Although supercritical carbon dioxide(SC-CO_(2))fracturing shows tremendous potential for maximizing injection efficiency and enhancing storage volumes,few investigations have been reported on the SC-CO_(2) fracturing...Although supercritical carbon dioxide(SC-CO_(2))fracturing shows tremendous potential for maximizing injection efficiency and enhancing storage volumes,few investigations have been reported on the SC-CO_(2) fracturing characteristics of tight basalts and the reactions between fractured basalt and SC-CO_(2).In this study,hydraulic fracturing experiments were conducted on cylindrical basalt specimens using water and SC-CO_(2) as fracturing fluids.Geometric parameters were proposed to characterize the fracture morphologies based on the three-dimensional(3D)reconstructions of fracture networks.The rock slices with induced fractures after SC-CO_(2) fracturing were then processed for fluid(deionized water/SC-CO_(2))-basalt reaction tests.The experimental results demonstrate that SC-CO_(2) fracturing can induce complex and tortuous fractures with spatially dispersed morphologies.Other fracturing behaviors accompanying the acoustic emission(AE)signals and pump pressure changes show that the AE activity responds almost simultaneously to variation in the pump pressure.The fractured basalt blocks exposed to both SC-CO_(2) and water exhibit rough and uneven surfaces,along with decreased intensities in the element peaks,indicating that solubility trapping predominantly occurs during the early injection stage.The above findings provide a laboratory research basis for understanding the fracturing and sequestration issues related to effective CO_(2) utilization.展开更多
The corrosion behavior of 304LN austenitic stainless steel in supercritical CO_(2) at 650℃ was investigated.The results show that 304LN follows Wagner’s law kinetics,forming a protective oxide flm consisting of SiO_...The corrosion behavior of 304LN austenitic stainless steel in supercritical CO_(2) at 650℃ was investigated.The results show that 304LN follows Wagner’s law kinetics,forming a protective oxide flm consisting of SiO_(2),(Cr,Mn)3O_(4),and Cr2O_(3) from the inner to outer layers.A shallow carburization depth of approximately 130 nm indicates excellent resistance to carburization.The roles of key elements in 18/8 austenitic stainless steel represented by 304LN,such as Cr,Ni,and Si,were analyzed,highlighting their contributions to anti-carburization performance and corrosion resistance under harsh conditions.展开更多
Carbon dioxide(CO_(2))geological sequestration represents a critical technology in mitigating climate change.Shale reservoirs demonstrate a pronounced affinity for CO_(2),resulting in adsorption-induced swelling that ...Carbon dioxide(CO_(2))geological sequestration represents a critical technology in mitigating climate change.Shale reservoirs demonstrate a pronounced affinity for CO_(2),resulting in adsorption-induced swelling that significantly impacts permeability,mechanical strength,injection efficiency,and sequestration safety.For this,we tried to explore the key factors driving the swelling of shale upon CO_(2)injection and its subsequent impact on reservoir properties.Utilizing a self-developed high-temperature-pressure gas adsorption apparatus,we measured strain in Jurassic shale at 308 K under constant hydrostatic pressure with helium(He)at 1300 psi(1 psi=6.895 kPa)and CO_(2)at 850 psi.Next,we investigated the influence of CO_(2)concentration on swelling protentional while maintaining constant pressure,uncovering the anisotropic deformation in relation to pressure.It shows that CO_(2)adsorption induces significant swelling in shale,following a Langmuir-type pressure relationship.Deformation is more pronounced perpendicular than that parallel to the bedding plane.At low pressure,vertical swelling is 2.28 times greater than the horizontal;while at high pressure,the vertical compression is 31.26 times greater than the horizontal.It seems that the anisotropic swelling enhances permeability predictions during CO_(2)injection.Mixed gases under constant compression can prompt gas desorption,stress redistribution,and alterations in pore structure,amplifying He compression effect.The strain induced after replacing CO_(2)with He exceeds that from pure He injection.The asynchronous response of CO_(2)-induced swelling and mechanical compression can precipitate crack propagation and fracturing.Overall,anisotropic swelling from CO_(2)adsorption changes pore structure and permeability,affecting fluid flow and storage.Considering CO_(2)concentration and anisotropic characteristics in reservoir modeling is essential for optimizing injection strategies and enhancing reservoir efficiency.展开更多
