given and possible future research is outlined.

Poly(vinylidene fluoride)(PVDF) has become one of the most popular materials for membrane preparation via nonsolvent induced phase separation(NIPS) process.In this study,an amphiphilic block copolymer,Pluronic F127,has been used as both a pore-former and a surface-modifier in the fabrication of PVDF hollow fiber membranes to enhance the membrane permeability and hydrophilicity.The effects of 2nd additive and coagulant temperature on the formation of PVDF/Pluronic F127 membranes have also been investigated.The as-spun hollow fibers were characterized in terms of cross-sectional morphology,pure water permeation(PWP),relative molecular mass cut-off(MWCO),membrane chemistry,and hydrophilicity.It was observed that the addition of Pluronic F127 significantly increased the PWP of as-spun fibers,while the membrane contact angle was reduced.However,the size of macrovoids in the membranes was undesirably large.The addition of a 2nd additive,including lithium chloide(LiCl) and water,or an increase in coagulant temperature was found to effectively suppress the macrovoid formation in the Pluronic-containing membranes.In addition,the use of LiCl as a 2nd additive also further enhanced the PWP and hydrophilicity of the membranes,while the surface pore size became smaller.PVDF hollow fiber with a PWP as high as 2530 L·m^-2L·m^-2·h^-1·MPa^-1h^-1·MPa^-1,a MWCO of 53000 and a contact angle of 71° was successfully fabricated with 3%(by mass) of Pluronic F127 and 3%(by mass) of LiCl at a coagulant temperature of 25℃,which shows better performance as compared with most of PVDF hollow fiber membranes made by NIPS method.

This research evaluated the use of sewage sludge and refuse incineration bottom ash to replace calcium sulfoaluminate cement(CSA) in making controlled low-strength material(CLSM).Various properties of CLSM mixtures were characterized in terms of unconfined compressive strength,microstructure and leachability.It was found that the strength of tested CLSM mixtures ranged from 3.6 to 9.0 MPa,over the upper excavatable limit of 2.1 MPa.The micro-structural analysis revealed that sewage sludge and bottom ash were crystallochemically incorporated within CLSM systems by forming the needle-like ettringite(C₃A·3CS·H₃₂) with exiguous tubers via the typical Pozzolanic Reaction,leading to a dense and low-porosity microstructure.Furthermore,the toxicity characteristic leaching procedure evidenced that the cumulative leachable metals in the leachate were much below the regulatory thresholds.The potential for using sewage sludge and bottom ash in CLSM making was thus confirmed.

One-dimensional strontium hydroxyapatite(Sr-HAp) nanorods were successfully synthesized by a simple solvothermal method.The products were characterized via X-ray diffraction(XRD),Fourier transform infrared(FT-IR),cold field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),photoluminescence(PL) excitation and emission spectra.The experimental results indicated that oleic acid as a surfactant played a key role in confining the growth of the Sr-HAp powders.A possible formation mechanism of the one-dimensional nanorod was proposed and elaborated.Moreover,the as-obtained Sr-HAp samples showed an intense and bright emission band centered at 460 nm under long-wavelength UV light excitation and the contents of NaOH used in the synthetic process had an obvious impact on the optical performance of Sr-HAp powders.The possible luminescent mechanism of the Sr-HAp samples was discussed.

A novel polyglycidylmethacrylate(PGMA) microspheres with high adsorption capacity of Cr(VI) was prepared by cerium(IV) initiated graft polymerization of tentacle-type polymer chains with amino group on polymer microspheres with hydroxyl groups.The micron-sized PGMA microspheres were prepared by a dispersion polym-erization method and subsequently modified by ring-opening reaction to introduce functional hydroxyl groups.The polymer microspheres were characterized by scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FTIR).The results indicated that the polymer microspheres had an average diameter of 5 μm with uniform size distribution.The free amino group content was determined to be 5.13 mmol·g^-1 for g-PGMA-NH₂ mi-crospheres by potentiometric and conductometric titration methods.The Cr(VI) adsorption results indicated that the graft polymerization of tentacle-type polymer chains on the polymer microspheres could produce adsorbents with high adsorption capacity(500 mg·g^-1).The polymer microspheres with grafted tentacle polymer chains have potential application in large-scale removal of Cr(VI) in aqueous solution.

The magnetic poly-(methacrylate-divinyl benzene) microspheres with micron size were synthesized by modified suspension polymerization method.Adsorption of Cr(VI) from aqueous solution by magnetic poly-(MA-DVB) microspheres with surface amination was investigated.The adsorption processes were carried out under diversified conditions of pH value,adsorption time and temperature to evaluate the performance of the magetic microspheres.The optimum pH value for Cr(VI) adsorption was found as 3.The adsorption capacity increased with adsorption time and attained an optimum at 60 min.The adsorption processes for magnetic microspheres was endothermic reaction,and the adsorption capacity increased with increasing temperature.

