Top Cited
1
2019, 10(2): 97-103.
DOI: 10.13264/j.cnki.ysjskx.2019.02.014
Abstract：
The eutrophication of water bodies is usually caused by excess emission of nutrients such as nitrogen and phosphorus in water bodies. Phosphorus is the main element limiting the eutrophication of water bodies. When the phosphorus content in the water column exceeds 0.02 mg/L, eutrophication can occur. It is of great significance to study the dephosphorization processes to solve the environmental pollution of eutrophication. In this paper, dephosphorization processes by microbial, chemical and physical-chemical methods were reviewed. The characteristics and application status of chemical coagulation precipitation, crystallization and adsorption methods in chemical and physical-chemical dephosphorization were emphatically introduced. This paper described the development direction of chemical phosphorus removal, and further proposed the development of more economical and environmentally friendly chemical dephosphorization technologies.
The eutrophication of water bodies is usually caused by excess emission of nutrients such as nitrogen and phosphorus in water bodies. Phosphorus is the main element limiting the eutrophication of water bodies. When the phosphorus content in the water column exceeds 0.02 mg/L, eutrophication can occur. It is of great significance to study the dephosphorization processes to solve the environmental pollution of eutrophication. In this paper, dephosphorization processes by microbial, chemical and physical-chemical methods were reviewed. The characteristics and application status of chemical coagulation precipitation, crystallization and adsorption methods in chemical and physical-chemical dephosphorization were emphatically introduced. This paper described the development direction of chemical phosphorus removal, and further proposed the development of more economical and environmentally friendly chemical dephosphorization technologies.
2
2019, 10(2): 31-46.
DOI: 10.13264/j.cnki.ysjskx.2019.02.006
Abstract：
Al-Li alloys have gained attention for their use in weight and stiffness-critical structures used in aircraft, aerospace and military application. Work on Li additions to Al was reported as early as 1920s and Al-Li alloys have been developed to the 3rd generation. China still has a gap with foreign countries in the research, development, production and application of Al-Li alloys. Al-Li alloy could be divided into wrought Al-Li alloys and cast Al-Li alloys, and wrought Al-Li alloys have been widely applied in the field of aerospace. This article describes the precipitates, corrosion, heat treatment and weldability of wrought Al-Li alloys. Meanwhile, the research status of cast aluminum-lithium alloys is summarized from the aspects of development and application and alloy development.
Al-Li alloys have gained attention for their use in weight and stiffness-critical structures used in aircraft, aerospace and military application. Work on Li additions to Al was reported as early as 1920s and Al-Li alloys have been developed to the 3rd generation. China still has a gap with foreign countries in the research, development, production and application of Al-Li alloys. Al-Li alloy could be divided into wrought Al-Li alloys and cast Al-Li alloys, and wrought Al-Li alloys have been widely applied in the field of aerospace. This article describes the precipitates, corrosion, heat treatment and weldability of wrought Al-Li alloys. Meanwhile, the research status of cast aluminum-lithium alloys is summarized from the aspects of development and application and alloy development.
3
2018, 9(5): 66-71.
DOI: 10.13264/j.cnki.ysjskx.2018.05.012
Abstract：
In recent years, with the rapid development of social economy, the problem of soil polluted by heavy metals is becoming more and more obvious.Soil pollution not only causes harm to the whole soil circle, but also has certain influence on other large circles, such as water pollution.Air pollution, etc.The pollution sources can be divided into natural and artificial sources.The heavy metal elements involved are mainly Hg、Cd、Pb、Cr、As、Zn、Cu、Ni and so on.How to effectively control soil heavy metal pollution is of great significance to the safety of agricultural products and the healthy development of human beings.In this paper, the sources of soil heavy metal pollution, the status quo of soil remediation research at home and abroad, and the research progress of soil heavy metal pollution remediation technology are described in this paper.At present, the main technologies used in soil heavy metal pollution remediation are physical remediation.Chemical remediation, bioremediation, agroecological remediation and combined remediation technology.The principles, applicable conditions, application examples and advantages and disadvantages of each remediation technique are described.Among them, bioremediation is the most commonly used method.Because of the superiority of other single remediation techniques, joint remediation can be regarded as the key development direction in the field of soil remediation in the future, in order to learn from the experience of the treatment of contaminated soil in China.
