In recent years,ozone has become one of the key pollutants affecting the urban air qual-ity.Direct catalytic decomposition of ozone emerges as an effective method for ozone re-moval.Field experimentswere conducted to ...In recent years,ozone has become one of the key pollutants affecting the urban air qual-ity.Direct catalytic decomposition of ozone emerges as an effective method for ozone re-moval.Field experimentswere conducted to evaluate the effectiveness of exteriorwall coat-ings with ozone decomposition catalysts for ozone removal in practical applications.ANSYS 2020R1 software was first used for simulation and analysis of ozone concentration and flow fields to investigate the decomposition boundary of these wall coatings.The results show that the exterior wall coatings with manganese-based catalysts can effectively reduce the ozone concentration near the wall coating.The ozone decomposition efficiency is nega-tively correlated with the distance fromthe coating and the decomposition boundary range is around 18 m.The decomposition boundary will increase with the increase of tempera-ture,and decrease with the increase of the wind speed and the relative humidity.These results underscore the viability of using exterior wall coatings with catalysts for controlling ozone pollution in atmospheric environments.This approach presents a promising avenue for addressing ozone pollution through self-purifying materials on building external wall.展开更多
With the development of activated sludge model, the simulation software for the design and operation of wastewater treatment plant （WWTP） was produced and has been widely used. The dynamic change of the quality and ...With the development of activated sludge model, the simulation software for the design and operation of wastewater treatment plant （WWTP） was produced and has been widely used. The dynamic change of the quality and flow of influent are major factors causing the unstable operation of wastewater treatment process. As a basic model, ASMI model was used for the simulation of activated sludge process, and double exponential model was selected for the simulation of secondary sedimentation tank. The influences of influent change to the aeration tank and secondary sedimentation tank were investigated, and the relationship among influent change, the quality of effluent and the level of sludge blanket in secondary sedimentation tank was established. On the basis of the simulation results, the operation of the WWTP could be adjusted under the dynamic change of the influent. Furthermore, the controlling strategy combined the feed-forward on the influent flow and the feedback on the level of sludge blanket in the secondary sedimentation tank was studied.展开更多
An increasing divergence regarding fuel consumption(and/or CO_(2)emissions) between realworld and type-approval values for light-duty gasoline vehicles(LDGVs) has posed severe challenges to mitigating greenhouse gases...An increasing divergence regarding fuel consumption(and/or CO_(2)emissions) between realworld and type-approval values for light-duty gasoline vehicles(LDGVs) has posed severe challenges to mitigating greenhouse gases(GHGs) and achieving carbon emissions peak and neutrality. To address this divergence issue, laboratory test cycles with more real-featured and transient traffic patterns have been developed recently, for example, the China Lightduty Vehicle Test Cycle for Passenger cars(CLTC-P). We collected fuel consumption and CO_(2)emissions data of a LDGV under various conditions based on laboratory chassis dynamometer and on-road tests. Laboratory results showed that both standard test cycles and setting methods of road load affected fuel consumption slightly, with variations of less than 4%. Compared to the type-approval value, laboratory and on-road fuel consumption of the tested LDGV over the CLTC-P increased by 9% and 34% under the reference condition(i.e., air conditioning off, automatic stop and start(STT) on and two passengers). On-road measurement results indicated that fuel consumption under the low-speed phase of the CLTC-P increased by 12% due to the STT off, although only a 4% increase on average over the entire cycle. More fuel consumption increases(52%) were attributed to air conditioning usage and full passenger capacity. Strong correlations(R2> 0.9) between relative fuel consumption and average speed were also identified. Under traffic congestion(average speed below 25 km/hr), fuel consumption was highly sensitive to changes in vehicle speed. Thus,we suggest that real-world driving conditions cannot be ignored when evaluating the fuel economy and GHGs reduction of LDGVs.展开更多
Based on the relationship between water environment system and human society,water environment carrying capacity(WECC)probes into supporting ability of complex water environment system to the human society.Recent year...Based on the relationship between water environment system and human society,water environment carrying capacity(WECC)probes into supporting ability of complex water environment system to the human society.Recent years,due to the shortage of water resources and serious water pollution in several watersheds in China,the research of watershed water environment carrying capacity(WWECC)becomes very important.The conception,connotation and method of representation of WWECC are discussed deeply in this paper.It shows that WWECC is a kind of index that instructs whether the water environment system in watershed can continue to support the development of social economy and ecology,it is dimensionless number.展开更多
The nondestructive characterization of the mixing state of individual fine particles using the traditional single particle analysis technique remains a challenge.In this study,fine particles were collected during haze...The nondestructive characterization of the mixing state of individual fine particles using the traditional single particle analysis technique remains a challenge.In this study,fine particles were collected during haze events under different pollution levels from September 5 to 112017 in Beijing,China.A nondestructive surface-enhanced Raman scattering(SERS)technique was employed to investigate the morphology,chemical composition,and mixing state of the multiple components in the individual fine particles.Optical image and SERS spectral analysis results show that soot existing in the form of opaque material was predominant during clear periods(PM_(2.5)≤75μg/m^(3)).During polluted periods(PM_(2.5)>75μg/m^(3)),opaque particles mixed with transparent particles(nitrates and sulfates)were generally observed.Direct classical least squares analysis further identified the relative abundances of the three major components of the single particles:soot(69.18%),nitrates(28.71%),and sulfates(2.11%).A negative correlation was observed between the abundance of soot and the mass concentration of PM_(2.5).Furthermore,mapping analysis revealed that on hazy days,PM_(2.5)existed as a core-shell structure with soot surrounded by nitrates and sulfates.This mixing state analysis method for individual PM_(2.5)particles provides information regarding chemical composition and haze formation mechanisms,and has the potential to facilitate the formulation of haze prevention and control policies.展开更多
