Effective wind energy harvesting represents a viable solution to the global energy shortage and environmental pollution.Triboelectric nanogenerators(TENGs)hold great potential in wind energy harvesting;yet,there is li...Effective wind energy harvesting represents a viable solution to the global energy shortage and environmental pollution.Triboelectric nanogenerators(TENGs)hold great potential in wind energy harvesting;yet,there is little research on constant current TENGs for this purpose.Herein,a novel rotary bicharacteristic current TENG(R-BC-TENG)with constant current output for ambient wind energy harvesting is proposed,which delivers a low crest factor of 1.0187.Through the synergistic integration of triboelectrification,electrostatic discharge,and electrostatic induction,an average power density of 2.4 W m^(−2) Hz−1 and a charge density of 1.86 mC m−2 for the R-BC-TENG are achieved,with the charge density surpassing that reported in most previous studies.The minimum starting wind speed of R-BC-TENG is as low as 2.8 m s−1 while maintaining 100%performance after 12,700 cycles.Moreover,a self-powered air purification system,based on the R-BC-TENG,is developed,with the ability to generate 1,400,000 ions cm−3 and settle dust within 50 s.This work provides a paradigm for harvesting wind energy to achieve constant current output as well as safe and efficient air purification.展开更多
In this work,based on the role of pre-ionization of the non-uniform electric field and its effect of reducing the collisional ionization coefficient,a diffuse dielectric barrier discharge plasma is formed in the open ...In this work,based on the role of pre-ionization of the non-uniform electric field and its effect of reducing the collisional ionization coefficient,a diffuse dielectric barrier discharge plasma is formed in the open space outside the electrode structure at a lower voltage by constructing a three-dimensional non-uniform spatial electric field using a contact electrode structure.The air purification study is also carried out.Firstly,a contact electrode structure is constructed using a three-dimensional wire electrode.The distribution characteristics of the spatial electric field formed by this electrode structure are analyzed,and the effects of the non-uniform electric field and the different angles of the vertical wire on the generation of three-dimensional spatial diffuse discharge are investigated.Secondly,the copper foam contact electrode structure is constructed using copper foam material,and the effects of different mesh sizes on the electric field distribution are analyzed.The results show that as the mesh size of the copper foam becomes larger,a strong electric field region exists not only on the surface of the insulating layer,but also on the surface of the vertical wires inside the copper foam,i.e.,the strong electric field region shows a three-dimensional distribution.Besides,as the mesh size increases,the area of the vertical strong electric field also increases.However,the electric field strength on the surface of the insulating layer gradually decreases.Therefore,the appropriate mesh size can effectively increase the discharge area,which is conducive to improving the air purification efficiency.Finally,a highly permeable stacked electrode structure of multilayer wire-copper foam is designed.In combination with an ozone treatment catalyst,an air purification device is fabricated,and the air purification experiment is carried out.展开更多
In some old industrial plants,in order to meet the increasingly strict requirements of pollutant emission limits,it is necessary to install the compact filtration and/or purification devices in a given narrow machine ...In some old industrial plants,in order to meet the increasingly strict requirements of pollutant emission limits,it is necessary to install the compact filtration and/or purification devices in a given narrow machine room.Different types of structural configuration might influence air distribution inside these devices.The unreasonable air distribution might lead each part of filtration or purification media to operating at largely different air flow rates.Based on a computational fluid dynamics(CFD)model,this study explores the influence of different outlet positions and different upper heights on the flow field inside chamber.The porous medium model is employed to simulate the air flow in porous media.The changing structural configurations include three positioning cases of the outlet opening and eight height cases of the upper chamber.The root mean square is defined as the non-uniformity coefficient to evaluate the uniformity of air flow distribution.The results show that the farther distance between inlet and outlet openings will bring more uniform air distribution,and the increasing height of upper chamber totally trends to exhibit more uniform air distribution.展开更多
A novel nano-TiO2-xNx composite was used as photocatalyst and added to the interior wall paint. The average diameter of nano-TiO2-xNx was about 20 nm. The majority crystal component of the sample was anatase and its o...A novel nano-TiO2-xNx composite was used as photocatalyst and added to the interior wall paint. The average diameter of nano-TiO2-xNx was about 20 nm. The majority crystal component of the sample was anatase and its optical absorption edge was shifted from 387 nm to 520 nm significantly. Nano-composite paint containing different dosage of nano- TiO2-xNx was investigated to study the properties of formaldehyde decomposition in the air. Testing results show that the formaldehyde decomposition ratio of that nano-paint can almost reach above 80%, especially for that of the paint containing 3% （w/w） nano-TiO2-xNx which exceeded 90%. The primary investigation on the reaction kinetics of photocatalytic formaldehyde decomposition indicated that the experiment data well fit the model of first-order reaction kinetics.展开更多
This study was designed to isolate endophytic fungi from A. mongholicus （growing in northeast China） to determine whether they can produce bioactive metabolites. Four strains of endophytic fungi （strains 16, 17, 23...This study was designed to isolate endophytic fungi from A. mongholicus （growing in northeast China） to determine whether they can produce bioactive metabolites. Four strains of endophytic fungi （strains 16, 17, 23 and 75） were successfully isolated from A. mongholicus using the surface disinfection method. According to ITS-rDNA sequences analysis, strains 16 and 75 were identified as Fusarium oxysporum, and strains 17 and 23 were identified as Bionectria ochroleuca. We applied the Box-Behnken design （BBD） to optimize the liquid fermentation conditions and obtain the maximum cell dry weight （CDW） yield. Opti-mal parameters were obtained under the following experimental condi-tions：temperature of 28＆#176;C, potato dextrose agar （PDA） liquid medium of 80 mL and rotation speed of 150 rpm. The four isolated endophytic fungi did not produce astragalosides I-IV, flavonoids or polysaccharides. Iso-lation of additional species of endophytic fungi from A. mongholicus and determination of their capacity to produce biologically active substances are subjects in need of further research.展开更多
