The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.H...The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.However,whether an increased maize density can compensate for the negative effects of reduced water and N supply on grain yield and N uptake in the arid irrigated areas remains unknown.This study is part of a long-term positioning trial that started in 2016.A split-split plot field experiment of maize was implemented in the arid irrigated area of northwestern China in 2020 to 2021.The treatments included two irrigation levels:local conventional irrigation reduced by 20%(W1,3,240 m^(3)ha^(-1))and local conventional irrigation(W2,4,050 m^(3)ha^(-1));two N application rates:local conventional N reduced by 25%(N1,270 kg ha^(-1))and local conventional N(360 kg ha^(-1));and three planting densities:local conventional density(D1,75,000 plants ha^(-1)),density increased by 30%(D2,97,500 plants ha-1),and density increased by 60%(D3,120,000 plants ha^(-1)).Our results showed that the grain yield and aboveground N accumulation of maize were lower under the reduced water and N inputs,but increasing the maize density by 30% can compensate for the reductions of grain yield and aboveground N accumulation caused by the reduced water and N supply.When water was reduced while the N application rate remained unchanged,increasing the planting density by 30% enhanced grain yield by 13.9% and aboveground N accumulation by 15.3%.Under reduced water and N inputs,increasing the maize density by 30% enhanced N uptake efficiency and N partial factor productivity,and it also compensated for the N harvest index and N metabolic related enzyme activities.Compared with W2N2D1,the N uptake efficiency and N partial factor productivity increased by 28.6 and 17.6%under W1N1D2.W1N2D2 had 8.4% higher N uptake efficiency and 13.9% higher N partial factor productivity than W2N2D1.W1N2D2 improved urease activity and nitrate reductase activity by 5.4% at the R2(blister)stage and 19.6% at the V6(6th leaf)stage,and increased net income and the benefit:cost ratio by 22.1 and 16.7%,respectively.W1N1D2 and W1N2D2 reduced the nitrate nitrogen and ammoniacal nitrogen contents at the R6 stage in the 40-100 cm soil layer,compared with W2N2D1.In summary,increasing the planting density by 30% can compensate for the loss of grain yield and aboveground N accumulation under reduced water and N inputs.Meanwhile,increasing the maize density by 30% improved grain yield and aboveground N accumulation when water was reduced by 20% while the N application rate remained constant in arid irrigation areas.展开更多
Photocatalytic water splitting and carbon dioxide reduction provide us clean and sustainable energy resources. The carbon dioxide reduction is also the redemption of the greenhouse effect. MoS/TiOphotocatalysts based ...Photocatalytic water splitting and carbon dioxide reduction provide us clean and sustainable energy resources. The carbon dioxide reduction is also the redemption of the greenhouse effect. MoS/TiOphotocatalysts based on TiOnanoplates have been synthesized via a hydrothermal acidification route for water and carbon dioxide reduction reactions. This facile approach generates well dispersed Mo S3 with low crystallinity on the surface of TiOnanoplates. The as-synthesized MoS/TiOphotocatalyst showed considerable activity for both water reduction and carbon dioxide reduction. The thermal treatment effects of TiO, the loading percentage of MoSand the crystalline phase of TiOhave been investigated towards the photocatalytic performance. TiOnanoplate synthesized through hydrothermal reaction with the presence of HF acid is an ideal semiconductor material for the loading of MoSfor photocatalytic water and carbon dioxide reduction simultaneously in EDTA sacrificial solution.展开更多
Developing high activity and low-cost materials to produce hydrogen by the sustainable way of photoelectrochemical is key to social development.The abundance and inexpensive Cu_(2)O has been received increasing resear...Developing high activity and low-cost materials to produce hydrogen by the sustainable way of photoelectrochemical is key to social development.The abundance and inexpensive Cu_(2)O has been received increasing research as its suitable energy level for photocatalytic water reduction.However,the fast charge recombination rate and the sluggish catalytic kinetics are the huge challenges facing the Cu_(2)O photoreduction.Here,the highly reactive Cu_(2)O@C-MoS_(2)photocathode is constructed by depositing dual-cocatalysts of the carbon layer and MoS_(2)nanosheets on Cu_(2)O nanowires to realize efficient water reduction.An impressive carrier concentration of 6.59×10^(23)cm^(-3)is received,which is 2.78 times of the bare Cu_(2)O,resulting in remarkable enhancement in photocurrent density of 3.34 times for the Cu_(2)O@CMoS_(2)photocathode.Moreover,the applied bias photon-to-current conversion efficiency of the bare Cu_(2)O enhanced 4.5 times from 0.16%to 0.72%in the Cu_(2)O@C-MoS_(2)photocathode.The analysis shows that the Cu_(2)O as light absorber,the carbon layer as electron transfer promoter,and MoS_(2)nanosheets as catalytic sites,thus facilitating chrage separation and enhancing catalytic kinetics.This system paves a feasible strategy for designing other photoelectrodes to realize efficient charge separation and high catalytic activity.展开更多