Environmental impact of pollutants can be analyzed effectively by acquiring fish behavioral signals in water with biological behavior sensors. However, a variety of factors, such as the complexity of biological organi...Environmental impact of pollutants can be analyzed effectively by acquiring fish behavioral signals in water with biological behavior sensors. However, a variety of factors, such as the complexity of biological organisms themselves, the device error and the environmental noise, may compromise the accuracy and timeliness of model predictions. The current methods lack prior knowledge about the fish behavioral signals corresponding to characteristic pollutants, and in the event of a pollutant invasion, the fish behavioral signals are poorly discriminated. Therefore, we propose a novel method based on Bayesian sequential,which utilizes multi-channel prior knowledge to calculate the outlier sequence based on wavelet feature followed by calculating the anomaly probability of observed values. Furthermore, the relationship between the anomaly probability and toxicity is analyzed in order to achieve forewarning effectively. At last, our algorithm for fish toxicity detection is verified by integrating the data on laboratory acceptance of characteristic pollutants. The results show that only one false positive occurred in the six experiments, the present algorithm is effective in suppressing false positives and negatives, which increases the reliability of toxicity detections, and thereby has certain applicability and universality in engineering applications.展开更多
In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state（UASS）with anaerobic filter（AF） system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was inves...In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state（UASS）with anaerobic filter（AF） system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0–431 m L O2/gvswere conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431 m L O2/gvsincreased the methane yield by 82.2%. Aeration intensities of 0–355 m L O2/gvswere conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen（DO） of UASS and AF reactors kept around 1.39 ±0.27 and 0.99 ± 0.38 mg/L, respectively. p H was relatively stable around 7.11 ± 0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85 ± 7 m L/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.展开更多
Although a relationship between epigenetics and aging phenotypic changes has been established,a theoretical explanation of the intrinsic connection between the epigenetics and aging is lacking.In this essay,we propose...Although a relationship between epigenetics and aging phenotypic changes has been established,a theoretical explanation of the intrinsic connection between the epigenetics and aging is lacking.In this essay,we propose that epigenetic recording of varied cell environment and complex history could be an origin of cellular aging.Through epigenetic modifications,the environment and historical events can induce the chromatin template into an activated or repressive accessible structure,thereby shaping the DNA template into a spectrum of chromatin states.The inner nature of diversity and conflicts born by the cell environment and its historical events are hence recorded into the chromatin template.This could result in a dissipated spectrum of the chromatin state and chaos in overall gene expression.An unavoidable degradation of epigenome entropy,similar to Shannon entropy,would be consequently induced.The resultant disorder in epigenome,characterized by corrosion of epigenome entropy as reflected in chromatin template,can be stably memorized and propagated through cell division.Furthermore,the hysteretic nature of epigenetics responding to the emerging environment could exacerbate the degradation of epigenome entropy.As well as stochastic errors,we propose that outside entropy(or chaos) derived from the varied environment and complex cell history,gradually input and imprinted into the chromatin via epigenetic modifications,would lead inevitably to cellular aging,the extent of which could be aggravated by hysteresis of epigenetics without error erasing and correction.展开更多
In the present study,we investigated the influence of surface fluorine(F)on TiO_(2)for the photocatalytic oxidation(PCO)of toluene.TiO_(2)modified with different F content was prepared and tested.It was found that wit...In the present study,we investigated the influence of surface fluorine(F)on TiO_(2)for the photocatalytic oxidation(PCO)of toluene.TiO_(2)modified with different F content was prepared and tested.It was found that with the increasing of F content,the toluene conversion rate first increased and then decreased.However,CO_(2)mineralization efficiency showed the opposite trend.Based on the characterizations,we revealed that F substitutes the surface hydroxyl of TiO_(2)to form the structure of≡Ti-F.The presence of the appropriate amount of surface≡Ti-F on TiO_(2)greatly enhanced the separation of photogenerated carriers,which facilitated the generation of·OH and promoted the activity for the PCO of toluene.It was further revealed that the increase of only·OH promoted the conversion of toluene to ring-containing intermediates,causing the accumulation of intermediates and then conversely inhibited the·OH generation,which led to the decrease of the CO_(2)mineralization efficiency.The above results could provide guidance for the rational design of photocatalysts for toluene oxidation.展开更多
Tuojiang River Basin is a first-class tributary of the upper reaches of the Yangtze River—which is the longest river in China.As phytoplankton are sensitive indicators of trophic changes inwater bodies,characterizing...Tuojiang River Basin is a first-class tributary of the upper reaches of the Yangtze River—which is the longest river in China.As phytoplankton are sensitive indicators of trophic changes inwater bodies,characterizing phytoplankton communities and their growth influencing factors in polluted urban rivers can provide new ideas for pollution control.Here,we used direct microscopic count and environmental DNA(eDNA)metabarcoding methods to investigate phytoplankton community structure in Tuojiang River Basin(Chengdu,Sichuan Province,China).The association between phytoplankton community structure and water environmental factors was evaluated by Mantel analysis.Additional environmental monitoring data were used to pinpoint major factors that influenced phytoplankton growth based on structural equation modeling.At the phylum level,the dominant phytoplankton taxa identified by the conventional microscopic method mainly belonged to Bacillariophyta,Chlorophyta,and Cyanophyta,in contrast with Chlorophyta,Dinophyceae,and Bacillariophyta identified by eDNA metabarcoding.Inα-diversity analysis,eDNA metabarcoding detected greater species diversity and achieved higher precision than the microscopic method.Phytoplankton growth was largely limited by phosphorus based on the nitrogen-to-phosphorus ratios>16:1 in all water samples.Redundancy analysis and structural equation modeling also confirmed that the nitrogen-to-phosphorus ratio was the principal factor influencing phytoplankton growth.The results could be useful for implementing comprehensive management of the river basin environment.It is recommended to control the discharge of point-and surface-source pollutants and the concentration of dissolved oxygen in areas with excessive nutrients(e.g.,Jianyang-Ziyang).Algae monitoring techniques and removal strategies should be improved in 201 Hospital,Hongrihe Bridge and Colmar Town areas.展开更多
NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.A...NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.An innovative V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst for NO_(x)removal was prepared in this study.The influences of Ce and Ta in the V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst on the SCR performance and physicochemical properties were investigated.The V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst not only exhibited excellent SCR activity in a wide temperature window,but also presented strong resistance to H_(2)Oand SO_(2)at 275◦C.A series of characterizationmethods was used to study the catalysts,including H2-temperature programmed reduction,X-ray photoelectron spectroscopy,NH_(3)-temperature programmed desorption,etc.It was discovered that a synergistic effect existed between Ce and Ta species.The introduction of Ce and Ta enlarged the specific surface area,increased the amount of acid sites and the ratio of Ce^(3+),(V^(3+)+V^(4+))and Oα,and strengthened the redox capability which were related to synergistic effect between Ce and Ta species,significantly improving the NH_(3)-SCR activity.展开更多
To develop efficient catalysts for ambient carbon monoxide(CO)oxidation is significant for indoor air purification and also for many industrial applications.In this work,the catalytic activity for CO oxidation were en...To develop efficient catalysts for ambient carbon monoxide(CO)oxidation is significant for indoor air purification and also for many industrial applications.In this work,the catalytic activity for CO oxidation were enhanced by tuning the metal-support interaction of Ru/CeO_(2)catalysts.A series of Ru/CeO_(2)catalysts were synthesized by an impregnation method with calcination at 100,200,400 and 600℃,respectively,to regulate the Ru-CeO_(2)interaction.We discovered that low temperature calcination(100℃)induced more Ru-O-Ce bonds and stronger Ru-CeO_(2)interaction,while high temperature calcination(≥400℃)caused the agglomeration of Ru species with more Ru-O-Ru bonds and weaker Ru-CeO_(2)interaction,resulting in the lower redox capacity of these catalysts,as well as lower catalytic activity for CO oxidation.Only calcination at moderate 200℃ can induce the moderate interaction between Ru species and CeO_(2)support,which can keep the high dispersion of RuO_(x)species with the high redox capacity,thus leading to complete elimination of 500 ppm CO at room temperature on Ru/Ce-200 catalyst.展开更多
In this work,a new process for achieving the recovery of elemental sulfur by utilizing a fluidized catalytic cracking(FCC) riser reactor for SOxtreatment(FCC-DeSOx) is proposed.The process leverages the high temperatu...In this work,a new process for achieving the recovery of elemental sulfur by utilizing a fluidized catalytic cracking(FCC) riser reactor for SOxtreatment(FCC-DeSOx) is proposed.The process leverages the high temperatures and hydrocarbon concentrations in the FCC riser reactor to convert SOxinto H_(2)S.Subsequently,H_(2)S,along with the cracked gas,is processed downstream to produce sulfur.Thermodynamic analysis of the key reduction reactions in the FCC-DeSOxprocess revealed that complete conversion of SOxto H_(2)S is feasible in the dry gas(hydrogen-rich) prelift zone,as well as the upper and lower zones of the riser,upon achieving thermodynamic equilibrium.Experimental studies were conducted to replicate the conditions of these reaction zones using a low concentration of hydrogen gas as the reducing agent.Through process optimization,investigation of the minimum reaction time,and kinetic studies,the potential of this method for the complete reduction of SOxwas further confirmed.展开更多
Two kinds of oxide-zeolite composite support,Ce-beta and Zr-beta were prepared by a simple wet impregnation method and adopted for the preparation of palladium-based catalysts for catalytic oxidation of methane.The Pd...Two kinds of oxide-zeolite composite support,Ce-beta and Zr-beta were prepared by a simple wet impregnation method and adopted for the preparation of palladium-based catalysts for catalytic oxidation of methane.The Pd/6.8Zr-beta catalyst showed superiormethane oxidation performance,achieving T_(50) and T90 of 417℃ and 451℃,respectively,together with robust hydrothermal stability.Kinetic analysis has shown that incorporating Zr into the catalyst significantly enhanced its efficiency,nearly tripling the turnover frequency(TOF)for methane combustion compared to the Pd/beta catalyst.This enhanced performance was attributed to the dispersion of Zr on the zeolite surface,which not only promoted the formation of active PdO sites but also helped maintain the high Pd^(2+)content via facilitating the oxygen migration during the reaction,thus improving both the catalyst’s activity and stability.In the Pd/8.6Ce-beta catalyst,doped CeO_(2) tended to aggregate in the zeolite’s pores,adversely affecting the catalyst’s efficiency.This aggregation promoted the formation of inactive Pd^(4+) species,a result of the enhanced metal-support interaction.This finding is critical for understanding the implications of dopant selection in the design of high-activity methane oxidation catalysts.展开更多
Post-etching method using dilute acid solutions is an effective technology to modulate the surface compositions of metal-oxide catalysts.Here theα-MnO_(2) catalyst treated with 0.1 mol/L nitric acid exhibits higher o...Post-etching method using dilute acid solutions is an effective technology to modulate the surface compositions of metal-oxide catalysts.Here theα-MnO_(2) catalyst treated with 0.1 mol/L nitric acid exhibits higher ozone decomposition activity at high relative humidity than the counterpart treated with acetic acid.Besides the increases in surface area and lattice dislocation,the improved activity can be due to relatively higher Mn valence on the surface and newly-formed Brønsted acid sites adjacent to oxygen vacancies.The remnant nitro species deposited on the catalyst by nitric acid treatment is ideal hydrophobic groups at ambient conditions.The decomposition route is also proposed based on the DRIFTS and DFT calculations:ozone is facile to adsorb on the oxygen vacancy,and the protonic H of Brønsted acid sites bonds to the terminal oxygen of ozone to accelerate its cleavage to O_(2),reducing the reaction energy barrier of O_(2) desorption.展开更多
