The interlayer clay-organic complex is an important clay-organic association in sedimentary environments. The interlayer region of clay minerals not only provides storage space for organic matter, but also possesses s...The interlayer clay-organic complex is an important clay-organic association in sedimentary environments. The interlayer region of clay minerals not only provides storage space for organic matter, but also possesses solid acid sites; and these acid sites were proposed to be involved with the transformation of organic matter into liquid and gaseous hydrocarbons. However, the effect of the organic matter storage in the interlayer space of clay minerals on the hydrocarbons generation has not been made clear. In this study, the interlayer complex of 12-aminolauric acid (ALA) and Na+-montmorillonite (Na+-Mt), labeled as ALAinter-Mt (Na), was synthesized to investigate the role of the interlayer space of montmorillonite in hydrocarbon generation. Simply mixed ALA-Mt complex [ALA-Mt (Na)] was also prepared for comparison. The pyrolysis of ALA and ALA-Mt complexes was studied using thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR) and a high temperature-pressure system (a confined gold capsule-autoclave system).展开更多
The Shilu Fe-polymetallic ore deposit,a famous hematite-rich Fe-ore deposit,is situated at the western Hainan Province of south China.The deposit characterizes the upper Fe ores and the lower Co-Cu ores,which are main...The Shilu Fe-polymetallic ore deposit,a famous hematite-rich Fe-ore deposit,is situated at the western Hainan Province of south China.The deposit characterizes the upper Fe ores and the lower Co-Cu ores,which are mainly hosted within a low-grade to medium-grade,dominantly submarine metamorphosed siliciclastic and carbonate sedimentary succession of the Neoproterozoic Shilu Group.Three facies types of metamorphosed BIFs,i.e.the oxide facies,the silicate-oxide facies and the sulfide-carbonate facies BIFs,are identified within the sixth sequence of the Shilu Group.The oxide facies BIF(i.e.the Fe-rich itabirites or ores)consists of alternating hematite-rich microbands with quartz-rich microbands;the silicate-oxide facies BIF(i.e.the Fe-poor itabirites or ores)comprises alternating millimeter-to a few tens meter-scale,magnetite-hematite-rich bands with calcsilicate-rich(garnet+actinolite+diopside+epidote+quartz)meso-to microbands;and the sulfide-carbonate facies BIF(i.e.the Co-Cu ores)contains alternating macro-to mesobands of Co-bearing pyrite and pyrrhotite,and chalcopyrite with mesobands of dolomite+calcite+diopside+quartz and/or chlorite+sericite+quartz.The blastooolitic,blastopelletoid blastocolloidal and blastopsammitic textures,and blasobedding structures which most likely represent primary sedimentation are often observed in these BIF facies.The interbedded host rocks with the BIFs mainly are the pyroxene-amphibole rocks and the banded or impure dolostones,and also contain banded or laminated structures,and lepido-gra-noblastic,nematoblastic and/or blastoclastic textures.Compositionally,the main host rocks,the pyroxene-amphibole rocks contain basic-intermediate SiO_2(~54.00 wt.%),CaO(~14.19 wt.%),MgO(~9.68 wt.%)and Al_2O_3(~8.49 wt.%)with a positive correlation between Al_2O_3 and TiO_2.The UCC-like Zr and Hf abundances,high Ba content andεNd(t)value(^-5.99)as well as the ratios of La/YbPAAS(0.17~1.00),δEuPAAS(0.88~1.12)andδCePAAS(0.93~1.13)commonly reveal that the protoliths to this type rocks are hydrogenic with a large contribution of terrigenous sediments and minor hydrothermal input.The high CaO+MgO+LOI contents and the extremely low trace element and REEconcentrations as well as the ratios of Y/Ho(44~45),δEuPAAS(1.13~1.57)andδCePAAS(0.69~0.98)reflect a marine origin with minor terrigenous materials for the banded or impure dolostones.Moreover,this type rocks also account for a negativeεNd(t)value(^-7.49).The oxide facies BIF is dominated by Fe_2O_3+FeO(~75.59wt.%)and SiO_2(~20.47 wt.%)with aεNd(t)value of^-6.10.The variable contents in Al_2O_3,TiO 2,K2O,Na2O,Zr,Hf and∑REE,and variable ratios of Y/Ho(24~39)andδEuPAAS(0.86~11.07)suggest the precursor sediments to this facies BIF are admixtures of sea-floor hydrothermal fluids and seawaters with minor involvement of detrital components.Compared to the oxide facies BIF,the silicate-oxide facies BIF is lower in Fe_2O_3+Fe O(~39.81wt.%)and Ba but higher in SiO_2(~42.54 wt.