Drinking water loss or Non-Revenue Water (NRW) threatens the financial viability of water utilities and sustainable natural water resource management. However, little attention has been paid to quantitative assessment...Drinking water loss or Non-Revenue Water (NRW) threatens the financial viability of water utilities and sustainable natural water resource management. However, little attention has been paid to quantitative assessment of the spatial distribution of water losses in Rwanda. Therefore, this study focused on the magnitude of water losses, the associated environmental and socio-economic consequences, as well as the potential benefits from water loss reduction in Rwanda. Based on water usage records from the Water and Sanitation Corporation (WASAC) of Rwanda, NRW was calculated for 15 WASAC branches and Provinces, from July 2013 to June 2014, by using the International Water Association (IWA) standard water balance approach. The results highlight an annual NRW of 16,502,198 or 41% of the total water produced, inducing a revenue loss of US$ 8,713,156. In 14 of the 15 WASAC water branches and all Rwandan provinces, the NRW ratios exceed the NRW threshold (10%) recommended by the American Water Works Association (AWWA). Because of the lost revenue, the water facilities may not expand quickly enough to meet the demands of the rapidly growing population. The suggested 50% reduction in NRW would provide additional 8,251,100 m<sup>3</sup> of treated water yearly, enough to serve extra 41,925 households or irrigate 661 ha of cropland and save US$ 4,356,579, which would reduce the financial gap in Rwanda’s National Water Improvement Project by more than 24%.展开更多
Remote sensing and GIS applications are being widely used for various projects relating to natural resource management. Forests are very important national assets for economic, environmental protection, social and cul...Remote sensing and GIS applications are being widely used for various projects relating to natural resource management. Forests are very important national assets for economic, environmental protection, social and cultural values and should be conserved in order to realize all these benefits. Kenya’s forests are rapidly declining due to pressure from increased population, technological innovation, urbanization human development and other land uses. Mau forest is one of the major forests in Kenya that is a catchment area for many Great Rift Valley lakes within the country and faces a lot of destruction. Continued destruction of the Mau forest will cause catastrophic environmental damage, resulting in massive food crises and compromising the livelihoods of millions of Kenyans, and the possible collapse of the tourism industry. The purpose of this research was to investigate the relationship between the increasing rate of deforestation and the reduction of the volumes of water in the neighboring lakes between the years 1989 to 2010. Satellite images from Landsat-5 Thematic Mapper (TM) and Landsat-7 Enhanced Thematic Mapper (ETM+) were used for the detection of changes in the Mau forest and the dynamics of the neighboring water bodies that included lakes: Naivasha, Baringo, Nakuru, Elementaita and Bogoria. The research showed that from a period of 1989 to 2010 Mau forest has been decreasing due to deforestation and the water bodies have irregular dynamics in that, from 1989 to 2000, there was rise in the volume of water, this is attributed to the El Nino rains experienced in the country during the year 1997 and 1998. But between 2000 and 2010 the volume decreased as the forest is also decreasing. It is recommended that the government creates awareness to sensitize the public on the importance of such forests as catchment areas in Kenya.展开更多
An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures: low-temperature roasting of vanadium-bearing titanomagnetite and water lea...An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures: low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°C, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70 wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.展开更多
