The porous medium has an important effect on hydrate formation.In this paper,the formation process and the gas storage capacity of the methane hydrate were investigated with A-type zeolite and Sodium Dodecyl Sulfate (...The porous medium has an important effect on hydrate formation.In this paper,the formation process and the gas storage capacity of the methane hydrate were investigated with A-type zeolite and Sodium Dodecyl Sulfate (SDS) existing in the system.The results show that A-type zeolite can influence methane hydrate formation.At the temperature of 273.5 K and pressure of 8.3 MPa,the distilled water with A-type zeolite can form methane hydrate with gaseous methane in 12 hours.The formation process of the system with A-type zeolite was quite steady and the amount of A-type zeolite can influence the gas storage capacity significantly.The adding of A-type zeolite with 0.067 g·(g water)-1 into 2×10-3 g·g-1 SDS-water solution can increase the gas storage capacity,and the maximum increase rate was 31%.Simultaneously the promotion effect on hydrate formation of 3A-type zeolite is much more obvious than that of 5A-type zeolite when the water adding amounts are 0.033 g·g-1 and 0.067 g·g-1 at the experimental conditions.展开更多
High quality A-type zeolite membranes, with enlarged area over 70 cm2, were successfully synthesized on a tubular a-Al2O3 support by applying the vacuum seeding method.
A facile strategy without organic template was developed for the conversion of fly ash to LTA-type zeolite(LTA-Z),which could be used as a good adsorbent for the removal of acid fuchsin(AF).XRD results indicated that ...A facile strategy without organic template was developed for the conversion of fly ash to LTA-type zeolite(LTA-Z),which could be used as a good adsorbent for the removal of acid fuchsin(AF).XRD results indicated that the pure crystalline product was obtained with the structure of LTA-type zeolite.SEM investigations showed that the well-defined LTA-Z crystals exhibited uniform size with the same cubic shape.The maximum AF adsorption amount was observed at pH=5,slightly lower than pHPZC of LTA-Z.Higher temperature favored AF adsorption onto LTA-Z and it was an endothermic process.Furthermore,AF adsorption amount increased with initial AF concentration increasing and LTA-Z dosage decreasing.Surface sorption governed this process at the initial 120 min period,followed by the internal diffusion of AF molecules between porous sites.The Langmuir model was determined as the adsorption isothermal,suggesting that the monolayer coverage of AF on LTA-Z surface was involved.展开更多
Selective catalytic reduction with NH3(NH3-SCR)is an important means of NO_(x) abatement from stationary and mobile sources,and the key element is efficient and stable NH3-SCR catalysts.In this study,we propose a meth...Selective catalytic reduction with NH3(NH3-SCR)is an important means of NO_(x) abatement from stationary and mobile sources,and the key element is efficient and stable NH3-SCR catalysts.In this study,we propose a method to construct superior Fe-Beta catalysts based on Al-rich zeolites.This strategy successfully promotes the formation of NH3-SCR-active isolated Fe^(3+)species,thus effectively improving the low-temperature activity of the Fe-Beta catalysts.Thanks to the abundant Brønsted acid sites of the Al-rich zeolite,the Fe_(2)O_(3) particles are redispersed and anchored as isolated Fe^(3+)during hydrothermal aging.This dynamic evolution of Fe species makes up for the adverse effect of dealumination of the Al-rich zeolite framework and achieves high stability for the Al-rich Fe-Beta catalyst.This study may promote the understanding of highly efficient and stable catalyst design using Al-rich zeolites.展开更多
Methanol-to-hydrocarbons(MTH)reaction comprises a set of crucial catalytic processes to produce light olefins,gasoline,or aromatics.MTH reaction is a classic example of reaction complexity in zeolite catalysis.The mol...Methanol-to-hydrocarbons(MTH)reaction comprises a set of crucial catalytic processes to produce light olefins,gasoline,or aromatics.MTH reaction is a classic example of reaction complexity in zeolite catalysis.The molecular understanding of reaction routes and deactivation mechanisms still encounters many challenges.Herein,we chose HZSM-22 zeolite with the simple one-dimensional 10-membered ring(10-MR)channel as a prototypical system,leveraging the spatial nanoconfinement effect of its unique pore architecture to minimize reaction complexity.The identification of the molecular structures of coke species with acene-,biphenyl-,or fluorene-typed structures was made possible through a combination of the advanced matrix-assisted laser desorption/ionization Fourier-transform ion cyclotron resonance mass spectrometry(MALDI FT-ICR MS)with the gas chromatography-mass spectrometer(GC-MS)technique.With this,we uncovered two modes of growth mechanism of coke molecules,i.e.,a stepwise route and a dehydrogenative coupling route.The findings deepen the mechanistic understanding of zeolite deactivation and provide a theoretical foundation for designing coke-resistant catalysts.展开更多
Rare earth(RE)Y-type zeolite was synthesized in situ by acidic co-hydrolysis route and hydrothermal method.The key process parameters were optimized based on the RE utilization rate.The effect of inducing a rotating p...Rare earth(RE)Y-type zeolite was synthesized in situ by acidic co-hydrolysis route and hydrothermal method.The key process parameters were optimized based on the RE utilization rate.The effect of inducing a rotating packed bed(RPB)in premixing and crystallization on crystallinity and RE utilization rate was further investigated.The results indicate that lanthanide(La)cations are successfully introduced into the sodalite cage of Y-type zeolite.The optimized conditions are that the molar ratio of Si/La is 150,premixing for 5 h,crystallization at 90℃ for 18 h,and calcination at 550℃ for 3.5 h.At this stage,the RE utilization rate reaches 74.5%.Compared with the conventional stirred tank reactor(STR),RPB can effectively shorten the premixing time and crystallization time by 4.3 h and 6 h,improve the crystallinity by 23%and RE utilization rate by 7.5%.The RE utilization rate is more than 80%by RPB,surpassing the effectiveness of using the one-exchange one-calcination process in the traditional liquid ion exchange process.It is expected to provide a reference for the in-situ efficient and green synthesis of RE zeolite.展开更多