%),Al2O3(~3.60 wt.%),TiO_2(~0.19 wt.%),MgO(~1.12 wt.%),CaO(~9.06 wt.%),K_2O(~0.98 wt.%),Mn and Zr.The ratios of Y/Ho(25~34),La/YbPAAS(0.14-0.74)andδEuPAAS(0.91~1.12)most likely are linked to higher degree of detrital contamintants.While the sulfide-caronate facies BIF is main but variable in Fe_2O_3+Fe O(15.79~57.91 wt.%),SiO 2(0.54~61.52 wt.%),MgO(0.12~16.09wt.%),CaO(0.17~23.41 wt.%)and LOI(8.28-30.06 wt.%).The generally low contents in trace elements(including REE)except for an obvious enrichment in Pb,and the positive Ce anomalies(δCePAAS=1.04~1.95)and negative Pr anomalies(δPrPAAS=0.67~0.93),as well as the variable ratios ofδEuPAAS(0.72~1.71),La/YbPAAS(0.26~1.60)and Y/Ho(26~57)suggest that the precursors to the sulfide-carbonate facies BIF mainly are metalliferious sediments from deep-marine hydrotheral source with minor detrital components.The T2DM ages(ca.2.0 Ga)imply that the Shilu BIFs and interbedded host rocks contain a component with Paleoproterozoic crustal residence age due to a significant crustal accretion event at ca.2.0 Ga in Hainan Island.In connection with the petrographical and mineralogical relationship,we conclude that the precursor precipitates to the Shilu BIFs are variable degree of admixtures of the Fe-Co-Cu-(Si)-rich hydrothermal fluids and detrital components from seawater and fresh water carring continental landmass;whereas the protolith to the main interbedded host rocks,i.e.the pyroxene-amphibole rocks,most likely was terrigenous,fine-grained clastic-sediments but with significant input of hydrothermal fluids in a seawater environment.As a result,a continent marginal marine basin is proposed for deposition of the Shilu BIFs and interbedded host rocks.Sea-level fluctuations caused by marine transgression–regressions possibly contributed to changes in the composition and varied input of the terrigenous sediments.展开更多
Naturally occurring tubular halloysite is a potential drug carrier because of the significant deposit, unique mesoscopic (2-50 nm) or even macroscopic (>50 nm) lumen, and excellent biocompatibility. The drugs loade...Naturally occurring tubular halloysite is a potential drug carrier because of the significant deposit, unique mesoscopic (2-50 nm) or even macroscopic (>50 nm) lumen, and excellent biocompatibility. The drugs loaded on halloysite exhibited slow release under the diffusion limitation by the halloysite nanotube. However, due to the weak interaction between halloysite and guest, the loading capacity of halloysite was relatively low. This drawback severely limits the application of halloysite as carrier in pharmaceutics. In this study, the performance of halloysite as carrier for ibuprofen (IBU) loading was investigated for the first time. The effects of 3-aminopropyltriethoxysilane (APTES) modification and thermal treatment of halloysite on the loading and release of IBU were also studied. The purified halloysites were heated at 120 ℃ and 400 ℃ (labeled as Hal/120 and Hal/400), and then modified with APTES (labeled as Hal/120-A and Hal/400-A). The loading of IBU was achieved by soaking method (labeled as IBU-Hal/120, IBU-Hal/400, IBU-Hal/120-A, and IBU-Hal/400-A.). The in vitro drug delivery assays were performed in phosphate buffer solution. IBU was loaded mainly into the lumen and partially on the external surface of halloysite. The order of IBU contents was as follows: IBU-Hal/400-A (14.8wt%) > IBU-Hal/120-A (12.7wt%) > IBU-Hal/400 (11.8wt%) > IBU-Hal/120 (11.7wt%). The IBU was initially anchored to the surface hydroxyl groups of halloysite by hydrogen bonding, followed by further bonding of IBU with the anchored IBU to form hydrogen-bonded aggregates. The APTES modification of halloysite promoted the loading of IBU by introducing a strong affinity through electrostatic attraction between the introduced aminopropyl groups of APTES and the carboxyl groups of IBU. Thermal treatment at 400°C did not destroy the tubular morphology or the crystal structure of halloysite and had little effect on IBU loading in unmodified halloysite. However, thermal treatment by reducing water content in halloysite restricted the grafting of APTES in the lumen space, and further increased IBU loading. All IBU-loaded samples exhibit a burst release with a following slow release. However, owing to the strong electrostatic attraction in modified samples, the burst release was much more suppressed and the release rate was also lower than that in unmodified ones. The in vitro release profiles of the IBU-loaded samples were well fitted with the modified Korsmeyer-Peppas model. The IBU release mechanism of the unmodified samples was Fickian diffusion; however it was non-Fickian diffusion for the modified samples. The findings are of significance for broadening the use of halloysite as carrier for drugs and other active molecules in the pharmaceutical, pesticides, and coating industries.展开更多