By using total volatile organic compounds （TVOC） as the objective volatile pollutant, the purification efficiency of some representative air purifiers bought in the market was determined under the relatively indepen...By using total volatile organic compounds （TVOC） as the objective volatile pollutant, the purification efficiency of some representative air purifiers bought in the market was determined under the relatively independent and stable environmental conditions supplied by the self-made multi- functional environmental test chamber. Various evaluation parameters of TVOC were calculated based on the tested results, such as purification ef- ficiency and removal rate. The results showed that the TVOC purification efficiency increased with enhancing the temperature or lessening the rela- tive humidity, but this effect is not obvious. The air purifiers which use photocatalytic technology have higher TVOC purification efficiency than those which only use some adsorption technology. The purification efficiency and removal rate can be more accurate to evaluate the purification efficiency of air purifiers.展开更多
Cerium dioxide(CeO_(2))is a significant rare earth oxide with the merits of rich oxygen defects,specific4f^(1)5d^(1)orbitals,and superior oxygen storage-release capacity in Ce^(4+)/Ce^(3+)reversibility pairs,and has b...Cerium dioxide(CeO_(2))is a significant rare earth oxide with the merits of rich oxygen defects,specific4f^(1)5d^(1)orbitals,and superior oxygen storage-release capacity in Ce^(4+)/Ce^(3+)reversibility pairs,and has been widely investigated as an active photocatalytic material for air pollution remediation.To enhance the photocatalytic efficiency of CeO_(2),recent developments of numerous modification strategies have been employed to broaden the light absorption range and reduce the recombination rate of electron-hole pairs.This review summarizes the fabrication of modified CeO_(2)catalysts,including metal or nonmetal doping,heterostructure construction and oxygen vacancy manufacturing,to provide insight into how those advanced techniques improve the photocatalytic activity.Moreover,this work provides a detailed discussion on the usage of modified CeO_(2)in the fields of air pollution control,including nitrogen oxides removal,volatile organic compounds elimination and the purification of carbon dioxide.Finally,the potential future development and further research on the modification of CeO_(2)has been identified.展开更多
Soil biofiltration, also known as soil bed reactor (SBR), technology was originally developed in Germany to take advantage of the diversity in microbial mechanisms to control gases producing malodor in industrial proc...Soil biofiltration, also known as soil bed reactor (SBR), technology was originally developed in Germany to take advantage of the diversity in microbial mechanisms to control gases producing malodor in industrial processes. The approach has since gained wider international acceptance and continues to see improvements to maximize microbial and process efficiency and extend the range of problematical gases for which the technology can be an effective control. We review the basic mechanisms which underlay microbial soil processes involved in air purification, advantages and limitations of the technology and the current research status of the approach. Soil biofiltration has lower capital and operating/energetic costs than conventional technologies and is well adapted to handle contaminants in moderate concentrations. The systems can be engineered to optimize efficiency though manipulation of temperature, pH, moisture content, soil organic matter and airflow rates. Soil air biofiltration technology was modified for application in the Biosphere 2 project, which demonstrated in preparatory research with a number of closed system testbeds that soil could also support crop plants while also serving as soil filters with airpumps to push air through the soil. This Biosphere 2 research demonstrated in several closed system testbeds that a number of important trace gases could be kept under control and led to the engineering of the entire agricultural soil of Biosphere 2 to serve as a soil filtration unit for the facility. Soil biofiltration, coupled with food crop production, as a component of bioregenerative space life support systems has the advantages of lower energy use and avoidance of the consumables required for other air purification approaches. Expanding use of soil biofiltration can aid a number of environmental applications, from the mitigation of indoor air pollution, as a method of reducing global warming impact of methane (biogas), improvement of industrial air emissions and prevention of accidental release of toxic gases.展开更多
Sadatomi and Kawahara developed a special twin-fluid atomizer called a multi-fluid mixer, which can spray mists by supplying air alone because water is automatically sucked by a vacuum pressure arisen inside the mixer...Sadatomi and Kawahara developed a special twin-fluid atomizer called a multi-fluid mixer, which can spray mists by supplying air alone because water is automatically sucked by a vacuum pressure arisen inside the mixer. In the present paper, firstly, some applications of the mists sprayed by the atomizer are described. Secondly, the performance of the twin-fluid atomizer with best performance was compared with those of the commercial twin-fluid MMA100 type together with the single-fluid swirl type. In the CO2 adsorption tests, mists were sprayed five minutes by the respective types in turn in a test room, and time variations of CO2 concentration in air after the introduction of CO2 in the room were measured at the bottom of the room to compare the CO2 adsorption rates by the mists for the respective cases. In addition, diameters of droplets for the respective types were measured with a microscope. As a result, superiority of our twin-fluid atomizer was confirmed, because 40% droplets were 20 to 40 μm in diameter, and the CO2 adsorption rate by the mists with our twin-fluid atomizer was 25% higher than that with the commercial ones.展开更多
The interaction between ultrasound and the air-liquid interface is widely involved in sonar communication,medical imaging,acoustic detection,etc.In this work,we report an intriguing bubbling phenomenon occurring at th...The interaction between ultrasound and the air-liquid interface is widely involved in sonar communication,medical imaging,acoustic detection,etc.In this work,we report an intriguing bubbling phenomenon occurring at the liquid surface exposed to acoustic radiation.The phenomenon can be robustly triggered once the distance between the liquid surface and the acoustic probe is adjusted to multiples of half sound wavelength.It is clarified that the bubbling is attributed to the Helmholtz resonance of the liquid concavity caused by the acoustic radiation force.The sizes of the final obtained bubbles show a universal scaling law with acoustic Bond number and acoustic Reynolds number:R≈λ·Bo_(a)·(Re_(a))^(1/2),which is independent of the types of liquids.Moreover,it was found that the bubbling phenomenon showed a significantly enhanced particle absorption ability,thus shedding light on the development of solid filter-free air purification techniques.展开更多