Process characteristics of CO₂ absorption using aqueous monoethanolamine(MEA) in a microchannel reactor were investigated experimentally in this work.A T-type rectangular microchannel with a hydraulic diameter of 408 μm was used.Operating parameters,i.e.temperature,pressure and molar ratio of MEA to CO₂ were studied.Under 3 MPa pressure,the mole fraction of CO₂ in gas phase could decrease from 32.3% to 300×10^-6 at least when gas hourly space velocity ranged from 14400 to 68600 h^-1 and molar ratio of MEA to CO₂ was kept at 2.2.In particular,the effects of temperature on CO₂ absorption flux,mass transfer driving force,gas-liquid contact time and enhancement factor were analyzed in detail and found that mass transfer enhancement by chemical reaction was a crucial factor for the process of CO₂ absorption.

Due to their negligible volatility,reasonable thermal stability,strong dissolubility,wide liquid range and tunability of structure and property,ionic liquids have been regarded as emerging candidate reagents for CO₂ capture from industries gases.In this review,the research progresses in CO₂ capture using conventional ionic liquids,functionalized ionic liquids,supported ionic-liquids membranes,polymerized ionic liquids and mixtures of ionic liquids with some molecular solvents were investigated and reviewed.Discussion of relevant research fields was presented and the future developments were suggested.

Lewis acidic 1-allyl-3-methylimidazolium chloroaluminate ionic liquids were used as promising electrolytes in the low-temperature electrodeposition of aluminium.Systematic studies on deposition process have been performed by cyclic voltammetry and chronoamperometry.The surface morphology and X-ray diffraction(XRD) patterns of deposits prepared at different experimental conditions were also investigated.It was shown that the nu-cleation density and growth rate of crystallites had a great effect on the structure of aluminium deposited.The crys-tallographic orientation of deposits was mainly influenced by temperature and current density.Smooth,dense and well adherent aluminium coatings were obtained on copper substrates at 10-25 mA·cm^-2 and 313.2-353.2 K.More-over,the current efficiency of deposition and purity of aluminium have been significantly improved,demonstrating that the ionic liquids tested have a prospectful potential in electroplating and electrorefining of aluminium.

Fe-based ionic liquid(Fe-IL) was synthesized by mixing FeCl₃·6H₂O and 1-butyl-3-methylimidazolium chloride [Bmim]Cl in this paper.The phase diagram of a ternary Fe-IL,ethanol and water system was investigated to construct a ternary desulfurization solution for wet flue gas desulfurization.The effects of flow rate and concentration of SO₂,reaction temperature,pH and Fe-IL fraction in aqueous desulfurization solution on the desulfurization efficiency were investigated.The results shows that the best composition of ternary desulfurization solution of Fe-IL,ethanol and water is 1:1.5:3 by volume ratio,and pH should be controlled at 2.0.Under such conditions,a desulfurization rate greater than 90% could be obtained.The product of sulfuric acid had inhibition effect on the wet desulfurization process.With applying this new ternary desulfurization solution,not only the catalyst Fe-IL can be recycled and reused,but also the product sulfuric acid can be separated directly from the ternary desulfurization system.

Functionalized ionic liquids containing ethyoxyl groups were synthesized and immobilized on magnetic silica nanoparticles(MSNP) prepared by two steps,i.e.,Fe₃O₄ synthesis and silica shell growth on the surface.This magnetic nanoparticle supported ionic liquid(MNP-IL) were applied in the immobilization of penicillin G acylase(PGA).The MSNPs and MNP-ILs were characterized by the means of Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and vibrating sample magnetometer(VSM).The results showed that the average size of magnetic Fe₃O₄ nanoparticles and MSNPs were ~10 and ~90 nm,respectively.The saturation magnetizations of magnetic Fe₃O₄ nanoparticles and MNP-ILs were 63.7 and 26.9 A·m²·kg^-1,respectively.The MNP-IL was successfully applied in the immobilization of PGA.The maximum amount of loaded enzyme was about 209 mg·g^-1(based on carrier),and the highest enzyme activity of immobilized PGA(based on ImPGA) was 261 U·g^-1.Both the amount of loaded enzyme and the activity of ImPGA are at the same level of or higher than that in previous reports.After 10 consecutive operations,ImPGA still maintained 62% of its initial activity,indicating the good recovery property of ImPGA activity.The ionic liquid modified magnetic particles integrate the magnetic properties of Fe₃O₄ and the structure-tunable properties of ionic liquids,and have extensive potential uses in protein immobilization and magnetic bioseparation.This work may open up a novel strategy to immobilize proteins by ionic liquids.