With the development of the global economy and the continuous consumption of fossil energy,a large amount of greenhouse gas CO_(2) has been emitted into the atmosphere.Therefore,how to reduce the concentration of CO_(...With the development of the global economy and the continuous consumption of fossil energy,a large amount of greenhouse gas CO_(2) has been emitted into the atmosphere.Therefore,how to reduce the concentration of CO_(2) in the atmosphere and convert it into high value-added products has gradually become a hot spot in scientific research.Photocatalytic CO_(2) reduction technology can combine semiconductor with solar energy to convert CO_(2) into high value-added organic carbon source through photocatalysis,which is of great significance for the effective utilization of solar energy and the emission reduction of CO_(2).After decades of exploration,many effective photocatalysts have been discovered.Among them,Bi_(2)WO_(6) with visible light absorption ability,as a new-type bismuth-based catalyst,has been widely studied due to its unique two-dimensional layered structure,stability,low cost and non-toxicity,et al.In this review,recent Advances of Bi_(2)WO_(6) in photocatalytic CO_(2) reduction reaction are summarized,including reaction mechanism,product selective regulation,In-situ Fourier transform infrared spectra application,density functional theory calculation,and various modification strategies.Finally,based on the in-depth understanding of the above advances,the future modification strategies and design ideas of Bi_(2)WO_(6) in the field of photocatalytic CO_(2) research are proposed.This has important practical significance for the latter design and development of Bi_(2)WO_(6)-based composite photocatalysts with high CO_(2) conversion performance.展开更多
Wet flue gas desulfurization(WFGD)could effectively reduce sulfur dioxide emission.However,magnesium sulfite(MgSO_(3)),a by-product of desulfurization,was easy to result in secondary pollution.In this study,the solid ...Wet flue gas desulfurization(WFGD)could effectively reduce sulfur dioxide emission.However,magnesium sulfite(MgSO_(3)),a by-product of desulfurization,was easy to result in secondary pollution.In this study,the solid catalyst Co-Bent(bentonite supported cobalt)was prepared by blending method for MgSO_(3) oxidation with bentonite as the carrier and cobalt as the active component.At the calcination temperature of 550℃ and the Co loading level of 3 wt.%,the catalyst showed excellent catalytic performance for the oxidation of high concentration MgSO_(3) slurry,and the oxidation rate of MgSO_(3) was 0.13 mol/(L·h).The research indicated that the active component was uniformly distributed within porous structure of the catalyst as Co_(3)O_(4),which facilitated the oxidation of SO_(3)^(2-) catalyzed by Co_(3)O_(4).Kinetic researches indicated the oxidation rate of MgSO_(3) was influenced by the catalyst dosage,the reaction temperature,the solution pH,the airflow rate,and the SO_(3)^(2-) concentration.Additionally,after recycling experiments,the regenerated catalyst retained its high catalytic performance for the MgSO_(3) oxidation.The reaction mechanism for the catalytic oxidation of MgSO_(3) by Co-Bent catalyst was also proposed.The generation of active free radicals(OH·,SO_(4)^(-)·,SO_(3)^(-)·,SO_(5)^(-)·)accelerated the MgSO_(3) oxidation.These results provide theoretical support for the treatment of MgSO_(3) and the development of durable catalyst.展开更多
To promote growth,terrestrial plants release photosynthetic products into the rhizosphere in the form of root exudates through their root systems.Under the attraction of root exudates,plant growth-promoting rhizobacte...To promote growth,terrestrial plants release photosynthetic products into the rhizosphere in the form of root exudates through their root systems.Under the attraction of root exudates,plant growth-promoting rhizobacteria(PGPR)colonize the rhizosphere to stimulate plant growth and/or suppress the growth of pathogenic microorganisms.The rhizospheric recruitment of PGPR,as well as the establishment of root-microbe interactions,is initiated by chemotaxis towards root exudates.Over the past several decades,scientists have made notable strides in identifying representative chemoeffectors in root exudates,as well as the corresponding chemoreceptors.We review here the most recent developments in rhizospheric chemotaxis,particularly the chemoeffectors in root exudates,the structural and functional characterization of methyl-accepting chemotaxis proteins of PGPR,and the impacts of rhizospheric chemotaxis on root colonization,biofilm formation,and other root-microbe interactions during recruitment.Finally,we propose several perspectives that aim to fully unlock the potential of PGPR as bioinoculants in sustainable agriculture.展开更多
Hydrocarbons(HCs),as major poisoning substances,have a crucial influence on NH_(3)-SCR catalysts.In this work,the effects of C_(3)H_(6)on fresh and hydrothermally aged Cu-SSZ-39 catalysts with different copper content...Hydrocarbons(HCs),as major poisoning substances,have a crucial influence on NH_(3)-SCR catalysts.In this work,the effects of C_(3)H_(6)on fresh and hydrothermally aged Cu-SSZ-39 catalysts with different copper contents were investigated.All catalysts suffered a deactivation above 250℃,especially between 300-400℃,which was mainly related to the reaction between NH_(3)and C_(3)H_(6).However,the hydrothermally aged and the high-copper-loaded Cu-SSZ-39 catalysts could achieve a recovery of NH_(3)-SCR performance at high temperatures.Such activity recovery was attributed to the oxidation of C_(3)H_(6)by CuxOy species,which therefore inhibited the reaction between NH_(3)and C_(3)H_(6).As a result,more NH_(3)could be available for the NH_(3)-SCR reaction and the Cu-SSZ-39 catalysts could maintain a good catalytic activity.Based on these findings,we proposed that high loaded Cu-SSZ-39 catalysts with a little CuOx formed are preferred for application.展开更多
The abatement of NO_(x)from diesel vehicle exhaust is of great importance for improving the atmospheric enviro nment.Cu-SSZ-39 zeolites possess the potential for application in the diesel vehicle aftertreatment system...The abatement of NO_(x)from diesel vehicle exhaust is of great importance for improving the atmospheric enviro nment.Cu-SSZ-39 zeolites possess the potential for application in the diesel vehicle aftertreatment system.Phosphorus(P)and hydrocarbons(HCs)present in the exhaust have negative impacts on the catalysts.To enhance the resistance of Cu-SSZ-39 catalysts to P and HCs,various rare earth metals were doped.Loading of 1 wt%Ce on the Cu-SSZ-39 catalyst improves the resistance to P and HCs simultaneously.The promotion mechanism was investigated through H_(2)-temperature programmed reduction(H_(2)-TPR),ultraviolet visible diffuse reflectance spectroscopy(UV-vis-DRS),diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS),X-ray photoelectron spectroscopy(XPS),energy dispersive spectroscopy(EDS)and theoretical calculation.On the one hand,Ce species can act as sacrificial sites,preferentially binding with P.On the other hand,Ce doping induces the formation of CuO species,promoting the oxidation of C_(3)H_(6)and preventing the consumption of NH_(3)from the reaction with C_(3)H_(6).Ce acting as bi-functional sites enhances the P and HCs resistance of Cu-SSZ-39 catalysts,further brightening its practical application.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52470114 and 52022104)the National Key R&D Program of China(No.2022YFC3702802)the Youth Innovation Promotion Association,CAS(No.Y2021020).