In recent years, with the rapid development of social economy, the problem of soil polluted by heavy metals is becoming more and more obvious.Soil pollution not only causes harm to the whole soil circle, but also has certain influence on other large circles, such as water pollution.Air pollution, etc.The pollution sources can be divided into natural and artificial sources.The heavy metal elements involved are mainly Hg、Cd、Pb、Cr、As、Zn、Cu、Ni and so on.How to effectively control soil heavy metal pollution is of great significance to the safety of agricultural products and the healthy development of human beings.In this paper, the sources of soil heavy metal pollution, the status quo of soil remediation research at home and abroad, and the research progress of soil heavy metal pollution remediation technology are described in this paper.At present, the main technologies used in soil heavy metal pollution remediation are physical remediation.Chemical remediation, bioremediation, agroecological remediation and combined remediation technology.The principles, applicable conditions, application examples and advantages and disadvantages of each remediation technique are described.Among them, bioremediation is the most commonly used method.Because of the superiority of other single remediation techniques, joint remediation can be regarded as the key development direction in the field of soil remediation in the future, in order to learn from the experience of the treatment of contaminated soil in China.
4
2018, 9(4): 83-88.
DOI: 10.13264/j.cnki.ysjskx.2018.04.014
Abstract：
Excessive discharge of ammonia-based wastewater causes serious damage to the ecosystem. The research progress of ammonia nitrogen wastewater treatment is reviewed. This article introduces traditional treatment technologies (biological method, blow-off method, chemical precipitation method, break point chlorination method, ion exchange method, and membrane absorption method) and new treatment technologies (microwave assisted method and ultrasonic method). We briefly introduce the application principles and applicable scope of various methods, and analyze the possible advantages and disadvantages of various processing technologies.
Excessive discharge of ammonia-based wastewater causes serious damage to the ecosystem. The research progress of ammonia nitrogen wastewater treatment is reviewed. This article introduces traditional treatment technologies (biological method, blow-off method, chemical precipitation method, break point chlorination method, ion exchange method, and membrane absorption method) and new treatment technologies (microwave assisted method and ultrasonic method). We briefly introduce the application principles and applicable scope of various methods, and analyze the possible advantages and disadvantages of various processing technologies.
5
2021, 12(4): 112-125.
DOI: 10.13264/j.cnki.ysjskx.2021.04.015
Abstract：
With the accelerated social development and continuous sophistication of science and technology, rare earth metals have shown their unique advantages in improving product quality and performance. However, there are also problems, including long cycle of traditional preparation methods for rare earth materials and inadequate research into high-end application fields. On the basis of introducing the latest progress in the preparation of rare earth materials, for instance, technologies of exchange ion, thermal decomposition, hydrothermal/solvothermal, co-precipitation, and sol-gel, this paper details the high-end applications of rare earth in permanent magnet materials, luminescent materials, catalytic materials, hydrogen storage materials, and high purity targets. On the basis of the above analysis, we know that developing rare earth preparation methods and exploring new materials are closely related to bring out the full potential of the rare metals in the fields of electronic information, automobile exhaust purification, aerospace, physiology, and medical treatment. At the same time, the prospects of increasing the added value of rare earth products, developing new rare earth materials, optimizing production process, and developing high-end applications are put forward.
With the accelerated social development and continuous sophistication of science and technology, rare earth metals have shown their unique advantages in improving product quality and performance. However, there are also problems, including long cycle of traditional preparation methods for rare earth materials and inadequate research into high-end application fields. On the basis of introducing the latest progress in the preparation of rare earth materials, for instance, technologies of exchange ion, thermal decomposition, hydrothermal/solvothermal, co-precipitation, and sol-gel, this paper details the high-end applications of rare earth in permanent magnet materials, luminescent materials, catalytic materials, hydrogen storage materials, and high purity targets. On the basis of the above analysis, we know that developing rare earth preparation methods and exploring new materials are closely related to bring out the full potential of the rare metals in the fields of electronic information, automobile exhaust purification, aerospace, physiology, and medical treatment. At the same time, the prospects of increasing the added value of rare earth products, developing new rare earth materials, optimizing production process, and developing high-end applications are put forward.
6
2019, 10(1): 60-66.