FAU zeolites have emerged as multifunctional materials with broad applications in catalysis and adsorption,owing to their hierarchical pore architectures,elevated specific surface areas,and adjustable extra-framework ...FAU zeolites have emerged as multifunctional materials with broad applications in catalysis and adsorption,owing to their hierarchical pore architectures,elevated specific surface areas,and adjustable extra-framework cationic sites.This review provides a critical overview of recent advances in FAU zeolite research with emphasis on their roles in environmental pollutant mitigation.A bibliometric analysis was performed to ascertain worldwide research trends,cooperation networks,and principal theme areas.Strategies for synthesis and functionalization,including crystallization pathways,one-pot methods,and post-synthetic modifications,were systematically evaluated for their capacity to tailor structural and physicochemical properties.Environmental applications were discussed in detail,particularly in heavy metal extraction,CO_(2)capture,and catalytic NOx reduction.Despite these advances,challenges persisted,notably restricted chemical stability under extreme pH conditions,scalability obstacles from laboratory to industrial production,and the necessity for enhanced catalytic efficiency.By integrating fundamental understanding with application-oriented perspectives,this review identifies existing knowledge gaps and delineates future directions for the rational design of FAU zeolites toward sustainable environmental remediation.展开更多
The identical molecular size and similar physical properties of carbon dioxide(CO_(2))and acetylene(C_(2)H_(2))make their adsorptive separation extremely challenging to achieve with most adsorbents.Reports on the sepa...The identical molecular size and similar physical properties of carbon dioxide(CO_(2))and acetylene(C_(2)H_(2))make their adsorptive separation extremely challenging to achieve with most adsorbents.Reports on the separation of CO_(2)and C_(2)H_(2)mixtures by zeolites are even rarer with the mechanism of adsorptive separation requiring further exploration.In this paper,we report that ion modulation of zeolite 5A promotes the difference in kinetic diffusion of CO_(2)and C_(2)H_(2),realizing the inverse separation of zeolite from selective adsorption of C_(2)H_(2)to selective adsorption of CO_(2).Creating a compact pore space restricting the orientation of gas molecules enables charge recognition.The positive electrostatic potential at the pore openings was utilized to hinder the diffusion of C_(2)H_(2)between the cages while ensuring the transfer of CO_(2),increasing their diffusion differences in pore channels and leading to the CO_(2)/C_(2)H_(2)kinetic selectivity of 31.97.Grand canonical Monte Carlo(GCMC)simulation demon-strates that the CO_(2)distribution in K-5A-βis significantly higher than that of C_(2)H_(2).Dynamic breakthrough ex-periments verify the excellent performance of material in practical CO_(2)/C_(2)H_(2)separation,for CO_(2)/C_(2)H_(2)(50/50 and 1/99,V/V)mixtures can be separated in one step,thus directly generating high purity C_(2)H_(2)(>99.95%),which provides a promising thought for the zeolite-based separation of CO_(2)and C_(2)H_(2).展开更多
A-type zeolite membranes were prepared on the nonporous metal supports by using electrophoretic tech- nique. The as-synthesized membranes were characterized by XRD and SEM. The effect of the applied potential on the f...A-type zeolite membranes were prepared on the nonporous metal supports by using electrophoretic tech- nique. The as-synthesized membranes were characterized by XRD and SEM. The effect of the applied potential on the formation of the A-type zeolite membrane was investigated, and the formation mechanism of zeolite membrane in the electric field was discussed. The results showed that the negative charged zeolite particles could migrate to the anode metal surface homogenously and rapidly under the action of the applied electric field, consequently formed uniform and dense membranes in short time. The applied potential had great effect on the membrane formation, and more uniform and denser zeolite membranes were prepared on the non- porous metal supports with 1 V potential.展开更多
The petrogenesis and genetic link to polymetallic mineralization of the granites in the Dayishan complex,southern Hunan province remain debated.Here,we present an integrated study on the petrology,zircon U-Pb ages and...The petrogenesis and genetic link to polymetallic mineralization of the granites in the Dayishan complex,southern Hunan province remain debated.Here,we present an integrated study on the petrology,zircon U-Pb ages and whole-rock geochemistry for this complex.Our findings indicate that the southern complex consists of(amphibole-bearing)biotite granites and muscovite granites emplaced at 153-151 Ma,and the central and northern complex consists of two-mica granites and tourmaline-bearing muscovite granites,respectively with the former emplaced at 164 Ma and the latter at 150 Ma.The(amphibole-bearing)biotite granites have SiO_(2) contents of 68.0-73.8 wt% and are enriched in alkalis and rare earth elements and depleted in Sr and Ba.They display Zr+Y+Ce+Nb>350 ppm and 10000×Ga/Al>2.6 along with high zircon saturation temperatures(821-883oC).The two-mica granites and(tourmaline-bearing)muscovite granites have high SiO_(2)(74.4-77.3 wt%)and low Ga/Al,Zr+Nb+Ce+Y,K/Rb,Zr/Hf,and Nb/Ta along with low zircon saturation temperatures(709-817℃).Geochemical characteristics suggest that the(amphibole-bearing)biotite granites are A-type granites generated through shallow dehydration melting of early Paleozoic granitoids,and that the two-mica granites and(tourmaline-bearing)muscovite granites are fractionated A-type granites produced through fractionation crystallization from the(amphibole-bearing)biotite granites accompanied by fluid fractionation.展开更多
