The widely utilized high efficient particulate air filters(HEPA)and electrostatic precipitator(ESP)respectively has the shortcomings of relatively high energy consumption and low filtration efficiency.In order to over...The widely utilized high efficient particulate air filters(HEPA)and electrostatic precipitator(ESP)respectively has the shortcomings of relatively high energy consumption and low filtration efficiency.In order to overcome the disadvantages of two traditional air filtration system,electrostatic assisted air filtration system(combining HEPA and ESP)has been proven to achieve high filtration efficiency and low energy consumption simultaneously.Predicting of V-I characteristics of electrostatic filtration system with configuration of“pin to filter medium to grounded device”is very essential and challenging due to the back corona phenomenon.This study utilized the back-corona based current model to predict the V-I characteristics of electrostatic system with different filter medium types and“pin-to-filter”distances.Experiments are conducted to provide data for model validation by changing filter types and locations of discharge pin.The results indicated that both of the predicted values of total discharge current and back-corona induced current agreed well with the experimentally measured data.This validated mathematical model could be used for preliminary design of electrostatic assisted filtration system with configuration of“pin to filter to grounded device”.Based on the V-I characteristics predicted by the semi-empirical model,the electrostatic filtration efficiency could be estimated.展开更多
The increasing severity of air pollution necessitates more effective and sustained air filtration technology.Concurrently,the desire for more environmentally friendly,sustainable materials with better filtering perfor...The increasing severity of air pollution necessitates more effective and sustained air filtration technology.Concurrently,the desire for more environmentally friendly,sustainable materials with better filtering performance and less environmental impact drives the move away from conventional synthetic membranes.This review presents lignocellulosic biocomposite(LigBioComp)membranes as an alternative to traditional synthetic membranes.It focuses on their materials,fabrication,and functionalization techniques while exploring challenges and proposing methods for resourceful utilization.Renowned for their abundance and renewable nature,lignocellulosic materials consist of cellulose,hemicellulose,and lignin.Various applications can benefit from their antibacterial properties,large surface area,and remarkable mechanical strength.LigBioComp membranes are fabricated through casting,electrospinning,and freeze-drying,with advancements in fabrication techniques enhancing their performance and applicability.It is suggested to use solvent-free or low-solvent techniques such as Layer-by-Layer assembly to minimize environmental impact.Freeze-drying and electrospinning with green solvents can be used for achieving specific membrane properties,though energy consumption should be considered.Apply dry-wet spinning and solvent casting processes selectively.Functional groups,including carboxyl,hydroxyl,or amino groups,can significantly improve the membrane’s capacity to capture particulate matter.Chemical etching or the precise deposition of nanoparticles can further optimize pore size and distribution.The choice of chemicals and methods is critical in functionalization,with silane coupling agents,polyethyleneimine,and polydopamine.Future research should prioritize refining fabrication methods,advancing functionalization strategies,and conducting performance and recyclability assessments on hybrid and composite materials.This will enhance integrated systems and contribute to the development of smart filters.展开更多
A mass flow matching model(MFMM)was established for studying the stable status of solution electrospinning.The study of the solution droplet status at the needle tip focused on various combinations of applied voltages...A mass flow matching model(MFMM)was established for studying the stable status of solution electrospinning.The study of the solution droplet status at the needle tip focused on various combinations of applied voltages and injection rates to figure out their influence on steadily fabricating polyvinyl alcohol(PVA)nanofibers prepared from PVA spinning solutions with two different mass fractions(10%and 16%).The results revealed that during the stable electrospinning,the influence resulted from the change of the injection rate approximately canceled out the impact brought by adjusting the applied voltage,leading to almost the same morphology as that of the PVA nanofibers.And the mass fraction of PVA in the spinning solution dominated the structure and the diameter distribution of the electrospun nanofibers.Under stable electrospinning conditions,the composite membrane was produced by depositing PVA nanofibers on the polyethylene terephthalate(PET)nonwoven substrate for an air filtration test.Furthermore,the prepared composite membrane exhibited a high air filtration efficiency(99.97%)and a low pressure drop(120 Pa)for 300-500 nm neutralized polystyrene latex(PSL)aerosol particles,demonstrating its potential as an alternative for a variety of commercial applications in air filtration.展开更多
Objective Evidence on potential cardiovascular benefits of personal-level intervention among the elderly exposed to high levels of particulate matter(PM)remains limited.We aimed to assess improvements in surrogate mar...Objective Evidence on potential cardiovascular benefits of personal-level intervention among the elderly exposed to high levels of particulate matter(PM)remains limited.We aimed to assess improvements in surrogate markers of cardiovascular injury in vulnerable populations at risks by using indoor air filtration units.Methods We conducted a randomized crossover trial for 2 separate 2-week air filtration interventions in 20 households of patients with stable chronic obstructive pulmonary disease and their partners in the winter of 2013,with concurrent measurements of indoor PM.The changes in biomarkers indicative of cardiac injury,atherosclerosis progression and systemic inflammation following intervention were evaluated using linear mixed-effect models.Results In the analysis,average levels of indoor PM with aerodynamic diameters<2.5µm(PM2.5)decreased significantly by 59.2%(from 59.6 to 24.3µg/m3,P<0.001)during the active air filtration.The reduction was accompanied by improvements in levels of high-sensitivity cardiac troponin I by−84.6%(95%confidence interval[CI]:−90.7 to−78.6),growth differentiation factor-15 by−48.1%(95%CI:−31.2 to−25.6),osteoprotegerin by−65.4%(95%CI:−56.5 to−18.7),interleukin-4 by−46.6%(95%CI:−62.3 to−31.0)and myeloperoxidase by−60.3%(95%CI:−83.7 to−3.0),respectively.Conclusion Indoor air filtration intervention may provide potential cardiovascular benefits in vulnerable populations at risks.展开更多
