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
A series of gluscose derivatives were designed, synthesized, and their structures were confirmed by IR, NMR and elementary analysis. All new compounds are highly soluble in liquid or supercritical carbon dioxide. The ...A series of gluscose derivatives were designed, synthesized, and their structures were confirmed by IR, NMR and elementary analysis. All new compounds are highly soluble in liquid or supercritical carbon dioxide. The compound with electron-withdrawing substituent on benzene ring had even better solubility than the compounds with electron-donating substituent.展开更多
1 Introduction Nowadays, green chemistry has received increased attention. The use of water and scCO2 as a solvent or reagent is an important field for organic reactions and green chemistry both in laboratory and indu...1 Introduction Nowadays, green chemistry has received increased attention. The use of water and scCO2 as a solvent or reagent is an important field for organic reactions and green chemistry both in laboratory and industry.展开更多
Teroolymerization of enichlorohydrin（ECH）-maleic anhydride（MAn）-carbon dioxide（CO;） was carried out by using Y(P;);-Al（i-Bu）;as catalyst for the first time.The terpolymersobtained were characterized by IR and;...Teroolymerization of enichlorohydrin（ECH）-maleic anhydride（MAn）-carbon dioxide（CO;） was carried out by using Y(P;);-Al（i-Bu）;as catalyst for the first time.The terpolymersobtained were characterized by IR and;H-NMR.It was foundthat the composition of the teroolymer was influenced by theaddition mode,initial monomer charge ratio,etc.展开更多
Objective: To evaluate the anti-tumor effects of SeO2 and its mechanisms on three human lung cancer cell lines. Methods: Three lung cancer cells A549, GLC-82 and PG were treated with 3-30 μmol/L SeO2. Flow cytometry ...Objective: To evaluate the anti-tumor effects of SeO2 and its mechanisms on three human lung cancer cell lines. Methods: Three lung cancer cells A549, GLC-82 and PG were treated with 3-30 μmol/L SeO2. Flow cytometry was used to detect apoptosis, and analyze the changes of expression of p53 and Bcl-2, as well as ROS and Ca2+ level within cells. Results:SeO2 markedly inhibited cell proliferation and viability, and prompted apoptosis after 48 h treatment. SeO2 at 10 μmol/L induced 47.8% apoptosis in A549 cells, 40.8% in GLC-82 cells, 18.2% in PG cells. SeO2 at 30 μmol/L induced 37.8% apoposis in PG cells,but did not increase apoptotic raes in other two cells. SeO2 could down-regulate the mean fluorescent intensity of Bcl-2 from 65.8 to 9.6 in A549, but not in GLC-82 and in PG cells, up-regulate wild type p53 level in all three cells. SeO2 decreased the ROS and Ca2+ level markedly within three tested cells. Conclusion: SeO2 showed anti-tumor effect via apoptosis pathway in three lung cancer cell lines. The decrease of ROS and Ca2+ level within cells as well as regulation of Bcl-2 and p53 expression may play important roles in above apoptotic procedure.展开更多
Synthesis of cyclic carbonates from carbon dioxide(CO_(2))and epoxides is an effective pathway for the CO_(2) utilization.Although various metal catalysts have been reported,it is highly desirable to develop a method ...Synthesis of cyclic carbonates from carbon dioxide(CO_(2))and epoxides is an effective pathway for the CO_(2) utilization.Although various metal catalysts have been reported,it is highly desirable to develop a method for the reuse or recycling of catalysts.Herein,an N-heterocyclic carbene-pyridine molybdenum complex supported over SBA-15(Mo@SBA-15)was used as an efficient and recyclable catalyst for converting CO_(2) and epoxides into cyclic carbonates.Mo@SBA-15 in combination with tetra-butylammonium bromide(TBAB)shows high catalytic activity in the synthesis of cyclic carbonates under 100℃and 1 MPa CO_(2) pressure.In addition,Mo@SBA-15 was reused seven times without any significant activity loss.展开更多