Recycling rare earth elements(REEs)from waste is necessary for an environmentally sustainable reuse and wastewater management approach.Na-A zeolite was synthesized from coal fly ash(CFA)and applied for Ce^(3+)adsorpti...Recycling rare earth elements(REEs)from waste is necessary for an environmentally sustainable reuse and wastewater management approach.Na-A zeolite was synthesized from coal fly ash(CFA)and applied for Ce^(3+)adsorption.Fourier transform infrared(FTIR)spectra show peaks at 790,500 and 467 cm^(-1),which are bond vibrations of Si-O-Si,Si with Al-O and Si-O-.The surface area is 15.88 m^(2)/g,with a pore size of 2.14 nm.SEM images show a cubic shape,which indicates the formation of zeolite.Field emission and energy disperse spectroscopy(EDS)shows the formation of Si,Al,Na,and O.Na-A zeolite was applied for Ce^(3+)adsorption.The optimum conditions for Ce^(3+)adsorption are 50 ppm concentration,360 min,and pH 6.The maximum adsorption capacity is 176.49 mg/g.Based on the results,it is found that the adsorption of Ce^(3+)by Na-A zeolite is pseudo-second-order.The desorption test using HNO_(3) is more effective than using HCl and H_(2)SO_(4).A desorption efficiency of 97.22%is obtained at 4 cycles.Adsorption test using real sample wastewater demonstrates an adsorption efficiency of 83.35%.展开更多
Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive st...Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented growth.The obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.展开更多
Propane dehydrogenation(PDH)has emerged as a key on-purpose technology for the production of propylene,but it often depends on toxic chromium and expensive platinum catalysts,highlighting the need for environmentally ...Propane dehydrogenation(PDH)has emerged as a key on-purpose technology for the production of propylene,but it often depends on toxic chromium and expensive platinum catalysts,highlighting the need for environmentally friendly and cost-effective alternatives.In this study,we developed a facile impregnation method to fabricate unsaturated Co single-atoms with a tricoordinated Co_(1)O_(3)H_(x) structure by regulating silanol nests in purely siliceous Beta zeolites.Detailed PDH catalytic tests and characterizations revealed a positive correlation between the presence of silanol nests and enhanced catalytic activity.Additionally,the unsaturated Co single-atoms exhibited a carbon deposition rate more than an order of magnitude slower than that of Co nanoparticles.Notably,the optimized Co_(0.3%)/deAl-meso-Beta catalyst achieved a record-high propylene formation rate of 21.2 mmol_(C3H6) g_(cat)^(-1) h^(-1),with an exceptional propylene selectivity of 99.1%at 550℃.Moreover,the Co_(0.3%)/deAl-meso-Beta catalyst demonstrated excellent stability,with negligible deactivation after 5 consecutive regeneration cycles.This study emphasizes the pivotal role of silanol nests of zeolites in stabilizing and modulating the coordination environment of metallic active sites,providing valuable insights for the design of high-activity,high-stability,and low-cost PDH catalysts.展开更多
Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used ...Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used active metals in PNA and VOC catalysts,respectively.However,despite the same metal/zeolite composition,the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd^(2+) and Pt^(0),respectively,both of which are different from each other.As a result,various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages.No matter which type of metal species is needed,the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable.The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals(Pd,Pt,etc.)as effective PNA or VOC catalysts.To give a better understanding of the relationship between efficient metal species and the introduced methods,the species that contributed to the NOx adsorption(PNA)and VOCs deep catalytic oxidation were first summarized and compared.Then,based on the above discussion,the detailed construction strategies for different active sites in PNA and VOC catalysts,respectively,were elaborated in terms of synthetic routes,precursor selection,and zeolite carrier requirements.It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity,selectivity and stability.展开更多
Hydrocracking technology represents a crucial position in the conversion of heavy oil and the transformation development from oil refining to the chemical industry.The properties of catalysts are one of the key factor...Hydrocracking technology represents a crucial position in the conversion of heavy oil and the transformation development from oil refining to the chemical industry.The properties of catalysts are one of the key factors in the hydrocracking process.As the main acidic component of hydrocracking catalyst,the influence of zeolite properties on the reaction performance has been the focus of research.In this study,a series of NiMo/Al_(2)O_(3)-Y catalysts were prepared using different Y zeolites as acidic components,and their performances in the hydrocracking of n-C_(10)were also evaluated.The structure-activity relationship between Y zeolite and the cracking performance of n-C_(10)was investigated with machine learning.First,a database of the physical and chemical properties of Y zeolite and their performance was established,and the correlation analysis was also conducted.Parameters such as the cell constant,acid content,acid strength,B/L ratio,mesopore volume,micropore volume of Y zeolite,and the reaction temperature were selected as independent variables.The conversion of n-C_(10)and the ratios of products C_(3)/C_(7)and i-C_(4)/n-C_(4)were selected as dependent variables.A model was established by the random forest algorithm and a new zeolite was predicted based on it.The results of model prediction were in good agreement with the experimental results.The R^(2)of the n-C_(10)conversion,C_(3)/C_(7)ratio,and i-C_(4)/n-C_(4)ratio were 0.9866,0.9845,and 0.9922,and the minimum root mean square error values were 0.0163,0.101,and 0.0211,respectively.These results can provide reference for the development of high performance hydrocracking catalyst and technology.展开更多