Nanoparticles in air are of particular concern for public health and employee exposure in work-places. Therefore, it is very important to prepare effective filters for their removal. In this work filters were prepared...Nanoparticles in air are of particular concern for public health and employee exposure in work-places. Therefore, it is very important to prepare effective filters for their removal. In this work filters were prepared from nanocellulose, i.e. cellulose nanofibrils (CNF). CNF was produced using two methods giving two different qualities of CNF. One quality had negative charges on the fibril surfaces while the other was neutral, and had in addition thinner fibrils compared to the other qualities. Filter samples were produced from water dispersions of CNF, by removal of the water by freeze drying. The performance of the CNF based filters was assessed and compared with filters based on synthetic polymer fibres. The ability to collect NaCl particles with a broad size distribution, ranging from nanometer to micrometer scale, was determined. CNF filters showed quality values comparable with the synthetic polymer based filters. Filters based on both the two CNF qualities had very good filtration efficiency for a given pressure drop across the filter.展开更多
Air-borne pollutants in particulate matter(PM)form,produced either physically during industrial processes or certain biological routes,have posed a great threat to human health.Particularly during the current COVID-19...Air-borne pollutants in particulate matter(PM)form,produced either physically during industrial processes or certain biological routes,have posed a great threat to human health.Particularly during the current COVID-19 pandemic,effective filtration of the virus is an urgent matter worldwide.In this review,we first introduce some fundamentals about PM,including its source and classification,filtration mechanisms,and evaluation parameters.Advanced filtration materials and their functions are then summarized,among which polymers and MOFs are discussed in detail together with their antibacterial performance.The discussion on the application is divided into end-of-pipe treatment and source control.Finally,we conclude this review with our prospective view on future research in this area.展开更多
Functionalization of polymer foams by surface coating is of great interest for advanced flow-interactive materials working with well-controlled 3D open channels.However,realizing heavy functional coating via a fast an...Functionalization of polymer foams by surface coating is of great interest for advanced flow-interactive materials working with well-controlled 3D open channels.However,realizing heavy functional coating via a fast and recyclable way remains a big challenge.Here,inspired by the battery electrodes,we propose a scalable mechanic-assisted heavy coating strategy based on the design of sticky jammed fluid(SJF)to conquer the above challenge.Similar to the electrode slurry,the SJF is dominated by a high concentration of active material(≥20 wt%of active carbon,for instance)uniformly dispersed in a protein binder solution.Due to the sticky and solidrich nature of the SJF,one can realize a high coating efficiency of 60 wt%gain per coating.The critical factors controlling the coating processing and quality are further identified and discussed.Furthermore,the functionalized foam is demonstrated as a high-performance shape-customizable toxic gas remover,which can absorb formaldehyde very efficiently at different circumstances,including static adsorption,flow-based filtration,and source interception.Finally,the foam skeleton and the active materials are easily recycled by a facile solvent treatment.This study may inspire new scalable way for fast,heavy,and customizable functionalization of polymeric foams.展开更多
Publisher Correction:Advanced Fiber Materials(2025)7:620-632.https://doi.org/10.1007/s42765-025-00511-2.In this article Xin Ning should have been denoted as a corresponding author alongside Xuefang Wang.The original a...Publisher Correction:Advanced Fiber Materials(2025)7:620-632.https://doi.org/10.1007/s42765-025-00511-2.In this article Xin Ning should have been denoted as a corresponding author alongside Xuefang Wang.The original article has been corrected.展开更多
Biodegradable polylactic acid(PLA)melt-blown nonwovens(MN)are regarded as the promising alternatives for petroleumbased air filtration mediums.However,the filtration performances of most PLA MN were greatly relied on ...Biodegradable polylactic acid(PLA)melt-blown nonwovens(MN)are regarded as the promising alternatives for petroleumbased air filtration mediums.However,the filtration performances of most PLA MN were greatly relied on their electrostatic effects which would suffer from inevitable attenuation caused by environment conditions during long-term storage.Herein,the innovative combination of breath-figure(BF)and melt-blowing technologies was proposed to prepare the hierarchically structured PLA MN-bearing BF net pattern(PMBP)for enhanced air filtration.Initially,melt-blowing technology was employed to conduct large-scale preparation of PLA MN with a low-pressure drop of 25.7 Pa but an unsatisfactory PM_(2.5)(aerodynamic diameter below 2.5μm)filtration efficiency of 59.5%.At the optimized BF processing conditions involving polymer concentration of 0.5 wt%in hexafluoroisopropanol and relative humidity of 50%,the resultant BF net pattern exhibited uniformly microporous structure with the average pore size low to 1.02μm.The integration of large-pore PLA MN and small-pore net pattern endowed PMBP with hierarchical structures,which induced PMBP displaying excellent filtration performances(filtration efficiency of 95.8%and pressure drop of 39.3 Pa),and eliminating over 99% of PM_(2.5)particles within 3 min in the actual smoke test,even without the benefit of static charges.The filtration performances of the PMBP remained stable in high-humidity environments and during long-term storage.Furthermore,the PMBP also exhibited exceptional self-cleaning properties.Overall,this work opens up a promising approach to develop fully bio-based and high-performance filtration materials with hierarchical structures.展开更多