In this study, fly ash obtained from a coal burning power plant was used to remove iron from coal mine drainage as well as raising the pH to acceptable limits for natural water using column chromatography. The results...In this study, fly ash obtained from a coal burning power plant was used to remove iron from coal mine drainage as well as raising the pH to acceptable limits for natural water using column chromatography. The results of this study indicate that fly ash has the ability to completely remove iron and reduce acidity of coal mine water drainage. This approach can be extended to include other contaminants such as magnesium.展开更多
1 Introduction In the south of Eastern Transbaikalia in the border area with China and Mongolia,there are at least 300 saline without outlet lakes.They are confined to the semi-arid zone Daurian steppes with pronounce...1 Introduction In the south of Eastern Transbaikalia in the border area with China and Mongolia,there are at least 300 saline without outlet lakes.They are confined to the semi-arid zone Daurian steppes with pronounced continental salinization processes and are mostly located on the bottoms of the intermountain basins.Their origin is related to evaporative concentration of fresh waters lakes filling.展开更多
Experimental results of sound transmission loss in a range of frequency through bubbly curtains were obtained, where the air content was in a wide range by means of varying pressure differences and the diameters of th...Experimental results of sound transmission loss in a range of frequency through bubbly curtains were obtained, where the air content was in a wide range by means of varying pressure differences and the diameters of the pores of bubble-produce apparatus . Vibration reduction of a vessel in water due to the bubbly curtain was found.展开更多
Photoelectrochemical (PEC) water splitting by photocathodes based on p-type semiconductors is a promising process for direct and efficient hydrogen generation. The identification of ideal photocathode materials with...Photoelectrochemical (PEC) water splitting by photocathodes based on p-type semiconductors is a promising process for direct and efficient hydrogen generation. The identification of ideal photocathode materials with a high photoconversion efficiency and long-term stability is still a significant challenge. Herein, we propose a new photocathode consisting of Cu2S-coated Cu2O nanowires (NWs) supported on a three-dimensional porous copper foam. The Cu2S thin layer is generated in situ on the surface of the Cu2O NWs and has four functions: (1) sensitizer, with a band gap of 1.2 eV, for extending the range of optical absorption into the near-infrared region; (2) electron trapper, with appropriate energy level alignment to Cu2O, for achieving effective electron transfer and trapping; (3) electrocatalyst, with excellent electrocatalytic activity for the hydrogen evolution reaction; and (4) protector, preventing direct contact between Cu2O and the electrolyte in order to significantly increase the stability. A photocathode based on the tetrafunctional Cu2S-coated Cu2O NWs exhibits significantly enhanced PEC performance and remarkably improved long-term stability under illumination. The present strategy, based on the in situ generation of multifunctional layers, opens a new avenue for the rational design of photocathodes for PEC water reduction.展开更多
In order to prevent the powdering of a sintered ore from influencing the smooth operation of a blast furnace,the conventional way to deal with it is that the CaCl2 solution is prepared by tap water,and then the soluti...In order to prevent the powdering of a sintered ore from influencing the smooth operation of a blast furnace,the conventional way to deal with it is that the CaCl2 solution is prepared by tap water,and then the solution is sprayed onto the sintered ore for improving its RDI(low temperature reduction degradation index).The CaCl2 solution prepared by adding acid and alkaline waste water resulted from cold rolling is sprayed onto the sintered ore to improve its RDI.The values of RDI+6.3 and RDI+3.15 of the sintered ore which is sprayed by the CaCl2 solution with the CaCl2 concentration of 3.5%(mass percent) are increased by 17.5% and 11.63%,but the index of RDI-0.5 is decreased by 3.1% when the spraying amount of the solution is making up 0.5% of the total sintered ore sprayed in comparison with those of the sintered ore which is not sprayed by using the CaCl2 solution.Experimental results show that after the CaCl2 solutions prepared by adding the acid and alkaline waste water are sprayed on the sintered ore,RDI of the ore can be remarkably improved and therefore another way for recycling acid and alkaline waste water can be available,by which both cost for treating waste water and cost for producing a sintered ore can be decreased and environment is free of pollution by harmful substances in the waste water.展开更多