Shale gas, which is derived from organic matters in shale and stored in shale deposits, is an important unconventional gas resource and attracts attention due to its significant requirement in the hydrocarbon producti...Shale gas, which is derived from organic matters in shale and stored in shale deposits, is an important unconventional gas resource and attracts attention due to its significant requirement in the hydrocarbon production. Methane (CH4) is the dominant component of shale gas, and adsorbed gas is an important reservoir form. Many studies have investigated the adsorption capacities and adsorption mechanisms of CH4 in shale. Organic matters and clay minerals have been proposed to be the two major components for CH4 adsorption. Adsorption of CH4 in organic matters, such as the adsorption capacity and effects of characteristics of the organic matters, has been well investigated. However, studies on CH4 adsorption on clay minerals have mainly focused on evaluating the adsorption capacity, and very little information about the adsorption mechanism has been provided. For example, the adsorption sites and factors influencing CH4 adsorption on clay minerals remain unclear. Three main reasons account for this: (1) the co-existence of organic matters in samples affects the evaluation of CH4 adsorption on clay minerals; (2) the pressures used during adsorption are not representative of actual reservoir pressures; and (3) the clay minerals selected have low swelling capacity and a smaller interlayer distances than a CH4 size, resulting in the misunderstanding of the CH4 adsorption sites.展开更多
Porous carbons are extensively applied in gas separation, water purification, catalytic reaction, and electrochemical processing, attributing to their high specific surface area, large pore volume, chemical inertness,...Porous carbons are extensively applied in gas separation, water purification, catalytic reaction, and electrochemical processing, attributing to their high specific surface area, large pore volume, chemical inertness, and good mechanical and thermal stability. The templating method is widely used to synthesize porous carbons with the controlled pore structure. Among them, preparation of diatomite-templated carbons attracts increasing attention because the obtained carbon has unique developed macropores and exhibits the promising application in adsorption and support of large-sized molecules. Macroporous diatomite-templated carbons are prepared by using additive or inherent solid acid sites of diatomite as the catalyst. The obtained carbons showed tubular and pillared macroporous structures, and had a few mesopores and micropores. However, the carbons possessed the small specific surface area and micropore volume, and thus showed the low adsorption capacity of small-sized molecules, such as methylene blue (MB). In this case, enhancement of porosity, especially microporosity, is necessary.展开更多
文摘The interlayer clay-organic complex is an important clay-organic association in sedimentary environments. The interlayer region of clay minerals not only provides storage space for organic matter, but also possesses solid acid sites; and these acid sites were proposed to be involved with the transformation of organic matter into liquid and gaseous hydrocarbons. However, the effect of the organic matter storage in the interlayer space of clay minerals on the hydrocarbons generation has not been made clear. In this study, the interlayer complex of 12-aminolauric acid (ALA) and Na+-montmorillonite (Na+-Mt), labeled as ALAinter-Mt (Na), was synthesized to investigate the role of the interlayer space of montmorillonite in hydrocarbon generation. Simply mixed ALA-Mt complex [ALA-Mt (Na)] was also prepared for comparison. The pyrolysis of ALA and ALA-Mt complexes was studied using thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR) and a high temperature-pressure system (a confined gold capsule-autoclave system).