Air pollution caused by the rapid development of industry has always been a great issue to the environment and human being’s health.However,the efficient and persistent filtration to PM_(0.3) remains a great challeng...Air pollution caused by the rapid development of industry has always been a great issue to the environment and human being’s health.However,the efficient and persistent filtration to PM_(0.3) remains a great challenge.Herein,a self-powered filter with micro-nano composite structure composed of polybutanediol succinate(PBS)nanofiber membrane and polyacrylonitrile(PAN)nanofiber/polystyrene(PS)microfiber hybrid mats was prepared by electrospinning.The balance between pressure drop and filtration efficiency was achieved through the combination of PAN and PS.In addition,an arched TENG structure was created using the PAN nanofiber/PS microfiber composite mat and PBS fiber membrane.Driven by respiration,the two fiber membranes with large difference in electronegativity achieved contact friction charging cycles.The open-circuit voltage of the triboelectric nanogenerator(TENG)can reach to about 8 V,and thus the high filtration efficiency for particles was achieved by the electrostatic capturing.After contact charging,the filtration efficiency of the fiber membrane for PM_(0.3) can reach more than 98%in harsh environments with a PM_(2.5) mass concentration of 23,000µg/m^(3),and the pressure drop is about 50 Pa,which doesn’t affect people’s normal breathing.Meanwhile,the TENG can realize self-powered supply by continuously contacting and separating the fiber membrane driven by respiration,which can ensure the long-term stability of filtration efficiency.The filter mask can maintain a high filtration efficiency(99.4%)of PM_(0.3) for 48 consecutive hours in daily environments.展开更多
Fiber morphology with off-standing branches,as found in nature,e.g.,in goose downy feather,provides exquisite functions that can be barely achieved by man-made fiber systems.In this work,we develop a simple and scalab...Fiber morphology with off-standing branches,as found in nature,e.g.,in goose downy feather,provides exquisite functions that can be barely achieved by man-made fiber systems.In this work,we develop a simple and scalable method for generating downy feather-like para-aramid fibers and assemblies.Through treating commercial para-aramid microfibers with mild alkaline solution(low concentration of NaOH),a synergistic effect of chemical hydrolysis and physical shearing is successfully triggered to generate abundant nanofiber branches on the surface of para-aramid fibers.When compared with conventional monotonous structures,nonwovens composed of downy feather-like fibers exhibit a typical multiscale fiber morphology,larger specific surface area and smaller pore size,thus showing enhanced particles adsorption capacity(over twice of the pristine nonwoven),excellent oil absorption capacity(increased by~50%),improved air filtration performances(doubled the filtration efficiency)and effective thermal insulation(thermal conductivity=26.1 mW·m^(−1)·K^(−1)).More attractively,the intrinsic flame-retardant nature of para-aramid is well inherited by the downy feather-like fibers,and the fabrication process requires neither sophisticated equipment,nor tedious procedures,making us believe the strong competitiveness of these fibers and assemblies.展开更多
This work proposes a vibrating mesh screen as an alternative to the static mesh screen currently used in conventional flooded-bed dust scrubbers for removing airborne coal mine dust in the continuous mining environmen...This work proposes a vibrating mesh screen as an alternative to the static mesh screen currently used in conventional flooded-bed dust scrubbers for removing airborne coal mine dust in the continuous mining environment.Fundamental assessments suggest that a vibrating screen may improve the dust collection efficiency of scrubber systems and mitigate the clogging issues associated with the conventional design.To evaluate this hypothesis,computational fluid dynamics(CFD)simulations were carried out to assess the effects of vibration conditions(i.e.,frequency and amplitude)on the dust particle-mesh interaction and mesh wetting conditions,which are the two decisive factors in determining the dust collection efficiency.The results suggest that the vibrating mesh screen can enhance dust particle collision opportunities on the mesh and increase mesh wetted area as compared to the static mesh screen.The effects of mesh screen aperture,coal dust concentration,and spray nozzle flow rate on the performance of the vibrating mesh are also evaluated.Finally,a simplified three-phase flow simulation including airflow,dust particles,and water droplet spray is performed,and the results reflect a significant improvement of dust collection efficiency in the liquid-coated vibrating mesh screen.展开更多
With the accelerated development of global industrialization,environmental issues,such as airborne and water pollution caused by suspended solid particulate matter(PM)seriously endanger ecosystems and human health.Fib...With the accelerated development of global industrialization,environmental issues,such as airborne and water pollution caused by suspended solid particulate matter(PM)seriously endanger ecosystems and human health.Fibrous filtration and separation membranes provide an effective approach to pollution treatment,yet they still face challenges in efficient and high-flux purification of highly permeable ultrafine particles.Herein,an ultrafine nanofiber-based membrane with rational hierarchical networks is designed for both air and water filtration.Through the proposed jet branching electrospinning strategy,a multiscale fiber membrane consisting of ultrafine nanofibers,medium fibers,and coarse submicron fibers is prepared.It possesses the merits of ultrafine fiber diameter,ultralow pore size,high specific surface area,and unique hybrid structure.Benefiting from these features,the obtained multiscale fibrous filter shows superior PM0.3 air filtration performance(99.96%PM0.3 removal,low pressure drop of 89 Pa)and water filtration capacity(ultrafine particle rejection efficiency of 99.50%,water flux of 9028.84 L m^(-2) h^(-1)).Moreover,the controllable structure of a multiscale fiber filter also endows itself with stable and durable filtration capacity.This work may provide meaningful references for the development of high-performance filtration and separation materials.展开更多
Polymer fiber filters play a vital role in removing particulate matter(PM),reducing environmental risk factors and cardiovascular diseases.However,the contradiction between high filtration efficiency and low airflow r...Polymer fiber filters play a vital role in removing particulate matter(PM),reducing environmental risk factors and cardiovascular diseases.However,the contradiction between high filtration efficiency and low airflow resistance limits the filtration performance of polymer filters,while exacerbating the microplastic contamination.Herein,we proposed an interface polarization strategy to fabricate a biodegradable fiber membrane with a high relative dielectric constant to filter the PM in a high-efficiency and low-resistance way.The membrane was constructed by silk fibroin(SF)and wool fiber membrane(Wool),where the SF bonded on the wool surface to form a crosslinked network.Specifically,polar groups(-NH_(2)/-OH)on SF form a dynamic hydrogen-bonding network with airborne water molecules,enhancing the interface polarization and elevating the relative dielectric constant to 8.4.Based on this high dielectric constant,Wool loaded with 20 mg of SF(SF@Wool)reaches PM_(0.3)filtration efficiency of 99.69%,with air resistance of 8 Pa.Meanwhile,SF@Wool exhibits filtration efficiency decay of less than 0.5%over 30 d,demonstrating excellent long-term stability.Furthermore,the biodegradable properties of SF@Wool effectively prevent microplastic pollution(it can be completely degraded in soil within 14 d after treatment with alkaline solution).展开更多
