Electrochemical transformation emerges as an important solution to sustainable energy conversion and chemical production.Conventional electrolytic systems usually operate under galvanostatic or potentiostatic conditio...Electrochemical transformation emerges as an important solution to sustainable energy conversion and chemical production.Conventional electrolytic systems usually operate under galvanostatic or potentiostatic conditions that sometimes result in unsatisfactory efficiencies or selectivities.Pulse electrolysis by pulsating and programming the potentials/currents can feature unique tunability to the electrodeelectrolyte interface properties that can give rise to drastically different electrochemical behaviors compared to the steady-state counterparts.Although invented almost 100 years ago,pulse electrolysis has received little attention over the period,but has recently attracted a revived focus toward the energyefficient electrolysis.This review will summarize the history and recent efforts of pulse electrolysis in three categories:water electrolysis,CO_(2)electrolysis and other electrolysis.In each section,the advantage of pulse electrolysis over steady-state electrolysis will be discussed in detail,giving a comprehensive overview of the pulse effect on the electrolytic systems.Finally,we will provide our vision of future directions in pulse electrolysis based on previous works.展开更多
The aim of this work is to boost the combined hydrogen and added-values compounds generation(acetaldehyde, acetic acid and ethyl acetate) through ethanol electrochemical reforming using bimetallic anodes. In particula...The aim of this work is to boost the combined hydrogen and added-values compounds generation(acetaldehyde, acetic acid and ethyl acetate) through ethanol electrochemical reforming using bimetallic anodes. In particular, the influence of the secondary metal on the electrochemical performance as well as on the product distribution was studied. For that purpose, Pt X/C electrocatalysts(where X corresponds to Cu, Co, Ni and Ru) were synthesized by the modified polyol method and tested in both half-cell and proton exchange membrane(PEM) cell configurations. Characterization results showed that incorporation of Ni and Co into the Pt matrix enhances the morphological properties of the material, providing smaller crystallite sizes, higher active surface areas and hence, better dispersion when comparing to Ru and Cu-based electrocatalysts. Ethanol oxidation reaction(EOR) was evaluated by cyclic, linear voltammetry and chronopotentiometry assays. Pt Co/C and Pt Ni/C exhibited the highest electrocatalytic activity at high polarization levels, which translate into an improvement of more than 30%(up to 1050 m A cm^(-2)) in the hydrogen production and chemical yields. On the other hand, Pt Ru/C results more advantageous for a lower potential interval(<0.85 V) promoting the acetic acid production despite sacrificing ethanol conversion. Pt Cu/C presented the lowest results in both electrochemical performance and product distribution. Such differences in the electrochemical performance can be rationalized in terms of the synergistic effect between both metals(particle size distribution, grade of dispersion and hydrophilic behavior), which demonstrate that the incorporation of a different secondary metal plays an essential role in the EOR development.展开更多
Solar energy utilization has drawn attention due to ever-increasing environmental and energy issues.Photoelectrochemical(PEC)and photocatalytic(PC)water splitting for hydrogen production,which is the most popular and ...Solar energy utilization has drawn attention due to ever-increasing environmental and energy issues.Photoelectrochemical(PEC)and photocatalytic(PC)water splitting for hydrogen production,which is the most popular and well-established solar-to-chemical conversion process,has been studied thoroughly to date but is now facing limitations related to low conversion efficiency.To resolve this issue,research in PEC cells or photocatalysts has recently aimed to produce alternative value-added chemicals by modifying their redox reactions,which potentially enables high economic reward to compensate for the low efficiency.Here,various kinds of redox reactions that decouple classic water splitting reactions to produce value-added chemicals via PEC and PC processes are introduced.Successful coupling of CO_(2) reduction,O_(2) reduction and organic synthesis with either water oxidation or water reduction is comprehensively discussed from the perspective of basic fundamental and product selectivity in terms of the band structure of materials,cocatalyst design,and thermodynamics and kinetics of the reactions.Throughout the review,future challenges and opportunities are suggested with respect to the redesigned artificial synthesis,which might be an alternative development for the commercialization of PEC or PC value-added chemical production technologies in the near future.展开更多