High-capacity LiBH_(4)is a promising solid hydrogen storage material.However,the large electron cloud density between the B-H bonds in LiBH_(4)induces high dehydrogenation temperatures and sluggish dehydrogenation kin...High-capacity LiBH_(4)is a promising solid hydrogen storage material.However,the large electron cloud density between the B-H bonds in LiBH_(4)induces high dehydrogenation temperatures and sluggish dehydrogenation kinetics.To solve the above problems,it is proposed to enhance the hydrogen storage properties of LiBH_(4)through the synergistic effect of Brønsted and Lewis acid in Hβzeolite.Composite hydrogen storage systems with different mass ratios were prepared by simple ball-milling.At a LiBH_(4)-to-Hβmass ratio of 6:4,the 6LiBH_(4)-4Hβsystem released hydrogen at 190℃and achieved a hydrogen release capacity of 7.0 wt%H_(2)upon heating to 400℃.More importantly,the hydrogen release capacity of the system reached 6.02 wt%at 350℃under isothermal conditions after 100 min and 7.2 wt%at 400℃under isothermal conditions after 80 min,whereas the pristine LiBH_(4)only achieved 2.2 wt%.The improvement in hydrogen storage performance of the system was mainly attributed to two factors:(i)Lewis acid sites with acceptable electrons in the Hβweaken the electron density of B-H bonds in LiBH_(4),and(ii)the H+proton from the Brønsted acid sites and H−of LiBH_(4)undergo a H^(+)+H^(−)=H_(2)reaction.Theoretical calculations revealed that the Lewis and Brønsted acid sites in the Hβzeolite are conducive to the weakening of B-H bonds and that storage charge transfer occurs near the Lewis acid sites.The present work provides new insights into improving the hydrogen storage performance of LiBH_(4)by weakening the B-H bonds in the LiBH_(4).展开更多
Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol ...Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol for reducing NO_(x)emissions.Nowadays,zeolitebased NH_(3)-SCR catalysts have been industrialized and widespread used in this field.Nevertheless,with the increasingly stringent environmental regulations and implementation of the requirement of“zero emission”of diesel engine exhaust,it is extremely urgent to prepare catalysts with superior NH_(3)-SCR activity and exceptional resistance to poisons(SO2,alkali metals,hydrocarbons,etc.).Core-shell structure zeolite-based catalysts(CSCs)have shown great promise in NH_(3)-SCR of NO_(x)in recent years by virtue of its relatively higher low-temperature activity,broader operation temperature window and outstanding resistance to poisons.This review mainly focuses on the recent progress of CSCs for NH_(3)-SCR of NO_(x)with three extensively investigated SSZ-13,ZSM-5,Beta zeolites as cores.The reaction mechanisms of resistance to sulfur poisoning,alkali metal poisoning,hydrocarbon poisoning,and hydrothermal aging are summarized.Moreover,the important role of interfacial effect between core and shell in the reaction of NH_(3)-SCR was clarified.Finally,the future development and application outlook of CSCs are prospected.展开更多
The Suzhou granitic pluton is the first identified Nb-Ta-rich granite in China.To reveal the genetic link between the sequence of magmatic and hydrothermal evolution and Nb-Ta mineralization in different intrusive pha...The Suzhou granitic pluton is the first identified Nb-Ta-rich granite in China.To reveal the genetic link between the sequence of magmatic and hydrothermal evolution and Nb-Ta mineralization in different intrusive phases of the Suzhou granite,whole-rock geochemistry,geochemistry and U-Th-Pb dating of monazite was analyzed.The unique geochemical characteristics show that the Suzhou pluton can be discriminated as an A-type granite.LA-ICP-MS U-Th-Pb dating of monazite in both the medium-and coarse-grained biotite granite(MBG)and the fine-grained biotite granite(FBG)indicates that the granite formed between 124 and 127 Ma.Based on geochemical characteristics and mineral textures,the MBG(Mnz-Ia)and FBG(Mnz-Ib)monazites are classified as magmatic monazites;another monazite(Mnz-II)from the MBG formed during a magmatic-hydrothermal transitional stage.Nb-Ta in the Suzhou pluton gradually concentrated during fractional crystallization and alteration of Ti-rich minerals and biotite.Ultimately,with the involvement of F-Li-rich fluid,Nb-Ta mineralization occurred during the magmatic-hydrothermal transition.The Suzhou pluton is considered part of a 600-km-and NE-SW-trending Nb-rich A-type granite belt together with other Early Cretaceous A-type granites in the Jiangnan Orogen that offers prospects of a new target for Nb-Ta prospecting.展开更多
Granite origin is crucial to understanding the evolution of continental crust,yet many concerns about granite genesis remain yielding ongoing debates.A new integrated study of petrology,geochronology,mineral chemistry...Granite origin is crucial to understanding the evolution of continental crust,yet many concerns about granite genesis remain yielding ongoing debates.A new integrated study of petrology,geochronology,mineral chemistry and whole-rock geochemistry of the Dupangling granitic complex in South China,indicate that the granites in the western complex were emplaced during the Caledonian(418 Ma);they have SiO_(2)contents of 68.1-70.4 wt%,and are calc-alkaline and strongly peraluminous with high maficity[(TFe_(2)O_(3)+MgO)>4.0 wt%]and exhibit^(87)Sr/^(86)Sr(t)of 0.7234-0.7311 andε_(Nd)(t)of-9.0 to-6.7.The granites in the eastern complex,emplaced during the Indosinian(212 Ma),have high SiO_(2)contents(73.3-79.8 wt%)and exhibit affinities with A-type granites,such as enrichment in alkalis and rare earth elements(REEs),and depletion in Sr and Ba along with high TFeO/(TFeO+MgO),Ga/Al and Zr+Y+Ce+Nb;these granites exhibit^(87)Sr/^(86)Sr(t)of 0.7221 andε_(Nd)(t)of-9.2 to-7.5.Geochemical characteristics suggest that the older Caledonian granites were derived through dehydration melting of Paleoproterozoic metasedimentary rocks plus additional(~20%-32%)input from mafic magma,whereas the Indosinian granites were generated through shallow dehydration melting of the Caledonian granitoids.展开更多
基金Supported by the National Natural Science Foundation of China （50876107）, the National Basic Research Program of China （2009CB219504）, NSFC-Guangdong Union Foundation （NSFC-U0733033） and CAS Program （KGCX2-YW-805）.