DOI: 10.13264/j.cnki.ysjskx.2019.01.010
Abstract：
With the rapid development of science and technology, cemented carbide tools used in mechanical processing and mining are developing constantly. Therefore, the technology of tool coating is becoming more and more diversified and complex, and the requirements for production process are also increasing. In this paper, two main preparation methods of cemented carbide tool coatings, chemical vapor deposition (CVD) and physical vapor deposition (PVD), were introduced. The development of tool coatings in recent years, including single component coatings, multi-component coatings, multi-layer coatings and gradient coatings, was briefly described. Several new coatings popular at present were summarized: diamond coatings, diamond-like carbon coatings, cubic boron nitride coatings and carbon nitride coatings. Finally, the development direction of cemented carbide tool coatings in the future was presented.
With the rapid development of science and technology, cemented carbide tools used in mechanical processing and mining are developing constantly. Therefore, the technology of tool coating is becoming more and more diversified and complex, and the requirements for production process are also increasing. In this paper, two main preparation methods of cemented carbide tool coatings, chemical vapor deposition (CVD) and physical vapor deposition (PVD), were introduced. The development of tool coatings in recent years, including single component coatings, multi-component coatings, multi-layer coatings and gradient coatings, was briefly described. Several new coatings popular at present were summarized: diamond coatings, diamond-like carbon coatings, cubic boron nitride coatings and carbon nitride coatings. Finally, the development direction of cemented carbide tool coatings in the future was presented.
7
Abstract：
The criticalrare earth (RE) elements (Pr, Nd, Dy, Tb)have been overusedwith the expanding application areas and surging demand of RE permanent magnetic materials.High abundant rare earth (HARE) elements such as La, Ce, Y, however, are constantly overstocked.They can not only reduce costs, but also be used to achieve a comprehensive balancedutilization of rare earth resources. It is imperative, important and necessary to do research and develop the cost-effective HARE permanent magnetic materials for national strategic security and the reduction of the costs of raw materials. The higher value utilization of these magnetic materials has been extensively studied by a large number of scholars in various groups. The systematic studies focus on the thermal stability of the main phase, the type of the second phase, the phase precipitation behavior, the valence state and metallurgical behavior of trace elements sinceall of these parameters are quite different from those of the widely used Nd-based commercial magnets. This paper has reviewed the recent progress of their phase structures, magnetic properties, microstructuresand corrosion resistance of the magnetic materials and shed light on their research and development.
The criticalrare earth (RE) elements (Pr, Nd, Dy, Tb)have been overusedwith the expanding application areas and surging demand of RE permanent magnetic materials.High abundant rare earth (HARE) elements such as La, Ce, Y, however, are constantly overstocked.They can not only reduce costs, but also be used to achieve a comprehensive balancedutilization of rare earth resources. It is imperative, important and necessary to do research and develop the cost-effective HARE permanent magnetic materials for national strategic security and the reduction of the costs of raw materials. The higher value utilization of these magnetic materials has been extensively studied by a large number of scholars in various groups. The systematic studies focus on the thermal stability of the main phase, the type of the second phase, the phase precipitation behavior, the valence state and metallurgical behavior of trace elements sinceall of these parameters are quite different from those of the widely used Nd-based commercial magnets. This paper has reviewed the recent progress of their phase structures, magnetic properties, microstructuresand corrosion resistance of the magnetic materials and shed light on their research and development.
8
2018, 9(1): 86-91.
DOI: 10.13264/j.cnki.ysjskx.2018.01.015
Abstract：
Arsenic is one of the most common and harmful substances in environmental pollution, Its pollution of water resources is a global environmental problem, a serious threat to human health, so the treatment of arsenic containing wastewater has been widespread concern.The principle, characteristics and application status of the main treatment methods of arsenic containing wastewater in recent years were summarized. The adsorption and biological methods were mainly elaborated, and their advantages and commonalities were analyzed, so as to provide technical support and help in the actual process.
Arsenic is one of the most common and harmful substances in environmental pollution, Its pollution of water resources is a global environmental problem, a serious threat to human health, so the treatment of arsenic containing wastewater has been widespread concern.The principle, characteristics and application status of the main treatment methods of arsenic containing wastewater in recent years were summarized. The adsorption and biological methods were mainly elaborated, and their advantages and commonalities were analyzed, so as to provide technical support and help in the actual process.
9
2019, 10(1): 34-40.