A mixed oxidant of chlorine dioxide(ClO_(2))and NaClO was often used in water treatment.A novel UVA-LED(_(365) nm)-activated mixed ClO_(2)/NaClO process was proposed for the degradation of micropollutants in this stud...A mixed oxidant of chlorine dioxide(ClO_(2))and NaClO was often used in water treatment.A novel UVA-LED(_(365) nm)-activated mixed ClO_(2)/NaClO process was proposed for the degradation of micropollutants in this study.Carbamazepine(CBZ)was selected as the target pollutant.Compared with the UVA_(365)/ClO_(2) process,the UVA_(365)/ClO_(2)/NaClO process can improve the degradation of CBZ,with the rate constant increasing from 2.11×10^(−4) sec^(−1) to 2.74×10^(−4) sec^(−1).In addition,the consumption of oxidants in the UVA_(365)/ClO_(2)/NaClO process(73.67%)can also be lower than that of UVA_(365)/NaClO(86.42%).When the NaClO ratio increased,both the degradation efficiency of CBZ and the consumption of oxidants can increase in the UVA_(365)/ClO_(2)/NaClO process.The solution pH can affect the contribution of NaClO in the total oxidant ratio.When the pH range of 6.0-8.0,the combination process can generate more active species to promote the degradation of CBZ.The change of active species with oxidant molar ratio was investigated in the UVA_(365)/ClO_(2)/NaClO process.When ClO_(2) acted as the main oxidant,HO·and Cl·were the main active species,while when NaClO was the main oxidant,ClO·played a role in the system.Both chloride ion(Cl^(-)),bicarbonate ion(HCO_(3)^(-)),and nitrate ion(NO_(3)^(-))can promote the reaction system.As the concentration of NaClO in the reaction solution increased,the generation of chlorates will decrease.The UVA_(365)/ClO_(2)/NaClO process can effectively control the formation of volatile disinfection by-products(DBPs),and with the increase of ClO_(2) dosage,the formation of DBPs can also decrease.展开更多
The steel industry produces many byproducts, requiring extensive land for storage and causing significant environmental contamination. Industrial effluents discharged into water bodies negatively impact both aquatic e...The steel industry produces many byproducts, requiring extensive land for storage and causing significant environmental contamination. Industrial effluents discharged into water bodies negatively impact both aquatic ecosystems and human health. To solve this problem, this study synthesized a composite of titanium dioxide (TiO2) and steel slag nanocomposites (SSNC) at a 1:2 mass ratio to create a robust photocatalyst for the treatment of synthetic wastewater. The efficacy of this catalyst in degrading various dye pollutants, including methylene blue (MB), was tested under simulated solar light conditions. Comprehensive analyses were conducted to assess the physical and chemical characteristics, crystalline structure, energy gap, and point of zero charge of the composite. The TiO2-SSNC composite catalyst exhibited excellent stability, with a point of zero charge at 8.342 and an energy gap of 2.4 eV. The degradation process conformed to pseudo-first-order kinetics. Optimization of operational parameters was achieved through the response surface methodology. Reusability tests demonstrated that the TiO2-SSNC composite catalyst effectively degraded up to 93.41% of MB in the suspended mode and 92.03% in the coated mode after five cycles. Additionally, the degradation efficiencies for various dyes were significant, highlighting the potential of the composite for broad applications in industrial wastewater treatment. This study also explored the degradation mechanisms and identified byproducts, establishing a pathway for contaminant breakdown. The cost-benefit analysis revealed a total cost of 0.842 8 USD per cubic meter for each treatment activity, indicating low operational and production costs. These findings underscore the promise of the TiO2-SSNC composite as a cost-effective and efficient alternative for wastewater purification.展开更多
Carbon dioxide enhanced oil recovery(CO_(2)-EOR)technology is used for oil production and CO_(2) storage in reservoirs.Methods are being constantly developed to optimize oil recovery and CO_(2) storage during the CO_(...Carbon dioxide enhanced oil recovery(CO_(2)-EOR)technology is used for oil production and CO_(2) storage in reservoirs.Methods are being constantly developed to optimize oil recovery and CO_(2) storage during the CO_(2) displacement process,especially for low-permeability reservoirs under varying geological conditions.In this study,long-core experiments and trans-scale numerical simulations are employed to examine the characteristics of oil production and CO_(2) storage.Optimal production parameters for the target reservoir are also proposed.The results indicate that maintaining the pressure at 1.04 to 1.10 times the minimum miscible pressure(MMP)and increasing the injection rate can enhance oil production in the early stage of reservoir development.In contrast,reducing the injection rate at the later stages prevents CO_(2) channeling,thus improving oil recovery and CO_(2) storage efficiency.A solution-doubling factor is introduced to modify the calculation method for CO_(2) storage,increasing its accuracy to approximately 90%.Before CO_(2) breakthrough,prioritizing oil production is recommended to maximize the economic benefits of this process.In the middle stage of CO_(2) displacement,decreasing the injection rate optimizes the coordination between oil displacement and CO_(2) storage.Further,in the late stage,reduced pressure and injection rates are required as the focus shifts to CO_(2) storage.展开更多