文摘The porous medium has an important effect on hydrate formation.In this paper,the formation process and the gas storage capacity of the methane hydrate were investigated with A-type zeolite and Sodium Dodecyl Sulfate (SDS) existing in the system.The results show that A-type zeolite can influence methane hydrate formation.At the temperature of 273.5 K and pressure of 8.3 MPa,the distilled water with A-type zeolite can form methane hydrate with gaseous methane in 12 hours.The formation process of the system with A-type zeolite was quite steady and the amount of A-type zeolite can influence the gas storage capacity significantly.The adding of A-type zeolite with 0.067 g·(g water)-1 into 2×10-3 g·g-1 SDS-water solution can increase the gas storage capacity,and the maximum increase rate was 31%.Simultaneously the promotion effect on hydrate formation of 3A-type zeolite is much more obvious than that of 5A-type zeolite when the water adding amounts are 0.033 g·g-1 and 0.067 g·g-1 at the experimental conditions.
文摘High quality A-type zeolite membranes, with enlarged area over 70 cm2, were successfully synthesized on a tubular a-Al2O3 support by applying the vacuum seeding method.
基金supported by the National Natural Science Foundation of China (Grant No. 51002040)New Century Excellent Talents in Heilongjiang Provincial Universities (Grant No. 1253-NCET-010)+2 种基金Natural Science Youth Fund of Heilongjiang Province (Grant No. QC2012C084)Science Foundation of the Heilongjiang Education Office (Grant No. 12521071)Young Outstanding Talents Project of Harbin University of Science and Technology
文摘A facile strategy without organic template was developed for the conversion of fly ash to LTA-type zeolite(LTA-Z),which could be used as a good adsorbent for the removal of acid fuchsin(AF).XRD results indicated that the pure crystalline product was obtained with the structure of LTA-type zeolite.SEM investigations showed that the well-defined LTA-Z crystals exhibited uniform size with the same cubic shape.The maximum AF adsorption amount was observed at pH=5,slightly lower than pHPZC of LTA-Z.Higher temperature favored AF adsorption onto LTA-Z and it was an endothermic process.Furthermore,AF adsorption amount increased with initial AF concentration increasing and LTA-Z dosage decreasing.Surface sorption governed this process at the initial 120 min period,followed by the internal diffusion of AF molecules between porous sites.The Langmuir model was determined as the adsorption isothermal,suggesting that the monolayer coverage of AF on LTA-Z surface was involved.
基金supported by the National Key R&D Program of China(No.2023YFC3707200)the National Natural Science Foundation of China(Nos.22306191 and 52270112).
文摘Selective catalytic reduction with NH3(NH3-SCR)is an important means of NO_(x) abatement from stationary and mobile sources,and the key element is efficient and stable NH3-SCR catalysts.In this study,we propose a method to construct superior Fe-Beta catalysts based on Al-rich zeolites.This strategy successfully promotes the formation of NH3-SCR-active isolated Fe^(3+)species,thus effectively improving the low-temperature activity of the Fe-Beta catalysts.Thanks to the abundant Brønsted acid sites of the Al-rich zeolite,the Fe_(2)O_(3) particles are redispersed and anchored as isolated Fe^(3+)during hydrothermal aging.This dynamic evolution of Fe species makes up for the adverse effect of dealumination of the Al-rich zeolite framework and achieves high stability for the Al-rich Fe-Beta catalyst.This study may promote the understanding of highly efficient and stable catalyst design using Al-rich zeolites.
基金financially supported by the National Key R&D Program of China(2024YFB4105401)the National Natural Science Foundation of China(22372164,22288101 and 22072148)。
文摘Methanol-to-hydrocarbons(MTH)reaction comprises a set of crucial catalytic processes to produce light olefins,gasoline,or aromatics.MTH reaction is a classic example of reaction complexity in zeolite catalysis.The molecular understanding of reaction routes and deactivation mechanisms still encounters many challenges.Herein,we chose HZSM-22 zeolite with the simple one-dimensional 10-membered ring(10-MR)channel as a prototypical system,leveraging the spatial nanoconfinement effect of its unique pore architecture to minimize reaction complexity.The identification of the molecular structures of coke species with acene-,biphenyl-,or fluorene-typed structures was made possible through a combination of the advanced matrix-assisted laser desorption/ionization Fourier-transform ion cyclotron resonance mass spectrometry(MALDI FT-ICR MS)with the gas chromatography-mass spectrometer(GC-MS)technique.With this,we uncovered two modes of growth mechanism of coke molecules,i.e.,a stepwise route and a dehydrogenative coupling route.The findings deepen the mechanistic understanding of zeolite deactivation and provide a theoretical foundation for designing coke-resistant catalysts.
基金supported by the NationalKey Research and Development Program of China(2023YFA1507701)National Natural Science Foundation of China(U22B6011,22288102)“Announcement and Challenge”Science and Technology Project of Xinjiang Uygur Autonomous Region(XJKJTJBGS-2023).
文摘Rare earth(RE)Y-type zeolite was synthesized in situ by acidic co-hydrolysis route and hydrothermal method.The key process parameters were optimized based on the RE utilization rate.The effect of inducing a rotating packed bed(RPB)in premixing and crystallization on crystallinity and RE utilization rate was further investigated.The results indicate that lanthanide(La)cations are successfully introduced into the sodalite cage of Y-type zeolite.The optimized conditions are that the molar ratio of Si/La is 150,premixing for 5 h,crystallization at 90℃ for 18 h,and calcination at 550℃ for 3.5 h.At this stage,the RE utilization rate reaches 74.5%.Compared with the conventional stirred tank reactor(STR),RPB can effectively shorten the premixing time and crystallization time by 4.3 h and 6 h,improve the crystallinity by 23%and RE utilization rate by 7.5%.The RE utilization rate is more than 80%by RPB,surpassing the effectiveness of using the one-exchange one-calcination process in the traditional liquid ion exchange process.It is expected to provide a reference for the in-situ efficient and green synthesis of RE zeolite.