A pressured microwave-assisted hydrolysis(PMAH) technique has been developed for hydrolyzing the crude glycyrrhizic acid(GA) extracted from licorice root to prepare glycyrrhetinic acid(GRA).In order to optimize the efficiency of PMAH,several experimental parameters were investigated,including liquid-solid ratio,hydrolysis time,sulfuric acid concentration and hydrolysis temperature.The optimized hydrolysis conditions were as follows:pressured microwave-assisted hydrolysis of crude GA for 21 min(taking 15 min to reach 150℃,and holding it for 6 min) at 150℃(at a radiation power of 450 W) in 3%-5% sulfuric acid solution with the liquid-solid(ml·g^-1 crude GA) ratio of 25:1.As a result of the considerable saving in time and higher product yields(up to 90%),PMAH was proved more effective than conventional methods.

Using rectorite extrudates from calcined rectorite powder as the starting material,a series of ZSM-5/rectorite composites were prepared via the in-situ crystallization method.The physicochemical properties and propylene boosting performance of the resulting samples were characterized by using X-ray diffraction,scan-ning electronic microscopy/energy dispersive spectrometer,N₂ adsorption-desorption,and Fourier transformed in-frared spectroscopy of pyridine adsorption,respectively,and assessed by using Daqing atmospheric residue as feed-stock.The results showed that the ZSM-5/rectorite composites in which the ZSM-5 phase grows in-situ as a 2-3 μm thick layer on rectorite particles have a trimodal microporous-mesoporous-macroporous structure and thus exhibit outstanding propylene boosting performance.Compared with a commercial ZSM-5 incorporated fluid catalytic cracking catalyst,the ZSM-5/rectorite composite incorporated catalyst increased the yield and selectivity of pro-pylene by 2.44% and 5.35%,respectively.

As the core of the Energy-Minimization Multi-Scale(EMMS) approach,the so-called stability condition has been proposed to reflect the compromise between different dominant mechanisms and believed to be indispensable for understanding the complex nature of gas-solid fluidization systems.This approach was recently extended to the study of gas-liquid bubble columns.In this article,we try to analyze the intrinsic similarity between gas-solid and gas-liquid systems by using the EMMS approach.First,the model solution spaces for the two systems are depicted through a unified numerical solution strategy,so that we are able to find three structural hierarchies in the EMMS model for gas-solid systems.This may help to understand the roles of cluster diameter correlation and stability condition.Second,a common characteristic of gas-solid and gas-liquid systems can be found by comparing the model solutions for the two systems,albeit structural parameters and stability criteria are specific in each system:two local minima of the micro-scale energy dissipation emerges simultaneously in the solution space of structure parameters,reflecting the compromise of two different dominant mechanisms.They may share an equal value at a critical condition of operating conditions,and the global minimum may shift from one to the other when the operating condition changes.As a result,structure parameters such as voidage or gas hold-up exhibit a jump change due to this shift,leading to dramatic structure variation and hence regime transition of these systems.This demonstrates that it is the stability condition that drives the structure variation and system evolution,which may be the intrinsic similarity of gas-solid and gas-liquid systems.

Mixing problems are most likely encountered and sometimes can be severe in scaling-up projects.Micro-mixing is an important aspect for fast or quasi-instantaneous reactions.Poor micro-mixing might produce more undesired by-products,leading to higher purification costs.This paper gives an extensive review and analysis of micro-mixing studies in single-and multiphase stirred tanks.The relevant experiment techniques,micro-mixing models and numerical approaches are critically reviewed and analyzed with remarks and perspectives.The reported studies on two-phase micro-mixing experiments and on the impact of the presence of the dispersed phases on turbu-lence have been limited to a narrow range of conditions.More importantly,disparities widely exist among different reports.Both Lagrangian and Eulerian models are based on oversimplified assumptions,which may lead to uncertainties or even unrealistic results.A heuristic model,which is from the perspective of CFD(computational fluid dynamics) and can cover the whole spectrum of scales and also focus on every sub-process,is desired in the future.

Numerical solution of yield viscoplastic fluid flow is hindered by the singularity inherent to the Herschel-Bulkley model.A finite difference method over the boundary-fitted orthogonal coordinate system is utilized to investigate numerically the fully developed steady flow of non-Newtonian yield viscoplastic fluid through concentric and eccentric annuli.The fluid rheology is described with the Herschel-Bulkley model.The numerical simulation based on a continuous viscoplastic approach to the Herschel-Bulkley model is found in poor accordance with the experimental data on volumetric flow rate of a bentonite suspension.A strict mathematical model for Herschel-Bulkley fluid flow is established and the corresponding numerical procedures are proposed.However,only the case of flow of a Herschel-Bulkley fluid in a concentric annulus is resolved based on the presumed flow structure by using the common optimization technique.Possible flow structures in an eccentric annulus are presumed,and further challenges in numerical simulation of the Herschel-Bulkley fluid flow are suggested.