DOI: 10.13264/j.cnki.ysjskx.2019.01.006
Abstract：
An accurate quantification and calculation of CO2 emission in iron and steel manufacturing lays the foundation for analyzing and assessing its environmental impact and various emission reduction technologies. Based on the actual field data of Y steel mill in 2015, we calculated the CO2 emissions per ton of Y steel mills by using domestically recommended input-output method and the life cycle method recommended by the World Steel Association. The result indicates that the CO2 emission per ton of steel produced calculated by the life cycle method is 2.183 t CO2, which is significantly higher than the CO2 emission of 1.940 t CO2 calculated by domestic input and output method. This is mainly due to the fact that the calculation method proposed by the World Steel Association is more inclusive in statistics and takes into consideration the carbon dioxide emissions generated in upstream materials and energy. Based on the input-output method and the life cycle method, we propose a kind of greenhouse gas emission calculation method based on the LCA method that meets the national realities of Chinese steel companies from the perspectives of calculation boundary, emission factors, material and energy classification and evaluation baseline.
An accurate quantification and calculation of CO2 emission in iron and steel manufacturing lays the foundation for analyzing and assessing its environmental impact and various emission reduction technologies. Based on the actual field data of Y steel mill in 2015, we calculated the CO2 emissions per ton of Y steel mills by using domestically recommended input-output method and the life cycle method recommended by the World Steel Association. The result indicates that the CO2 emission per ton of steel produced calculated by the life cycle method is 2.183 t CO2, which is significantly higher than the CO2 emission of 1.940 t CO2 calculated by domestic input and output method. This is mainly due to the fact that the calculation method proposed by the World Steel Association is more inclusive in statistics and takes into consideration the carbon dioxide emissions generated in upstream materials and energy. Based on the input-output method and the life cycle method, we propose a kind of greenhouse gas emission calculation method based on the LCA method that meets the national realities of Chinese steel companies from the perspectives of calculation boundary, emission factors, material and energy classification and evaluation baseline.
10
2018, 9(3): 65-69.
DOI: 10.13264/j.cnki.ysjskx.2018.03.011
Abstract：
The heat-resistant Al alloy has a good prospect for application, and progress has been made in alloy design and its fabricating technologies. The main technologies in improving the heat-resistant properties of Al alloy include adding alloy elements to precipitate stable strengthening phases with a high melting point from aluminum alloy and achieving the precipitates in dispersed distribution by solidification control, heat-treatment and other technological measures to stabilize the matrix and strengthen the grain boundary. Currently, the top priority is to lower the manufacturing cost.
The heat-resistant Al alloy has a good prospect for application, and progress has been made in alloy design and its fabricating technologies. The main technologies in improving the heat-resistant properties of Al alloy include adding alloy elements to precipitate stable strengthening phases with a high melting point from aluminum alloy and achieving the precipitates in dispersed distribution by solidification control, heat-treatment and other technological measures to stabilize the matrix and strengthen the grain boundary. Currently, the top priority is to lower the manufacturing cost.
11
2017, 8(4): 105-110.
DOI: 10.13264/j.cnki.ysjskx.2017.04.018
Abstract：
The treatment of acid mine drainage (AMD) is difficult in environmental remediation process, due to its big yield, long formation time and dispersed place of production. This paper introduced sources and harms of AMD and summarized source control technologies, such as covering, fungicide, surface passivation and neutralizing treatment by separating metal sulphides from air, inhibiting microbial activity and reducing the activity of iron. However, these technologies had some disadvantages, such as easy oxidation of covering material, fungicide efficiency affected by environment extremely, pre oxidation and limited species of passivation agent, low efficiency of mixed neutralizing agent. The future treatment of AMD will be focusing on developing new bactericide, passivation agent to carry out scientific treatment by combining technologies of source control, monitoring of water quality and quantity and end treatment.
The treatment of acid mine drainage (AMD) is difficult in environmental remediation process, due to its big yield, long formation time and dispersed place of production. This paper introduced sources and harms of AMD and summarized source control technologies, such as covering, fungicide, surface passivation and neutralizing treatment by separating metal sulphides from air, inhibiting microbial activity and reducing the activity of iron. However, these technologies had some disadvantages, such as easy oxidation of covering material, fungicide efficiency affected by environment extremely, pre oxidation and limited species of passivation agent, low efficiency of mixed neutralizing agent. The future treatment of AMD will be focusing on developing new bactericide, passivation agent to carry out scientific treatment by combining technologies of source control, monitoring of water quality and quantity and end treatment.