基金supported by foundation of Guizhou Provincial Basic Research Program Natural Sciencel Youth Guidance Project(No.QN[2025]090)Special post of Guizhou University(No.[2024]20).
文摘FAU zeolites have emerged as multifunctional materials with broad applications in catalysis and adsorption,owing to their hierarchical pore architectures,elevated specific surface areas,and adjustable extra-framework cationic sites.This review provides a critical overview of recent advances in FAU zeolite research with emphasis on their roles in environmental pollutant mitigation.A bibliometric analysis was performed to ascertain worldwide research trends,cooperation networks,and principal theme areas.Strategies for synthesis and functionalization,including crystallization pathways,one-pot methods,and post-synthetic modifications,were systematically evaluated for their capacity to tailor structural and physicochemical properties.Environmental applications were discussed in detail,particularly in heavy metal extraction,CO_(2)capture,and catalytic NOx reduction.Despite these advances,challenges persisted,notably restricted chemical stability under extreme pH conditions,scalability obstacles from laboratory to industrial production,and the necessity for enhanced catalytic efficiency.By integrating fundamental understanding with application-oriented perspectives,this review identifies existing knowledge gaps and delineates future directions for the rational design of FAU zeolites toward sustainable environmental remediation.
基金support from the National Key R&D Program of China(2022YFB3806802)the National Natural Science Foundation of China(22278287,22278288,and 22090062).
文摘The identical molecular size and similar physical properties of carbon dioxide(CO_(2))and acetylene(C_(2)H_(2))make their adsorptive separation extremely challenging to achieve with most adsorbents.Reports on the separation of CO_(2)and C_(2)H_(2)mixtures by zeolites are even rarer with the mechanism of adsorptive separation requiring further exploration.In this paper,we report that ion modulation of zeolite 5A promotes the difference in kinetic diffusion of CO_(2)and C_(2)H_(2),realizing the inverse separation of zeolite from selective adsorption of C_(2)H_(2)to selective adsorption of CO_(2).Creating a compact pore space restricting the orientation of gas molecules enables charge recognition.The positive electrostatic potential at the pore openings was utilized to hinder the diffusion of C_(2)H_(2)between the cages while ensuring the transfer of CO_(2),increasing their diffusion differences in pore channels and leading to the CO_(2)/C_(2)H_(2)kinetic selectivity of 31.97.Grand canonical Monte Carlo(GCMC)simulation demon-strates that the CO_(2)distribution in K-5A-βis significantly higher than that of C_(2)H_(2).Dynamic breakthrough ex-periments verify the excellent performance of material in practical CO_(2)/C_(2)H_(2)separation,for CO_(2)/C_(2)H_(2)(50/50 and 1/99,V/V)mixtures can be separated in one step,thus directly generating high purity C_(2)H_(2)(>99.95%),which provides a promising thought for the zeolite-based separation of CO_(2)and C_(2)H_(2).
文摘A-type zeolite membranes were prepared on the nonporous metal supports by using electrophoretic tech- nique. The as-synthesized membranes were characterized by XRD and SEM. The effect of the applied potential on the formation of the A-type zeolite membrane was investigated, and the formation mechanism of zeolite membrane in the electric field was discussed. The results showed that the negative charged zeolite particles could migrate to the anode metal surface homogenously and rapidly under the action of the applied electric field, consequently formed uniform and dense membranes in short time. The applied potential had great effect on the membrane formation, and more uniform and denser zeolite membranes were prepared on the non- porous metal supports with 1 V potential.
基金supported financially by the National Natural Science Foundation of China(Grant Nos.41872054 and 41272083)。
文摘The petrogenesis and genetic link to polymetallic mineralization of the granites in the Dayishan complex,southern Hunan province remain debated.Here,we present an integrated study on the petrology,zircon U-Pb ages and whole-rock geochemistry for this complex.Our findings indicate that the southern complex consists of(amphibole-bearing)biotite granites and muscovite granites emplaced at 153-151 Ma,and the central and northern complex consists of two-mica granites and tourmaline-bearing muscovite granites,respectively with the former emplaced at 164 Ma and the latter at 150 Ma.The(amphibole-bearing)biotite granites have SiO_(2) contents of 68.0-73.8 wt% and are enriched in alkalis and rare earth elements and depleted in Sr and Ba.They display Zr+Y+Ce+Nb>350 ppm and 10000×Ga/Al>2.6 along with high zircon saturation temperatures(821-883oC).The two-mica granites and(tourmaline-bearing)muscovite granites have high SiO_(2)(74.4-77.3 wt%)and low Ga/Al,Zr+Nb+Ce+Y,K/Rb,Zr/Hf,and Nb/Ta along with low zircon saturation temperatures(709-817℃).Geochemical characteristics suggest that the(amphibole-bearing)biotite granites are A-type granites generated through shallow dehydration melting of early Paleozoic granitoids,and that the two-mica granites and(tourmaline-bearing)muscovite granites are fractionated A-type granites produced through fractionation crystallization from the(amphibole-bearing)biotite granites accompanied by fluid fractionation.