文摘In recent years,ozone has become one of the key pollutants affecting the urban air qual-ity.Direct catalytic decomposition of ozone emerges as an effective method for ozone re-moval.Field experimentswere conducted to evaluate the effectiveness of exteriorwall coat-ings with ozone decomposition catalysts for ozone removal in practical applications.ANSYS 2020R1 software was first used for simulation and analysis of ozone concentration and flow fields to investigate the decomposition boundary of these wall coatings.The results show that the exterior wall coatings with manganese-based catalysts can effectively reduce the ozone concentration near the wall coating.The ozone decomposition efficiency is nega-tively correlated with the distance fromthe coating and the decomposition boundary range is around 18 m.The decomposition boundary will increase with the increase of tempera-ture,and decrease with the increase of the wind speed and the relative humidity.These results underscore the viability of using exterior wall coatings with catalysts for controlling ozone pollution in atmospheric environments.This approach presents a promising avenue for addressing ozone pollution through self-purifying materials on building external wall.
文摘With the development of activated sludge model, the simulation software for the design and operation of wastewater treatment plant （WWTP） was produced and has been widely used. The dynamic change of the quality and flow of influent are major factors causing the unstable operation of wastewater treatment process. As a basic model, ASMI model was used for the simulation of activated sludge process, and double exponential model was selected for the simulation of secondary sedimentation tank. The influences of influent change to the aeration tank and secondary sedimentation tank were investigated, and the relationship among influent change, the quality of effluent and the level of sludge blanket in secondary sedimentation tank was established. On the basis of the simulation results, the operation of the WWTP could be adjusted under the dynamic change of the influent. Furthermore, the controlling strategy combined the feed-forward on the influent flow and the feedback on the level of sludge blanket in the secondary sedimentation tank was studied.
基金sponsored by the National Natural Science Foundation of China (Nos. 52170111 and 41977180)the first China First Automobile Works (FAW)-Volkswagen China Environmental Protection Foundation automobile environmental protection innovation leading plan。
文摘An increasing divergence regarding fuel consumption(and/or CO_(2)emissions) between realworld and type-approval values for light-duty gasoline vehicles(LDGVs) has posed severe challenges to mitigating greenhouse gases(GHGs) and achieving carbon emissions peak and neutrality. To address this divergence issue, laboratory test cycles with more real-featured and transient traffic patterns have been developed recently, for example, the China Lightduty Vehicle Test Cycle for Passenger cars(CLTC-P). We collected fuel consumption and CO_(2)emissions data of a LDGV under various conditions based on laboratory chassis dynamometer and on-road tests. Laboratory results showed that both standard test cycles and setting methods of road load affected fuel consumption slightly, with variations of less than 4%. Compared to the type-approval value, laboratory and on-road fuel consumption of the tested LDGV over the CLTC-P increased by 9% and 34% under the reference condition(i.e., air conditioning off, automatic stop and start(STT) on and two passengers). On-road measurement results indicated that fuel consumption under the low-speed phase of the CLTC-P increased by 12% due to the STT off, although only a 4% increase on average over the entire cycle. More fuel consumption increases(52%) were attributed to air conditioning usage and full passenger capacity. Strong correlations(R2> 0.9) between relative fuel consumption and average speed were also identified. Under traffic congestion(average speed below 25 km/hr), fuel consumption was highly sensitive to changes in vehicle speed. Thus,we suggest that real-world driving conditions cannot be ignored when evaluating the fuel economy and GHGs reduction of LDGVs.
基金supported by Programfor New Century Excellent Talents in University(No.NCET-06-0130).
文摘Based on the relationship between water environment system and human society,water environment carrying capacity(WECC)probes into supporting ability of complex water environment system to the human society.Recent years,due to the shortage of water resources and serious water pollution in several watersheds in China,the research of watershed water environment carrying capacity(WWECC)becomes very important.The conception,connotation and method of representation of WWECC are discussed deeply in this paper.It shows that WWECC is a kind of index that instructs whether the water environment system in watershed can continue to support the development of social economy and ecology,it is dimensionless number.
基金supported by the National Natural Science Foundation of China(Nos.21707077,21775042)the National Key Research and Development Program of China(No.2017YFA0207003)the Fundamental Research Funds for the Central Universities(No.2020 MS037)。
文摘The nondestructive characterization of the mixing state of individual fine particles using the traditional single particle analysis technique remains a challenge.In this study,fine particles were collected during haze events under different pollution levels from September 5 to 112017 in Beijing,China.A nondestructive surface-enhanced Raman scattering(SERS)technique was employed to investigate the morphology,chemical composition,and mixing state of the multiple components in the individual fine particles.Optical image and SERS spectral analysis results show that soot existing in the form of opaque material was predominant during clear periods(PM_(2.5)≤75μg/m^(3)).During polluted periods(PM_(2.5)>75μg/m^(3)),opaque particles mixed with transparent particles(nitrates and sulfates)were generally observed.Direct classical least squares analysis further identified the relative abundances of the three major components of the single particles:soot(69.18%),nitrates(28.71%),and sulfates(2.11%).A negative correlation was observed between the abundance of soot and the mass concentration of PM_(2.5).Furthermore,mapping analysis revealed that on hazy days,PM_(2.5)existed as a core-shell structure with soot surrounded by nitrates and sulfates.This mixing state analysis method for individual PM_(2.5)particles provides information regarding chemical composition and haze formation mechanisms,and has the potential to facilitate the formulation of haze prevention and control policies.
基金supported by the National Key R & D Program of China (No. 2019YFD0901100)the Frontier Science Key Program of the Chinese Academy of Sciences (No. QYZDY-SSWDQC004)。
文摘Environmental impact of pollutants can be analyzed effectively by acquiring fish behavioral signals in water with biological behavior sensors. However, a variety of factors, such as the complexity of biological organisms themselves, the device error and the environmental noise, may compromise the accuracy and timeliness of model predictions. The current methods lack prior knowledge about the fish behavioral signals corresponding to characteristic pollutants, and in the event of a pollutant invasion, the fish behavioral signals are poorly discriminated. Therefore, we propose a novel method based on Bayesian sequential,which utilizes multi-channel prior knowledge to calculate the outlier sequence based on wavelet feature followed by calculating the anomaly probability of observed values. Furthermore, the relationship between the anomaly probability and toxicity is analyzed in order to achieve forewarning effectively. At last, our algorithm for fish toxicity detection is verified by integrating the data on laboratory acceptance of characteristic pollutants. The results show that only one false positive occurred in the six experiments, the present algorithm is effective in suppressing false positives and negatives, which increases the reliability of toxicity detections, and thereby has certain applicability and universality in engineering applications.