12
2018, 9(1): 92-97.
DOI: 10.13264/j.cnki.ysjskx.2018.01.016
Abstract：
Using sulfate-reducing bacteria(SRB) to treat acidic mine wastewater is a hot research topic, and it has a very wide application in practical productions. This paper briefly introduces the sources, characteristics and hazards of acid mine wastewater.The mechanism of SRB treating acid mine wastewater is mainly introduced. This paper summarizes the development of SRB treatment process in acid mine wastewater, and puts forward some problems of it.
Using sulfate-reducing bacteria(SRB) to treat acidic mine wastewater is a hot research topic, and it has a very wide application in practical productions. This paper briefly introduces the sources, characteristics and hazards of acid mine wastewater.The mechanism of SRB treating acid mine wastewater is mainly introduced. This paper summarizes the development of SRB treatment process in acid mine wastewater, and puts forward some problems of it.
13
2017, 8(1): 134-138.
DOI: 10.13264/j.cnki.ysjskx.2017.01.023
Abstract：
Mineral processing wastewater contains a lot of metal elements. The direct discharge without any treatment will cause serious pollution on water and environment. However, it could be reused in an ore beneficiation process with proper treatment. Based on analyzing the sources of wastewater and its characteristics, the most commonly used treatment technologies for mineral processing wastewater were summarized. The achievements and problems in wastewater treatment in China are reviewed, and the future directions of research and development of wastewater treatment are put forward.
Mineral processing wastewater contains a lot of metal elements. The direct discharge without any treatment will cause serious pollution on water and environment. However, it could be reused in an ore beneficiation process with proper treatment. Based on analyzing the sources of wastewater and its characteristics, the most commonly used treatment technologies for mineral processing wastewater were summarized. The achievements and problems in wastewater treatment in China are reviewed, and the future directions of research and development of wastewater treatment are put forward.
14
Abstract：
In the recent decade, China mainly contributed the worldwide production and increase of lead and zinc, such that China became a veritable lead and zinc producer, which results in huge resource and environment burdens. In this article, main issues and development existing in China's lead and zinc processing technologies in the metallurgy industry were discussed, based on systematic introduction and summarization of the situation, development, characteristic and adaptability of these technologies. Given the consumption structure, the raw material for lead production will mainly originate from secondary lead-bearing materials, while that for zinc production will still originate from raw ores. Thus, millions of tons of zinc-containing slags will annually generate during processing raw lead-bearing ores. Notably, the innocent treatment of these slags should be worth considering.
In the recent decade, China mainly contributed the worldwide production and increase of lead and zinc, such that China became a veritable lead and zinc producer, which results in huge resource and environment burdens. In this article, main issues and development existing in China's lead and zinc processing technologies in the metallurgy industry were discussed, based on systematic introduction and summarization of the situation, development, characteristic and adaptability of these technologies. Given the consumption structure, the raw material for lead production will mainly originate from secondary lead-bearing materials, while that for zinc production will still originate from raw ores. Thus, millions of tons of zinc-containing slags will annually generate during processing raw lead-bearing ores. Notably, the innocent treatment of these slags should be worth considering.
15
2017, 8(2): 83-89.
DOI: 10.13264/j.cnki.ysjskx.2017.02.014
Abstract：
It is difficult to enrich the gold by conventional method for some refractory gold ore, hence, pretreatment is an effective way to improve the gold leaching ratio. In this paper, problems existing in treating gold ore were briefly analyzed, and the present situation and progress of some pretreatment methods were introduced. Advantages, disadvantages and prospects of these methods were also analyzed.
It is difficult to enrich the gold by conventional method for some refractory gold ore, hence, pretreatment is an effective way to improve the gold leaching ratio. In this paper, problems existing in treating gold ore were briefly analyzed, and the present situation and progress of some pretreatment methods were introduced. Advantages, disadvantages and prospects of these methods were also analyzed.
16
2019, 10(3): 92-98.