基金Project supported by Rumah Program 2023 and Net Zero Emission Program(1507/Ⅱ.7/HK.01.00/6/2023)a research facility from the National Research and Innovation Agency of Republic of Indonesia。
文摘Recycling rare earth elements(REEs)from waste is necessary for an environmentally sustainable reuse and wastewater management approach.Na-A zeolite was synthesized from coal fly ash(CFA)and applied for Ce^(3+)adsorption.Fourier transform infrared(FTIR)spectra show peaks at 790,500 and 467 cm^(-1),which are bond vibrations of Si-O-Si,Si with Al-O and Si-O-.The surface area is 15.88 m^(2)/g,with a pore size of 2.14 nm.SEM images show a cubic shape,which indicates the formation of zeolite.Field emission and energy disperse spectroscopy(EDS)shows the formation of Si,Al,Na,and O.Na-A zeolite was applied for Ce^(3+)adsorption.The optimum conditions for Ce^(3+)adsorption are 50 ppm concentration,360 min,and pH 6.The maximum adsorption capacity is 176.49 mg/g.Based on the results,it is found that the adsorption of Ce^(3+)by Na-A zeolite is pseudo-second-order.The desorption test using HNO_(3) is more effective than using HCl and H_(2)SO_(4).A desorption efficiency of 97.22%is obtained at 4 cycles.Adsorption test using real sample wastewater demonstrates an adsorption efficiency of 83.35%.
基金Joint Project of Dalian University of Technology-Dalian Institute of Chemical Physics (HX20230236)。
文摘Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented growth.The obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.
文摘Propane dehydrogenation(PDH)has emerged as a key on-purpose technology for the production of propylene,but it often depends on toxic chromium and expensive platinum catalysts,highlighting the need for environmentally friendly and cost-effective alternatives.In this study,we developed a facile impregnation method to fabricate unsaturated Co single-atoms with a tricoordinated Co_(1)O_(3)H_(x) structure by regulating silanol nests in purely siliceous Beta zeolites.Detailed PDH catalytic tests and characterizations revealed a positive correlation between the presence of silanol nests and enhanced catalytic activity.Additionally,the unsaturated Co single-atoms exhibited a carbon deposition rate more than an order of magnitude slower than that of Co nanoparticles.Notably,the optimized Co_(0.3%)/deAl-meso-Beta catalyst achieved a record-high propylene formation rate of 21.2 mmol_(C3H6) g_(cat)^(-1) h^(-1),with an exceptional propylene selectivity of 99.1%at 550℃.Moreover,the Co_(0.3%)/deAl-meso-Beta catalyst demonstrated excellent stability,with negligible deactivation after 5 consecutive regeneration cycles.This study emphasizes the pivotal role of silanol nests of zeolites in stabilizing and modulating the coordination environment of metallic active sites,providing valuable insights for the design of high-activity,high-stability,and low-cost PDH catalysts.
基金supported by Zhongtian Iron and Steel-University of Science and Technology Beijing Youth Science and Technology Innovation Fund(No.FZTNTC2024050005)National Engineering Laboratory for Mobile Source Emission Control Technology,China(No.NELMS2020A07)The Fundamental Research Funds for the Central Universities,China(No.FRF-AT-20-12)。
文摘Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used active metals in PNA and VOC catalysts,respectively.However,despite the same metal/zeolite composition,the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd^(2+) and Pt^(0),respectively,both of which are different from each other.As a result,various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages.No matter which type of metal species is needed,the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable.The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals(Pd,Pt,etc.)as effective PNA or VOC catalysts.To give a better understanding of the relationship between efficient metal species and the introduced methods,the species that contributed to the NOx adsorption(PNA)and VOCs deep catalytic oxidation were first summarized and compared.Then,based on the above discussion,the detailed construction strategies for different active sites in PNA and VOC catalysts,respectively,were elaborated in terms of synthetic routes,precursor selection,and zeolite carrier requirements.It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity,selectivity and stability.
文摘Hydrocracking technology represents a crucial position in the conversion of heavy oil and the transformation development from oil refining to the chemical industry.The properties of catalysts are one of the key factors in the hydrocracking process.As the main acidic component of hydrocracking catalyst,the influence of zeolite properties on the reaction performance has been the focus of research.In this study,a series of NiMo/Al_(2)O_(3)-Y catalysts were prepared using different Y zeolites as acidic components,and their performances in the hydrocracking of n-C_(10)were also evaluated.The structure-activity relationship between Y zeolite and the cracking performance of n-C_(10)was investigated with machine learning.First,a database of the physical and chemical properties of Y zeolite and their performance was established,and the correlation analysis was also conducted.Parameters such as the cell constant,acid content,acid strength,B/L ratio,mesopore volume,micropore volume of Y zeolite,and the reaction temperature were selected as independent variables.The conversion of n-C_(10)and the ratios of products C_(3)/C_(7)and i-C_(4)/n-C_(4)were selected as dependent variables.A model was established by the random forest algorithm and a new zeolite was predicted based on it.The results of model prediction were in good agreement with the experimental results.The R^(2)of the n-C_(10)conversion,C_(3)/C_(7)ratio,and i-C_(4)/n-C_(4)ratio were 0.9866,0.9845,and 0.9922,and the minimum root mean square error values were 0.0163,0.101,and 0.0211,respectively.These results can provide reference for the development of high performance hydrocracking catalyst and technology.
基金supported by the National Natural Science Foundation of China(No.52201274)the Project of Education Department of Shanxi Province(No.22JK0419).