A new material for both magnetic coupling and electrocatalytic hydrogen generation based on a copper complex,[(HL)CuCl-CuCl(HL)]HCl 1 is prepared by the reaction of 2-(pyridylmethyl)amino-N,N-bis(2-methylene-4,...A new material for both magnetic coupling and electrocatalytic hydrogen generation based on a copper complex,[(HL)CuCl-CuCl(HL)]HCl 1 is prepared by the reaction of 2-(pyridylmethyl)amino-N,N-bis(2-methylene-4,6-difluorophenol)(H2L) and CuCl2·2H2O.In solid,complex 1 is built from two copper units([(HL)CuCl]),and exhibits an antiferromagnetic exchange interaction between copper(Ⅱ) ions(J=-160cm^-1).In liquid,1 can electrocatalyze hydrogen generation both from acetic acid with a turnover frequency(TOF) of 16.3 moles of hydrogen per mole of catalyst per hour at an overpotential(OP)of 941.6 mV(in DMF),and a neutral buffer with a TOF of 1415.6 moles of hydrogen per mole of catalyst per hour at an OP of 787.6 mV.展开更多
Sonophotocatalysis combines ultrasonic and light irradiations to drastically boost the chemical reaction rate and has attracted many interests for its potential applications in the environmental remediation and protec...Sonophotocatalysis combines ultrasonic and light irradiations to drastically boost the chemical reaction rate and has attracted many interests for its potential applications in the environmental remediation and protection. However, it still remains unclear whether the light irradiation could couple with the ultrasound to prompt the sonophotocatalytic process. Here, we selectively excited the TiO2 and Au to manipulate the electronic structures of Au/TiO2 and studied their influence in sonophotocatalytic water(H2 O) reduction. Surprisingly, no significant increase of the hydrogen(H2) production rate was observed under either the UV light irradiation or the visible light irradiation, suggesting that the change in electronic structures of Au/TiO2 does not prompt the generation of free radicals under sonication and the reaction is dominated by the recovery of active sites through ultrasound. Our findings established an indepth understanding of the origin of the enhanced catalytic activity in sonophotocatalysis.展开更多
基金financial support of the National Natural Science Foundation of China(U21A20218 and 32101857)the‘Double First-Class’Key Scientific Research Project of Education Department in Gansu Province,China(GSSYLXM-02)+1 种基金the Fuxi Young Talents Fund of Gansu Agricultural University,China(Gaufx03Y10)the“Innovation Star”Program of Graduate Students in 2023 of Gansu Province,China(2023CXZX681)。
文摘The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.However,whether an increased maize density can compensate for the negative effects of reduced water and N supply on grain yield and N uptake in the arid irrigated areas remains unknown.This study is part of a long-term positioning trial that started in 2016.A split-split plot field experiment of maize was implemented in the arid irrigated area of northwestern China in 2020 to 2021.The treatments included two irrigation levels:local conventional irrigation reduced by 20%(W1,3,240 m^(3)ha^(-1))and local conventional irrigation(W2,4,050 m^(3)ha^(-1));two N application rates:local conventional N reduced by 25%(N1,270 kg ha^(-1))and local conventional N(360 kg ha^(-1));and three planting densities:local conventional density(D1,75,000 plants ha^(-1)),density increased by 30%(D2,97,500 plants ha-1),and density increased by 60%(D3,120,000 plants ha^(-1)).Our results showed that the grain yield and aboveground N accumulation of maize were lower under the reduced water and N inputs,but increasing the maize density by 30% can compensate for the reductions of grain yield and aboveground N accumulation caused by the reduced water and N supply.When water was reduced while the N application rate remained unchanged,increasing the planting density by 30% enhanced grain yield by 13.9% and aboveground N accumulation by 15.3%.Under reduced water and N inputs,increasing the maize density by 30% enhanced N uptake efficiency and N partial factor productivity,and it also compensated for the N harvest index and N metabolic related enzyme activities.Compared with W2N2D1,the N uptake efficiency and N partial factor productivity increased by 28.6 and 17.6%under W1N1D2.W1N2D2 had 8.4% higher N uptake efficiency and 13.9% higher N partial factor productivity than W2N2D1.W1N2D2 improved urease activity and nitrate reductase activity by 5.4% at the R2(blister)stage and 19.6% at the V6(6th leaf)stage,and increased net income and the benefit:cost ratio by 22.1 and 16.7%,respectively.W1N1D2 and W1N2D2 reduced the nitrate nitrogen and ammoniacal nitrogen contents at the R6 stage in the 40-100 cm soil layer,compared with W2N2D1.In summary,increasing the planting density by 30% can compensate for the loss of grain yield and aboveground N accumulation under reduced water and N inputs.Meanwhile,increasing the maize density by 30% improved grain yield and aboveground N accumulation when water was reduced by 20% while the N application rate remained constant in arid irrigation areas.