DOI: 10.13264/j.cnki.ysjskx.2019.03.016
Abstract：
The rapid development of the chemical industry leads to a large amount of high salt organic wastewater, and it is also increasing year by year. The difficulty and cost involved in dealing with high salt organic wastewater are very high due to its properties of high salinity and refractory. In this paper, we reviewed the advantages and disadvantages of various methods for its treatment and focused on the research progress and application of various processes. Comprehensive analysis suggests that its research should focus on developing new materials and reagents, exploring efficient and energy-saving physicochemical-biochemical combination process, improving the efficiency in its treatment and reducing treatment costs.
The rapid development of the chemical industry leads to a large amount of high salt organic wastewater, and it is also increasing year by year. The difficulty and cost involved in dealing with high salt organic wastewater are very high due to its properties of high salinity and refractory. In this paper, we reviewed the advantages and disadvantages of various methods for its treatment and focused on the research progress and application of various processes. Comprehensive analysis suggests that its research should focus on developing new materials and reagents, exploring efficient and energy-saving physicochemical-biochemical combination process, improving the efficiency in its treatment and reducing treatment costs.
17
2019, 10(1): 13-19, 27.
DOI: 10.13264/j.cnki.ysjskx.2019.01.003
Abstract：
In this paper, the impurity elements such as arsenic, antimony and bismuth in the copper smelting process were used as research objects. By comparing and analyzing the actual production data, a preliminary understanding has been made of the distribution of arsenic, antimony and bismuth in different processes in the copper smelting. The results show that the distribution of arsenic, antimony and bismuth in different smelting processes is quite different. Arsenic, antimony and bismuth in copper concentrates are mainly converted to by-products such as dust, slag, anode slime and black copper after smelting, blowing and electrolytic refining. The main methods, technological process, technological parameters and achievements in recent years are introduced of recovering arsenic, antimony and bismuth from by-products of copper smelting.
In this paper, the impurity elements such as arsenic, antimony and bismuth in the copper smelting process were used as research objects. By comparing and analyzing the actual production data, a preliminary understanding has been made of the distribution of arsenic, antimony and bismuth in different processes in the copper smelting. The results show that the distribution of arsenic, antimony and bismuth in different smelting processes is quite different. Arsenic, antimony and bismuth in copper concentrates are mainly converted to by-products such as dust, slag, anode slime and black copper after smelting, blowing and electrolytic refining. The main methods, technological process, technological parameters and achievements in recent years are introduced of recovering arsenic, antimony and bismuth from by-products of copper smelting.
18
2018, 9(3): 34-41.
DOI: 10.13264/j.cnki.ysjskx.2018.03.007
Abstract：
The calcium sulfate whiskers(CSW), made from gypsum mine or desulfurized gypsum, are a kind of industrial by-product. They are sub-nanofibrous materials used as the modifying agents, with good shape, large length-diameter ratio, large specific surface area and uniform cross section. Their wide use is limited by their low yield and poor quality. Their morphology and formation mechanism were focused first in the paper. Following it was the summary of their preparation methods at home and abroad. The research progress of preparation technologies such as atmospheric acidification, hydrothermal synthesis, ion exchange and micro-emulsion were introduced, and their advantages and disadvantages were both analyzed. Finally, their application in the field of material modification and environmental protection was discussed. This paper has an important influence on the further study of the preparation method and formation mechanism of CSW and can provide scientific guidance for its application in the future and comprehensive recycling of mineral resources.
The calcium sulfate whiskers(CSW), made from gypsum mine or desulfurized gypsum, are a kind of industrial by-product. They are sub-nanofibrous materials used as the modifying agents, with good shape, large length-diameter ratio, large specific surface area and uniform cross section. Their wide use is limited by their low yield and poor quality. Their morphology and formation mechanism were focused first in the paper. Following it was the summary of their preparation methods at home and abroad. The research progress of preparation technologies such as atmospheric acidification, hydrothermal synthesis, ion exchange and micro-emulsion were introduced, and their advantages and disadvantages were both analyzed. Finally, their application in the field of material modification and environmental protection was discussed. This paper has an important influence on the further study of the preparation method and formation mechanism of CSW and can provide scientific guidance for its application in the future and comprehensive recycling of mineral resources.
19
2021, 12(2): 30-42.