A kind of second-order implicit fractional step characteristic finite difference method is presented in this paper for the numerically simulation coupled system of enhanced (chemical) oil production in porous media....A kind of second-order implicit fractional step characteristic finite difference method is presented in this paper for the numerically simulation coupled system of enhanced (chemical) oil production in porous media. Some techniques, such as the calculus of variations, energy analysis method, commutativity of the products of difference operators, decomposition of high-order difference operators and the theory of a priori estimates are introduced and an optimal order error estimates in l^2 norm is derived. This method has been applied successfully to the numerical simulation of enhanced oil production in actual oilfields, and the simulation results ate quite interesting and satisfactory.展开更多
In the early days after the founding of New China, there were only some poorly equipped small chemical factories in the cities of Shanghai, Shenyang. Dalian, Nanjing and Tianjin across the country, with a total output...In the early days after the founding of New China, there were only some poorly equipped small chemical factories in the cities of Shanghai, Shenyang. Dalian, Nanjing and Tianjin across the country, with a total output value of RMB 170 million. Now, 45 years later, the chemical industry boasts 23 branches. 40, 000 kinds of products, a total output value of RMB 330 billion and a total import and export volume of RMB 20 billion, according to Gu Xiulian, Minister of Chemical Industry in a speech at the ’94 Beijing International展开更多
GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon ...GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon with combustion gravimetric method.展开更多
1 Introduction Magnesium salts are very important by-product of salt lake industry in West China.Nearly 200 million cubic meters of waste brine are released to the environment
A kind of second-order implicit upwind fractional step finite difference methods are presented for the numerical simulation of coupled systems for enhanced (chemical) oil production with capillary force in the porou...A kind of second-order implicit upwind fractional step finite difference methods are presented for the numerical simulation of coupled systems for enhanced (chemical) oil production with capillary force in the porous media. Some techniques, e.g., the calculus of variations, the energy analysis method, the commutativity of the products of difference operators, the decomposition of high-order difference operators, and the theory of a priori estimate, are introduced. An optimal order error estimate in the l2 norm is derived. The method is successfully used in the numerical simulation of the enhanced oil production in actual oilfields. The simulation results are satisfactory and interesting.展开更多
Polyvinylpyrrolidone (PVP) developed by the Henan Kaiyuan Refined Chemical Works is a kind of soluble high molecular refined chemical product, with strong solvency and bond power and it is a principal medicinal supple...Polyvinylpyrrolidone (PVP) developed by the Henan Kaiyuan Refined Chemical Works is a kind of soluble high molecular refined chemical product, with strong solvency and bond power and it is a principal medicinal supplementary ingredient. It can be used as a bonding agent for making medicinal tablets and particles, and as a dissolving agent for injection a gents, a diluent for capsules, a liquor and pigmentated agent,展开更多
Following high speed growth in consecutive years, the development speed of China’s chemical products imports & exports declined by a wide margin in 1996. The annual total import & export value of chemical pro...Following high speed growth in consecutive years, the development speed of China’s chemical products imports & exports declined by a wide margin in 1996. The annual total import & export value of chemical products was US$31.7 billion, a growth of 6.6 percent over 1995. The growth range was down 30 percentage points compared with the rate in the same period of the previous year. Of these, export value was US$12.396 billion, a growth of 4.7 percent; import value was US$19.297 billion, a growth of 8 percent. The growth rate was down 27 and 33 percentage points over the previous year respectively.展开更多
This standard specifies the method summary, reagents, apparatus, sampling, procedure, test results calculation and permissible tolerance of the determination of magnesium oxide by CyDTA volumetric method.