Air pollutants,which are composed of diverse components such as particulate matter(PM),volatile organic compounds(VOCs),nitrogen oxides(NOx),sulfur dioxide(SO2),and pathogenic microorganisms,have adverse effects on bo...Air pollutants,which are composed of diverse components such as particulate matter(PM),volatile organic compounds(VOCs),nitrogen oxides(NOx),sulfur dioxide(SO2),and pathogenic microorganisms,have adverse effects on both the eco-system and human health.While existing air purification technologies can effectively eliminate these pollutants through mul-tiple processes targeting specific components,they often entail high energy consumption,maintenance costs,and complexity.Recent developments in air purification technology based on multifunctional nanofibrous membranes present a promising single-step solution for the effective removal of diverse air pollutants.Through synergistic integration with functional mate-rials,other functional materials,such as those with catalytic,adsorption,and antimicrobial properties,can be incorporated into nanofibrous membranes.In this review,the design concepts and fabrication strategies of multifunctional nanofibrous membranes to facilitate the integrated removal of multiple air pollutants are explored.Additionally,nanofibrous membrane preparation methods,PM removal mechanisms,and performance metrics are introduced.Next,methods for removing vari-ous air pollutants are outlined,and different air purification materials are reviewed.Finally,the design approaches and the state-of-the-art of multifunctional nanofibrous membranes for integrated air purification are highlighted.展开更多
The incidences of nosocomial infections(NIs)are increasing throughout the world,especially for those airborne diseases caused by pathogens or air particulates that float in air.In this study,we designed and manufactur...The incidences of nosocomial infections(NIs)are increasing throughout the world,especially for those airborne diseases caused by pathogens or air particulates that float in air.In this study,we designed and manufactured a desk for clinic consultation room air purification and air isolation between doctor and patient.The air isolation and purification(AIP)desk has a high efficiency particulate air(HEPA)filter on the tope and several primary efficiency filters on the sides for air purification.The air circulating between inlet and outlet forms a wind-curtain between doctor and patient.The Computational Fluid Dynamics(CFD)model was used to calculate the speed of the air flow and the angle of sampler.We tested the air purification function of the AIP desk in rooms sized about 3.6×2.8×2.8 m(L×W×H)and found that the AIP desk could significantly remove the tested air pollutants like smoke particulates and microorganisms like Staphylococcus albus(S.albus)and human adenovirus type 5(HAdV-5).The wind-curtain can significantly block the exhale air of patient being transmitted to the respiratory area of doctor setting in the opposite of AIP desk.Thus,the AIP desk can be used in hospital setting to reduce the risk of NIs and protect both doctors and patients.展开更多
In countries suffering from heavy ambient air pollution,ventilation is a problem,as ventilation intakes outdoor air pollutants,such as particulate matter with an aerodynamic diameter less than 2.5 μm(PM_(2.5)),while ...In countries suffering from heavy ambient air pollution,ventilation is a problem,as ventilation intakes outdoor air pollutants,such as particulate matter with an aerodynamic diameter less than 2.5 μm(PM_(2.5)),while removing indoor air pollutants.Thus,it is important to identify appropriate ventilation-purification strategies to build healthy indoor environments with low energy consumption.This study reports the comparison of two sets of strategies,i.e.,mechanical ventilation with filters and natural ventilation with indoor air cleaners,in respect to energy consumption and the PMzs and carbon dioxide(CO_(2))exposure of occupants in a typical apartment in Beijing,China.A dynamic mass balance model was employed to calculate the PM2.5 and CO_(2) exposure concentrations,while the energy consumption of heating and cooling was simulated with the Designer's Simulation Toolkit.It was found that natural ventilation with air cleaners provided lower PIVhs exposure compared with that of mechanical ventilation with filters;however,mechanical ventilation achieved a lower CO_(2) exposure concentration.The annual cooling,heating,and fan energy consumption of natural ventilation strategies are lower than those of mechanical ventilation strategies.With respect to natural ventilation,an infiltration rate of 0.3-0.4 h^(-1)was the preferred setting,which led to low PM23 and CO_(2) exposure with lower energy consumption.The basic requirements for controlling indoor PM2.5 could be met if the threshold is set at 25 pg/m3.The results provide guidelines on how to combine multiple ventilation purification strategies to improve indoor air quality with lower energy usage.展开更多
With the acceleration of the urban industrialization process,air pollutant emission has increased sharply,which seriously endangers the ecological environment and human beings.Solar-driven photocatalysis has the broad...With the acceleration of the urban industrialization process,air pollutant emission has increased sharply,which seriously endangers the ecological environment and human beings.Solar-driven photocatalysis has the broad-spectrum activity for various inorganic to organic pollutants at ambient temperature without harsh reaction conditions,which shows a very broad application prospect in air purification.However,the photocatalysis technology suffers from the unrevealed reaction me-chanism and the deactivation of photocatalysts,which severely limits its practical application.Currently,there is still a huge gap between basic research and industrial application in the field of photocatalytic air purification.This review summarizes recent progress on photocatalytic degradation of air pollutants and categorizes them based on the types of photocatalytic materials and air pollutants,with a focus on photocatalytic reaction mechanisms and the application scenarios of photocatalytic air purification to identify this gap.We also critically discussed the major challenges for promoting applications of photo-catalytic technology and put forward the development prospect.展开更多
The separation stability under high-humidity is significant in practical applications for air filters.Herein,hydrophobic polyvinyl chloride(PVC)nanofiber filters with bead-on-string structure are designed to steadily ...The separation stability under high-humidity is significant in practical applications for air filters.Herein,hydrophobic polyvinyl chloride(PVC)nanofiber filters with bead-on-string structure are designed to steadily remove particle matter under high relative humidity of 90%-95%.The developed hydrophobic filters possess comparable separation performance with the hydrophilic one,but greatly enhanced stability.After the introduction of beadon-string structure,the filtration performance can be furtherly improved due to the formed large cavities and hydrophobicity.Such hydrophobic PVC filters can be promising candidates for air purification in practical applications especially in wet seasons.展开更多