基金supported by the Fundamental Research Funds for the Central Universities of Chinathe Starting Research Funds of Shaanxi Normal University for Mainstay Young Scholars+2 种基金the National Environment Agency of Singapore under the Environment Technology Research Programme(ETRP)through Project No.ETRP 1002 103Singapore National Research Foundation(NRF)through the Singapore-Berkeley Research Initiative for Sustainable Energy(SinBeRISE)Cambridge Centre for Carbon Reduction in Chemical Technology(C4T)CREATE Programmes
文摘Photocatalytic water splitting and carbon dioxide reduction provide us clean and sustainable energy resources. The carbon dioxide reduction is also the redemption of the greenhouse effect. MoS/TiOphotocatalysts based on TiOnanoplates have been synthesized via a hydrothermal acidification route for water and carbon dioxide reduction reactions. This facile approach generates well dispersed Mo S3 with low crystallinity on the surface of TiOnanoplates. The as-synthesized MoS/TiOphotocatalyst showed considerable activity for both water reduction and carbon dioxide reduction. The thermal treatment effects of TiO, the loading percentage of MoSand the crystalline phase of TiOhave been investigated towards the photocatalytic performance. TiOnanoplate synthesized through hydrothermal reaction with the presence of HF acid is an ideal semiconductor material for the loading of MoSfor photocatalytic water and carbon dioxide reduction simultaneously in EDTA sacrificial solution.
基金supported financially by the National Natural Science Foundation of China(Nos.51571151,51701139,51671143,and U1601216)the China Postdoctoral Science Foundation(2019M661014)the Tianjin Natural Science Foundation(No.16JCYBJC17600)。
文摘Developing high activity and low-cost materials to produce hydrogen by the sustainable way of photoelectrochemical is key to social development.The abundance and inexpensive Cu_(2)O has been received increasing research as its suitable energy level for photocatalytic water reduction.However,the fast charge recombination rate and the sluggish catalytic kinetics are the huge challenges facing the Cu_(2)O photoreduction.Here,the highly reactive Cu_(2)O@C-MoS_(2)photocathode is constructed by depositing dual-cocatalysts of the carbon layer and MoS_(2)nanosheets on Cu_(2)O nanowires to realize efficient water reduction.An impressive carrier concentration of 6.59×10^(23)cm^(-3)is received,which is 2.78 times of the bare Cu_(2)O,resulting in remarkable enhancement in photocurrent density of 3.34 times for the Cu_(2)O@CMoS_(2)photocathode.Moreover,the applied bias photon-to-current conversion efficiency of the bare Cu_(2)O enhanced 4.5 times from 0.16%to 0.72%in the Cu_(2)O@C-MoS_(2)photocathode.The analysis shows that the Cu_(2)O as light absorber,the carbon layer as electron transfer promoter,and MoS_(2)nanosheets as catalytic sites,thus facilitating chrage separation and enhancing catalytic kinetics.This system paves a feasible strategy for designing other photoelectrodes to realize efficient charge separation and high catalytic activity.
文摘Drinking water loss or Non-Revenue Water (NRW) threatens the financial viability of water utilities and sustainable natural water resource management. However, little attention has been paid to quantitative assessment of the spatial distribution of water losses in Rwanda. Therefore, this study focused on the magnitude of water losses, the associated environmental and socio-economic consequences, as well as the potential benefits from water loss reduction in Rwanda. Based on water usage records from the Water and Sanitation Corporation (WASAC) of Rwanda, NRW was calculated for 15 WASAC branches and Provinces, from July 2013 to June 2014, by using the International Water Association (IWA) standard water balance approach. The results highlight an annual NRW of 16,502,198 or 41% of the total water produced, inducing a revenue loss of US$ 8,713,156. In 14 of the 15 WASAC water branches and all Rwandan provinces, the NRW ratios exceed the NRW threshold (10%) recommended by the American Water Works Association (AWWA). Because of the lost revenue, the water facilities may not expand quickly enough to meet the demands of the rapidly growing population. The suggested 50% reduction in NRW would provide additional 8,251,100 m<sup>3</sup> of treated water yearly, enough to serve extra 41,925 households or irrigate 661 ha of cropland and save US$ 4,356,579, which would reduce the financial gap in Rwanda’s National Water Improvement Project by more than 24%.