To improve the efficiency of the carbon dioxide cycling process and to reduce the regeneration energy consumption, a sterically hindered amine of 2-amino-2-methyl-1- propranol （AMP） was investigated to determine its...To improve the efficiency of the carbon dioxide cycling process and to reduce the regeneration energy consumption, a sterically hindered amine of 2-amino-2-methyl-1- propranol （AMP） was investigated to determine its regeneration behavior as a CO2 absorbent. The CO2 absorption and amine regeneration characteristics were experimentally examined under various operating conditions. The regeneration efficiency increased from 86.2% to 98.3% during the temperature range of 358 to 403 K. The most suitable regeneration temperature for AMP was 383 K, in this experiment condition, and the regeneration efficiency of absorption/regeneration runs descended from 98.3% to 94.0%. A number of heat-stable salts （HSS） could cause a reduction in CO2 absorption capacity and regeneration efficiency. The results indicated that aqueous AMP was easier to regenerate with less loss of absorption capacity than other amines, such as, monoethanolamine （MEA）, diethanolamine （DEA）, diethylenetriamine （DETA）, and N-methyldiethanolamine （MDEA）.展开更多
The Cu2O/SiC photocatalyst was obtained from SiC nanoparticles （NPs） modified by Cu2O. Their photocatalytic activities for reducing CO2 to CH3OH under visible light irradiation have been investigated. The results in...The Cu2O/SiC photocatalyst was obtained from SiC nanoparticles （NPs） modified by Cu2O. Their photocatalytic activities for reducing CO2 to CH3OH under visible light irradiation have been investigated. The results indicated that besides a small quantity of 6H-SiC, SiC NPs mainly consisted of 3C-SiC. The band gaps of SiC and Cu2O were estimated to be about 1.95 and 2.23 eV from UV-Vis spectra, respectively. The Cu2O modification can enhance the photocatalytic performance of SiC NPs, and the largest yields of methanol on SiC, Cu2O and Cu2O/SiC photocatalysts under visible light irradiation were 153, 104 and 191μmol/g, respectively.展开更多
Dehydrogenation of ethane to ethylene in CO_2 was investigated overCeO_2/γ-Al_2O_3 catalysts at 700℃ in a conventional flow reactor operating at atmosphericpressure. XRD, BET and microcalori-metric adsorption techni...Dehydrogenation of ethane to ethylene in CO_2 was investigated overCeO_2/γ-Al_2O_3 catalysts at 700℃ in a conventional flow reactor operating at atmosphericpressure. XRD, BET and microcalori-metric adsorption techniques were used to characterize thestructure and surface acidity/basicity of the CeO_2/γ-Al_2O_3 catalysts. The results show that thesurface acidity decreased while the surface basicity increased after the addition of CeO_2 toγ-Al_2O_3. Accordingly, the activity of the hydrogenation reaction of CO_2 increased, which mightbe responsible for the enhanced conversion in the dehydrogenation of ethane to ethylene. The highestethane conversion obtained was about 15% for the 25%CeO_2/γ-Al_2O_3. The selectivity to ethylenewas high for all the CeO_2, γ-Al_2O_3 and CeO2/γ-Al_2O_3 catalysts.展开更多
The synthesis of ultrafine cerium dioxide precursor via homogeneous precipitation was studied. Mixed aqueous solution of anhydrous cerium nitrate and urea was first heated to 85℃ for 2 h, and the prepared suspension ...The synthesis of ultrafine cerium dioxide precursor via homogeneous precipitation was studied. Mixed aqueous solution of anhydrous cerium nitrate and urea was first heated to 85℃ for 2 h, and the prepared suspension was then aged at room temperature for various periods of time. White precipitate was finally collected by centrifuging and washed with distilled water and anhydrous ethanol. The obtained cerium dioxide (CeO2) precursor was observed with SEM. It was found that the morphology and size of the precursor were strongly affected by aging time and stirring conditions (with or without stirring). The precipitated fine spherical particles of the precursor changed their shape from ellipse to slice or directly to slice. Fine spherical monodispersed (300 nm) precursor powders could be obtained by controlling the aging time. Stirring the solution also could change the reaction process and thus the morphology and size of the precursor were changed.展开更多
