In order to recover the SiO_2 contained in the mother liquor in the course ofNaY zeolite synthesis to minimize pollution, the influence of various preparation conditions on thefiltering velocity of gel slurry was stud...In order to recover the SiO_2 contained in the mother liquor in the course ofNaY zeolite synthesis to minimize pollution, the influence of various preparation conditions on thefiltering velocity of gel slurry was studied using the SiO_2/Al_2O_3 gel recovered from the NaYmother liquor in the laboratory. The results of study had shown that at a SiO_2/Al_2O_3 ratio in thefeed equating to 9∶1 the SiO_2 recovery rate and Al_2O_3 utilization rate were high with a fasterflow velocity of the filtrate. The pH value of the system had great impact on the flow velocity offiltrate. Between the two methods for regulating the pH value, the one for formation ofsilica/alumina gel slurry by addition of sulfuric acid prior to adding aluminium sulfate in thesolution could secure a faster filtration velocity. The filtration velocity was decreased in tandemwith increasing SiO_2 concentration in mother liquor, meanwhile an increase in dry filter cakeyield.展开更多
In this paper,the particle-loaden filtration of real fibre media was numerically studied using computational fluid dynamics(CFD)and discrete element method(DEM)method.The filtration performance was comprehensively ana...In this paper,the particle-loaden filtration of real fibre media was numerically studied using computational fluid dynamics(CFD)and discrete element method(DEM)method.The filtration performance was comprehensively analysed by combining fluid and particle properties into a single dimensionless number,Stokes number(St).The results indicated that the capture efficiency increased with St until it stabilised at a certain limit value,which was in good agreement with the results of the previous empirical laws,confirming the accuracy and reliability of the CFD-DEM algorithm.In addition,the capture contribution of fluid and particle properties were investigated.It was found that increasing particle size and density was effective in improving capture efficiency.Moreover,reducing fluid viscosity was the most favourable condition for improving filtration performance.For the dynamic filtration of particle size d_(p)=2–4μm,the evolution of the capture efficiency and the pressure drop for d_(p)==4μm was higher than that of other particle sizes due to the easy formation of the dendrite structure.In terms of the quality factor,the fibre layer exhibited a better filtration performance for particles with a diameter of 4.0μm.This study provided a good understanding of dynamic particle-loaden filtration,which is useful for the optimal design of fibre filters.展开更多
Bioaerosol filtration is crucial for improving indoor air quality and reducing cross-infection risk.It is necessary to conduct a comprehensive study on the bioaerosol filtration performance of air filters under differ...Bioaerosol filtration is crucial for improving indoor air quality and reducing cross-infection risk.It is necessary to conduct a comprehensive study on the bioaerosol filtration performance of air filters under different influencing factors.Firstly,this study proposed a standardized test scheme for the comprehensive evaluation of bioaerosol filtration performance.Additionally,the high-efficiency particulate air(H13)and medium-efficiency particulate air(F8)filters were evaluated in depth using Serratia marcescens bioaerosol,considering the face velocity,relative humidity(RH),and operating time.This study also investigated the impact of removing static electricity on the bioaerosol filtration efficiency(BFE)of F-filter materials.The pressure drop(ΔP)value of H13-filter and the BFE of F8-filter were significantly affected by face velocity and RH.When the face velocity increased from 5 to 20 cm/s,the H13-filter maintained a BFE above 99%,whileΔP increased by 303 Pa.During a 90 min test,the maximum change in the BFE of the H13-filter was 0.80%andΔP increased by 26 Pa.Conversely,the BFE of the F8-filter decreased by up to 12.21%,whileΔP increased by only 3 Pa.Higher RH resulted in more pronounced changes in BFE.After removing the static electricity from the F8-filter material,the BFE decreased significantly,with a maximum reduction of 25%.The results may provide valuable insights into the application of conventional filters in bioaerosol filtration and serve as a guide for the enhancement and optimization of filter design.展开更多
A novel functional magnetic polyimide loaded with cobalt ferrite nanoparticles by coprecipitation method was proposed,and XRD,FTIR,SEM technologies were employed to study their physicochemical properties.The filtra-ti...A novel functional magnetic polyimide loaded with cobalt ferrite nanoparticles by coprecipitation method was proposed,and XRD,FTIR,SEM technologies were employed to study their physicochemical properties.The filtra-tion performance of non-magnetic and magnetic polyimide were examined by experimental system.The effects of dust resistance,filtration velocity and initial dust concentration on the filtration performance of magnetic polyimide were investigated under different dust loadings.The results revealed that presence of𝜌-лconjuga-tion between the cobalt ferrite and polyimide fiber resulted in easily load on the fiber surface for cobalt ferrite nanoparticles.The magnetic polyimide exhibited good filtration efficiency especially in the range of particle size less than 2μm.The filtration efficiency of magnetic polyimide filter materials increased by nearly 20%com-pared with the primary polyimide.Due to the loading of cobalt ferrite,the resistance of the magnetic polyimide increased,while the resistance growth rate decreased from 100%to 29%with increased filtration velocity from 0.5 m/min to 2.5 m/min.展开更多
文摘In order to recover the SiO_2 contained in the mother liquor in the course ofNaY zeolite synthesis to minimize pollution, the influence of various preparation conditions on thefiltering velocity of gel slurry was studied using the SiO_2/Al_2O_3 gel recovered from the NaYmother liquor in the laboratory. The results of study had shown that at a SiO_2/Al_2O_3 ratio in thefeed equating to 9∶1 the SiO_2 recovery rate and Al_2O_3 utilization rate were high with a fasterflow velocity of the filtrate. The pH value of the system had great impact on the flow velocity offiltrate. Between the two methods for regulating the pH value, the one for formation ofsilica/alumina gel slurry by addition of sulfuric acid prior to adding aluminium sulfate in thesolution could secure a faster filtration velocity. The filtration velocity was decreased in tandemwith increasing SiO_2 concentration in mother liquor, meanwhile an increase in dry filter cakeyield.