Pigments Everbright Brand pigments, exported in the past four decades, rank first in China for their annual export volume because of wide variety and stable colour. Inorganic pigments: iron oxide red, iron oxide yello...Pigments Everbright Brand pigments, exported in the past four decades, rank first in China for their annual export volume because of wide variety and stable colour. Inorganic pigments: iron oxide red, iron oxide yellow, iron oxide black, ultramaring blue, milori blue, lead oxide red,展开更多
The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were colle...The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were collected both during off-season agriculture and pluvial agriculture from April to October 2022. The samples were analyzed for trace metals according to the standard methods of the US EPA 2007 with a microwave plasma atomic emission spectrometer (MP-AES), Agilent Model 4210. The pollution level was assessed using contamination factor (Cf) and modified contamination degree (mCd). During the off-season, the concentration of trace metals followed in descending order as Mn > Cr > Cu > Pb > Zn. As, Cd, Co, Hg, Ni, Sb and Se were below the detectable limits. In pluvial season, the concentration of traces of metal follows the order Mn > Cr > Zn > Cu > Ni > Pb > Hg > As. Cd, Co, Sb and Se remain below the detectable limits. The concentrations of Cr, Mn and Zn were lower in the off-season agriculture than in pluvial agriculture. For Cu and Pb, the concentrations were higher in the off-season than in pluvial agriculture. The Cf ranges from 0.24 to 11.70 depending on the considered trace metal. The Cf values of As, Ni, Pb, Zn and Mn indicated that the agricultural study soil was lowery contaminated by these trace metals. The agricultural study soil was moderately contaminated by Cr and Cu, and highly contaminated by Hg. Globally the agricultural study soil presents a moderate degree of contamination (mCd 2.25) by the eight trace metals studied. This result provides information on understanding the risks of trace metal contamination of agricultural soil. It is important to anticipate the control of soil contamination through regular monitoring of toxic metals in agricultural soils, control the quality of chemicals used in agriculture and regulate their use.展开更多
This study examines the large amount of agricultural waste produced in Egypt between 2010 and 2019 by analysing data from various departments within the Agriculture Ministry.It also provides a comprehensive database o...This study examines the large amount of agricultural waste produced in Egypt between 2010 and 2019 by analysing data from various departments within the Agriculture Ministry.It also provides a comprehensive database on the biomass available from agricultural waste in Egypt and its potential applications for producing power,heat and chemical products.When biomass-pyrolysis systems powered by solar energy are used,research demonstrates the potential to convert agricultural waste into a variety of chemical compounds.This approach utilizes solar energy,a clean and renewable source,and has wide-ranging industrial and power generation applications.Despite Egypt’s reliance on agriculture,the country currently utilizes little biomass for energy production and has not previously used it as a source for creating chemical products,which could potentially save on the imported oil used in these industries.The findings of the study are graphically presented using histograms,pie charts,etc.The overall production of residues reached the 30-Mt level in 2019.Because it contains the most rice-cultivated land,Dakahlia(Lower Egypt region)produces the highest percentage of the total residue(37.17%).Qena governorate(Upper Egypt region)produces 1.14 metric tons of residues,with sugarcane accounting for 20.3%of the total.展开更多
Hydrogen is an attractive energy carrier due to the high conversion efficiency and low pollutant emission.Chemical looping hydrogen production(CLHP)is an available way for producing high purity hydrogen with relativel...Hydrogen is an attractive energy carrier due to the high conversion efficiency and low pollutant emission.Chemical looping hydrogen production(CLHP)is an available way for producing high purity hydrogen with relatively low penalty energy and CO_(2)is captured simultaneously.Three reactors are usually contained for CLHP system including air reactor(AR),fuel reactor(FR)and steam reactor(SR).In current work,we focus on the performance of CLHP system,which is the basement for operation and design.Numerical simulations are carried out for analyzing the flow behavior and the numerical structure is built according to the experimental unit constructed at Southeast University,China.Results show that the operation of L-valve influences most the solid circulating rate of system and particles pass L-valve easily with large aeration rate.Mass distribution results indicate that fuel reactor has the capacity for particles storage.Increase of gas inlet rate of steam reactor leads to more particles leave steam reactor and accumulate into fuel reactor.L-valve can prevent the gas leakage between reactors and it will be adopted for reactive unit.Combining the operation of fuel reactor and L-valve,the system can reach steady state and get the regulating ability.展开更多
Microorganisms have been the main sources for the production of chemicals.Production of chemicals requires the development of low-cost and higher-yield processes.Towards this goal,microbial strains with higher levels ...Microorganisms have been the main sources for the production of chemicals.Production of chemicals requires the development of low-cost and higher-yield processes.Towards this goal,microbial strains with higher levels of production should be first considered.Metabolic engineering has been used extensively over the past two to three decades to increase production of these chemicals.Advances in omics technology and computational simulation are allowing us to perform metabolic engineering at the systems level.By combining the results of omics analyses and computational simulation,systems biology allows us to understand cellular physiology and characteristics,which can subsequently be used for designing strategies.Here,we review the current status of metabolic engineering based on systems biology for chemical production and discuss future prospects.展开更多