基金funding from the German Federal Ministry of Education and Research (No. 03SF0381A)the National Natural Science Foundation of China (No. 21206084)the National Key Technology Support Program of China (No. 2014BAC27B01)
文摘In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state（UASS）with anaerobic filter（AF） system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0–431 m L O2/gvswere conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431 m L O2/gvsincreased the methane yield by 82.2%. Aeration intensities of 0–355 m L O2/gvswere conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen（DO） of UASS and AF reactors kept around 1.39 ±0.27 and 0.99 ± 0.38 mg/L, respectively. p H was relatively stable around 7.11 ± 0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85 ± 7 m L/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.
基金Project supported by the National Key R&D Program of China(No.2017YFA0605001)the National Natural Science Foundation of China(Nos.21876011 and 91547207)the Fund for Innovative Research Group of the National Natural Science Foundation of China(No.51721093)
文摘Although a relationship between epigenetics and aging phenotypic changes has been established,a theoretical explanation of the intrinsic connection between the epigenetics and aging is lacking.In this essay,we propose that epigenetic recording of varied cell environment and complex history could be an origin of cellular aging.Through epigenetic modifications,the environment and historical events can induce the chromatin template into an activated or repressive accessible structure,thereby shaping the DNA template into a spectrum of chromatin states.The inner nature of diversity and conflicts born by the cell environment and its historical events are hence recorded into the chromatin template.This could result in a dissipated spectrum of the chromatin state and chaos in overall gene expression.An unavoidable degradation of epigenome entropy,similar to Shannon entropy,would be consequently induced.The resultant disorder in epigenome,characterized by corrosion of epigenome entropy as reflected in chromatin template,can be stably memorized and propagated through cell division.Furthermore,the hysteretic nature of epigenetics responding to the emerging environment could exacerbate the degradation of epigenome entropy.As well as stochastic errors,we propose that outside entropy(or chaos) derived from the varied environment and complex cell history,gradually input and imprinted into the chromatin via epigenetic modifications,would lead inevitably to cellular aging,the extent of which could be aggravated by hysteresis of epigenetics without error erasing and correction.
基金supported by the National Natural Science Foundation of China(Nos.21976196,22276204).
文摘In the present study,we investigated the influence of surface fluorine(F)on TiO_(2)for the photocatalytic oxidation(PCO)of toluene.TiO_(2)modified with different F content was prepared and tested.It was found that with the increasing of F content,the toluene conversion rate first increased and then decreased.However,CO_(2)mineralization efficiency showed the opposite trend.Based on the characterizations,we revealed that F substitutes the surface hydroxyl of TiO_(2)to form the structure of≡Ti-F.The presence of the appropriate amount of surface≡Ti-F on TiO_(2)greatly enhanced the separation of photogenerated carriers,which facilitated the generation of·OH and promoted the activity for the PCO of toluene.It was further revealed that the increase of only·OH promoted the conversion of toluene to ring-containing intermediates,causing the accumulation of intermediates and then conversely inhibited the·OH generation,which led to the decrease of the CO_(2)mineralization efficiency.The above results could provide guidance for the rational design of photocatalysts for toluene oxidation.
基金supported by the National Natural Science Foundation of China (No.72091511)the Science Fund for Distinguished Young Scholars of Hebei Province (No.E2022402064).
文摘Tuojiang River Basin is a first-class tributary of the upper reaches of the Yangtze River—which is the longest river in China.As phytoplankton are sensitive indicators of trophic changes inwater bodies,characterizing phytoplankton communities and their growth influencing factors in polluted urban rivers can provide new ideas for pollution control.Here,we used direct microscopic count and environmental DNA(eDNA)metabarcoding methods to investigate phytoplankton community structure in Tuojiang River Basin(Chengdu,Sichuan Province,China).The association between phytoplankton community structure and water environmental factors was evaluated by Mantel analysis.Additional environmental monitoring data were used to pinpoint major factors that influenced phytoplankton growth based on structural equation modeling.At the phylum level,the dominant phytoplankton taxa identified by the conventional microscopic method mainly belonged to Bacillariophyta,Chlorophyta,and Cyanophyta,in contrast with Chlorophyta,Dinophyceae,and Bacillariophyta identified by eDNA metabarcoding.Inα-diversity analysis,eDNA metabarcoding detected greater species diversity and achieved higher precision than the microscopic method.Phytoplankton growth was largely limited by phosphorus based on the nitrogen-to-phosphorus ratios>16:1 in all water samples.Redundancy analysis and structural equation modeling also confirmed that the nitrogen-to-phosphorus ratio was the principal factor influencing phytoplankton growth.The results could be useful for implementing comprehensive management of the river basin environment.It is recommended to control the discharge of point-and surface-source pollutants and the concentration of dissolved oxygen in areas with excessive nutrients(e.g.,Jianyang-Ziyang).Algae monitoring techniques and removal strategies should be improved in 201 Hospital,Hongrihe Bridge and Colmar Town areas.
基金supported by the National Natural Science Foundation of China(Nos.22276182 and 22188102)the Natural Science Foundation of Fujian Province,China(No.2023J06048)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2021303).
文摘NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.An innovative V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst for NO_(x)removal was prepared in this study.The influences of Ce and Ta in the V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst on the SCR performance and physicochemical properties were investigated.The V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst not only exhibited excellent SCR activity in a wide temperature window,but also presented strong resistance to H_(2)Oand SO_(2)at 275◦C.A series of characterizationmethods was used to study the catalysts,including H2-temperature programmed reduction,X-ray photoelectron spectroscopy,NH_(3)-temperature programmed desorption,etc.It was discovered that a synergistic effect existed between Ce and Ta species.The introduction of Ce and Ta enlarged the specific surface area,increased the amount of acid sites and the ratio of Ce^(3+),(V^(3+)+V^(4+))and Oα,and strengthened the redox capability which were related to synergistic effect between Ce and Ta species,significantly improving the NH_(3)-SCR activity.