PM2.5 can easily penetrate indoor spaces through natural or mechanical ventilation systems,posing a serious threat to human health.Fiber filtration is the predominant technique for indoor particulate matter purificati...PM2.5 can easily penetrate indoor spaces through natural or mechanical ventilation systems,posing a serious threat to human health.Fiber filtration is the predominant technique for indoor particulate matter purification.However,there is an inherent trade-off between achieving high filtration efficiency and maintaining low resistance.Therefore,this study employs a simple and fast adhesive method to fabricate a composite material composed of micro-biochar(BC)and polyurethane(PU)coarse fibers(BC@PU).We developed an electrostatic-assisted air filtration device system that leverages the electrostatic interaction between charged particles and polarized fibers to achieve high-efficiency,low-resistance air filtration.At a face air velocity of 0.4 m/s,the BC-1.5@PU material achieves a remarkable 98.83%removal efficiency for particles in the 0.3-0.5µm size range,while maintaining a minimal pressure drop of approximately 7 Pa,with the best CQF(comprehensive quality factor)value of 0.408 Pa^(-1),which was a remarkable 94.06%improvement over the bare PU material.In addition,the simulation results indicate that the micro-biochar significantly enhances the effective electric field range within the composite fibers.It indicates that this composite fiber holds great potential for air purification in ventilation systems.展开更多
The contribution of leakage in a baghouse filter （defined as a short circuit between the upstream and downstream sides of the filter） to the emission of fine particles is quantified in comparison to other dust emiss...The contribution of leakage in a baghouse filter （defined as a short circuit between the upstream and downstream sides of the filter） to the emission of fine particles is quantified in comparison to other dust emission sources, and the influence of key operating variables on overall system response is analyzed. The study was conducted on a well-maintained pilot-scale filter unit （9 bags of 500 g/m^2 calendered polyester needle felt; total surface area 4.2 m^2） operated in Ap-controlled mode over a range of pulsing intensities, with two types of test dust （one free-flowing and the other cohesive） at inlet concentrations of 10 and 30 g/m^3. Leaks included single holes between 0.5 and 4 mm diameter, intentionally placed in either the plenum plate or one of the filter bags, as well as seamlines from bag confectioning. Emissions were sep- arated by source into a transient contribution due to dust penetration through the filter bags after each cleaning pulse, and a continuous contribution from leaks. This separation was based on a novel method of data processing that relies on time-resolved concentration measurements with a specially calibrated optical particle counter. Tiny leaks on the order of 1 mm generated the same emission level as all the bags combined, and dominated continuous emissions. The equivalent leak cross section （leakage = media emission） was about 1 ppm of the total installed filter surface, independent of upstream dust concentra- tion. Leakage through open seamlines amounted to 75% of media emissions in case of free-flowing test dust. Leakage was restricted to aerodynamic diameters less than ~5 μm （roughly the PM2.s mass frac- tion）. For comparison, time-averaged mass penetration through conventional needle-felt media ranged from about 10^-5 to 10^-6, depending on cohesiveness of the particle material and pulse cleaning intensity, giving emission levels between about 0.02 and 0.2 mg/m^3 at the reference concentration of 10 R/m^2.展开更多
Filtration materials are designed with nanofibrous structures to address the trade-off effect between filtration efficiency and resistance.However,achieving a breakthrough in these performance metrics remains challeng...Filtration materials are designed with nanofibrous structures to address the trade-off effect between filtration efficiency and resistance.However,achieving a breakthrough in these performance metrics remains challenging.Inspired by the white stork wing,we present a novel rod‒ribbon interwoven nanofiber membrane with ultraefficient filtration efficiency for PM.The silica(SiO_(2))/tin dioxide(SnO_(2))hybrid membrane was fabricated using a one-step electrospinning approach,where its unique structure was formed under the influence of solvent nonequilibrium evaporation during the electrospinning process.The optimized interwoven structure enables the membranes to achieve an outstanding filtration efficiency of 99.96%for PM0.3 at an airflow velocity of 5.33 cm/s while maintaining a minimal pressure drop of 62 Pa(Qf=0.12 Pa^(−1)).The mechanisms underlying the material's formation and the enhancement of its filtration performance were systematically analyzed.Consequently,this study provides novel insights and methodologies for developing high-performance air filtration materials,thereby supporting the strategic objectives of low-carbon development.展开更多
The worldwide COVID-19 pandemic has led to an attention on the usage of personal protective face masks.However,the longevity and safety of the commercial face masks are limited due to the charge dissipation of the ele...The worldwide COVID-19 pandemic has led to an attention on the usage of personal protective face masks.However,the longevity and safety of the commercial face masks are limited due to the charge dissipation of the electret meltblown nonwovens,which are dominate in the face mask filters.Herein,we design a type of multi-layer structured nonwovens using meltblowing and electrospinning technologies.The complex nonwovens involving meltblown and electrospun fibers are designed to possess multilevel fiber diameters and pore sizes.The micro/nanofibers with porous and wrinkled surface morphologies can well capture particulate matters(PMs),and the multilevel pore sizes contribute to low air resistance under high filtration efficiency.Airflow field simulation was carried out to understand the pressure distribution within the nonwovens in the filtration process.Meanwhile,by adding Ag nanoparticles(AgNPs)as additives,the nonwovens exhibit excellent antibacterial performance.The resultant nonwovens exhibit filtration efficiency of 99.1%for PM0.3 and low pressure drop of 105 Pa under the 10.67 cm/s inlet air velocity,and antibacterial rate of>99.99%for Escherichia coli.These performances and functions make the designed complex nonwovens a promising filter core for face masks.展开更多
基金The authors would like to acknowledge the coordinated support from Natural Science Foundation of China(Grant No.51808138,51778385,51878442).