Synergistic interplays involving multiple active centers originating from TiO2 nanotube layers(TNT)and ruthenium(Ru)species comprising of both single atoms(SAs)and nanoparticles(NPs)augment the alkaline hydrogen evolu...Synergistic interplays involving multiple active centers originating from TiO2 nanotube layers(TNT)and ruthenium(Ru)species comprising of both single atoms(SAs)and nanoparticles(NPs)augment the alkaline hydrogen evolution reaction(HER)by enhancing Volmer kinetics from rapid water dissociation and improving Tafel kinetics from efficient H*desorption.Atomic layer deposition of Ru with 50 process cycles results in a mixture of Ru SAs and 2.8-0.4 nm NPs present on TNT layers,and it emerges with the highest HER activity among all the electrodes synthesized.A detailed study of the Ti and Ru species using different high-resolution techniques confirmed the presence of Ti^(3+)states and the coexistence of Ru SAs and NPs.With insights from literature,the role of Ti^(3+),appropriate work functions of TNT layers and Ru,and the synergistic effect of Ru SAs and Ru NPs in improving the performance of alkaline HER were elaborated and justified.The aforementioned characteristics led to a remarkable performance by having 9mV onset potentials and 33 mV dec^(-1) of Tafel slopes and a higher turnover frequency of 1.72 H2 s^(-1) at 30 mV.Besides,a notable stability from 28 h staircase chronopotentiometric measurements for TNT@Ru surpasses TNT@Pt in comparison.展开更多
基金supported by the National Key Research and Development Project(Grant No.2023YFE0110900)the National Natural Science Foundation of China(Grant No.42320104003)the Shanghai Pujiang Programme(Grant No.23PJD105).
文摘Although supercritical carbon dioxide(SC-CO_(2))fracturing shows tremendous potential for maximizing injection efficiency and enhancing storage volumes,few investigations have been reported on the SC-CO_(2) fracturing characteristics of tight basalts and the reactions between fractured basalt and SC-CO_(2).In this study,hydraulic fracturing experiments were conducted on cylindrical basalt specimens using water and SC-CO_(2) as fracturing fluids.Geometric parameters were proposed to characterize the fracture morphologies based on the three-dimensional(3D)reconstructions of fracture networks.The rock slices with induced fractures after SC-CO_(2) fracturing were then processed for fluid(deionized water/SC-CO_(2))-basalt reaction tests.The experimental results demonstrate that SC-CO_(2) fracturing can induce complex and tortuous fractures with spatially dispersed morphologies.Other fracturing behaviors accompanying the acoustic emission(AE)signals and pump pressure changes show that the AE activity responds almost simultaneously to variation in the pump pressure.The fractured basalt blocks exposed to both SC-CO_(2) and water exhibit rough and uneven surfaces,along with decreased intensities in the element peaks,indicating that solubility trapping predominantly occurs during the early injection stage.The above findings provide a laboratory research basis for understanding the fracturing and sequestration issues related to effective CO_(2) utilization.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA0410000)the CAS Project for Young Scientists in Basic Research(No.YSBR-043)+1 种基金the CNNC Science Fund for Talented Young Scholars,the National Funding Program for Postdoctoral Researchers(GZC20232747)the Youth Innovation Promotion Association CAS(2022187).
文摘The corrosion behavior of 304LN austenitic stainless steel in supercritical CO_(2) at 650℃ was investigated.The results show that 304LN follows Wagner’s law kinetics,forming a protective oxide flm consisting of SiO_(2),(Cr,Mn)3O_(4),and Cr2O_(3) from the inner to outer layers.A shallow carburization depth of approximately 130 nm indicates excellent resistance to carburization.The roles of key elements in 18/8 austenitic stainless steel represented by 304LN,such as Cr,Ni,and Si,were analyzed,highlighting their contributions to anti-carburization performance and corrosion resistance under harsh conditions.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(Grant No.52121003)the National Natural Science Foundation of China(Grant No.52104046).