The mitigation of environmental and energy crises could be advanced by reclaiming platinum group precious metals(PGMs) from decommissioned air purification catalysts. However, the complexity of catalyst composition an...The mitigation of environmental and energy crises could be advanced by reclaiming platinum group precious metals(PGMs) from decommissioned air purification catalysts. However, the complexity of catalyst composition and the high chemical inertness of PGMs significantly impede this process. Consequently,recovering PGMs from used industrial catalysts is crucial and challenging. This study delves into an environmentally friendly approach to selectively recover PGMs from commercial air purifiers using photocatalytic redox technology. Our investigation focuses on devising a comprehensive strategy for treating three-way catalysts employed in automotive exhaust treatment. By meticulously pretreating and modifying reaction conditions, we achieved noteworthy results, completely dissolving and separating rhodium(Rh), palladium(Pd), and platinum(Pt) within a 12-h time frame. Importantly, the solubility selectivity persists despite the remarkably similar physicochemical properties of Rh, Pd, and Pt. To bolster the environmental sustainability of our method, we harness sunlight as the energy source to activate the photocatalysts, facilitating the complete dissolution of precious metals under natural light irradiation. This ecofriendly recovery approach demonstrated on commercial air purifiers, exhibits promise for broader application to a diverse range of deactivated air purification catalysts, potentially enabling implementation on a large scale.展开更多
A novel purification process is involved to obtain the high purity[>99%(by mass)]dodecanedioic acid(DC_(12)).It involves a re-crystallization followed by molecular distillation from the crude product.The objective ...A novel purification process is involved to obtain the high purity[>99%(by mass)]dodecanedioic acid(DC_(12)).It involves a re-crystallization followed by molecular distillation from the crude product.The objective of this study is to investigate general conditions,feed rate,distilling temperature and vacuum,necessary for centrifugal distillation of DC_(12).Under the optimum conditions,distilling temperature 180℃,pressure 30 Pa and feed flow rate700 ml·h^(-1),the purity of DC_(12) in the residence reached 97.55%with a yield of 53.18%by the analysis of gas chromatography.Multiple-pass distillation made a considerable contribution by improving the purity to99.22%.Additionally,the effect of pretreatment(re-crystallization) on distillation process was revealed through a series of comparative experiments.展开更多
Tannase was extracted from a new fungal strain Penicillium verrucosum using coffee pulp as a substrate by solid state fermentation. The extracellular tannase was purified using Sephadex G-100 to 86.02 folds with 34.3%...Tannase was extracted from a new fungal strain Penicillium verrucosum using coffee pulp as a substrate by solid state fermentation. The extracellular tannase was purified using Sephadex G-100 to 86.02 folds with 34.3% yield and a single band corresponding to 81 kDa was observed in SDS-PAGE. Tannase was immobilized on alginate by entrapment method. The graphical analysis of the effect of the substrate concentration on the tannase activity yielded a Km of 48.88 mM and a Vmax of 169.49 U/mL. The optimum temperature and pH of the enzyme were 30 ℃ and pH 5. The thermal stability, as well as stability over a wide range ofpH, was significantly improved by the immobilization process. The activity was enhanced by Mg^2＋ （23.5%） and K^＋ （5.3%）, whereas Zn^2＋, Cu^2＋, Ca^2＋, NH^4＋ and Hg^2＋ inhibited tannase activity. Maximum substrate bioconversion （58.94%） from tannic acid to gallic acid and tea cream solubilisation （32.82%） was achieved using immobilized tannase. The extracellular tannase produced by P. verrucosum showed distinctive characteristics such as monomeric structure and activation by Mg^2＋, suggesting a new kind of fungal tannase with biotechnological potential.展开更多
The aim was to explore the purification ability of potted taxus for indoor sulfur dioxide pollution. Three taxus cultivars were placed in different rooms. The air in the rooms was sampled continuously at the flow rate...The aim was to explore the purification ability of potted taxus for indoor sulfur dioxide pollution. Three taxus cultivars were placed in different rooms. The air in the rooms was sampled continuously at the flow rate of 0.5 ml/min, and the content of sulfur dioxide was determined by formaldehyde absorbing-pararosaniline spectrophotometry. The obtained linear equation for sulfur dioxide was as follows： y=0.030 1 x＋0.023 5, F=0.999 7. The content of sulfur dioxide in the three rooms placed with different taxus cultivars all declined, suggesting that potted taxus has a certain ability to purify sulfur dioxide. Among the taxus cultivars, Taxus yunnanensis showed the highest purification rate, followed by Taxus chinensis vat. mairei and Taxus media cv. Hicksii.展开更多
The effect of different extraction and purification conditions on the microbial protein obtained from solid-state fermentation(SSF)and the effect of periodical dynamic changes of air on protein have been studied.The m...The effect of different extraction and purification conditions on the microbial protein obtained from solid-state fermentation(SSF)and the effect of periodical dynamic changes of air on protein have been studied.The mechanism of solid-state fermentation with periodical dynamic changes of air is also discussed.Compared with static solid-state fermentation,periodical dynamic changes of air afford a higher protein mass;from 1 g of the fermentation microbe,5.3 mg of the intracellular protein(an increase of 34.63%)and 9.09 mg of the extracellular protein(an increase of 17.8%)were obtained on the sixth day of fermentation.The filter paper activity and carboxymethyl cellulose activity(FPA and CMCase)of the extracellular protein are 1.739μmol/s and 109.592μmol/s,respectively,which represent increases of 60.1%and 21.2%over the corresponding values for static solid-state fermentation.The FPA and CMCase of the intra-cellular protein are 0.245μmol/s and 6.392μmol/s,respec-tively,which represent decreases of 22.2%and 38.7%over the corresponding values for static solid-state fermentation.The enzyme activity of the microbial extracellular protein in solid-state fermentation with periodical dynamic changes of air on the fifth day is nearly equal to that on the sixth day without periodical dynamic changes of air,so the period of fermentation can be shortened.The sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)experiments suggest that pulsating air pressure stimulation leads to a decrease in the amount of protein component with molecule mass of about 80400Da,and an increase in the amount of protein component with molecule mass of about 28520Da.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52076024 and 52572203)the Natural Science Foundation of Chongqing(Grant No.cstc2021jcyj-msxmX0625)the Fundamental Research Funds for Central Universities(Grant Nos.2023CDJXY-0049 and 2025CDJ-IAISYB-030).