文摘The widely utilized high efficient particulate air filters(HEPA)and electrostatic precipitator(ESP)respectively has the shortcomings of relatively high energy consumption and low filtration efficiency.In order to overcome the disadvantages of two traditional air filtration system,electrostatic assisted air filtration system(combining HEPA and ESP)has been proven to achieve high filtration efficiency and low energy consumption simultaneously.Predicting of V-I characteristics of electrostatic filtration system with configuration of“pin to filter medium to grounded device”is very essential and challenging due to the back corona phenomenon.This study utilized the back-corona based current model to predict the V-I characteristics of electrostatic system with different filter medium types and“pin-to-filter”distances.Experiments are conducted to provide data for model validation by changing filter types and locations of discharge pin.The results indicated that both of the predicted values of total discharge current and back-corona induced current agreed well with the experimentally measured data.This validated mathematical model could be used for preliminary design of electrostatic assisted filtration system with configuration of“pin to filter to grounded device”.Based on the V-I characteristics predicted by the semi-empirical model,the electrostatic filtration efficiency could be estimated.
基金funded by the Universiti Teknologi Malaysia(UTM)through research Grant Number:06E05.
文摘The increasing severity of air pollution necessitates more effective and sustained air filtration technology.Concurrently,the desire for more environmentally friendly,sustainable materials with better filtering performance and less environmental impact drives the move away from conventional synthetic membranes.This review presents lignocellulosic biocomposite(LigBioComp)membranes as an alternative to traditional synthetic membranes.It focuses on their materials,fabrication,and functionalization techniques while exploring challenges and proposing methods for resourceful utilization.Renowned for their abundance and renewable nature,lignocellulosic materials consist of cellulose,hemicellulose,and lignin.Various applications can benefit from their antibacterial properties,large surface area,and remarkable mechanical strength.LigBioComp membranes are fabricated through casting,electrospinning,and freeze-drying,with advancements in fabrication techniques enhancing their performance and applicability.It is suggested to use solvent-free or low-solvent techniques such as Layer-by-Layer assembly to minimize environmental impact.Freeze-drying and electrospinning with green solvents can be used for achieving specific membrane properties,though energy consumption should be considered.Apply dry-wet spinning and solvent casting processes selectively.Functional groups,including carboxyl,hydroxyl,or amino groups,can significantly improve the membrane’s capacity to capture particulate matter.Chemical etching or the precise deposition of nanoparticles can further optimize pore size and distribution.The choice of chemicals and methods is critical in functionalization,with silane coupling agents,polyethyleneimine,and polydopamine.Future research should prioritize refining fabrication methods,advancing functionalization strategies,and conducting performance and recyclability assessments on hybrid and composite materials.This will enhance integrated systems and contribute to the development of smart filters.
文摘A mass flow matching model(MFMM)was established for studying the stable status of solution electrospinning.The study of the solution droplet status at the needle tip focused on various combinations of applied voltages and injection rates to figure out their influence on steadily fabricating polyvinyl alcohol(PVA)nanofibers prepared from PVA spinning solutions with two different mass fractions(10%and 16%).The results revealed that during the stable electrospinning,the influence resulted from the change of the injection rate approximately canceled out the impact brought by adjusting the applied voltage,leading to almost the same morphology as that of the PVA nanofibers.And the mass fraction of PVA in the spinning solution dominated the structure and the diameter distribution of the electrospun nanofibers.Under stable electrospinning conditions,the composite membrane was produced by depositing PVA nanofibers on the polyethylene terephthalate(PET)nonwoven substrate for an air filtration test.Furthermore,the prepared composite membrane exhibited a high air filtration efficiency(99.97%)and a low pressure drop(120 Pa)for 300-500 nm neutralized polystyrene latex(PSL)aerosol particles,demonstrating its potential as an alternative for a variety of commercial applications in air filtration.
基金This work was supported by Beijing Natural Science Foundation(7222246)Royal Dutch Philips Electronics Ltd.(Grant NL18-2100478471).
文摘Objective Evidence on potential cardiovascular benefits of personal-level intervention among the elderly exposed to high levels of particulate matter(PM)remains limited.We aimed to assess improvements in surrogate markers of cardiovascular injury in vulnerable populations at risks by using indoor air filtration units.Methods We conducted a randomized crossover trial for 2 separate 2-week air filtration interventions in 20 households of patients with stable chronic obstructive pulmonary disease and their partners in the winter of 2013,with concurrent measurements of indoor PM.The changes in biomarkers indicative of cardiac injury,atherosclerosis progression and systemic inflammation following intervention were evaluated using linear mixed-effect models.Results In the analysis,average levels of indoor PM with aerodynamic diameters<2.5µm(PM2.5)decreased significantly by 59.2%(from 59.6 to 24.3µg/m3,P<0.001)during the active air filtration.The reduction was accompanied by improvements in levels of high-sensitivity cardiac troponin I by−84.6%(95%confidence interval[CI]:−90.7 to−78.6),growth differentiation factor-15 by−48.1%(95%CI:−31.2 to−25.6),osteoprotegerin by−65.4%(95%CI:−56.5 to−18.7),interleukin-4 by−46.6%(95%CI:−62.3 to−31.0)and myeloperoxidase by−60.3%(95%CI:−83.7 to−3.0),respectively.Conclusion Indoor air filtration intervention may provide potential cardiovascular benefits in vulnerable populations at risks.
文摘Nanoparticles in air are of particular concern for public health and employee exposure in work-places. Therefore, it is very important to prepare effective filters for their removal. In this work filters were prepared from nanocellulose, i.e. cellulose nanofibrils (CNF). CNF was produced using two methods giving two different qualities of CNF. One quality had negative charges on the fibril surfaces while the other was neutral, and had in addition thinner fibrils compared to the other qualities. Filter samples were produced from water dispersions of CNF, by removal of the water by freeze drying. The performance of the CNF based filters was assessed and compared with filters based on synthetic polymer fibres. The ability to collect NaCl particles with a broad size distribution, ranging from nanometer to micrometer scale, was determined. CNF filters showed quality values comparable with the synthetic polymer based filters. Filters based on both the two CNF qualities had very good filtration efficiency for a given pressure drop across the filter.