文摘Carbon dioxide(CO_(2))geological sequestration represents a critical technology in mitigating climate change.Shale reservoirs demonstrate a pronounced affinity for CO_(2),resulting in adsorption-induced swelling that significantly impacts permeability,mechanical strength,injection efficiency,and sequestration safety.For this,we tried to explore the key factors driving the swelling of shale upon CO_(2)injection and its subsequent impact on reservoir properties.Utilizing a self-developed high-temperature-pressure gas adsorption apparatus,we measured strain in Jurassic shale at 308 K under constant hydrostatic pressure with helium(He)at 1300 psi(1 psi=6.895 kPa)and CO_(2)at 850 psi.Next,we investigated the influence of CO_(2)concentration on swelling protentional while maintaining constant pressure,uncovering the anisotropic deformation in relation to pressure.It shows that CO_(2)adsorption induces significant swelling in shale,following a Langmuir-type pressure relationship.Deformation is more pronounced perpendicular than that parallel to the bedding plane.At low pressure,vertical swelling is 2.28 times greater than the horizontal;while at high pressure,the vertical compression is 31.26 times greater than the horizontal.It seems that the anisotropic swelling enhances permeability predictions during CO_(2)injection.Mixed gases under constant compression can prompt gas desorption,stress redistribution,and alterations in pore structure,amplifying He compression effect.The strain induced after replacing CO_(2)with He exceeds that from pure He injection.The asynchronous response of CO_(2)-induced swelling and mechanical compression can precipitate crack propagation and fracturing.Overall,anisotropic swelling from CO_(2)adsorption changes pore structure and permeability,affecting fluid flow and storage.Considering CO_(2)concentration and anisotropic characteristics in reservoir modeling is essential for optimizing injection strategies and enhancing reservoir efficiency.
基金supported by the National Natural Science Foundation of China (No.52170006)。
文摘A mixed oxidant of chlorine dioxide(ClO_(2))and NaClO was often used in water treatment.A novel UVA-LED(_(365) nm)-activated mixed ClO_(2)/NaClO process was proposed for the degradation of micropollutants in this study.Carbamazepine(CBZ)was selected as the target pollutant.Compared with the UVA_(365)/ClO_(2) process,the UVA_(365)/ClO_(2)/NaClO process can improve the degradation of CBZ,with the rate constant increasing from 2.11×10^(−4) sec^(−1) to 2.74×10^(−4) sec^(−1).In addition,the consumption of oxidants in the UVA_(365)/ClO_(2)/NaClO process(73.67%)can also be lower than that of UVA_(365)/NaClO(86.42%).When the NaClO ratio increased,both the degradation efficiency of CBZ and the consumption of oxidants can increase in the UVA_(365)/ClO_(2)/NaClO process.The solution pH can affect the contribution of NaClO in the total oxidant ratio.When the pH range of 6.0-8.0,the combination process can generate more active species to promote the degradation of CBZ.The change of active species with oxidant molar ratio was investigated in the UVA_(365)/ClO_(2)/NaClO process.When ClO_(2) acted as the main oxidant,HO·and Cl·were the main active species,while when NaClO was the main oxidant,ClO·played a role in the system.Both chloride ion(Cl^(-)),bicarbonate ion(HCO_(3)^(-)),and nitrate ion(NO_(3)^(-))can promote the reaction system.As the concentration of NaClO in the reaction solution increased,the generation of chlorates will decrease.The UVA_(365)/ClO_(2)/NaClO process can effectively control the formation of volatile disinfection by-products(DBPs),and with the increase of ClO_(2) dosage,the formation of DBPs can also decrease.
基金supported by the Department of Chemical and Petrochemical Engineering,Egypt-Japan University of Science and Technology.