Zeolites are characterized by their microporous,crystalline structures with a four-connected framework with variable compositions,predominantly aluminosilicates.They are extensively utilized as adsorbents,catalysts,an...Zeolites are characterized by their microporous,crystalline structures with a four-connected framework with variable compositions,predominantly aluminosilicates.They are extensively utilized as adsorbents,catalysts,and ion exchangers across domestic and industrial sectors.With the ongoing energy transition from fossil fuels to renewable sources and the pursuit of environmentally sustainable development,zeolites are increasingly being explored beyond their traditional application fields.They are investigated for their adsorption and catalytic capabilities in the protection and restoration of air,water,and soil quality,as well as in the environmentally friendly“green”production of chemicals.This review article details these novel and potential applications of zeolites,emphasizing the unique properties that render them suitable for each specific use case and discussing how these properties can be fine-tuned through material selection or tailored synthesis methods.展开更多
In chemical product design,the aim is to formulate a product with desired performance.Ingredients and internal product structure are two key drivers of product performance with direct impact on the mechanical,electric...In chemical product design,the aim is to formulate a product with desired performance.Ingredients and internal product structure are two key drivers of product performance with direct impact on the mechanical,electrical,and thermal properties.Thus,there is a keen interest in elucidating the dependence of product performance on ingredients,structure,and the manufacturing process to form the structure.Design of product structure,particularly microstructure,is an intrinsically complex problem that involves different phases of different physicochemical properties,mass fraction,morphology,size distribution,and interconnectivity.Recently,computational methods have emerged that assist systematic microstructure quantification and prediction.The objective of this paper is to review these computational methods and to show how these methods as well as other developments in product design can work seamlessly in a proposed performance,ingredients,structure,and manufacturing process framework for the design of structured chemical products.It begins with the desired target properties and key ingredients.This is followed by computation for microstructure and then selection of processing steps to realize this microstructure.The framework is illustrated with the design of nanodielectric and die attach adhesive products.展开更多
The coastal eco-city of Fuzhou in Southeastern China has experienced severe ozone(O_(3))episodes at times in recent years.In this study,three typical synoptic circulations types(CTs)that influenced more than 80%of O_(...The coastal eco-city of Fuzhou in Southeastern China has experienced severe ozone(O_(3))episodes at times in recent years.In this study,three typical synoptic circulations types(CTs)that influenced more than 80%of O_(3) polluted days in Fuzhou during 2014-2019 were identified using a subjective approach.The characteristics of meteorological conditions linked to photochemical formation and transport of O_(3) under the three CTs were summarized.Comprehensive Air Quality Model with extensions was applied to simulate O_(3) episodes and to quantify O_(3) sources from different regions in Fuzhou.When Fuzhou was located to the west of a high-pressure system(classified as“East-ridge”),more warm southwesterly currents flowed to Fuzhou,and the effects of cross-regional transport from Guangdong province and high local production promoted the occurrence of O_(3) episodes.Under a uniform pressure field with a low-pressure system occurring to the east of Fuzhou(defined as“East-low”),stagnant weather conditions caused the strongest local production of O_(3) in the atmospheric boundary layer.Controlled by high-pressure systems over the mainland(categorized as“Inland-high”),northerly airflows enhanced the contribution of cross-regional transport to O_(3) in Fuzhou.The abnormal increases of the“East-ridge”and“Inland-high”were closely related to O_(3) pollution in Fuzhou in April and May 2018,resulting in the annual maximum number of O_(3) polluted days during recent years.Furthermore,the rising number of autumn O_(3) episodes in 2017-2019 was mainly related to the“Inland-high”,indicating the aggravation of cross-regional transport and highlighting the necessity of enhanced regional collaboration and efforts in combating O_(3) pollution.展开更多
基金supports from the National Key R&D program of China(2019YFC1604602)supports from the National Key Basic Research Program of China(2019YFC1906700)the National Natural Science Foundation of China(21876049,51878643)。
文摘Electrochemical transformation emerges as an important solution to sustainable energy conversion and chemical production.Conventional electrolytic systems usually operate under galvanostatic or potentiostatic conditions that sometimes result in unsatisfactory efficiencies or selectivities.Pulse electrolysis by pulsating and programming the potentials/currents can feature unique tunability to the electrodeelectrolyte interface properties that can give rise to drastically different electrochemical behaviors compared to the steady-state counterparts.Although invented almost 100 years ago,pulse electrolysis has received little attention over the period,but has recently attracted a revived focus toward the energyefficient electrolysis.This review will summarize the history and recent efforts of pulse electrolysis in three categories:water electrolysis,CO_(2)electrolysis and other electrolysis.In each section,the advantage of pulse electrolysis over steady-state electrolysis will be discussed in detail,giving a comprehensive overview of the pulse effect on the electrolytic systems.Finally,we will provide our vision of future directions in pulse electrolysis based on previous works.