The Co-incorporated Ce1-xZrxO2 catalysts were prepared by co-precipitation for carbon dioxide reforming of methane.The ratio of Ce to Zr was varied to optimize the performances of co-precipitated Co-Ce-Zr-Ox catalysts...The Co-incorporated Ce1-xZrxO2 catalysts were prepared by co-precipitation for carbon dioxide reforming of methane.The ratio of Ce to Zr was varied to optimize the performances of co-precipitated Co-Ce-Zr-Ox catalysts.The prepared catalysts were characterized by various physico-chemical characterization techniques including TPR,X-ray diffraction,N2 adsorption at low temperature,XPS and CO2-TPSR.The co-precipitated Co-Ce0.8Zr0.2O2 sample containing 16% CoO exhibited a higher catalytic activity among the five catalysts,and the activity was maintained without significant loss during the reaction for 60 h.Under the conditions of 750 ℃,0.1 MPa,36000 ml/（h gcat）,and CO2/CH4 molar ratio of 1：1,the CO2 conversion over this catalyst was 75% while the CH4 conversion was 67%.The cubic Ce0.8Zr0.2O2 facilitated a higher dispersion and a higher reducibility of the cobalt component,and the apparent activation energy for Co-Ce0.8Zr0.2O2 sample was 49.1 kJ/mol in the CO2/CH4 reforming reaction.As a result,the Co-Ce0.8Zr0.2O2 sample exhibited a higher activity and stability for the reforming of CH4 with CO2.展开更多
The catalyst screening tests for carbon dioxide oxidative coupling of methane (CO2-OCM) have been investigated over ternary and binary metal oxide catalysts. The catalysts are prepared by doping MgO- and CeO2-based so...The catalyst screening tests for carbon dioxide oxidative coupling of methane (CO2-OCM) have been investigated over ternary and binary metal oxide catalysts. The catalysts are prepared by doping MgO- and CeO2-based solids with oxides from alkali (Li2O), alkaline earth (CaO), and transition metal groups (WO3 or MnO). The presence of the peroxide (O2-2) active sites on the Li2O2, revealed by Raman spectroscopy, may be the key factor in the enhanced performance of some of the Li2O/MgO catalysts. The high reducibility of the CeO2 catalyst, an important factor in the CO2-OCM catalyst activity, may be enhanced by the presence of manganese oxide species. The manganese oxide species increases oxygen mobility and oxygen vacancies in the CeO2 catalyst. Raman and Fourier Transform Infra Red (FT-IR) spectroscopies revealed the presence of lattice vibrations of metal-oxygen bondings and active sites in which the peaks corresponding to the bulk crystalline structures of Li2O, CaO, WO3 and MnO are detected. The performance of 5%MnO/15%CaO/CeO2 catalyst is the most potential among the CeO2-based catalysts, although lower than the 2%Li2O/MgO catalyst. The 2%Li2O/MgO catalyst showed the most promising C2+ hydrocarbons selectivity and yield at 98.0% and 5.7%, respectively.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.
文摘A series of gluscose derivatives were designed, synthesized, and their structures were confirmed by IR, NMR and elementary analysis. All new compounds are highly soluble in liquid or supercritical carbon dioxide. The compound with electron-withdrawing substituent on benzene ring had even better solubility than the compounds with electron-donating substituent.
基金the National Natural Science Foundation of China(Nos.20332030,20572027,20625205 and 20772034)Natural Science Foundation of Guangdong Province,China(No.07118070).
文摘1 Introduction Nowadays, green chemistry has received increased attention. The use of water and scCO2 as a solvent or reagent is an important field for organic reactions and green chemistry both in laboratory and industry.
文摘Teroolymerization of enichlorohydrin（ECH）-maleic anhydride（MAn）-carbon dioxide（CO;） was carried out by using Y(P;);-Al（i-Bu）;as catalyst for the first time.The terpolymersobtained were characterized by IR and;H-NMR.It was foundthat the composition of the teroolymer was influenced by theaddition mode,initial monomer charge ratio,etc.
基金This project was partially supported by Science Foundation of Lanzhou Command of PLA(No.YZ-0106).
