The radiological impact of coal ashes, with enhanced natural radioactivity in the storage site, is due to the presence of naturally occurring radionuclides. Some of these radionuclides have a radioactive period of sev...The radiological impact of coal ashes, with enhanced natural radioactivity in the storage site, is due to the presence of naturally occurring radionuclides. Some of these radionuclides have a radioactive period of several million years and will, therefore, have time to migrate to the soil, atmospheric air, surface water, and groundwater. This impact depends mainly on the activity of these coal ashes, the duration of exposure to such waste, transfers to the air, and the leaching phenomenon by rainwater. In this study, and so as to assess the radiological impact of coal ashes of the storage site of the JLEC-Morocco thermal power plant on environment, some analyses are performed by alpha dosimetry and a digital dosimeter on samples of coal ashes, soil, atmospheric air, surface water and groundwater belonging to a perimeter of 10 km around that site. The obtained results show that, within the studied area, the radiological impact on the soil of the coal ashes of the storage site is insignificant even though the concentrations of radon in the near vicinity (1 to 2 km) are moderately important, and remain below 200 Bq/m3. In the atmospheric air, this impact remains medium for the neighborhoods of the storage site (2 to 3 km) with radon activities superior to 10 Bq/m3. These results also show that there may be a water contamination of wells located at the storage site without any transfer of radioactivity into the groundwater of the area studied where the concentrations of radon are less than 11.1 Bq/l.展开更多
Municipal solid waste(MSW)storage sites are potential and overlooked contributors to microplastic(MP)pollution.Herein,the distribution and dispersion characteristics of MPs at MSW storage sites were investigated throu...Municipal solid waste(MSW)storage sites are potential and overlooked contributors to microplastic(MP)pollution.Herein,the distribution and dispersion characteristics of MPs at MSW storage sites were investigated through modeling,sampling analysis,and prediction methodologies.The results indicated a notable adsorption phenomenon of MPs on smooth surfaces within such sites,achieving high saturation levels and making MPs prone to re-release by airflow disturbance.Quantitative analysis revealed that the MP concentrations on these surfaces varied from 4.48×10^(5) to 1.90×10^(6) n/m^(2) and that MPs predominantly accumulated in the corner areas.Notably,MP accumulation on wall surfaces can be reduced by 76.4%using washing procedures.The majority of MPs were under 50μm in size and were primarily in fragment form.Operational activities such as ventilation and waste handling were identified to amplify the airborne spread of MPs.The atmospheric concentrations of MPs peaked seasonally,with concentrations of 28.25 n/m^(3) in summer and 3.90 n/m^(3) in winter,and the spatial dispersion ranged from 14.98 to 124.08 km^(2) per station.This study highlights that MSW storage sites are substantial yet overlooked sources of MP pollution,where wall surfaces play a critical role in MP adsorption and dispersal.The implementation of robust management and cleaning protocols is essential to mitigate the environmental footprint of MPs emanating from these locations.This study also provides a typical case for the precise prevention and control of MPs in the environment.展开更多
As a promising cathode material for aqueous zinc-ion batteries,1T-MoS_(2)has been extensively investigated because of its facile two-dimensional ion-diffusion channels and high electrical conductivity.However,the limi...As a promising cathode material for aqueous zinc-ion batteries,1T-MoS_(2)has been extensively investigated because of its facile two-dimensional ion-diffusion channels and high electrical conductivity.However,the limited number of available Zn storage sites,i.e.,limited capacity,hinders its application because the inserted Zn^(2+),which form strong electrostatic interactions with 1T-MoS_(2),preventing subsequent Zn^(2+)insertion.Currently,the approach of enlarging the interlayer distance to reduce electrostatic interactions has been commonly used to enhance the capacity and reduce Zn^(2+)migration barriers.However,an enlarged interlayer spacing can weaken the van der Waals force between 1T-MoS_(2)monolayers,easily disrupting the structural stability.Herein,to address this issue,an effective strategy based on Fe doping is proposed for 1T-MoS_(2)(Fe-1T-MoS_(2)).The theoretical calculations reveal that Fe doping can simultaneously moderate the rate of decrease in the adsorption energy after gradually increasing the number of stored atoms,and enhance the electron delocalization on metal-O bonds.Therefore,the experiment results show that Fe doping can simultaneously activate more Zn storage sites,thus enhancing the capacity,and stabilize the structural stability for improved cycling performance.Consequently,Fe-1T-MoS_(2)exhibits a larger capacity(189 mAh·g^(-1)at 0.1 A·g^(-1))and superior cycling stability(78%capacity retention after 400 cycles at 2 A·g^(-1))than pure 1T-MoS_(2).This work may open up a new avenue for constructing high-performance MoS_(2)-based cathodes.展开更多
Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries(SIBs).Ultra-micropores(<0.5 nm)of hard carbon can function as ionic sieves to reduce the diffusion...Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries(SIBs).Ultra-micropores(<0.5 nm)of hard carbon can function as ionic sieves to reduce the diffusion of slovated Na+but allow the entrance of naked Na^(+) into the pores,which can reduce the interficial contact between the electrolyte and the inner pores without sacrificing the fast diffusion kinetics.Herein,a molten diffusion-carbonization method is proposed to transform the micropores(>1 nm)inside carbon into ultra-micropores(<0.5 nm).Consequently,the designed carbon anode displays an enhanced capacity of 346 mAh g^(−1) at 30 mA g^(−1) with a high ICE value of~80.6%and most of the capacity(~90%)is below 1 V.Moreover,the high-loading electrode(~19 mg cm^(−2))exhibits a good temperature endurance with a high areal capacity of 6.14 mAh cm^(−2) at 25℃ and 5.32 mAh cm^(−2) at −20℃.Based on the in situ X-ray diffraction and ex situ solid-state nuclear magnetic resonance results,the designed ultra-micropores provide the extra Na+storage sites,which mainly contributes to the enhanced capacity.This proposed strategy shows a good potential for the development of high-performance SIBs.展开更多
Carbon dioxide （CO2） capture and geological storage （CCS） is one of promising technologies for greenhouse gas effect mitigation. Many geotechnical challenges remain during carbon dioxide storage field practices, a...Carbon dioxide （CO2） capture and geological storage （CCS） is one of promising technologies for greenhouse gas effect mitigation. Many geotechnical challenges remain during carbon dioxide storage field practices, among which effectively detecting CO2 from deep underground is one of engineering problems. This paper reviews monitoring techniques currently used during CO2 injection and storage. A method developed based on measuring seismic microtremors is of main interest. This method was first successfully used to characterize a site in this paper. To explore its feasibility in C02 storage monitoring, numerical simulations were conducted to investigate detectable changes in elastic wave signatures due to injection and geological storage of CO2. It is found that, although it is effective for shallow earth profile estimation, the surface wave velocity is not sensitive to the CO2 layer physical parameter variations,especially for a thin CO2 geological storage layer in a deep underground reservoir.展开更多
Carbon dioxide(CO_(2))geological utilization and storage(CGUS)is the key link of CO_(2)capture,utilization,and storage(CCUS).The accurate characterization of the geological body structure is a vital prerequisite of CG...Carbon dioxide(CO_(2))geological utilization and storage(CGUS)is the key link of CO_(2)capture,utilization,and storage(CCUS).The accurate characterization of the geological body structure is a vital prerequisite of CGUS.This paper gives a review of the multi-scale three-dimensional geological structure characterization and site selection of CO_(2)storage.It shows that there is a lack of systematic and high-precision methods for transparency characterization of multi-scale three-dimensional engineering geological structure and hydrogeological structure of a CO_(2)storage site.There is no clear understanding of the fracture evolution and gas-liquid migration process of multi-scale geological body structure under the disturbance of CO_(2)injection.There is a lack of sufficient quantitative methods for the dynamic evaluation of CO_(2)geological storage potential.The geological suitability evaluation method for site selection of CO_(2)storage is rough and has poor applicability,which is difficult to satisfy the urgent needs of CGUS site selection in the whole process of CO_(2)sequestration industrialization in the future.Thus,it is required to conduct studies on the transparency characterization of geological body structure and intelligent site selection for CO_(2)storage,which is of great importance for CGUS engineering practice.展开更多
For pseudocapacitive electrode materials(PseEMs),despite much progress having been made in achieving both high power density and high energy density,a general strategy to guide the enhancement of intrinsic capacitive ...For pseudocapacitive electrode materials(PseEMs),despite much progress having been made in achieving both high power density and high energy density,a general strategy to guide the enhancement of intrinsic capacitive properties of PseEMs remains lacking.Here,we demonstrate a universal chargecompensating strategy to improve the charge-storage capability of PseEMs intrinsically:ⅰ) in the electrolyte with anion as charge carriers(such as OH-),reducing the multivalent cations of PseEMs into lower valences could create more reversible low-to-high valence redox cou ples to promote the intercalation of the anions;ⅱ) in the electrolytes with cation as charge carriers(such as H^(+),Li^(+),Na^(+)),oxidizing the multivalent cations of PseEMs into higher valences could introduce more reversible high-to-low valence redox couples to promote the intercalation of the cations.And we demonstrated that the improved intrinsic charge-storage capability for PseEMs originates from the increased Faradaic charge storage sites.展开更多