文摘The Shilu Fe-polymetallic ore deposit,a famous hematite-rich Fe-ore deposit,is situated at the western Hainan Province of south China.The deposit characterizes the upper Fe ores and the lower Co-Cu ores,which are mainly hosted within a low-grade to medium-grade,dominantly submarine metamorphosed siliciclastic and carbonate sedimentary succession of the Neoproterozoic Shilu Group.Three facies types of metamorphosed BIFs,i.e.the oxide facies,the silicate-oxide facies and the sulfide-carbonate facies BIFs,are identified within the sixth sequence of the Shilu Group.The oxide facies BIF(i.e.the Fe-rich itabirites or ores)consists of alternating hematite-rich microbands with quartz-rich microbands;the silicate-oxide facies BIF(i.e.the Fe-poor itabirites or ores)comprises alternating millimeter-to a few tens meter-scale,magnetite-hematite-rich bands with calcsilicate-rich(garnet+actinolite+diopside+epidote+quartz)meso-to microbands;and the sulfide-carbonate facies BIF(i.e.the Co-Cu ores)contains alternating macro-to mesobands of Co-bearing pyrite and pyrrhotite,and chalcopyrite with mesobands of dolomite+calcite+diopside+quartz and/or chlorite+sericite+quartz.The blastooolitic,blastopelletoid blastocolloidal and blastopsammitic textures,and blasobedding structures which most likely represent primary sedimentation are often observed in these BIF facies.The interbedded host rocks with the BIFs mainly are the pyroxene-amphibole rocks and the banded or impure dolostones,and also contain banded or laminated structures,and lepido-gra-noblastic,nematoblastic and/or blastoclastic textures.Compositionally,the main host rocks,the pyroxene-amphibole rocks contain basic-intermediate SiO_2(~54.00 wt.%),CaO(~14.19 wt.%),MgO(~9.68 wt.%)and Al_2O_3(~8.49 wt.%)with a positive correlation between Al_2O_3 and TiO_2.The UCC-like Zr and Hf abundances,high Ba content andεNd(t)value(^-5.99)as well as the ratios of La/YbPAAS(0.17~1.00),δEuPAAS(0.88~1.12)andδCePAAS(0.93~1.13)commonly reveal that the protoliths to this type rocks are hydrogenic with a large contribution of terrigenous sediments and minor hydrothermal input.The high CaO+MgO+LOI contents and the extremely low trace element and REEconcentrations as well as the ratios of Y/Ho(44~45),δEuPAAS(1.13~1.57)andδCePAAS(0.69~0.98)reflect a marine origin with minor terrigenous materials for the banded or impure dolostones.Moreover,this type rocks also account for a negativeεNd(t)value(^-7.49).The oxide facies BIF is dominated by Fe_2O_3+FeO(~75.59wt.%)and SiO_2(~20.47 wt.%)with aεNd(t)value of^-6.10.The variable contents in Al_2O_3,TiO 2,K2O,Na2O,Zr,Hf and∑REE,and variable ratios of Y/Ho(24~39)andδEuPAAS(0.86~11.07)suggest the precursor sediments to this facies BIF are admixtures of sea-floor hydrothermal fluids and seawaters with minor involvement of detrital components.Compared to the oxide facies BIF,the silicate-oxide facies BIF is lower in Fe_2O_3+Fe O(~39.81wt.%)and Ba but higher in SiO_2(~42.54 wt.%),Al2O3(~3.60 wt.%),TiO_2(~0.19 wt.%),MgO(~1.12 wt.%),CaO(~9.06 wt.%),K_2O(~0.98 wt.%),Mn and Zr.The ratios of Y/Ho(25~34),La/YbPAAS(0.14-0.74)andδEuPAAS(0.91~1.12)most likely are linked to higher degree of detrital contamintants.While the sulfide-caronate facies BIF is main but variable in Fe_2O_3+Fe O(15.79~57.91 wt.%),SiO 2(0.54~61.52 wt.%),MgO(0.12~16.09wt.%),CaO(0.17~23.41 wt.%)and LOI(8.28-30.06 wt.%).The generally low contents in trace elements(including REE)except for an obvious enrichment in Pb,and the positive Ce anomalies(δCePAAS=1.04~1.95)and negative Pr anomalies(δPrPAAS=0.67~0.93),as well as the variable ratios ofδEuPAAS(0.72~1.71),La/YbPAAS(0.26~1.60)and Y/Ho(26~57)suggest that the precursors to the sulfide-carbonate facies BIF mainly are metalliferious sediments from deep-marine hydrotheral source with minor detrital components.The T2DM ages(ca.2.0 Ga)imply that the Shilu BIFs and interbedded host rocks contain a component with Paleoproterozoic crustal residence age due to a significant crustal accretion event at ca.2.0 Ga in Hainan Island.In connection with the petrographical and mineralogical relationship,we conclude that the precursor precipitates to the Shilu BIFs are variable degree of admixtures of the Fe-Co-Cu-(Si)-rich hydrothermal fluids and detrital components from seawater and fresh water carring continental landmass;whereas the protolith to the main interbedded host rocks,i.e.the pyroxene-amphibole rocks,most likely was terrigenous,fine-grained clastic-sediments but with significant input of hydrothermal fluids in a seawater environment.As a result,a continent marginal marine basin is proposed for deposition of the Shilu BIFs and interbedded host rocks.Sea-level fluctuations caused by marine transgression–regressions possibly contributed to changes in the composition and varied input of the terrigenous sediments.