文摘Remote sensing and GIS applications are being widely used for various projects relating to natural resource management. Forests are very important national assets for economic, environmental protection, social and cultural values and should be conserved in order to realize all these benefits. Kenya’s forests are rapidly declining due to pressure from increased population, technological innovation, urbanization human development and other land uses. Mau forest is one of the major forests in Kenya that is a catchment area for many Great Rift Valley lakes within the country and faces a lot of destruction. Continued destruction of the Mau forest will cause catastrophic environmental damage, resulting in massive food crises and compromising the livelihoods of millions of Kenyans, and the possible collapse of the tourism industry. The purpose of this research was to investigate the relationship between the increasing rate of deforestation and the reduction of the volumes of water in the neighboring lakes between the years 1989 to 2010. Satellite images from Landsat-5 Thematic Mapper (TM) and Landsat-7 Enhanced Thematic Mapper (ETM+) were used for the detection of changes in the Mau forest and the dynamics of the neighboring water bodies that included lakes: Naivasha, Baringo, Nakuru, Elementaita and Bogoria. The research showed that from a period of 1989 to 2010 Mau forest has been decreasing due to deforestation and the water bodies have irregular dynamics in that, from 1989 to 2000, there was rise in the volume of water, this is attributed to the El Nino rains experienced in the country during the year 1997 and 1998. But between 2000 and 2010 the volume decreased as the forest is also decreasing. It is recommended that the government creates awareness to sensitize the public on the importance of such forests as catchment areas in Kenya.
基金financially supported by the National Basic Research Program of China(Nos.2013CB632601 and 2013CB632604)the National Science Foundation for Distinguished Young Scholars of China(Nos.51125018 and 51504230)+3 种基金the Key Research Program of the Chinese Academy of Sciences(No.KGZD-EW-201-2)the National Natural Science Foundation of China(Nos.51374191,21106167,2160624,and 51104139)the Financial Grant from the China Postdoctoral Science Foundation(Nos.2012M510552 and 2013T60175)the Nonprofit Industry Research Subject of Environmental Projection(No.201509053)
文摘An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures: low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°C, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70 wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.
文摘In this study, fly ash obtained from a coal burning power plant was used to remove iron from coal mine drainage as well as raising the pH to acceptable limits for natural water using column chromatography. The results of this study indicate that fly ash has the ability to completely remove iron and reduce acidity of coal mine water drainage. This approach can be extended to include other contaminants such as magnesium.
基金supported by integrated project no. 38 of the Siberian Branch, Russian Academy of Sciences "Mineral lakes of Central Asia as archive of paleoclimatic records of high solution and renewal liquid ore"
文摘1 Introduction In the south of Eastern Transbaikalia in the border area with China and Mongolia,there are at least 300 saline without outlet lakes.They are confined to the semi-arid zone Daurian steppes with pronounced continental salinization processes and are mostly located on the bottoms of the intermountain basins.Their origin is related to evaporative concentration of fresh waters lakes filling.
基金The project is supported by National Natural Science Foundation of China and Nationalshipbuilding Corporation
文摘Experimental results of sound transmission loss in a range of frequency through bubbly curtains were obtained, where the air content was in a wide range by means of varying pressure differences and the diameters of the pores of bubble-produce apparatus . Vibration reduction of a vessel in water due to the bubbly curtain was found.
基金Z.H.Z. thanks to the support from "Yingcai" program of ECNU and the National Natural Science Foundation of China (NSFC) (No. 21405046).