基金National Natural Science Foundation of China (22075046,51972063)Natural Science Funds for Distinguished Young Scholar of Fujian Province (2020J06038)+2 种基金Natural Science Foundation of Fujian Province (2020J01514,2019J01652,2019J01256)China Postdoctoral Science Foundation (Pre-station) (Project No.2019TQ0061)111 Project (No.D17005).
文摘Air-borne pollutants in particulate matter(PM)form,produced either physically during industrial processes or certain biological routes,have posed a great threat to human health.Particularly during the current COVID-19 pandemic,effective filtration of the virus is an urgent matter worldwide.In this review,we first introduce some fundamentals about PM,including its source and classification,filtration mechanisms,and evaluation parameters.Advanced filtration materials and their functions are then summarized,among which polymers and MOFs are discussed in detail together with their antibacterial performance.The discussion on the application is divided into end-of-pipe treatment and source control.Finally,we conclude this review with our prospective view on future research in this area.
基金sponsored by the Double First-Class Construction Funds of Sichuan University and National Natural Science Foundation of China(NNSFC)financial support from the National Natural Science Foundation of China(NNSFC grants 51873126,51422305,and 51721091).
文摘Functionalization of polymer foams by surface coating is of great interest for advanced flow-interactive materials working with well-controlled 3D open channels.However,realizing heavy functional coating via a fast and recyclable way remains a big challenge.Here,inspired by the battery electrodes,we propose a scalable mechanic-assisted heavy coating strategy based on the design of sticky jammed fluid(SJF)to conquer the above challenge.Similar to the electrode slurry,the SJF is dominated by a high concentration of active material(≥20 wt%of active carbon,for instance)uniformly dispersed in a protein binder solution.Due to the sticky and solidrich nature of the SJF,one can realize a high coating efficiency of 60 wt%gain per coating.The critical factors controlling the coating processing and quality are further identified and discussed.Furthermore,the functionalized foam is demonstrated as a high-performance shape-customizable toxic gas remover,which can absorb formaldehyde very efficiently at different circumstances,including static adsorption,flow-based filtration,and source interception.Finally,the foam skeleton and the active materials are easily recycled by a facile solvent treatment.This study may inspire new scalable way for fast,heavy,and customizable functionalization of polymeric foams.
文摘Publisher Correction:Advanced Fiber Materials(2025)7:620-632.https://doi.org/10.1007/s42765-025-00511-2.In this article Xin Ning should have been denoted as a corresponding author alongside Xuefang Wang.The original article has been corrected.
基金support for this work was provided by a key project of State Key Laboratory of Bio-Fibers and Eco-Textiles of Qingdao University(RZ2000003348,ZDKT202109)major scientific and technological innovation projects of Shandong province(2019JZZY020220)+1 种基金in part by the Postdoctoral Innovation Project of Shandong Province(SDCX-ZG-202203011)the Qingdao Postdoctoral Applied Research Project,and the Ministry of Education's Industry University Research Collaborative Education Project(BINTECH-KJZX-20220831-17).
文摘Biodegradable polylactic acid(PLA)melt-blown nonwovens(MN)are regarded as the promising alternatives for petroleumbased air filtration mediums.However,the filtration performances of most PLA MN were greatly relied on their electrostatic effects which would suffer from inevitable attenuation caused by environment conditions during long-term storage.Herein,the innovative combination of breath-figure(BF)and melt-blowing technologies was proposed to prepare the hierarchically structured PLA MN-bearing BF net pattern(PMBP)for enhanced air filtration.Initially,melt-blowing technology was employed to conduct large-scale preparation of PLA MN with a low-pressure drop of 25.7 Pa but an unsatisfactory PM_(2.5)(aerodynamic diameter below 2.5μm)filtration efficiency of 59.5%.At the optimized BF processing conditions involving polymer concentration of 0.5 wt%in hexafluoroisopropanol and relative humidity of 50%,the resultant BF net pattern exhibited uniformly microporous structure with the average pore size low to 1.02μm.The integration of large-pore PLA MN and small-pore net pattern endowed PMBP with hierarchical structures,which induced PMBP displaying excellent filtration performances(filtration efficiency of 95.8%and pressure drop of 39.3 Pa),and eliminating over 99% of PM_(2.5)particles within 3 min in the actual smoke test,even without the benefit of static charges.The filtration performances of the PMBP remained stable in high-humidity environments and during long-term storage.Furthermore,the PMBP also exhibited exceptional self-cleaning properties.Overall,this work opens up a promising approach to develop fully bio-based and high-performance filtration materials with hierarchical structures.
基金National Key Research and Development Program of China(2022YFB3804905,2022YFB3804900,and 2019YFE0111200)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials(KF2320)+2 种基金National Natural Science Foundation of China(51972063,22075046)Natural Science Foundation of Fujian Province(2022J01568 and 2020J06038)State Key Laboratory of New Textile Materials and Advanced Processing Technologies(FZ2021012).
文摘Air pollution caused by the rapid development of industry has always been a great issue to the environment and human being’s health.However,the efficient and persistent filtration to PM_(0.3) remains a great challenge.Herein,a self-powered filter with micro-nano composite structure composed of polybutanediol succinate(PBS)nanofiber membrane and polyacrylonitrile(PAN)nanofiber/polystyrene(PS)microfiber hybrid mats was prepared by electrospinning.The balance between pressure drop and filtration efficiency was achieved through the combination of PAN and PS.In addition,an arched TENG structure was created using the PAN nanofiber/PS microfiber composite mat and PBS fiber membrane.Driven by respiration,the two fiber membranes with large difference in electronegativity achieved contact friction charging cycles.The open-circuit voltage of the triboelectric nanogenerator(TENG)can reach to about 8 V,and thus the high filtration efficiency for particles was achieved by the electrostatic capturing.After contact charging,the filtration efficiency of the fiber membrane for PM_(0.3) can reach more than 98%in harsh environments with a PM_(2.5) mass concentration of 23,000µg/m^(3),and the pressure drop is about 50 Pa,which doesn’t affect people’s normal breathing.Meanwhile,the TENG can realize self-powered supply by continuously contacting and separating the fiber membrane driven by respiration,which can ensure the long-term stability of filtration efficiency.The filter mask can maintain a high filtration efficiency(99.4%)of PM_(0.3) for 48 consecutive hours in daily environments.