基金We gratefully acknowledge the Spanish Ministry of Science and Innovation(project PID2019-107499RB-100 and FPI grant BES-2017-081181)for the financial support.
文摘The aim of this work is to boost the combined hydrogen and added-values compounds generation(acetaldehyde, acetic acid and ethyl acetate) through ethanol electrochemical reforming using bimetallic anodes. In particular, the influence of the secondary metal on the electrochemical performance as well as on the product distribution was studied. For that purpose, Pt X/C electrocatalysts(where X corresponds to Cu, Co, Ni and Ru) were synthesized by the modified polyol method and tested in both half-cell and proton exchange membrane(PEM) cell configurations. Characterization results showed that incorporation of Ni and Co into the Pt matrix enhances the morphological properties of the material, providing smaller crystallite sizes, higher active surface areas and hence, better dispersion when comparing to Ru and Cu-based electrocatalysts. Ethanol oxidation reaction(EOR) was evaluated by cyclic, linear voltammetry and chronopotentiometry assays. Pt Co/C and Pt Ni/C exhibited the highest electrocatalytic activity at high polarization levels, which translate into an improvement of more than 30%(up to 1050 m A cm^(-2)) in the hydrogen production and chemical yields. On the other hand, Pt Ru/C results more advantageous for a lower potential interval(<0.85 V) promoting the acetic acid production despite sacrificing ethanol conversion. Pt Cu/C presented the lowest results in both electrochemical performance and product distribution. Such differences in the electrochemical performance can be rationalized in terms of the synergistic effect between both metals(particle size distribution, grade of dispersion and hydrophilic behavior), which demonstrate that the incorporation of a different secondary metal plays an essential role in the EOR development.
基金Sungsoon Kim,Kwang Hee Kim and Cheoulwoo Oh contributed equally as cofirst authors.Kan Zhang acknowledges the support from NSFC(51802157,21902104)the Natural Science Foundation of Jiangsu Province of China(BZ2020063)Jong Hyeok Park acknowledges the support from the National Research Foundation(NRF)of Korea(2019R1A4A1029237,2021M3E6A1015823,2017M3A7B4041987).
文摘Solar energy utilization has drawn attention due to ever-increasing environmental and energy issues.Photoelectrochemical(PEC)and photocatalytic(PC)water splitting for hydrogen production,which is the most popular and well-established solar-to-chemical conversion process,has been studied thoroughly to date but is now facing limitations related to low conversion efficiency.To resolve this issue,research in PEC cells or photocatalysts has recently aimed to produce alternative value-added chemicals by modifying their redox reactions,which potentially enables high economic reward to compensate for the low efficiency.Here,various kinds of redox reactions that decouple classic water splitting reactions to produce value-added chemicals via PEC and PC processes are introduced.Successful coupling of CO_(2) reduction,O_(2) reduction and organic synthesis with either water oxidation or water reduction is comprehensively discussed from the perspective of basic fundamental and product selectivity in terms of the band structure of materials,cocatalyst design,and thermodynamics and kinetics of the reactions.Throughout the review,future challenges and opportunities are suggested with respect to the redesigned artificial synthesis,which might be an alternative development for the commercialization of PEC or PC value-added chemical production technologies in the near future.