文摘The radiological impact of coal ashes, with enhanced natural radioactivity in the storage site, is due to the presence of naturally occurring radionuclides. Some of these radionuclides have a radioactive period of several million years and will, therefore, have time to migrate to the soil, atmospheric air, surface water, and groundwater. This impact depends mainly on the activity of these coal ashes, the duration of exposure to such waste, transfers to the air, and the leaching phenomenon by rainwater. In this study, and so as to assess the radiological impact of coal ashes of the storage site of the JLEC-Morocco thermal power plant on environment, some analyses are performed by alpha dosimetry and a digital dosimeter on samples of coal ashes, soil, atmospheric air, surface water and groundwater belonging to a perimeter of 10 km around that site. The obtained results show that, within the studied area, the radiological impact on the soil of the coal ashes of the storage site is insignificant even though the concentrations of radon in the near vicinity (1 to 2 km) are moderately important, and remain below 200 Bq/m3. In the atmospheric air, this impact remains medium for the neighborhoods of the storage site (2 to 3 km) with radon activities superior to 10 Bq/m3. These results also show that there may be a water contamination of wells located at the storage site without any transfer of radioactivity into the groundwater of the area studied where the concentrations of radon are less than 11.1 Bq/l.
基金supported by the National Natural Science Foundation of China(Nos.41977331 and 42177203).
文摘Municipal solid waste(MSW)storage sites are potential and overlooked contributors to microplastic(MP)pollution.Herein,the distribution and dispersion characteristics of MPs at MSW storage sites were investigated through modeling,sampling analysis,and prediction methodologies.The results indicated a notable adsorption phenomenon of MPs on smooth surfaces within such sites,achieving high saturation levels and making MPs prone to re-release by airflow disturbance.Quantitative analysis revealed that the MP concentrations on these surfaces varied from 4.48×10^(5) to 1.90×10^(6) n/m^(2) and that MPs predominantly accumulated in the corner areas.Notably,MP accumulation on wall surfaces can be reduced by 76.4%using washing procedures.The majority of MPs were under 50μm in size and were primarily in fragment form.Operational activities such as ventilation and waste handling were identified to amplify the airborne spread of MPs.The atmospheric concentrations of MPs peaked seasonally,with concentrations of 28.25 n/m^(3) in summer and 3.90 n/m^(3) in winter,and the spatial dispersion ranged from 14.98 to 124.08 km^(2) per station.This study highlights that MSW storage sites are substantial yet overlooked sources of MP pollution,where wall surfaces play a critical role in MP adsorption and dispersal.The implementation of robust management and cleaning protocols is essential to mitigate the environmental footprint of MPs emanating from these locations.This study also provides a typical case for the precise prevention and control of MPs in the environment.
基金supported by the National Natural Science Foundation of China(No.52102318)the Fellowship of China Postdoctoral Science Foundation(Nos.2021TQ0287 and 2022M722855)Xingdian Talent Support Foundation of Yunnan Province(2020).
文摘As a promising cathode material for aqueous zinc-ion batteries,1T-MoS_(2)has been extensively investigated because of its facile two-dimensional ion-diffusion channels and high electrical conductivity.However,the limited number of available Zn storage sites,i.e.,limited capacity,hinders its application because the inserted Zn^(2+),which form strong electrostatic interactions with 1T-MoS_(2),preventing subsequent Zn^(2+)insertion.Currently,the approach of enlarging the interlayer distance to reduce electrostatic interactions has been commonly used to enhance the capacity and reduce Zn^(2+)migration barriers.However,an enlarged interlayer spacing can weaken the van der Waals force between 1T-MoS_(2)monolayers,easily disrupting the structural stability.Herein,to address this issue,an effective strategy based on Fe doping is proposed for 1T-MoS_(2)(Fe-1T-MoS_(2)).The theoretical calculations reveal that Fe doping can simultaneously moderate the rate of decrease in the adsorption energy after gradually increasing the number of stored atoms,and enhance the electron delocalization on metal-O bonds.Therefore,the experiment results show that Fe doping can simultaneously activate more Zn storage sites,thus enhancing the capacity,and stabilize the structural stability for improved cycling performance.Consequently,Fe-1T-MoS_(2)exhibits a larger capacity(189 mAh·g^(-1)at 0.1 A·g^(-1))and superior cycling stability(78%capacity retention after 400 cycles at 2 A·g^(-1))than pure 1T-MoS_(2).This work may open up a new avenue for constructing high-performance MoS_(2)-based cathodes.
