The emission of heavy-duty vehicles has raised great concerns worldwide.The complex working and loading conditions,which may differ a lot from PEMS tests,raised new challenges to the supervision and control of emissio...The emission of heavy-duty vehicles has raised great concerns worldwide.The complex working and loading conditions,which may differ a lot from PEMS tests,raised new challenges to the supervision and control of emissions,especially during real-world applications.On-board diagnostics(OBD)technology with data exchange enabled and strengthened the monitoring of emissions from a large number of heavy-duty diesel vehicles.This paper presents an analysis of the OBD data collected from more than 800 city and highway heavy-duty vehicles in China using remote OBD data terminals.Real-world NO_(x)and CO_(2)emissions of China-6 heavy-duty vehicles have been examined.The results showed that city heavy-duty vehicles had higher NO_(x)emission levels,which was mostly due to longer time of low SCR temperatures below 180°C.The application of novel methods based on 3BMAWalso found that heavy-duty diesel vehicles tended to have high NO_(x)emissions at idle.Also,little difference had been found in work-based CO_(2)emissions,and this may be due to no major difference were found in occupancies of hot running.展开更多
Biomass-based membranes have attracted increasing attentions due to their cheap and sustainable advantages.In this work,a novel thin-fiilm composite(TFC)nanofiltration(NF)membrane was fabricated through a facial inter...Biomass-based membranes have attracted increasing attentions due to their cheap and sustainable advantages.In this work,a novel thin-fiilm composite(TFC)nanofiltration(NF)membrane was fabricated through a facial interfacial polymerization(IP)process by initiate the crosslinking reaction between collagen fibers(CFs)and tannic acid(TA).The increased TA concentrations endowed the TFC membrane with a higher crosslinking degree,a thicker active layer and a rougher top surface.At optimized condition with 0.60 mg TA decoration,the TFC-3 membrane exhibited a high water permeability of 23.49 L m^(-2)h^(-1)bar^(-1)with high rejections above 98.0%for congo red,reactive blue 19,coomassie blue G-250,and methyl blue.Furthermore,the membrane preserved remarkable salt retentions(93.3%for Na_(2)SO_(4),83.4%for MgSO_(4),36.2%for MgCl_(2),and 26.4%for NaCl)and satisfying operation stability.This facial fabrication method offered a new insight to employ biomass for molecular precise separation.展开更多
Traditional nanofiltration membranes face challenges such as membrane fouling and difficulties in achieving precise separation of small organic molecules.A promising solution to these issues is the preparation of thin...Traditional nanofiltration membranes face challenges such as membrane fouling and difficulties in achieving precise separation of small organic molecules.A promising solution to these issues is the preparation of thin-film nanocomposite membranes.In this study,Cu and Ag bimetals were incorporated into covalent organic frameworks to fabricate thin-film nanocomposite membranes.The hydrophilic monomer 1,3,5-tris(4-aminophenyl)benzene of covalent organic frameworks was introduced as a water phase monomer during interfacial polymerization to enhance the organic-inorganic compatibility.The incorporated covalent organic frameworks within the thin-film nanocomposite membrane loosened the selective layer,resulting in an enhanced permeability of 24.6 LMH bar^(-1).The membrane exhibited a rejection rate over 99.0%for Congo Red,Xylene Brilliant Cyanine G,and Reactive Blue,while exhibiting relatively low rejection rates of MgCl_(2) and NaCl.Moreover,the outstanding catalytic capability of the incorporated bimetals led to a 4-nitrophenol conversion rate of 84.38%,enabling simultaneous conversion and separation.The integration of covalent organic frameworks and bimetals also imparted robust antibacterial properties,significantly enhancing operational stability.In conclusion,the covalent organic framework-Cu/Ag-based thin-film nanocomposite membrane demonstrated superior catalytic and separation capabilities,presenting a promising alternative for advanced filtration applications.展开更多
基金supported by the National Key Research and Development Project of China(No.2022YFC3701802)the National Natural Science Foundation of China(No.52272342)the Major Science and Technology Projects of Qinghai Province(No.2019-GX-A6).
文摘The emission of heavy-duty vehicles has raised great concerns worldwide.The complex working and loading conditions,which may differ a lot from PEMS tests,raised new challenges to the supervision and control of emissions,especially during real-world applications.On-board diagnostics(OBD)technology with data exchange enabled and strengthened the monitoring of emissions from a large number of heavy-duty diesel vehicles.This paper presents an analysis of the OBD data collected from more than 800 city and highway heavy-duty vehicles in China using remote OBD data terminals.Real-world NO_(x)and CO_(2)emissions of China-6 heavy-duty vehicles have been examined.The results showed that city heavy-duty vehicles had higher NO_(x)emission levels,which was mostly due to longer time of low SCR temperatures below 180°C.The application of novel methods based on 3BMAWalso found that heavy-duty diesel vehicles tended to have high NO_(x)emissions at idle.Also,little difference had been found in work-based CO_(2)emissions,and this may be due to no major difference were found in occupancies of hot running.
基金National Natural Science Foundation of China(Grant No:21908076)
文摘Biomass-based membranes have attracted increasing attentions due to their cheap and sustainable advantages.In this work,a novel thin-fiilm composite(TFC)nanofiltration(NF)membrane was fabricated through a facial interfacial polymerization(IP)process by initiate the crosslinking reaction between collagen fibers(CFs)and tannic acid(TA).The increased TA concentrations endowed the TFC membrane with a higher crosslinking degree,a thicker active layer and a rougher top surface.At optimized condition with 0.60 mg TA decoration,the TFC-3 membrane exhibited a high water permeability of 23.49 L m^(-2)h^(-1)bar^(-1)with high rejections above 98.0%for congo red,reactive blue 19,coomassie blue G-250,and methyl blue.Furthermore,the membrane preserved remarkable salt retentions(93.3%for Na_(2)SO_(4),83.4%for MgSO_(4),36.2%for MgCl_(2),and 26.4%for NaCl)and satisfying operation stability.This facial fabrication method offered a new insight to employ biomass for molecular precise separation.
基金sponsored by the National Natural Science Foundation of China(Grant No.NSFC-22378160 and U23A20688).
文摘Traditional nanofiltration membranes face challenges such as membrane fouling and difficulties in achieving precise separation of small organic molecules.A promising solution to these issues is the preparation of thin-film nanocomposite membranes.In this study,Cu and Ag bimetals were incorporated into covalent organic frameworks to fabricate thin-film nanocomposite membranes.The hydrophilic monomer 1,3,5-tris(4-aminophenyl)benzene of covalent organic frameworks was introduced as a water phase monomer during interfacial polymerization to enhance the organic-inorganic compatibility.The incorporated covalent organic frameworks within the thin-film nanocomposite membrane loosened the selective layer,resulting in an enhanced permeability of 24.6 LMH bar^(-1).The membrane exhibited a rejection rate over 99.0%for Congo Red,Xylene Brilliant Cyanine G,and Reactive Blue,while exhibiting relatively low rejection rates of MgCl_(2) and NaCl.Moreover,the outstanding catalytic capability of the incorporated bimetals led to a 4-nitrophenol conversion rate of 84.38%,enabling simultaneous conversion and separation.The integration of covalent organic frameworks and bimetals also imparted robust antibacterial properties,significantly enhancing operational stability.In conclusion,the covalent organic framework-Cu/Ag-based thin-film nanocomposite membrane demonstrated superior catalytic and separation capabilities,presenting a promising alternative for advanced filtration applications.