基金supported by the Fundamental Research Funds for the Central Universities and Graduate Student Innovation Fund of Donghua University(No.CUSF-DH-D2020021).
文摘Fiber morphology with off-standing branches,as found in nature,e.g.,in goose downy feather,provides exquisite functions that can be barely achieved by man-made fiber systems.In this work,we develop a simple and scalable method for generating downy feather-like para-aramid fibers and assemblies.Through treating commercial para-aramid microfibers with mild alkaline solution(low concentration of NaOH),a synergistic effect of chemical hydrolysis and physical shearing is successfully triggered to generate abundant nanofiber branches on the surface of para-aramid fibers.When compared with conventional monotonous structures,nonwovens composed of downy feather-like fibers exhibit a typical multiscale fiber morphology,larger specific surface area and smaller pore size,thus showing enhanced particles adsorption capacity(over twice of the pristine nonwoven),excellent oil absorption capacity(increased by~50%),improved air filtration performances(doubled the filtration efficiency)and effective thermal insulation(thermal conductivity=26.1 mW·m^(−1)·K^(−1)).More attractively,the intrinsic flame-retardant nature of para-aramid is well inherited by the downy feather-like fibers,and the fabrication process requires neither sophisticated equipment,nor tedious procedures,making us believe the strong competitiveness of these fibers and assemblies.
基金sponsored by the Alpha Foundation for the Improvement of Mine Safety and Health, Inc. (Alpha Foundation)
文摘This work proposes a vibrating mesh screen as an alternative to the static mesh screen currently used in conventional flooded-bed dust scrubbers for removing airborne coal mine dust in the continuous mining environment.Fundamental assessments suggest that a vibrating screen may improve the dust collection efficiency of scrubber systems and mitigate the clogging issues associated with the conventional design.To evaluate this hypothesis,computational fluid dynamics(CFD)simulations were carried out to assess the effects of vibration conditions(i.e.,frequency and amplitude)on the dust particle-mesh interaction and mesh wetting conditions,which are the two decisive factors in determining the dust collection efficiency.The results suggest that the vibrating mesh screen can enhance dust particle collision opportunities on the mesh and increase mesh wetted area as compared to the static mesh screen.The effects of mesh screen aperture,coal dust concentration,and spray nozzle flow rate on the performance of the vibrating mesh are also evaluated.Finally,a simplified three-phase flow simulation including airflow,dust particles,and water droplet spray is performed,and the results reflect a significant improvement of dust collection efficiency in the liquid-coated vibrating mesh screen.
基金financial support from the National Key Research and Development Program of China(2022YFB3804905 and 2022YFB3804900)National Natural Science Foundation of China(22375047,22378068,and 22378071)+1 种基金Natural Science Foundation of Fujian Province(2022J01568,2024J08373)111 Project(No.D17005).
文摘With the accelerated development of global industrialization,environmental issues,such as airborne and water pollution caused by suspended solid particulate matter(PM)seriously endanger ecosystems and human health.Fibrous filtration and separation membranes provide an effective approach to pollution treatment,yet they still face challenges in efficient and high-flux purification of highly permeable ultrafine particles.Herein,an ultrafine nanofiber-based membrane with rational hierarchical networks is designed for both air and water filtration.Through the proposed jet branching electrospinning strategy,a multiscale fiber membrane consisting of ultrafine nanofibers,medium fibers,and coarse submicron fibers is prepared.It possesses the merits of ultrafine fiber diameter,ultralow pore size,high specific surface area,and unique hybrid structure.Benefiting from these features,the obtained multiscale fibrous filter shows superior PM0.3 air filtration performance(99.96%PM0.3 removal,low pressure drop of 89 Pa)and water filtration capacity(ultrafine particle rejection efficiency of 99.50%,water flux of 9028.84 L m^(-2) h^(-1)).Moreover,the controllable structure of a multiscale fiber filter also endows itself with stable and durable filtration capacity.This work may provide meaningful references for the development of high-performance filtration and separation materials.
基金Fundamental Research Funds for the Central Universities(2232025A-05)National Key Research and Development Program of China(2022YFB3803502)+2 种基金National Natural Science Foundation of China(42442040,52408122)International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality(24520713300)Interdisciplinary Frontier Innovation Team Development Special Fund of Donghua University,and Shanghai Rising-Star Program(24QA2700100).
文摘Polymer fiber filters play a vital role in removing particulate matter(PM),reducing environmental risk factors and cardiovascular diseases.However,the contradiction between high filtration efficiency and low airflow resistance limits the filtration performance of polymer filters,while exacerbating the microplastic contamination.Herein,we proposed an interface polarization strategy to fabricate a biodegradable fiber membrane with a high relative dielectric constant to filter the PM in a high-efficiency and low-resistance way.The membrane was constructed by silk fibroin(SF)and wool fiber membrane(Wool),where the SF bonded on the wool surface to form a crosslinked network.Specifically,polar groups(-NH_(2)/-OH)on SF form a dynamic hydrogen-bonding network with airborne water molecules,enhancing the interface polarization and elevating the relative dielectric constant to 8.4.Based on this high dielectric constant,Wool loaded with 20 mg of SF(SF@Wool)reaches PM_(0.3)filtration efficiency of 99.69%,with air resistance of 8 Pa.Meanwhile,SF@Wool exhibits filtration efficiency decay of less than 0.5%over 30 d,demonstrating excellent long-term stability.Furthermore,the biodegradable properties of SF@Wool effectively prevent microplastic pollution(it can be completely degraded in soil within 14 d after treatment with alkaline solution).