基金Singapore MOE Tier Ⅱ grant R143-000-A29-112the National Research Foundation under the Grant of NRF2017NRF-NSFC001-007.
文摘Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries(SIBs).Ultra-micropores(<0.5 nm)of hard carbon can function as ionic sieves to reduce the diffusion of slovated Na+but allow the entrance of naked Na^(+) into the pores,which can reduce the interficial contact between the electrolyte and the inner pores without sacrificing the fast diffusion kinetics.Herein,a molten diffusion-carbonization method is proposed to transform the micropores(>1 nm)inside carbon into ultra-micropores(<0.5 nm).Consequently,the designed carbon anode displays an enhanced capacity of 346 mAh g^(−1) at 30 mA g^(−1) with a high ICE value of~80.6%and most of the capacity(~90%)is below 1 V.Moreover,the high-loading electrode(~19 mg cm^(−2))exhibits a good temperature endurance with a high areal capacity of 6.14 mAh cm^(−2) at 25℃ and 5.32 mAh cm^(−2) at −20℃.Based on the in situ X-ray diffraction and ex situ solid-state nuclear magnetic resonance results,the designed ultra-micropores provide the extra Na+storage sites,which mainly contributes to the enhanced capacity.This proposed strategy shows a good potential for the development of high-performance SIBs.
基金the financial supports from the State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining and Technology (No. SKLGDUEK1002)the Fundamental Research Funds for the Central Government Supported Universities of Tongji University, China (No. 0270219037)
文摘Carbon dioxide （CO2） capture and geological storage （CCS） is one of promising technologies for greenhouse gas effect mitigation. Many geotechnical challenges remain during carbon dioxide storage field practices, among which effectively detecting CO2 from deep underground is one of engineering problems. This paper reviews monitoring techniques currently used during CO2 injection and storage. A method developed based on measuring seismic microtremors is of main interest. This method was first successfully used to characterize a site in this paper. To explore its feasibility in C02 storage monitoring, numerical simulations were conducted to investigate detectable changes in elastic wave signatures due to injection and geological storage of CO2. It is found that, although it is effective for shallow earth profile estimation, the surface wave velocity is not sensitive to the CO2 layer physical parameter variations,especially for a thin CO2 geological storage layer in a deep underground reservoir.
基金supported by the National Natural Science Foundation of China(Grant No.42141009)the Key Research Program of the Institute of Geology and Geophysics,CAS(Grant No.IGGCAS-202201).
文摘Carbon dioxide(CO_(2))geological utilization and storage(CGUS)is the key link of CO_(2)capture,utilization,and storage(CCUS).The accurate characterization of the geological body structure is a vital prerequisite of CGUS.This paper gives a review of the multi-scale three-dimensional geological structure characterization and site selection of CO_(2)storage.It shows that there is a lack of systematic and high-precision methods for transparency characterization of multi-scale three-dimensional engineering geological structure and hydrogeological structure of a CO_(2)storage site.There is no clear understanding of the fracture evolution and gas-liquid migration process of multi-scale geological body structure under the disturbance of CO_(2)injection.There is a lack of sufficient quantitative methods for the dynamic evaluation of CO_(2)geological storage potential.The geological suitability evaluation method for site selection of CO_(2)storage is rough and has poor applicability,which is difficult to satisfy the urgent needs of CGUS site selection in the whole process of CO_(2)sequestration industrialization in the future.Thus,it is required to conduct studies on the transparency characterization of geological body structure and intelligent site selection for CO_(2)storage,which is of great importance for CGUS engineering practice.
基金supported by the National Natural Science Foundation of China(51972146,52072150)。
文摘For pseudocapacitive electrode materials(PseEMs),despite much progress having been made in achieving both high power density and high energy density,a general strategy to guide the enhancement of intrinsic capacitive properties of PseEMs remains lacking.Here,we demonstrate a universal chargecompensating strategy to improve the charge-storage capability of PseEMs intrinsically:ⅰ) in the electrolyte with anion as charge carriers(such as OH-),reducing the multivalent cations of PseEMs into lower valences could create more reversible low-to-high valence redox cou ples to promote the intercalation of the anions;ⅱ) in the electrolytes with cation as charge carriers(such as H^(+),Li^(+),Na^(+)),oxidizing the multivalent cations of PseEMs into higher valences could introduce more reversible high-to-low valence redox couples to promote the intercalation of the cations.And we demonstrated that the improved intrinsic charge-storage capability for PseEMs originates from the increased Faradaic charge storage sites.