文摘Objective: To evaluate the anti-tumor effects of SeO2 and its mechanisms on three human lung cancer cell lines. Methods: Three lung cancer cells A549, GLC-82 and PG were treated with 3-30 μmol/L SeO2. Flow cytometry was used to detect apoptosis, and analyze the changes of expression of p53 and Bcl-2, as well as ROS and Ca2+ level within cells. Results:SeO2 markedly inhibited cell proliferation and viability, and prompted apoptosis after 48 h treatment. SeO2 at 10 μmol/L induced 47.8% apoptosis in A549 cells, 40.8% in GLC-82 cells, 18.2% in PG cells. SeO2 at 30 μmol/L induced 37.8% apoposis in PG cells,but did not increase apoptotic raes in other two cells. SeO2 could down-regulate the mean fluorescent intensity of Bcl-2 from 65.8 to 9.6 in A549, but not in GLC-82 and in PG cells, up-regulate wild type p53 level in all three cells. SeO2 decreased the ROS and Ca2+ level markedly within three tested cells. Conclusion: SeO2 showed anti-tumor effect via apoptosis pathway in three lung cancer cell lines. The decrease of ROS and Ca2+ level within cells as well as regulation of Bcl-2 and p53 expression may play important roles in above apoptotic procedure.
文摘Synthesis of cyclic carbonates from carbon dioxide(CO_(2))and epoxides is an effective pathway for the CO_(2) utilization.Although various metal catalysts have been reported,it is highly desirable to develop a method for the reuse or recycling of catalysts.Herein,an N-heterocyclic carbene-pyridine molybdenum complex supported over SBA-15(Mo@SBA-15)was used as an efficient and recyclable catalyst for converting CO_(2) and epoxides into cyclic carbonates.Mo@SBA-15 in combination with tetra-butylammonium bromide(TBAB)shows high catalytic activity in the synthesis of cyclic carbonates under 100℃and 1 MPa CO_(2) pressure.In addition,Mo@SBA-15 was reused seven times without any significant activity loss.
文摘To improve the efficiency of the carbon dioxide cycling process and to reduce the regeneration energy consumption, a sterically hindered amine of 2-amino-2-methyl-1- propranol （AMP） was investigated to determine its regeneration behavior as a CO2 absorbent. The CO2 absorption and amine regeneration characteristics were experimentally examined under various operating conditions. The regeneration efficiency increased from 86.2% to 98.3% during the temperature range of 358 to 403 K. The most suitable regeneration temperature for AMP was 383 K, in this experiment condition, and the regeneration efficiency of absorption/regeneration runs descended from 98.3% to 94.0%. A number of heat-stable salts （HSS） could cause a reduction in CO2 absorption capacity and regeneration efficiency. The results indicated that aqueous AMP was easier to regenerate with less loss of absorption capacity than other amines, such as, monoethanolamine （MEA）, diethanolamine （DEA）, diethylenetriamine （DETA）, and N-methyldiethanolamine （MDEA）.
基金supported by the National Natural Science Foundation of China (Grant No. 20906034)the Key Academic Program of the 3rd Phase "211 Project" of South China Agricultural University (Grant No. 2009B010100001)China Postdoctoral Science Foundation (Grant No. 20080430820)
文摘The Cu2O/SiC photocatalyst was obtained from SiC nanoparticles （NPs） modified by Cu2O. Their photocatalytic activities for reducing CO2 to CH3OH under visible light irradiation have been investigated. The results indicated that besides a small quantity of 6H-SiC, SiC NPs mainly consisted of 3C-SiC. The band gaps of SiC and Cu2O were estimated to be about 1.95 and 2.23 eV from UV-Vis spectra, respectively. The Cu2O modification can enhance the photocatalytic performance of SiC NPs, and the largest yields of methanol on SiC, Cu2O and Cu2O/SiC photocatalysts under visible light irradiation were 153, 104 and 191μmol/g, respectively.