基金supported by the National Natural Science Foundation of China(Nos.22025604 and 22276204)the National Key R&D Program of China(Nos.2023YFC3708401 and 2022YFC3800404).
文摘To develop efficient catalysts for ambient carbon monoxide(CO)oxidation is significant for indoor air purification and also for many industrial applications.In this work,the catalytic activity for CO oxidation were enhanced by tuning the metal-support interaction of Ru/CeO_(2)catalysts.A series of Ru/CeO_(2)catalysts were synthesized by an impregnation method with calcination at 100,200,400 and 600℃,respectively,to regulate the Ru-CeO_(2)interaction.We discovered that low temperature calcination(100℃)induced more Ru-O-Ce bonds and stronger Ru-CeO_(2)interaction,while high temperature calcination(≥400℃)caused the agglomeration of Ru species with more Ru-O-Ru bonds and weaker Ru-CeO_(2)interaction,resulting in the lower redox capacity of these catalysts,as well as lower catalytic activity for CO oxidation.Only calcination at moderate 200℃ can induce the moderate interaction between Ru species and CeO_(2)support,which can keep the high dispersion of RuO_(x)species with the high redox capacity,thus leading to complete elimination of 500 ppm CO at room temperature on Ru/Ce-200 catalyst.
基金supported by General Program of National Natural Science Foundation of China (22178385)。
文摘In this work,a new process for achieving the recovery of elemental sulfur by utilizing a fluidized catalytic cracking(FCC) riser reactor for SOxtreatment(FCC-DeSOx) is proposed.The process leverages the high temperatures and hydrocarbon concentrations in the FCC riser reactor to convert SOxinto H_(2)S.Subsequently,H_(2)S,along with the cracked gas,is processed downstream to produce sulfur.Thermodynamic analysis of the key reduction reactions in the FCC-DeSOxprocess revealed that complete conversion of SOxto H_(2)S is feasible in the dry gas(hydrogen-rich) prelift zone,as well as the upper and lower zones of the riser,upon achieving thermodynamic equilibrium.Experimental studies were conducted to replicate the conditions of these reaction zones using a low concentration of hydrogen gas as the reducing agent.Through process optimization,investigation of the minimum reaction time,and kinetic studies,the potential of this method for the complete reduction of SOxwas further confirmed.
基金supported by the National Natural Science Foundation of China(Nos.U20B6004 and 22072179)。
文摘Two kinds of oxide-zeolite composite support,Ce-beta and Zr-beta were prepared by a simple wet impregnation method and adopted for the preparation of palladium-based catalysts for catalytic oxidation of methane.The Pd/6.8Zr-beta catalyst showed superiormethane oxidation performance,achieving T_(50) and T90 of 417℃ and 451℃,respectively,together with robust hydrothermal stability.Kinetic analysis has shown that incorporating Zr into the catalyst significantly enhanced its efficiency,nearly tripling the turnover frequency(TOF)for methane combustion compared to the Pd/beta catalyst.This enhanced performance was attributed to the dispersion of Zr on the zeolite surface,which not only promoted the formation of active PdO sites but also helped maintain the high Pd^(2+)content via facilitating the oxygen migration during the reaction,thus improving both the catalyst’s activity and stability.In the Pd/8.6Ce-beta catalyst,doped CeO_(2) tended to aggregate in the zeolite’s pores,adversely affecting the catalyst’s efficiency.This aggregation promoted the formation of inactive Pd^(4+) species,a result of the enhanced metal-support interaction.This finding is critical for understanding the implications of dopant selection in the design of high-activity methane oxidation catalysts.
基金supported by the National Natural Science Foundation of China(Nos.22206155 and T2341002)the Fundamental Research Funds for the Central Universities of China(Nos.2682022CX035 and 2682022KJ035)+2 种基金China Postdoctoral Science Foundation(Nos.2022M712632 and 2023T160547)Sichuan Science and Technology Program(No.2023JDRC0066)the State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex(No.SCAPC202109).
文摘Post-etching method using dilute acid solutions is an effective technology to modulate the surface compositions of metal-oxide catalysts.Here theα-MnO_(2) catalyst treated with 0.1 mol/L nitric acid exhibits higher ozone decomposition activity at high relative humidity than the counterpart treated with acetic acid.Besides the increases in surface area and lattice dislocation,the improved activity can be due to relatively higher Mn valence on the surface and newly-formed Brønsted acid sites adjacent to oxygen vacancies.The remnant nitro species deposited on the catalyst by nitric acid treatment is ideal hydrophobic groups at ambient conditions.The decomposition route is also proposed based on the DRIFTS and DFT calculations:ozone is facile to adsorb on the oxygen vacancy,and the protonic H of Brønsted acid sites bonds to the terminal oxygen of ozone to accelerate its cleavage to O_(2),reducing the reaction energy barrier of O_(2) desorption.
基金supported by the National Natural Science Foundation of China(No.22188102)China Postdoctoral Science Foundation(No.2020M670483)the Natural Science Foundation of Shandong Province,China(Nos.ZR2023MB049 and ZR2021QB129).
文摘With the development of the global economy and the continuous consumption of fossil energy,a large amount of greenhouse gas CO_(2) has been emitted into the atmosphere.Therefore,how to reduce the concentration of CO_(2) in the atmosphere and convert it into high value-added products has gradually become a hot spot in scientific research.Photocatalytic CO_(2) reduction technology can combine semiconductor with solar energy to convert CO_(2) into high value-added organic carbon source through photocatalysis,which is of great significance for the effective utilization of solar energy and the emission reduction of CO_(2).After decades of exploration,many effective photocatalysts have been discovered.Among them,Bi_(2)WO_(6) with visible light absorption ability,as a new-type bismuth-based catalyst,has been widely studied due to its unique two-dimensional layered structure,stability,low cost and non-toxicity,et al.In this review,recent Advances of Bi_(2)WO_(6) in photocatalytic CO_(2) reduction reaction are summarized,including reaction mechanism,product selective regulation,In-situ Fourier transform infrared spectra application,density functional theory calculation,and various modification strategies.Finally,based on the in-depth understanding of the above advances,the future modification strategies and design ideas of Bi_(2)WO_(6) in the field of photocatalytic CO_(2) research are proposed.This has important practical significance for the latter design and development of Bi_(2)WO_(6)-based composite photocatalysts with high CO_(2) conversion performance.