基金supported by the Major State Basic Research Development Program of China(G19990328)National Tackling Key Program(2011ZX05011-004+6 种基金2011ZX0505220050200069)National Natural Science Foundation of China(11101244112712311077112410372052)Doctorate Foundation of the Ministry of Education of China(20030422047)
文摘A kind of second-order implicit fractional step characteristic finite difference method is presented in this paper for the numerically simulation coupled system of enhanced (chemical) oil production in porous media. Some techniques, such as the calculus of variations, energy analysis method, commutativity of the products of difference operators, decomposition of high-order difference operators and the theory of a priori estimates are introduced and an optimal order error estimates in l^2 norm is derived. This method has been applied successfully to the numerical simulation of enhanced oil production in actual oilfields, and the simulation results ate quite interesting and satisfactory.
文摘In the early days after the founding of New China, there were only some poorly equipped small chemical factories in the cities of Shanghai, Shenyang. Dalian, Nanjing and Tianjin across the country, with a total output value of RMB 170 million. Now, 45 years later, the chemical industry boasts 23 branches. 40, 000 kinds of products, a total output value of RMB 330 billion and a total import and export volume of RMB 20 billion, according to Gu Xiulian, Minister of Chemical Industry in a speech at the ’94 Beijing International
文摘GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon with combustion gravimetric method.
基金supported by the National Natural Science Foundationthe National Key Technologies R&D Program (2011BAE28B01)the 863 Program (2013AA032501)
文摘1 Introduction Magnesium salts are very important by-product of salt lake industry in West China.Nearly 200 million cubic meters of waste brine are released to the environment
基金Project supported by the Major State Basic Research Development Program of China(No.G19990328)the National Natural Science Foundation of China(Nos.10771124,10372052,and 11101244)+2 种基金the National Tackling Key Problems Program of China(Nos.2011ZX05011-004,2011ZX05052,and 2005020069)the Doctorate Foundation of the Ministry of Education of China(No.20030422047)the Natural Science Foundation of Shandong Province of China(No.ZR2011AM015)
文摘A kind of second-order implicit upwind fractional step finite difference methods are presented for the numerical simulation of coupled systems for enhanced (chemical) oil production with capillary force in the porous media. Some techniques, e.g., the calculus of variations, the energy analysis method, the commutativity of the products of difference operators, the decomposition of high-order difference operators, and the theory of a priori estimate, are introduced. An optimal order error estimate in the l2 norm is derived. The method is successfully used in the numerical simulation of the enhanced oil production in actual oilfields. The simulation results are satisfactory and interesting.
文摘Polyvinylpyrrolidone (PVP) developed by the Henan Kaiyuan Refined Chemical Works is a kind of soluble high molecular refined chemical product, with strong solvency and bond power and it is a principal medicinal supplementary ingredient. It can be used as a bonding agent for making medicinal tablets and particles, and as a dissolving agent for injection a gents, a diluent for capsules, a liquor and pigmentated agent,
文摘Following high speed growth in consecutive years, the development speed of China’s chemical products imports & exports declined by a wide margin in 1996. The annual total import & export value of chemical products was US$31.7 billion, a growth of 6.6 percent over 1995. The growth range was down 30 percentage points compared with the rate in the same period of the previous year. Of these, export value was US$12.396 billion, a growth of 4.7 percent; import value was US$19.297 billion, a growth of 8 percent. The growth rate was down 27 and 33 percentage points over the previous year respectively.
文摘This standard specifies the method summary, reagents, apparatus, sampling, procedure, test results calculation and permissible tolerance of the determination of magnesium oxide by CyDTA volumetric method.