文摘Dehydrogenation of ethane to ethylene in CO_2 was investigated overCeO_2/γ-Al_2O_3 catalysts at 700℃ in a conventional flow reactor operating at atmosphericpressure. XRD, BET and microcalori-metric adsorption techniques were used to characterize thestructure and surface acidity/basicity of the CeO_2/γ-Al_2O_3 catalysts. The results show that thesurface acidity decreased while the surface basicity increased after the addition of CeO_2 toγ-Al_2O_3. Accordingly, the activity of the hydrogenation reaction of CO_2 increased, which mightbe responsible for the enhanced conversion in the dehydrogenation of ethane to ethylene. The highestethane conversion obtained was about 15% for the 25%CeO_2/γ-Al_2O_3. The selectivity to ethylenewas high for all the CeO_2, γ-Al_2O_3 and CeO2/γ-Al_2O_3 catalysts.
基金the Natural Science Foundation of Jiangsu Province under pro ject No.BK2002010.
文摘The synthesis of ultrafine cerium dioxide precursor via homogeneous precipitation was studied. Mixed aqueous solution of anhydrous cerium nitrate and urea was first heated to 85℃ for 2 h, and the prepared suspension was then aged at room temperature for various periods of time. White precipitate was finally collected by centrifuging and washed with distilled water and anhydrous ethanol. The obtained cerium dioxide (CeO2) precursor was observed with SEM. It was found that the morphology and size of the precursor were strongly affected by aging time and stirring conditions (with or without stirring). The precipitated fine spherical particles of the precursor changed their shape from ellipse to slice or directly to slice. Fine spherical monodispersed (300 nm) precursor powders could be obtained by controlling the aging time. Stirring the solution also could change the reaction process and thus the morphology and size of the precursor were changed.
文摘The Co-incorporated Ce1-xZrxO2 catalysts were prepared by co-precipitation for carbon dioxide reforming of methane.The ratio of Ce to Zr was varied to optimize the performances of co-precipitated Co-Ce-Zr-Ox catalysts.The prepared catalysts were characterized by various physico-chemical characterization techniques including TPR,X-ray diffraction,N2 adsorption at low temperature,XPS and CO2-TPSR.The co-precipitated Co-Ce0.8Zr0.2O2 sample containing 16% CoO exhibited a higher catalytic activity among the five catalysts,and the activity was maintained without significant loss during the reaction for 60 h.Under the conditions of 750 ℃,0.1 MPa,36000 ml/（h gcat）,and CO2/CH4 molar ratio of 1：1,the CO2 conversion over this catalyst was 75% while the CH4 conversion was 67%.The cubic Ce0.8Zr0.2O2 facilitated a higher dispersion and a higher reducibility of the cobalt component,and the apparent activation energy for Co-Ce0.8Zr0.2O2 sample was 49.1 kJ/mol in the CO2/CH4 reforming reaction.As a result,the Co-Ce0.8Zr0.2O2 sample exhibited a higher activity and stability for the reforming of CH4 with CO2.
文摘The catalyst screening tests for carbon dioxide oxidative coupling of methane (CO2-OCM) have been investigated over ternary and binary metal oxide catalysts. The catalysts are prepared by doping MgO- and CeO2-based solids with oxides from alkali (Li2O), alkaline earth (CaO), and transition metal groups (WO3 or MnO). The presence of the peroxide (O2-2) active sites on the Li2O2, revealed by Raman spectroscopy, may be the key factor in the enhanced performance of some of the Li2O/MgO catalysts. The high reducibility of the CeO2 catalyst, an important factor in the CO2-OCM catalyst activity, may be enhanced by the presence of manganese oxide species. The manganese oxide species increases oxygen mobility and oxygen vacancies in the CeO2 catalyst. Raman and Fourier Transform Infra Red (FT-IR) spectroscopies revealed the presence of lattice vibrations of metal-oxygen bondings and active sites in which the peaks corresponding to the bulk crystalline structures of Li2O, CaO, WO3 and MnO are detected. The performance of 5%MnO/15%CaO/CeO2 catalyst is the most potential among the CeO2-based catalysts, although lower than the 2%Li2O/MgO catalyst. The 2%Li2O/MgO catalyst showed the most promising C2+ hydrocarbons selectivity and yield at 98.0% and 5.7%, respectively.