文摘Naturally occurring tubular halloysite is a potential drug carrier because of the significant deposit, unique mesoscopic (2-50 nm) or even macroscopic (>50 nm) lumen, and excellent biocompatibility. The drugs loaded on halloysite exhibited slow release under the diffusion limitation by the halloysite nanotube. However, due to the weak interaction between halloysite and guest, the loading capacity of halloysite was relatively low. This drawback severely limits the application of halloysite as carrier in pharmaceutics. In this study, the performance of halloysite as carrier for ibuprofen (IBU) loading was investigated for the first time. The effects of 3-aminopropyltriethoxysilane (APTES) modification and thermal treatment of halloysite on the loading and release of IBU were also studied. The purified halloysites were heated at 120 ℃ and 400 ℃ (labeled as Hal/120 and Hal/400), and then modified with APTES (labeled as Hal/120-A and Hal/400-A). The loading of IBU was achieved by soaking method (labeled as IBU-Hal/120, IBU-Hal/400, IBU-Hal/120-A, and IBU-Hal/400-A.). The in vitro drug delivery assays were performed in phosphate buffer solution. IBU was loaded mainly into the lumen and partially on the external surface of halloysite. The order of IBU contents was as follows: IBU-Hal/400-A (14.8wt%) > IBU-Hal/120-A (12.7wt%) > IBU-Hal/400 (11.8wt%) > IBU-Hal/120 (11.7wt%). The IBU was initially anchored to the surface hydroxyl groups of halloysite by hydrogen bonding, followed by further bonding of IBU with the anchored IBU to form hydrogen-bonded aggregates. The APTES modification of halloysite promoted the loading of IBU by introducing a strong affinity through electrostatic attraction between the introduced aminopropyl groups of APTES and the carboxyl groups of IBU. Thermal treatment at 400°C did not destroy the tubular morphology or the crystal structure of halloysite and had little effect on IBU loading in unmodified halloysite. However, thermal treatment by reducing water content in halloysite restricted the grafting of APTES in the lumen space, and further increased IBU loading. All IBU-loaded samples exhibit a burst release with a following slow release. However, owing to the strong electrostatic attraction in modified samples, the burst release was much more suppressed and the release rate was also lower than that in unmodified ones. The in vitro release profiles of the IBU-loaded samples were well fitted with the modified Korsmeyer-Peppas model. The IBU release mechanism of the unmodified samples was Fickian diffusion; however it was non-Fickian diffusion for the modified samples. The findings are of significance for broadening the use of halloysite as carrier for drugs and other active molecules in the pharmaceutical, pesticides, and coating industries.
文摘Shale gas, which is derived from organic matters in shale and stored in shale deposits, is an important unconventional gas resource and attracts attention due to its significant requirement in the hydrocarbon production. Methane (CH4) is the dominant component of shale gas, and adsorbed gas is an important reservoir form. Many studies have investigated the adsorption capacities and adsorption mechanisms of CH4 in shale. Organic matters and clay minerals have been proposed to be the two major components for CH4 adsorption. Adsorption of CH4 in organic matters, such as the adsorption capacity and effects of characteristics of the organic matters, has been well investigated. However, studies on CH4 adsorption on clay minerals have mainly focused on evaluating the adsorption capacity, and very little information about the adsorption mechanism has been provided. For example, the adsorption sites and factors influencing CH4 adsorption on clay minerals remain unclear. Three main reasons account for this: (1) the co-existence of organic matters in samples affects the evaluation of CH4 adsorption on clay minerals; (2) the pressures used during adsorption are not representative of actual reservoir pressures; and (3) the clay minerals selected have low swelling capacity and a smaller interlayer distances than a CH4 size, resulting in the misunderstanding of the CH4 adsorption sites.
文摘Porous carbons are extensively applied in gas separation, water purification, catalytic reaction, and electrochemical processing, attributing to their high specific surface area, large pore volume, chemical inertness, and good mechanical and thermal stability. The templating method is widely used to synthesize porous carbons with the controlled pore structure. Among them, preparation of diatomite-templated carbons attracts increasing attention because the obtained carbon has unique developed macropores and exhibits the promising application in adsorption and support of large-sized molecules. Macroporous diatomite-templated carbons are prepared by using additive or inherent solid acid sites of diatomite as the catalyst. The obtained carbons showed tubular and pillared macroporous structures, and had a few mesopores and micropores. However, the carbons possessed the small specific surface area and micropore volume, and thus showed the low adsorption capacity of small-sized molecules, such as methylene blue (MB). In this case, enhancement of porosity, especially microporosity, is necessary.