基金supported by the State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology (No. 2022TS10)the Taishan Industrial Experts Programthe Natural Science Foundation of Shandong Province of China (No. ZR2023ME212).
文摘Wet flue gas desulfurization(WFGD)could effectively reduce sulfur dioxide emission.However,magnesium sulfite(MgSO_(3)),a by-product of desulfurization,was easy to result in secondary pollution.In this study,the solid catalyst Co-Bent(bentonite supported cobalt)was prepared by blending method for MgSO_(3) oxidation with bentonite as the carrier and cobalt as the active component.At the calcination temperature of 550℃ and the Co loading level of 3 wt.%,the catalyst showed excellent catalytic performance for the oxidation of high concentration MgSO_(3) slurry,and the oxidation rate of MgSO_(3) was 0.13 mol/(L·h).The research indicated that the active component was uniformly distributed within porous structure of the catalyst as Co_(3)O_(4),which facilitated the oxidation of SO_(3)^(2-) catalyzed by Co_(3)O_(4).Kinetic researches indicated the oxidation rate of MgSO_(3) was influenced by the catalyst dosage,the reaction temperature,the solution pH,the airflow rate,and the SO_(3)^(2-) concentration.Additionally,after recycling experiments,the regenerated catalyst retained its high catalytic performance for the MgSO_(3) oxidation.The reaction mechanism for the catalytic oxidation of MgSO_(3) by Co-Bent catalyst was also proposed.The generation of active free radicals(OH·,SO_(4)^(-)·,SO_(3)^(-)·,SO_(5)^(-)·)accelerated the MgSO_(3) oxidation.These results provide theoretical support for the treatment of MgSO_(3) and the development of durable catalyst.
基金sponsored by the National Science Foundation of China(Nos.52200189,52230006,and 32271700)the Guangxi Science and Technology Project,China(Nos.2021GXNSFBA220055,2020GXNSFAA297256,and Guike AB21220049)+2 种基金the Guangxi Key Laboratory of Environmental Pollution Control Theory and TechnologyGuangxi Engineering Research Center of Comprehensive Treatment for Agricultural Non-Point Source PollutionModern Industry College of Ecology and Environmental Protection from Guilin University of Technology,China for support。
文摘To promote growth,terrestrial plants release photosynthetic products into the rhizosphere in the form of root exudates through their root systems.Under the attraction of root exudates,plant growth-promoting rhizobacteria(PGPR)colonize the rhizosphere to stimulate plant growth and/or suppress the growth of pathogenic microorganisms.The rhizospheric recruitment of PGPR,as well as the establishment of root-microbe interactions,is initiated by chemotaxis towards root exudates.Over the past several decades,scientists have made notable strides in identifying representative chemoeffectors in root exudates,as well as the corresponding chemoreceptors.We review here the most recent developments in rhizospheric chemotaxis,particularly the chemoeffectors in root exudates,the structural and functional characterization of methyl-accepting chemotaxis proteins of PGPR,and the impacts of rhizospheric chemotaxis on root colonization,biofilm formation,and other root-microbe interactions during recruitment.Finally,we propose several perspectives that aim to fully unlock the potential of PGPR as bioinoculants in sustainable agriculture.
基金financially supported by the National Natural Science Foundation of China(Nos.52200136,52270112)National Energy-Saving and Low-Carbon Materials Production and Application Demonstration Platform Program(No.TC220H06N)Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001)。
文摘Hydrocarbons(HCs),as major poisoning substances,have a crucial influence on NH_(3)-SCR catalysts.In this work,the effects of C_(3)H_(6)on fresh and hydrothermally aged Cu-SSZ-39 catalysts with different copper contents were investigated.All catalysts suffered a deactivation above 250℃,especially between 300-400℃,which was mainly related to the reaction between NH_(3)and C_(3)H_(6).However,the hydrothermally aged and the high-copper-loaded Cu-SSZ-39 catalysts could achieve a recovery of NH_(3)-SCR performance at high temperatures.Such activity recovery was attributed to the oxidation of C_(3)H_(6)by CuxOy species,which therefore inhibited the reaction between NH_(3)and C_(3)H_(6).As a result,more NH_(3)could be available for the NH_(3)-SCR reaction and the Cu-SSZ-39 catalysts could maintain a good catalytic activity.Based on these findings,we proposed that high loaded Cu-SSZ-39 catalysts with a little CuOx formed are preferred for application.
基金Project supported by the National Key R&D Program of China(2023YFC3707201)National Natural Science Foundation of China(52200136,52270112,22106172)National Energy-Saving and Low-Carbon Materials Production and Application Demonstration Platform Program(TC220H06N)。
文摘The abatement of NO_(x)from diesel vehicle exhaust is of great importance for improving the atmospheric enviro nment.Cu-SSZ-39 zeolites possess the potential for application in the diesel vehicle aftertreatment system.Phosphorus(P)and hydrocarbons(HCs)present in the exhaust have negative impacts on the catalysts.To enhance the resistance of Cu-SSZ-39 catalysts to P and HCs,various rare earth metals were doped.Loading of 1 wt%Ce on the Cu-SSZ-39 catalyst improves the resistance to P and HCs simultaneously.The promotion mechanism was investigated through H_(2)-temperature programmed reduction(H_(2)-TPR),ultraviolet visible diffuse reflectance spectroscopy(UV-vis-DRS),diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS),X-ray photoelectron spectroscopy(XPS),energy dispersive spectroscopy(EDS)and theoretical calculation.On the one hand,Ce species can act as sacrificial sites,preferentially binding with P.On the other hand,Ce doping induces the formation of CuO species,promoting the oxidation of C_(3)H_(6)and preventing the consumption of NH_(3)from the reaction with C_(3)H_(6).Ce acting as bi-functional sites enhances the P and HCs resistance of Cu-SSZ-39 catalysts,further brightening its practical application.