文摘Effective wind energy harvesting represents a viable solution to the global energy shortage and environmental pollution.Triboelectric nanogenerators(TENGs)hold great potential in wind energy harvesting;yet,there is little research on constant current TENGs for this purpose.Herein,a novel rotary bicharacteristic current TENG(R-BC-TENG)with constant current output for ambient wind energy harvesting is proposed,which delivers a low crest factor of 1.0187.Through the synergistic integration of triboelectrification,electrostatic discharge,and electrostatic induction,an average power density of 2.4 W m^(−2) Hz−1 and a charge density of 1.86 mC m−2 for the R-BC-TENG are achieved,with the charge density surpassing that reported in most previous studies.The minimum starting wind speed of R-BC-TENG is as low as 2.8 m s−1 while maintaining 100%performance after 12,700 cycles.Moreover,a self-powered air purification system,based on the R-BC-TENG,is developed,with the ability to generate 1,400,000 ions cm−3 and settle dust within 50 s.This work provides a paradigm for harvesting wind energy to achieve constant current output as well as safe and efficient air purification.
基金supported by the Fundamental Research Funds for the Central Universities(No.2022YJS094)。
文摘In this work,based on the role of pre-ionization of the non-uniform electric field and its effect of reducing the collisional ionization coefficient,a diffuse dielectric barrier discharge plasma is formed in the open space outside the electrode structure at a lower voltage by constructing a three-dimensional non-uniform spatial electric field using a contact electrode structure.The air purification study is also carried out.Firstly,a contact electrode structure is constructed using a three-dimensional wire electrode.The distribution characteristics of the spatial electric field formed by this electrode structure are analyzed,and the effects of the non-uniform electric field and the different angles of the vertical wire on the generation of three-dimensional spatial diffuse discharge are investigated.Secondly,the copper foam contact electrode structure is constructed using copper foam material,and the effects of different mesh sizes on the electric field distribution are analyzed.The results show that as the mesh size of the copper foam becomes larger,a strong electric field region exists not only on the surface of the insulating layer,but also on the surface of the vertical wires inside the copper foam,i.e.,the strong electric field region shows a three-dimensional distribution.Besides,as the mesh size increases,the area of the vertical strong electric field also increases.However,the electric field strength on the surface of the insulating layer gradually decreases.Therefore,the appropriate mesh size can effectively increase the discharge area,which is conducive to improving the air purification efficiency.Finally,a highly permeable stacked electrode structure of multilayer wire-copper foam is designed.In combination with an ozone treatment catalyst,an air purification device is fabricated,and the air purification experiment is carried out.
基金National Key Research and Development Program of China(No.2018YFC0705305)。
文摘In some old industrial plants,in order to meet the increasingly strict requirements of pollutant emission limits,it is necessary to install the compact filtration and/or purification devices in a given narrow machine room.Different types of structural configuration might influence air distribution inside these devices.The unreasonable air distribution might lead each part of filtration or purification media to operating at largely different air flow rates.Based on a computational fluid dynamics(CFD)model,this study explores the influence of different outlet positions and different upper heights on the flow field inside chamber.The porous medium model is employed to simulate the air flow in porous media.The changing structural configurations include three positioning cases of the outlet opening and eight height cases of the upper chamber.The root mean square is defined as the non-uniformity coefficient to evaluate the uniformity of air flow distribution.The results show that the farther distance between inlet and outlet openings will bring more uniform air distribution,and the increasing height of upper chamber totally trends to exhibit more uniform air distribution.
基金Project supported by the Foundation of National Key Technologies R&D Program--Shanghai World Expo Special Project (Grant No.04DZ05803)
文摘A novel nano-TiO2-xNx composite was used as photocatalyst and added to the interior wall paint. The average diameter of nano-TiO2-xNx was about 20 nm. The majority crystal component of the sample was anatase and its optical absorption edge was shifted from 387 nm to 520 nm significantly. Nano-composite paint containing different dosage of nano- TiO2-xNx was investigated to study the properties of formaldehyde decomposition in the air. Testing results show that the formaldehyde decomposition ratio of that nano-paint can almost reach above 80%, especially for that of the paint containing 3% （w/w） nano-TiO2-xNx which exceeded 90%. The primary investigation on the reaction kinetics of photocatalytic formaldehyde decomposition indicated that the experiment data well fit the model of first-order reaction kinetics.
基金supported by grants from the Key Program of Natural Science Foundation of State(Grant No.81274010)Heilongjiang province outstanding youth fund(Grant No.JC201101)Talent fund of Heilongjiang University of Chinese Medicine Talent Fund
文摘This study was designed to isolate endophytic fungi from A. mongholicus （growing in northeast China） to determine whether they can produce bioactive metabolites. Four strains of endophytic fungi （strains 16, 17, 23 and 75） were successfully isolated from A. mongholicus using the surface disinfection method. According to ITS-rDNA sequences analysis, strains 16 and 75 were identified as Fusarium oxysporum, and strains 17 and 23 were identified as Bionectria ochroleuca. We applied the Box-Behnken design （BBD） to optimize the liquid fermentation conditions and obtain the maximum cell dry weight （CDW） yield. Opti-mal parameters were obtained under the following experimental condi-tions：temperature of 28＆#176;C, potato dextrose agar （PDA） liquid medium of 80 mL and rotation speed of 150 rpm. The four isolated endophytic fungi did not produce astragalosides I-IV, flavonoids or polysaccharides. Iso-lation of additional species of endophytic fungi from A. mongholicus and determination of their capacity to produce biologically active substances are subjects in need of further research.