DOI: 10.13264/j.cnki.ysjskx.2021.02.005
Abstract：
Two-dimensional materials (such as graphene) showed many physical and chemical properties due to their unique thickness dimensions and layered structure characteristics, such as high conductivity, stable chemical properties and large specific surface area, which led to the wide range of applications in environment, materials, energy, and catalysis. The combination of two-dimensional materials and semiconductors can not only have the advantages of a single component, but the interaction between each component may also cause the synergistic enhancement of intrinsic properties. Therefore, the two-dimensional material-semiconductor composite photocatalyst had received extensive attention. In this review, the classification of two-dimensional materials was first introduced, including graphene-based two-dimensional materials and graphene-like two-dimensional materials (hexagonal boron nitride, transition metal chalcogenides, graphite phase carbon nitride, black phosphorus, group IV grapheme-like materials, metal organic framework compounds and covalent organic framework compounds, layered double hydroxides). Secondly, the preparation of two-dimensional materials and semiconductor-two-dimensional materials photocatalysts was summarized, and the preparation strategies of two-dimensional materials were focused on "top-down" and "bottom-up". Finally, the applications of two-dimensional materials were reviewed based on photocatalytic degradation of organic pollutants and photolysis of water to produce hydrogen. Based on the research current and advances of two-dimensional materials, this article looked forward to the prospects of two-dimensional materials in the field of photocatalysis, with the purpose of improving their practical application value.
Two-dimensional materials (such as graphene) showed many physical and chemical properties due to their unique thickness dimensions and layered structure characteristics, such as high conductivity, stable chemical properties and large specific surface area, which led to the wide range of applications in environment, materials, energy, and catalysis. The combination of two-dimensional materials and semiconductors can not only have the advantages of a single component, but the interaction between each component may also cause the synergistic enhancement of intrinsic properties. Therefore, the two-dimensional material-semiconductor composite photocatalyst had received extensive attention. In this review, the classification of two-dimensional materials was first introduced, including graphene-based two-dimensional materials and graphene-like two-dimensional materials (hexagonal boron nitride, transition metal chalcogenides, graphite phase carbon nitride, black phosphorus, group IV grapheme-like materials, metal organic framework compounds and covalent organic framework compounds, layered double hydroxides). Secondly, the preparation of two-dimensional materials and semiconductor-two-dimensional materials photocatalysts was summarized, and the preparation strategies of two-dimensional materials were focused on "top-down" and "bottom-up". Finally, the applications of two-dimensional materials were reviewed based on photocatalytic degradation of organic pollutants and photolysis of water to produce hydrogen. Based on the research current and advances of two-dimensional materials, this article looked forward to the prospects of two-dimensional materials in the field of photocatalysis, with the purpose of improving their practical application value.
20
Abstract：
The secondary aluminum dross still contains a large amount of metallic aluminum, and its recycling is of great significance. In this paper, secondary aluminum ash was used as the raw material. After treating it by hydrochloric acid leaching, calcium aluminate was then added to prepare polyaluminum chloride (PAC). The influencing factors such as the concentration of HCl, leaching temperature, time, liquid-solid ratio, and calcium aluminate addition amount were mainly investigated. The best conditions for preparing polyaluminum chloride by acid leaching of secondary aluminum dross were as follows: the secondary aluminum dross after washing was leached at the HCl concentration of 6 mol/L, the liquid-solid ratio of 4∶1 mL/g, at 85 ℃ for 2 h, and then added calcium aluminate 12 g/80 mL to the acid leaching solution and reacted at 85 ℃ for 1.5 h. Under these conditions, the leaching rate of aluminum during the acid leaching process was 48.67%, and the liquid PAC prepared was fully compliance with the national standard.
The secondary aluminum dross still contains a large amount of metallic aluminum, and its recycling is of great significance. In this paper, secondary aluminum ash was used as the raw material. After treating it by hydrochloric acid leaching, calcium aluminate was then added to prepare polyaluminum chloride (PAC). The influencing factors such as the concentration of HCl, leaching temperature, time, liquid-solid ratio, and calcium aluminate addition amount were mainly investigated. The best conditions for preparing polyaluminum chloride by acid leaching of secondary aluminum dross were as follows: the secondary aluminum dross after washing was leached at the HCl concentration of 6 mol/L, the liquid-solid ratio of 4∶1 mL/g, at 85 ℃ for 2 h, and then added calcium aluminate 12 g/80 mL to the acid leaching solution and reacted at 85 ℃ for 1.5 h. Under these conditions, the leaching rate of aluminum during the acid leaching process was 48.67%, and the liquid PAC prepared was fully compliance with the national standard.
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