基金supported by the Department of Science and Technology of Jilin Province of China(grant No.20220508005RC)the National Natural Science Foundation of China(grant No.22208120).
文摘In this paper,the particle-loaden filtration of real fibre media was numerically studied using computational fluid dynamics(CFD)and discrete element method(DEM)method.The filtration performance was comprehensively analysed by combining fluid and particle properties into a single dimensionless number,Stokes number(St).The results indicated that the capture efficiency increased with St until it stabilised at a certain limit value,which was in good agreement with the results of the previous empirical laws,confirming the accuracy and reliability of the CFD-DEM algorithm.In addition,the capture contribution of fluid and particle properties were investigated.It was found that increasing particle size and density was effective in improving capture efficiency.Moreover,reducing fluid viscosity was the most favourable condition for improving filtration performance.For the dynamic filtration of particle size d_(p)=2–4μm,the evolution of the capture efficiency and the pressure drop for d_(p)==4μm was higher than that of other particle sizes due to the easy formation of the dendrite structure.In terms of the quality factor,the fibre layer exhibited a better filtration performance for particles with a diameter of 4.0μm.This study provided a good understanding of dynamic particle-loaden filtration,which is useful for the optimal design of fibre filters.
基金supported by National Outstanding Youth Science Fund Project of National Natural Science Foundation of China(No.42122058)National Natural Science Foundation of China(No.52208107)+1 种基金National Key R&D Program of China(2021YFF0604000)Outstanding Youth Science Foundation Program of Hebei Province(No.E2023502015).
文摘Bioaerosol filtration is crucial for improving indoor air quality and reducing cross-infection risk.It is necessary to conduct a comprehensive study on the bioaerosol filtration performance of air filters under different influencing factors.Firstly,this study proposed a standardized test scheme for the comprehensive evaluation of bioaerosol filtration performance.Additionally,the high-efficiency particulate air(H13)and medium-efficiency particulate air(F8)filters were evaluated in depth using Serratia marcescens bioaerosol,considering the face velocity,relative humidity(RH),and operating time.This study also investigated the impact of removing static electricity on the bioaerosol filtration efficiency(BFE)of F-filter materials.The pressure drop(ΔP)value of H13-filter and the BFE of F8-filter were significantly affected by face velocity and RH.When the face velocity increased from 5 to 20 cm/s,the H13-filter maintained a BFE above 99%,whileΔP increased by 303 Pa.During a 90 min test,the maximum change in the BFE of the H13-filter was 0.80%andΔP increased by 26 Pa.Conversely,the BFE of the F8-filter decreased by up to 12.21%,whileΔP increased by only 3 Pa.Higher RH resulted in more pronounced changes in BFE.After removing the static electricity from the F8-filter material,the BFE decreased significantly,with a maximum reduction of 25%.The results may provide valuable insights into the application of conventional filters in bioaerosol filtration and serve as a guide for the enhancement and optimization of filter design.
基金supported by the National Key Research and Develop-ment Program of China(2018YFC0705300)the Special Funds and Key Projects of Fundamental Scientific Research Business Fees in Central Universities(2232017A-09,CUSF-DH-d-2017097).
文摘A novel functional magnetic polyimide loaded with cobalt ferrite nanoparticles by coprecipitation method was proposed,and XRD,FTIR,SEM technologies were employed to study their physicochemical properties.The filtra-tion performance of non-magnetic and magnetic polyimide were examined by experimental system.The effects of dust resistance,filtration velocity and initial dust concentration on the filtration performance of magnetic polyimide were investigated under different dust loadings.The results revealed that presence of𝜌-лconjuga-tion between the cobalt ferrite and polyimide fiber resulted in easily load on the fiber surface for cobalt ferrite nanoparticles.The magnetic polyimide exhibited good filtration efficiency especially in the range of particle size less than 2μm.The filtration efficiency of magnetic polyimide filter materials increased by nearly 20%com-pared with the primary polyimide.Due to the loading of cobalt ferrite,the resistance of the magnetic polyimide increased,while the resistance growth rate decreased from 100%to 29%with increased filtration velocity from 0.5 m/min to 2.5 m/min.