基金supported by the National Natural Science Foundation of China(grant No.52406121,No.52176095)Anhui Provincial Natural Science Foundation(grant No.2308085ME189)Anhui Provincial Scientific Research Projects of Universities(grant No.2024AH050142).
文摘PM2.5 can easily penetrate indoor spaces through natural or mechanical ventilation systems,posing a serious threat to human health.Fiber filtration is the predominant technique for indoor particulate matter purification.However,there is an inherent trade-off between achieving high filtration efficiency and maintaining low resistance.Therefore,this study employs a simple and fast adhesive method to fabricate a composite material composed of micro-biochar(BC)and polyurethane(PU)coarse fibers(BC@PU).We developed an electrostatic-assisted air filtration device system that leverages the electrostatic interaction between charged particles and polarized fibers to achieve high-efficiency,low-resistance air filtration.At a face air velocity of 0.4 m/s,the BC-1.5@PU material achieves a remarkable 98.83%removal efficiency for particles in the 0.3-0.5µm size range,while maintaining a minimal pressure drop of approximately 7 Pa,with the best CQF(comprehensive quality factor)value of 0.408 Pa^(-1),which was a remarkable 94.06%improvement over the bare PU material.In addition,the simulation results indicate that the micro-biochar significantly enhances the effective electric field range within the composite fibers.It indicates that this composite fiber holds great potential for air purification in ventilation systems.
文摘The contribution of leakage in a baghouse filter （defined as a short circuit between the upstream and downstream sides of the filter） to the emission of fine particles is quantified in comparison to other dust emission sources, and the influence of key operating variables on overall system response is analyzed. The study was conducted on a well-maintained pilot-scale filter unit （9 bags of 500 g/m^2 calendered polyester needle felt; total surface area 4.2 m^2） operated in Ap-controlled mode over a range of pulsing intensities, with two types of test dust （one free-flowing and the other cohesive） at inlet concentrations of 10 and 30 g/m^3. Leaks included single holes between 0.5 and 4 mm diameter, intentionally placed in either the plenum plate or one of the filter bags, as well as seamlines from bag confectioning. Emissions were sep- arated by source into a transient contribution due to dust penetration through the filter bags after each cleaning pulse, and a continuous contribution from leaks. This separation was based on a novel method of data processing that relies on time-resolved concentration measurements with a specially calibrated optical particle counter. Tiny leaks on the order of 1 mm generated the same emission level as all the bags combined, and dominated continuous emissions. The equivalent leak cross section （leakage = media emission） was about 1 ppm of the total installed filter surface, independent of upstream dust concentra- tion. Leakage through open seamlines amounted to 75% of media emissions in case of free-flowing test dust. Leakage was restricted to aerodynamic diameters less than ~5 μm （roughly the PM2.s mass frac- tion）. For comparison, time-averaged mass penetration through conventional needle-felt media ranged from about 10^-5 to 10^-6, depending on cohesiveness of the particle material and pulse cleaning intensity, giving emission levels between about 0.02 and 0.2 mg/m^3 at the reference concentration of 10 R/m^2.
基金This work was supported by the National Natural Science Foundation of China (Nos.21203107,51422204,and 51372132) and the National Basic Research Program of China (No.2013CB228506).
基金the National Key Research and Development Project of China(2022YFB3804904)the National Natural Science Foundation of China Youth Fund(22208148)+1 种基金the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials(KF2401)the Jiangsu Future Membrane Technology Innovation Center(BM2021804).
文摘Filtration materials are designed with nanofibrous structures to address the trade-off effect between filtration efficiency and resistance.However,achieving a breakthrough in these performance metrics remains challenging.Inspired by the white stork wing,we present a novel rod‒ribbon interwoven nanofiber membrane with ultraefficient filtration efficiency for PM.The silica(SiO_(2))/tin dioxide(SnO_(2))hybrid membrane was fabricated using a one-step electrospinning approach,where its unique structure was formed under the influence of solvent nonequilibrium evaporation during the electrospinning process.The optimized interwoven structure enables the membranes to achieve an outstanding filtration efficiency of 99.96%for PM0.3 at an airflow velocity of 5.33 cm/s while maintaining a minimal pressure drop of 62 Pa(Qf=0.12 Pa^(−1)).The mechanisms underlying the material's formation and the enhancement of its filtration performance were systematically analyzed.Consequently,this study provides novel insights and methodologies for developing high-performance air filtration materials,thereby supporting the strategic objectives of low-carbon development.
基金the National Natural Science Foundation of China(No.12172087)Shanghai Frontier Science Research Center for Modern Textiles,Donghua University。
文摘The worldwide COVID-19 pandemic has led to an attention on the usage of personal protective face masks.However,the longevity and safety of the commercial face masks are limited due to the charge dissipation of the electret meltblown nonwovens,which are dominate in the face mask filters.Herein,we design a type of multi-layer structured nonwovens using meltblowing and electrospinning technologies.The complex nonwovens involving meltblown and electrospun fibers are designed to possess multilevel fiber diameters and pore sizes.The micro/nanofibers with porous and wrinkled surface morphologies can well capture particulate matters(PMs),and the multilevel pore sizes contribute to low air resistance under high filtration efficiency.Airflow field simulation was carried out to understand the pressure distribution within the nonwovens in the filtration process.Meanwhile,by adding Ag nanoparticles(AgNPs)as additives,the nonwovens exhibit excellent antibacterial performance.The resultant nonwovens exhibit filtration efficiency of 99.1%for PM0.3 and low pressure drop of 105 Pa under the 10.67 cm/s inlet air velocity,and antibacterial rate of>99.99%for Escherichia coli.These performances and functions make the designed complex nonwovens a promising filter core for face masks.