文摘High-capacity LiBH_(4)is a promising solid hydrogen storage material.However,the large electron cloud density between the B-H bonds in LiBH_(4)induces high dehydrogenation temperatures and sluggish dehydrogenation kinetics.To solve the above problems,it is proposed to enhance the hydrogen storage properties of LiBH_(4)through the synergistic effect of Brønsted and Lewis acid in Hβzeolite.Composite hydrogen storage systems with different mass ratios were prepared by simple ball-milling.At a LiBH_(4)-to-Hβmass ratio of 6:4,the 6LiBH_(4)-4Hβsystem released hydrogen at 190℃and achieved a hydrogen release capacity of 7.0 wt%H_(2)upon heating to 400℃.More importantly,the hydrogen release capacity of the system reached 6.02 wt%at 350℃under isothermal conditions after 100 min and 7.2 wt%at 400℃under isothermal conditions after 80 min,whereas the pristine LiBH_(4)only achieved 2.2 wt%.The improvement in hydrogen storage performance of the system was mainly attributed to two factors:(i)Lewis acid sites with acceptable electrons in the Hβweaken the electron density of B-H bonds in LiBH_(4),and(ii)the H+proton from the Brønsted acid sites and H−of LiBH_(4)undergo a H^(+)+H^(−)=H_(2)reaction.Theoretical calculations revealed that the Lewis and Brønsted acid sites in the Hβzeolite are conducive to the weakening of B-H bonds and that storage charge transfer occurs near the Lewis acid sites.The present work provides new insights into improving the hydrogen storage performance of LiBH_(4)by weakening the B-H bonds in the LiBH_(4).
基金supported by the Key Technologies Research and Development Program(No.2022YFB3504102)the National Natural Science Foundation of China(Nos.22035009,22002050,and 22202087)+2 种基金the National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2020B01)Fuyang Normal University Open Fund(No.FSKFKT006D)the Postdoctoral Science Foundation of China(Nos.2022T150765 and 2020M683154).
文摘Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol for reducing NO_(x)emissions.Nowadays,zeolitebased NH_(3)-SCR catalysts have been industrialized and widespread used in this field.Nevertheless,with the increasingly stringent environmental regulations and implementation of the requirement of“zero emission”of diesel engine exhaust,it is extremely urgent to prepare catalysts with superior NH_(3)-SCR activity and exceptional resistance to poisons(SO2,alkali metals,hydrocarbons,etc.).Core-shell structure zeolite-based catalysts(CSCs)have shown great promise in NH_(3)-SCR of NO_(x)in recent years by virtue of its relatively higher low-temperature activity,broader operation temperature window and outstanding resistance to poisons.This review mainly focuses on the recent progress of CSCs for NH_(3)-SCR of NO_(x)with three extensively investigated SSZ-13,ZSM-5,Beta zeolites as cores.The reaction mechanisms of resistance to sulfur poisoning,alkali metal poisoning,hydrocarbon poisoning,and hydrothermal aging are summarized.Moreover,the important role of interfacial effect between core and shell in the reaction of NH_(3)-SCR was clarified.Finally,the future development and application outlook of CSCs are prospected.
基金supported by the National Natural Science Foundation of China(Grant Nos.41903025 and 41803048)the National Nonprofit Institute Research Grant of IGGE(Grant Nos.AS2024J03,JY202106 and AS2022P03)+2 种基金the Hebei Key Science and Technology Program(Grant No.19057411Z)the National Science and Technology Major Project(Grant No.2024ZD1002402)the China Geological Survey Project(Grant No.DD20221807).
文摘The Suzhou granitic pluton is the first identified Nb-Ta-rich granite in China.To reveal the genetic link between the sequence of magmatic and hydrothermal evolution and Nb-Ta mineralization in different intrusive phases of the Suzhou granite,whole-rock geochemistry,geochemistry and U-Th-Pb dating of monazite was analyzed.The unique geochemical characteristics show that the Suzhou pluton can be discriminated as an A-type granite.LA-ICP-MS U-Th-Pb dating of monazite in both the medium-and coarse-grained biotite granite(MBG)and the fine-grained biotite granite(FBG)indicates that the granite formed between 124 and 127 Ma.Based on geochemical characteristics and mineral textures,the MBG(Mnz-Ia)and FBG(Mnz-Ib)monazites are classified as magmatic monazites;another monazite(Mnz-II)from the MBG formed during a magmatic-hydrothermal transitional stage.Nb-Ta in the Suzhou pluton gradually concentrated during fractional crystallization and alteration of Ti-rich minerals and biotite.Ultimately,with the involvement of F-Li-rich fluid,Nb-Ta mineralization occurred during the magmatic-hydrothermal transition.The Suzhou pluton is considered part of a 600-km-and NE-SW-trending Nb-rich A-type granite belt together with other Early Cretaceous A-type granites in the Jiangnan Orogen that offers prospects of a new target for Nb-Ta prospecting.
基金supported financially by the National Natural Science Foundation of China(Grant Nos.41872054 and 41272083)。
文摘Granite origin is crucial to understanding the evolution of continental crust,yet many concerns about granite genesis remain yielding ongoing debates.A new integrated study of petrology,geochronology,mineral chemistry and whole-rock geochemistry of the Dupangling granitic complex in South China,indicate that the granites in the western complex were emplaced during the Caledonian(418 Ma);they have SiO_(2)contents of 68.1-70.4 wt%,and are calc-alkaline and strongly peraluminous with high maficity[(TFe_(2)O_(3)+MgO)>4.0 wt%]and exhibit^(87)Sr/^(86)Sr(t)of 0.7234-0.7311 andε_(Nd)(t)of-9.0 to-6.7.The granites in the eastern complex,emplaced during the Indosinian(212 Ma),have high SiO_(2)contents(73.3-79.8 wt%)and exhibit affinities with A-type granites,such as enrichment in alkalis and rare earth elements(REEs),and depletion in Sr and Ba along with high TFeO/(TFeO+MgO),Ga/Al and Zr+Y+Ce+Nb;these granites exhibit^(87)Sr/^(86)Sr(t)of 0.7221 andε_(Nd)(t)of-9.2 to-7.5.Geochemical characteristics suggest that the older Caledonian granites were derived through dehydration melting of Paleoproterozoic metasedimentary rocks plus additional(~20%-32%)input from mafic magma,whereas the Indosinian granites were generated through shallow dehydration melting of the Caledonian granitoids.