文摘Pigments Everbright Brand pigments, exported in the past four decades, rank first in China for their annual export volume because of wide variety and stable colour. Inorganic pigments: iron oxide red, iron oxide yellow, iron oxide black, ultramaring blue, milori blue, lead oxide red,
文摘The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were collected both during off-season agriculture and pluvial agriculture from April to October 2022. The samples were analyzed for trace metals according to the standard methods of the US EPA 2007 with a microwave plasma atomic emission spectrometer (MP-AES), Agilent Model 4210. The pollution level was assessed using contamination factor (Cf) and modified contamination degree (mCd). During the off-season, the concentration of trace metals followed in descending order as Mn > Cr > Cu > Pb > Zn. As, Cd, Co, Hg, Ni, Sb and Se were below the detectable limits. In pluvial season, the concentration of traces of metal follows the order Mn > Cr > Zn > Cu > Ni > Pb > Hg > As. Cd, Co, Sb and Se remain below the detectable limits. The concentrations of Cr, Mn and Zn were lower in the off-season agriculture than in pluvial agriculture. For Cu and Pb, the concentrations were higher in the off-season than in pluvial agriculture. The Cf ranges from 0.24 to 11.70 depending on the considered trace metal. The Cf values of As, Ni, Pb, Zn and Mn indicated that the agricultural study soil was lowery contaminated by these trace metals. The agricultural study soil was moderately contaminated by Cr and Cu, and highly contaminated by Hg. Globally the agricultural study soil presents a moderate degree of contamination (mCd 2.25) by the eight trace metals studied. This result provides information on understanding the risks of trace metal contamination of agricultural soil. It is important to anticipate the control of soil contamination through regular monitoring of toxic metals in agricultural soils, control the quality of chemicals used in agriculture and regulate their use.
基金This work was supported by the Egyptian Science&Technology development Fund(STDF)of Egypt-China International Joint research(Grant No.41554).
文摘This study examines the large amount of agricultural waste produced in Egypt between 2010 and 2019 by analysing data from various departments within the Agriculture Ministry.It also provides a comprehensive database on the biomass available from agricultural waste in Egypt and its potential applications for producing power,heat and chemical products.When biomass-pyrolysis systems powered by solar energy are used,research demonstrates the potential to convert agricultural waste into a variety of chemical compounds.This approach utilizes solar energy,a clean and renewable source,and has wide-ranging industrial and power generation applications.Despite Egypt’s reliance on agriculture,the country currently utilizes little biomass for energy production and has not previously used it as a source for creating chemical products,which could potentially save on the imported oil used in these industries.The findings of the study are graphically presented using histograms,pie charts,etc.The overall production of residues reached the 30-Mt level in 2019.Because it contains the most rice-cultivated land,Dakahlia(Lower Egypt region)produces the highest percentage of the total residue(37.17%).Qena governorate(Upper Egypt region)produces 1.14 metric tons of residues,with sugarcane accounting for 20.3%of the total.
基金the National Key Research and Development Plan(No.2017YFE0112500)State Key Laboratory of Clean Energy Utilization(Open Fund Project No.ZJUCUE2022018)National Natural Science Foundation of China(No.51806192)。
文摘Hydrogen is an attractive energy carrier due to the high conversion efficiency and low pollutant emission.Chemical looping hydrogen production(CLHP)is an available way for producing high purity hydrogen with relatively low penalty energy and CO_(2)is captured simultaneously.Three reactors are usually contained for CLHP system including air reactor(AR),fuel reactor(FR)and steam reactor(SR).In current work,we focus on the performance of CLHP system,which is the basement for operation and design.Numerical simulations are carried out for analyzing the flow behavior and the numerical structure is built according to the experimental unit constructed at Southeast University,China.Results show that the operation of L-valve influences most the solid circulating rate of system and particles pass L-valve easily with large aeration rate.Mass distribution results indicate that fuel reactor has the capacity for particles storage.Increase of gas inlet rate of steam reactor leads to more particles leave steam reactor and accumulate into fuel reactor.L-valve can prevent the gas leakage between reactors and it will be adopted for reactive unit.Combining the operation of fuel reactor and L-valve,the system can reach steady state and get the regulating ability.
基金the National Natural Science Foundation of China(Grant No.30770066,200876181,and 20831006)Natural Science Foundation of Guangdong Province(No.07003631)the Project of Science and Technology of Guangdong Province(No.2007A010900001)for their financial support.