基金Supported by Special Fund for Scientific Research in the Public Interest from State General Administration of Quality Supervision(201010052)Special Fund for Science and Technology Plan from State General Administration of Quality Supervision(2010Q144)
文摘By using total volatile organic compounds （TVOC） as the objective volatile pollutant, the purification efficiency of some representative air purifiers bought in the market was determined under the relatively independent and stable environmental conditions supplied by the self-made multi- functional environmental test chamber. Various evaluation parameters of TVOC were calculated based on the tested results, such as purification ef- ficiency and removal rate. The results showed that the TVOC purification efficiency increased with enhancing the temperature or lessening the rela- tive humidity, but this effect is not obvious. The air purifiers which use photocatalytic technology have higher TVOC purification efficiency than those which only use some adsorption technology. The purification efficiency and removal rate can be more accurate to evaluate the purification efficiency of air purifiers.
基金financially supported by the National Key Research and Development Program of China(Nos.2022YFB3504100 and 2021YFB3500600)Jiangsu International Cooperation Project(No.BZ2021018)+5 种基金Key R&D Program of Jiangsu Province(No.BE2022142)Nanjing Science and Technology Top Experts Gathering PlanCooperation Foundation for the Chunhui Plan Program of Ministry of Education of China(No.202200554)Open Project Program of Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science(No.M2024-7)MOE,Open Project Program of Anhui Province Key Laboratory of Pollutant Sensitive Materials and Environmental Remediation(No.PSMER2023008)the Open Foundation of State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control(No.SEMPC2023004)。
文摘Cerium dioxide(CeO_(2))is a significant rare earth oxide with the merits of rich oxygen defects,specific4f^(1)5d^(1)orbitals,and superior oxygen storage-release capacity in Ce^(4+)/Ce^(3+)reversibility pairs,and has been widely investigated as an active photocatalytic material for air pollution remediation.To enhance the photocatalytic efficiency of CeO_(2),recent developments of numerous modification strategies have been employed to broaden the light absorption range and reduce the recombination rate of electron-hole pairs.This review summarizes the fabrication of modified CeO_(2)catalysts,including metal or nonmetal doping,heterostructure construction and oxygen vacancy manufacturing,to provide insight into how those advanced techniques improve the photocatalytic activity.Moreover,this work provides a detailed discussion on the usage of modified CeO_(2)in the fields of air pollution control,including nitrogen oxides removal,volatile organic compounds elimination and the purification of carbon dioxide.Finally,the potential future development and further research on the modification of CeO_(2)has been identified.
文摘Soil biofiltration, also known as soil bed reactor (SBR), technology was originally developed in Germany to take advantage of the diversity in microbial mechanisms to control gases producing malodor in industrial processes. The approach has since gained wider international acceptance and continues to see improvements to maximize microbial and process efficiency and extend the range of problematical gases for which the technology can be an effective control. We review the basic mechanisms which underlay microbial soil processes involved in air purification, advantages and limitations of the technology and the current research status of the approach. Soil biofiltration has lower capital and operating/energetic costs than conventional technologies and is well adapted to handle contaminants in moderate concentrations. The systems can be engineered to optimize efficiency though manipulation of temperature, pH, moisture content, soil organic matter and airflow rates. Soil air biofiltration technology was modified for application in the Biosphere 2 project, which demonstrated in preparatory research with a number of closed system testbeds that soil could also support crop plants while also serving as soil filters with airpumps to push air through the soil. This Biosphere 2 research demonstrated in several closed system testbeds that a number of important trace gases could be kept under control and led to the engineering of the entire agricultural soil of Biosphere 2 to serve as a soil filtration unit for the facility. Soil biofiltration, coupled with food crop production, as a component of bioregenerative space life support systems has the advantages of lower energy use and avoidance of the consumables required for other air purification approaches. Expanding use of soil biofiltration can aid a number of environmental applications, from the mitigation of indoor air pollution, as a method of reducing global warming impact of methane (biogas), improvement of industrial air emissions and prevention of accidental release of toxic gases.
文摘Sadatomi and Kawahara developed a special twin-fluid atomizer called a multi-fluid mixer, which can spray mists by supplying air alone because water is automatically sucked by a vacuum pressure arisen inside the mixer. In the present paper, firstly, some applications of the mists sprayed by the atomizer are described. Secondly, the performance of the twin-fluid atomizer with best performance was compared with those of the commercial twin-fluid MMA100 type together with the single-fluid swirl type. In the CO2 adsorption tests, mists were sprayed five minutes by the respective types in turn in a test room, and time variations of CO2 concentration in air after the introduction of CO2 in the room were measured at the bottom of the room to compare the CO2 adsorption rates by the mists for the respective cases. In addition, diameters of droplets for the respective types were measured with a microscope. As a result, superiority of our twin-fluid atomizer was confirmed, because 40% droplets were 20 to 40 μm in diameter, and the CO2 adsorption rate by the mists with our twin-fluid atomizer was 25% higher than that with the commercial ones.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12272314, and 11972303)。
文摘The interaction between ultrasound and the air-liquid interface is widely involved in sonar communication,medical imaging,acoustic detection,etc.In this work,we report an intriguing bubbling phenomenon occurring at the liquid surface exposed to acoustic radiation.The phenomenon can be robustly triggered once the distance between the liquid surface and the acoustic probe is adjusted to multiples of half sound wavelength.It is clarified that the bubbling is attributed to the Helmholtz resonance of the liquid concavity caused by the acoustic radiation force.The sizes of the final obtained bubbles show a universal scaling law with acoustic Bond number and acoustic Reynolds number:R≈λ·Bo_(a)·(Re_(a))^(1/2),which is independent of the types of liquids.Moreover,it was found that the bubbling phenomenon showed a significantly enhanced particle absorption ability,thus shedding light on the development of solid filter-free air purification techniques.
基金supported by the National Natural Science Foundation of China(Nos.22325804,22108119,21921006).