文摘Photoelectrochemical (PEC) water splitting by photocathodes based on p-type semiconductors is a promising process for direct and efficient hydrogen generation. The identification of ideal photocathode materials with a high photoconversion efficiency and long-term stability is still a significant challenge. Herein, we propose a new photocathode consisting of Cu2S-coated Cu2O nanowires (NWs) supported on a three-dimensional porous copper foam. The Cu2S thin layer is generated in situ on the surface of the Cu2O NWs and has four functions: (1) sensitizer, with a band gap of 1.2 eV, for extending the range of optical absorption into the near-infrared region; (2) electron trapper, with appropriate energy level alignment to Cu2O, for achieving effective electron transfer and trapping; (3) electrocatalyst, with excellent electrocatalytic activity for the hydrogen evolution reaction; and (4) protector, preventing direct contact between Cu2O and the electrolyte in order to significantly increase the stability. A photocathode based on the tetrafunctional Cu2S-coated Cu2O NWs exhibits significantly enhanced PEC performance and remarkably improved long-term stability under illumination. The present strategy, based on the in situ generation of multifunctional layers, opens a new avenue for the rational design of photocathodes for PEC water reduction.
基金Item Sponsored by National Natural Science Foundation of China(51274120)
文摘In order to prevent the powdering of a sintered ore from influencing the smooth operation of a blast furnace,the conventional way to deal with it is that the CaCl2 solution is prepared by tap water,and then the solution is sprayed onto the sintered ore for improving its RDI(low temperature reduction degradation index).The CaCl2 solution prepared by adding acid and alkaline waste water resulted from cold rolling is sprayed onto the sintered ore to improve its RDI.The values of RDI+6.3 and RDI+3.15 of the sintered ore which is sprayed by the CaCl2 solution with the CaCl2 concentration of 3.5%(mass percent) are increased by 17.5% and 11.63%,but the index of RDI-0.5 is decreased by 3.1% when the spraying amount of the solution is making up 0.5% of the total sintered ore sprayed in comparison with those of the sintered ore which is not sprayed by using the CaCl2 solution.Experimental results show that after the CaCl2 solutions prepared by adding the acid and alkaline waste water are sprayed on the sintered ore,RDI of the ore can be remarkably improved and therefore another way for recycling acid and alkaline waste water can be available,by which both cost for treating waste water and cost for producing a sintered ore can be decreased and environment is free of pollution by harmful substances in the waste water.
基金supported by the National Natural Science Foundation of China (Nos. 20971045, 21271073)
文摘A new material for both magnetic coupling and electrocatalytic hydrogen generation based on a copper complex,[(HL)CuCl-CuCl(HL)]HCl 1 is prepared by the reaction of 2-(pyridylmethyl)amino-N,N-bis(2-methylene-4,6-difluorophenol)(H2L) and CuCl2·2H2O.In solid,complex 1 is built from two copper units([(HL)CuCl]),and exhibits an antiferromagnetic exchange interaction between copper(Ⅱ) ions(J=-160cm^-1).In liquid,1 can electrocatalyze hydrogen generation both from acetic acid with a turnover frequency(TOF) of 16.3 moles of hydrogen per mole of catalyst per hour at an overpotential(OP)of 941.6 mV(in DMF),and a neutral buffer with a TOF of 1415.6 moles of hydrogen per mole of catalyst per hour at an OP of 787.6 mV.
基金supported by the National Science Foundation 9(NSF, No. DMR-1352328)supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, under Contract No. DE-SC0012704
文摘Sonophotocatalysis combines ultrasonic and light irradiations to drastically boost the chemical reaction rate and has attracted many interests for its potential applications in the environmental remediation and protection. However, it still remains unclear whether the light irradiation could couple with the ultrasound to prompt the sonophotocatalytic process. Here, we selectively excited the TiO2 and Au to manipulate the electronic structures of Au/TiO2 and studied their influence in sonophotocatalytic water(H2 O) reduction. Surprisingly, no significant increase of the hydrogen(H2) production rate was observed under either the UV light irradiation or the visible light irradiation, suggesting that the change in electronic structures of Au/TiO2 does not prompt the generation of free radicals under sonication and the reaction is dominated by the recovery of active sites through ultrasound. Our findings established an indepth understanding of the origin of the enhanced catalytic activity in sonophotocatalysis.