文摘Microorganisms have been the main sources for the production of chemicals.Production of chemicals requires the development of low-cost and higher-yield processes.Towards this goal,microbial strains with higher levels of production should be first considered.Metabolic engineering has been used extensively over the past two to three decades to increase production of these chemicals.Advances in omics technology and computational simulation are allowing us to perform metabolic engineering at the systems level.By combining the results of omics analyses and computational simulation,systems biology allows us to understand cellular physiology and characteristics,which can subsequently be used for designing strategies.Here,we review the current status of metabolic engineering based on systems biology for chemical production and discuss future prospects.
基金supported by Shandong Energy Institute(SEI S202107),Nature Science Foundation of Shandong Province(ZR2022MB053 and ZR2022QB216).
文摘Zeolites are characterized by their microporous,crystalline structures with a four-connected framework with variable compositions,predominantly aluminosilicates.They are extensively utilized as adsorbents,catalysts,and ion exchangers across domestic and industrial sectors.With the ongoing energy transition from fossil fuels to renewable sources and the pursuit of environmentally sustainable development,zeolites are increasingly being explored beyond their traditional application fields.They are investigated for their adsorption and catalytic capabilities in the protection and restoration of air,water,and soil quality,as well as in the environmentally friendly“green”production of chemicals.This review article details these novel and potential applications of zeolites,emphasizing the unique properties that render them suitable for each specific use case and discussing how these properties can be fine-tuned through material selection or tailored synthesis methods.
文摘In chemical product design,the aim is to formulate a product with desired performance.Ingredients and internal product structure are two key drivers of product performance with direct impact on the mechanical,electrical,and thermal properties.Thus,there is a keen interest in elucidating the dependence of product performance on ingredients,structure,and the manufacturing process to form the structure.Design of product structure,particularly microstructure,is an intrinsically complex problem that involves different phases of different physicochemical properties,mass fraction,morphology,size distribution,and interconnectivity.Recently,computational methods have emerged that assist systematic microstructure quantification and prediction.The objective of this paper is to review these computational methods and to show how these methods as well as other developments in product design can work seamlessly in a proposed performance,ingredients,structure,and manufacturing process framework for the design of structured chemical products.It begins with the desired target properties and key ingredients.This is followed by computation for microstructure and then selection of processing steps to realize this microstructure.The framework is illustrated with the design of nanodielectric and die attach adhesive products.
基金supported by the National Key Research and Development Program of China(Nos.2018YFC0213204,2018YFC0213506).
文摘The coastal eco-city of Fuzhou in Southeastern China has experienced severe ozone(O_(3))episodes at times in recent years.In this study,three typical synoptic circulations types(CTs)that influenced more than 80%of O_(3) polluted days in Fuzhou during 2014-2019 were identified using a subjective approach.The characteristics of meteorological conditions linked to photochemical formation and transport of O_(3) under the three CTs were summarized.Comprehensive Air Quality Model with extensions was applied to simulate O_(3) episodes and to quantify O_(3) sources from different regions in Fuzhou.When Fuzhou was located to the west of a high-pressure system(classified as“East-ridge”),more warm southwesterly currents flowed to Fuzhou,and the effects of cross-regional transport from Guangdong province and high local production promoted the occurrence of O_(3) episodes.Under a uniform pressure field with a low-pressure system occurring to the east of Fuzhou(defined as“East-low”),stagnant weather conditions caused the strongest local production of O_(3) in the atmospheric boundary layer.Controlled by high-pressure systems over the mainland(categorized as“Inland-high”),northerly airflows enhanced the contribution of cross-regional transport to O_(3) in Fuzhou.The abnormal increases of the“East-ridge”and“Inland-high”were closely related to O_(3) pollution in Fuzhou in April and May 2018,resulting in the annual maximum number of O_(3) polluted days during recent years.Furthermore,the rising number of autumn O_(3) episodes in 2017-2019 was mainly related to the“Inland-high”,indicating the aggravation of cross-regional transport and highlighting the necessity of enhanced regional collaboration and efforts in combating O_(3) pollution.