文摘Air pollutants,which are composed of diverse components such as particulate matter(PM),volatile organic compounds(VOCs),nitrogen oxides(NOx),sulfur dioxide(SO2),and pathogenic microorganisms,have adverse effects on both the eco-system and human health.While existing air purification technologies can effectively eliminate these pollutants through mul-tiple processes targeting specific components,they often entail high energy consumption,maintenance costs,and complexity.Recent developments in air purification technology based on multifunctional nanofibrous membranes present a promising single-step solution for the effective removal of diverse air pollutants.Through synergistic integration with functional mate-rials,other functional materials,such as those with catalytic,adsorption,and antimicrobial properties,can be incorporated into nanofibrous membranes.In this review,the design concepts and fabrication strategies of multifunctional nanofibrous membranes to facilitate the integrated removal of multiple air pollutants are explored.Additionally,nanofibrous membrane preparation methods,PM removal mechanisms,and performance metrics are introduced.Next,methods for removing vari-ous air pollutants are outlined,and different air purification materials are reviewed.Finally,the design approaches and the state-of-the-art of multifunctional nanofibrous membranes for integrated air purification are highlighted.
基金supported by grants from National Key Research and Development Program of China(2018YFC1200100 and 2020YFC0842400)Guangdong Medical Science and Technology Research Center Project(A2019460)+5 种基金Entrepreneurship Leadership Project in Guangzhou Development Zone of China(CY2018-003)Guangzhou Science and Technology Project(202008040002)Scientific Research Project of Guangdong Province Traditional Chinese Medicine Bureau(20201191)Innovative and Strong School Project of Guangdong Provincial Department of Education(2020KZDZX1122)Guangdong Science and Technology Project(2020B111106001)Foshan Science and Technology Innovation Project(2020001000416).
文摘The incidences of nosocomial infections(NIs)are increasing throughout the world,especially for those airborne diseases caused by pathogens or air particulates that float in air.In this study,we designed and manufactured a desk for clinic consultation room air purification and air isolation between doctor and patient.The air isolation and purification(AIP)desk has a high efficiency particulate air(HEPA)filter on the tope and several primary efficiency filters on the sides for air purification.The air circulating between inlet and outlet forms a wind-curtain between doctor and patient.The Computational Fluid Dynamics(CFD)model was used to calculate the speed of the air flow and the angle of sampler.We tested the air purification function of the AIP desk in rooms sized about 3.6×2.8×2.8 m(L×W×H)and found that the AIP desk could significantly remove the tested air pollutants like smoke particulates and microorganisms like Staphylococcus albus(S.albus)and human adenovirus type 5(HAdV-5).The wind-curtain can significantly block the exhale air of patient being transmitted to the respiratory area of doctor setting in the opposite of AIP desk.Thus,the AIP desk can be used in hospital setting to reduce the risk of NIs and protect both doctors and patients.
基金supported by the China Postdoctoral Science Foundation(No.2019M650013)Fundamental Research Funds for the Central Universities(No.FRF-TP-18-083A1)National Natural Science Foundation of China(No.51908032).
文摘In countries suffering from heavy ambient air pollution,ventilation is a problem,as ventilation intakes outdoor air pollutants,such as particulate matter with an aerodynamic diameter less than 2.5 μm(PM_(2.5)),while removing indoor air pollutants.Thus,it is important to identify appropriate ventilation-purification strategies to build healthy indoor environments with low energy consumption.This study reports the comparison of two sets of strategies,i.e.,mechanical ventilation with filters and natural ventilation with indoor air cleaners,in respect to energy consumption and the PMzs and carbon dioxide(CO_(2))exposure of occupants in a typical apartment in Beijing,China.A dynamic mass balance model was employed to calculate the PM2.5 and CO_(2) exposure concentrations,while the energy consumption of heating and cooling was simulated with the Designer's Simulation Toolkit.It was found that natural ventilation with air cleaners provided lower PIVhs exposure compared with that of mechanical ventilation with filters;however,mechanical ventilation achieved a lower CO_(2) exposure concentration.The annual cooling,heating,and fan energy consumption of natural ventilation strategies are lower than those of mechanical ventilation strategies.With respect to natural ventilation,an infiltration rate of 0.3-0.4 h^(-1)was the preferred setting,which led to low PM23 and CO_(2) exposure with lower energy consumption.The basic requirements for controlling indoor PM2.5 could be met if the threshold is set at 25 pg/m3.The results provide guidelines on how to combine multiple ventilation purification strategies to improve indoor air quality with lower energy usage.
基金supported by the National Natural Science Foundation of China(22176029,21822601)the Excellent Youth Foundation of Sichuan Province in China(2021JDJQ0006).
文摘With the acceleration of the urban industrialization process,air pollutant emission has increased sharply,which seriously endangers the ecological environment and human beings.Solar-driven photocatalysis has the broad-spectrum activity for various inorganic to organic pollutants at ambient temperature without harsh reaction conditions,which shows a very broad application prospect in air purification.However,the photocatalysis technology suffers from the unrevealed reaction me-chanism and the deactivation of photocatalysts,which severely limits its practical application.Currently,there is still a huge gap between basic research and industrial application in the field of photocatalytic air purification.This review summarizes recent progress on photocatalytic degradation of air pollutants and categorizes them based on the types of photocatalytic materials and air pollutants,with a focus on photocatalytic reaction mechanisms and the application scenarios of photocatalytic air purification to identify this gap.We also critically discussed the major challenges for promoting applications of photo-catalytic technology and put forward the development prospect.
基金funding from by the National Natural Science Foundation of China(21706076,21536005,51621001)the National Natural Science Foundation of the Guangdong Province(2014A030312007)+1 种基金Guangzhou Technology Project(201804010210)the State Key Laboratory of Pulp and Paper Engineering(201835)。
文摘The separation stability under high-humidity is significant in practical applications for air filters.Herein,hydrophobic polyvinyl chloride(PVC)nanofiber filters with bead-on-string structure are designed to steadily remove particle matter under high relative humidity of 90%-95%.The developed hydrophobic filters possess comparable separation performance with the hydrophilic one,but greatly enhanced stability.After the introduction of beadon-string structure,the filtration performance can be furtherly improved due to the formed large cavities and hydrophobicity.Such hydrophobic PVC filters can be promising candidates for air purification in practical applications especially in wet seasons.