文摘The steel industry produces many byproducts, requiring extensive land for storage and causing significant environmental contamination. Industrial effluents discharged into water bodies negatively impact both aquatic ecosystems and human health. To solve this problem, this study synthesized a composite of titanium dioxide (TiO2) and steel slag nanocomposites (SSNC) at a 1:2 mass ratio to create a robust photocatalyst for the treatment of synthetic wastewater. The efficacy of this catalyst in degrading various dye pollutants, including methylene blue (MB), was tested under simulated solar light conditions. Comprehensive analyses were conducted to assess the physical and chemical characteristics, crystalline structure, energy gap, and point of zero charge of the composite. The TiO2-SSNC composite catalyst exhibited excellent stability, with a point of zero charge at 8.342 and an energy gap of 2.4 eV. The degradation process conformed to pseudo-first-order kinetics. Optimization of operational parameters was achieved through the response surface methodology. Reusability tests demonstrated that the TiO2-SSNC composite catalyst effectively degraded up to 93.41% of MB in the suspended mode and 92.03% in the coated mode after five cycles. Additionally, the degradation efficiencies for various dyes were significant, highlighting the potential of the composite for broad applications in industrial wastewater treatment. This study also explored the degradation mechanisms and identified byproducts, establishing a pathway for contaminant breakdown. The cost-benefit analysis revealed a total cost of 0.842 8 USD per cubic meter for each treatment activity, indicating low operational and production costs. These findings underscore the promise of the TiO2-SSNC composite as a cost-effective and efficient alternative for wastewater purification.
基金funded by the National Science and Technology Major Project for the Exploration and Development of New Types of Oil and Gas(No.2024ZD14066)the National Natural Science Foundation of China(No.52274053)+1 种基金the Natural Science Foundation of Beijing Municipality(No.3173044)the Xinjiang Conglomerate Reservoir Laboratory Development Foundation Project(No.2020D04045)。
文摘Carbon dioxide enhanced oil recovery(CO_(2)-EOR)technology is used for oil production and CO_(2) storage in reservoirs.Methods are being constantly developed to optimize oil recovery and CO_(2) storage during the CO_(2) displacement process,especially for low-permeability reservoirs under varying geological conditions.In this study,long-core experiments and trans-scale numerical simulations are employed to examine the characteristics of oil production and CO_(2) storage.Optimal production parameters for the target reservoir are also proposed.The results indicate that maintaining the pressure at 1.04 to 1.10 times the minimum miscible pressure(MMP)and increasing the injection rate can enhance oil production in the early stage of reservoir development.In contrast,reducing the injection rate at the later stages prevents CO_(2) channeling,thus improving oil recovery and CO_(2) storage efficiency.A solution-doubling factor is introduced to modify the calculation method for CO_(2) storage,increasing its accuracy to approximately 90%.Before CO_(2) breakthrough,prioritizing oil production is recommended to maximize the economic benefits of this process.In the middle stage of CO_(2) displacement,decreasing the injection rate optimizes the coordination between oil displacement and CO_(2) storage.Further,in the late stage,reduced pressure and injection rates are required as the focus shifts to CO_(2) storage.
基金support from the European Union Horizon 2020 program(project HERMES,nr.952184)the Ministry of Education,Youth and Sports of the Czech Republic for supporting CEMNAT(LM2023037)+1 种基金Czech-NanoLab(LM2023051)infrastructures for providing ALD,SEM,EDX,XPS,TEM,and XRDCzech Science Foundation(project 23-08019X,EXPRO).
文摘Synergistic interplays involving multiple active centers originating from TiO2 nanotube layers(TNT)and ruthenium(Ru)species comprising of both single atoms(SAs)and nanoparticles(NPs)augment the alkaline hydrogen evolution reaction(HER)by enhancing Volmer kinetics from rapid water dissociation and improving Tafel kinetics from efficient H*desorption.Atomic layer deposition of Ru with 50 process cycles results in a mixture of Ru SAs and 2.8-0.4 nm NPs present on TNT layers,and it emerges with the highest HER activity among all the electrodes synthesized.A detailed study of the Ti and Ru species using different high-resolution techniques confirmed the presence of Ti^(3+)states and the coexistence of Ru SAs and NPs.With insights from literature,the role of Ti^(3+),appropriate work functions of TNT layers and Ru,and the synergistic effect of Ru SAs and Ru NPs in improving the performance of alkaline HER were elaborated and justified.The aforementioned characteristics led to a remarkable performance by having 9mV onset potentials and 33 mV dec^(-1) of Tafel slopes and a higher turnover frequency of 1.72 H2 s^(-1) at 30 mV.Besides,a notable stability from 28 h staircase chronopotentiometric measurements for TNT@Ru surpasses TNT@Pt in comparison.