基金supported by the National Key Research and Development Program of China (2020YFA0211004)the National Natural Science Foundation of China (22176128 and 22236005)+7 种基金the Innovation Program of Shanghai Municipal Education Commission (2023ZKZD50)Program of Shanghai Academic Research Leader (21XD1422800)Shanghai Government (22dz1205400 and 23520711100)Chinese Education Ministry Key Laboratory and International Joint Laboratory on Resource ChemistryShanghai Eastern Scholar Programthe “111 Innovation and Talent Recruitment Base on Photochemical and Energy Materials” (D18020)Shanghai Engineering Research Center of Green Energy Chemical Engineering (18DZ2254200)Shanghai Frontiers Science Center of Biomimetic Catalysis。
文摘The mitigation of environmental and energy crises could be advanced by reclaiming platinum group precious metals(PGMs) from decommissioned air purification catalysts. However, the complexity of catalyst composition and the high chemical inertness of PGMs significantly impede this process. Consequently,recovering PGMs from used industrial catalysts is crucial and challenging. This study delves into an environmentally friendly approach to selectively recover PGMs from commercial air purifiers using photocatalytic redox technology. Our investigation focuses on devising a comprehensive strategy for treating three-way catalysts employed in automotive exhaust treatment. By meticulously pretreating and modifying reaction conditions, we achieved noteworthy results, completely dissolving and separating rhodium(Rh), palladium(Pd), and platinum(Pt) within a 12-h time frame. Importantly, the solubility selectivity persists despite the remarkably similar physicochemical properties of Rh, Pd, and Pt. To bolster the environmental sustainability of our method, we harness sunlight as the energy source to activate the photocatalysts, facilitating the complete dissolution of precious metals under natural light irradiation. This ecofriendly recovery approach demonstrated on commercial air purifiers, exhibits promise for broader application to a diverse range of deactivated air purification catalysts, potentially enabling implementation on a large scale.
文摘A novel purification process is involved to obtain the high purity[>99%(by mass)]dodecanedioic acid(DC_(12)).It involves a re-crystallization followed by molecular distillation from the crude product.The objective of this study is to investigate general conditions,feed rate,distilling temperature and vacuum,necessary for centrifugal distillation of DC_(12).Under the optimum conditions,distilling temperature 180℃,pressure 30 Pa and feed flow rate700 ml·h^(-1),the purity of DC_(12) in the residence reached 97.55%with a yield of 53.18%by the analysis of gas chromatography.Multiple-pass distillation made a considerable contribution by improving the purity to99.22%.Additionally,the effect of pretreatment(re-crystallization) on distillation process was revealed through a series of comparative experiments.
文摘Tannase was extracted from a new fungal strain Penicillium verrucosum using coffee pulp as a substrate by solid state fermentation. The extracellular tannase was purified using Sephadex G-100 to 86.02 folds with 34.3% yield and a single band corresponding to 81 kDa was observed in SDS-PAGE. Tannase was immobilized on alginate by entrapment method. The graphical analysis of the effect of the substrate concentration on the tannase activity yielded a Km of 48.88 mM and a Vmax of 169.49 U/mL. The optimum temperature and pH of the enzyme were 30 ℃ and pH 5. The thermal stability, as well as stability over a wide range ofpH, was significantly improved by the immobilization process. The activity was enhanced by Mg^2＋ （23.5%） and K^＋ （5.3%）, whereas Zn^2＋, Cu^2＋, Ca^2＋, NH^4＋ and Hg^2＋ inhibited tannase activity. Maximum substrate bioconversion （58.94%） from tannic acid to gallic acid and tea cream solubilisation （32.82%） was achieved using immobilized tannase. The extracellular tannase produced by P. verrucosum showed distinctive characteristics such as monomeric structure and activation by Mg^2＋, suggesting a new kind of fungal tannase with biotechnological potential.
基金Supported by Key Science and Technology Program for Social Development of Guizhou Province(QKHSY[2013]3148)~~
文摘The aim was to explore the purification ability of potted taxus for indoor sulfur dioxide pollution. Three taxus cultivars were placed in different rooms. The air in the rooms was sampled continuously at the flow rate of 0.5 ml/min, and the content of sulfur dioxide was determined by formaldehyde absorbing-pararosaniline spectrophotometry. The obtained linear equation for sulfur dioxide was as follows： y=0.030 1 x＋0.023 5, F=0.999 7. The content of sulfur dioxide in the three rooms placed with different taxus cultivars all declined, suggesting that potted taxus has a certain ability to purify sulfur dioxide. Among the taxus cultivars, Taxus yunnanensis showed the highest purification rate, followed by Taxus chinensis vat. mairei and Taxus media cv. Hicksii.
基金supported by the National Basic Research Program of China(973 Program)(Grant No.2004CB719700)CAS Knowledge Innovation Program Important Direction Project(Grant No.KJCX2-SW·206)Hi-Tech Research and Development Program of China(863 program)(Grant No.2003AA514023).
文摘The effect of different extraction and purification conditions on the microbial protein obtained from solid-state fermentation(SSF)and the effect of periodical dynamic changes of air on protein have been studied.The mechanism of solid-state fermentation with periodical dynamic changes of air is also discussed.Compared with static solid-state fermentation,periodical dynamic changes of air afford a higher protein mass;from 1 g of the fermentation microbe,5.3 mg of the intracellular protein(an increase of 34.63%)and 9.09 mg of the extracellular protein(an increase of 17.8%)were obtained on the sixth day of fermentation.The filter paper activity and carboxymethyl cellulose activity(FPA and CMCase)of the extracellular protein are 1.739μmol/s and 109.592μmol/s,respectively,which represent increases of 60.1%and 21.2%over the corresponding values for static solid-state fermentation.The FPA and CMCase of the intra-cellular protein are 0.245μmol/s and 6.392μmol/s,respec-tively,which represent decreases of 22.2%and 38.7%over the corresponding values for static solid-state fermentation.The enzyme activity of the microbial extracellular protein in solid-state fermentation with periodical dynamic changes of air on the fifth day is nearly equal to that on the sixth day without periodical dynamic changes of air,so the period of fermentation can be shortened.The sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)experiments suggest that pulsating air pressure stimulation leads to a decrease in the amount of protein component with molecule mass of about 80400Da,and an increase in the amount of protein component with molecule mass of about 28520Da.
