Photocatalytic C-N coupling reactions using waste plastic-and biomass-based feedstocks with nitrogen-containing species have emerged as a promising route for the synthesis of high-value chemicals such as amides and am...Photocatalytic C-N coupling reactions using waste plastic-and biomass-based feedstocks with nitrogen-containing species have emerged as a promising route for the synthesis of high-value chemicals such as amides and amino acids.However,the complexity of multistep reaction routes and the presence of competing side reactions pose significant challenges,often leading to low yield and poor selectivity of target products.To substantially enhance the efficiency and selectivity of C-N coupling reactions,it is imperative to gain a thorough understanding of the underlying reaction mechanisms and to develop highly active photocatalysts.Such catalysts must be capable of effectively activating diverse substrates while maintaining an appropriate balance between the adsorption and desorption of carbon-and nitrogen-containing intermediates or radical species.In this review,we systematically summarize recent advances in photocatalytic C-N coupling for the production of amides and amino acids from waste plastic-and biomass-based feedstocks,with particular focus on catalyst selection,process design,control of reaction intermediates,and catalytic mechanisms.Furthermore,the technoeconomic feasibility and environmental impact of these C-N coupling reactions are evaluated using technoeconomic analysis and life-cycle assessment.Lastly,the current challenges and future prospects in this field are also discussed.This review aims to provide valuable insights for the development of high-efficiency photocatalytic C-N coupling reactions and to deepen the understanding of their catalytic mechanisms.展开更多
An important challenge in ensuring the long-term effectiveness of geological nuclear waste disposal is predicting the transportation of decay heat and gases released from nuclear waste canisters.In this study,thermo-h...An important challenge in ensuring the long-term effectiveness of geological nuclear waste disposal is predicting the transportation of decay heat and gases released from nuclear waste canisters.In this study,thermo-hydromechanical(THM)coupled simulations were conducted using the TOUGH + FLAC3D simulator to predict the THM behaviors of a generic nuclear waste repository over 100,000 years following closure.The designed engineered barrier system(EBS)consists of the waste canister,backfill,and concrete liner.The objective of this study is to evaluate the long-term performance of the repository in the presence of continued hydrogen(H_(2))and heat release around the canister.The simulation results show that thermal pressurization and gas accumulation significantly raise the pore pressure within the EBS and surrounding host rock,while the peak pore pressure is not likely to exceed the lithostatic stress so that there is no risk of widespread hydro-fracturing in the host rock.However,tension failure and fracturing can occur at the tunnel scale because of internal gas buildup.Meanwhile,the generated H_(2) continuously migrates outward and tends to accumulate in the concrete liner and excavation disturbed zone surrounding the tunnel because of lower capillary pressure.Nevertheless,the fluids that may contain radionuclides will not leach into the confining units over a 100,000-year time frame.Our analysis indicates that for the assumed disposal system in Opalinus Clay,the generated heat and gas can gradually be transported through the host rock without significantly disturbing the isolation characteristics of the repository.展开更多
To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study invest...To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study investigates the features of P and F in PG,and explores the decomposition of PF using hydrofluoric acid(HF)in the sulfuric acid system for K leaching and leaching of P and F in PG.The impact factors such as sulfuric acid concentration,reaction temperature,reaction time,material ratio(PG/PF),liquid–solid ratio,PF particle size,and PF calcination temperature on the leaching of P and K is systematically investigated in this paper.The results show that under optimal conditions,the leaching rate of K and P reach more than 93%and 96%,respectively.Kinetics study using shrinking core model(SCM)indicates two significant stages with internal diffusion predominantly controlling the leaching of K.The apparent activation energies of these two stages are 11.92 kJ·mol^(-1)and 11.55 kJ·mol^(-1),respectively.展开更多
Electrocatalysis offers efficient and targeted conversion of monomers derived from waste polyester plastics to chemical products under ambient temperature and pressure conditions.This review provides analysis of resea...Electrocatalysis offers efficient and targeted conversion of monomers derived from waste polyester plastics to chemical products under ambient temperature and pressure conditions.This review provides analysis of research on electrochemical upgrading of monomers derived from waste polyester plastics published from2021 to present.Factors for assessing upgrading of waste polyester plastics include alkaline hydrolysis pretreatment,indices of electrochemical reaction process(activity,stability,and techno-economic a nalysis),separation,and product recovery.Types of depolymerization monomers and their value-added products are summarized along with electrocatalytic mechanisms and reaction pathways.Notably,cathode coupled reactions offer significant value for anodic waste plastic oxidation during electrolysis processes.Development of bifunctional electrocatalysts can reduce the cost of coupled systems and complexity of the electrolyzer.Upgrading and recycling of waste plastic monomers using electrocatalytic technology should undergo downstream processing to form high-value products containing C-N and C-S derived functional groups obtained from depolymerized monomers,Electrochemical conversion and upgrading of monomers derived from waste polyester plastics can contribute to industrialization and global economies and help to realize environmental sustainability.展开更多
The management of nitrogenous waste emissions presents significant environmental and health challenges.Efficient and sustainable upcycling strategies are needed to convert waste nitrogen compounds into valuable resour...The management of nitrogenous waste emissions presents significant environmental and health challenges.Efficient and sustainable upcycling strategies are needed to convert waste nitrogen compounds into valuable resources.Electrocatalysis has emerged as a promising solution for waste management,but several challenges remain,including the identification of suitable electrocatalysts and understanding the complex reaction mechanisms.In this review,we focus on the progress in electrocatalytic oxidized nitrogen waste upgrading and utilization,highlighting the application of advanced in situ/operando characterization techniques,including X-ray spectroscopy,scanning electrochemical microscopy and others.These techniques provide valuable insights into the structural and chemical properties of electrocatalysts as well as intermediates during electrochemical reactions,enabling a better understanding of reaction mechanisms and optimization of reaction conditions.The review explores the mechanisms of electrocatalytic upcycling of nitrogenous waste,including nitrate/nitrite reduction,nitric oxide reduction,and carbon dioxide and nitrate co-reduction reactions.Additionally,future research directions and development trends are discussed,offering a relevant guide for the development of sustainable electrocatalytic technologies for waste management and resource recovery.展开更多
This work is devoted to numerical analysis of thermo-hydromechanical problem and cracking process in saturated porous media in the context of deep geological disposal of radioactive waste.The fundamental background of...This work is devoted to numerical analysis of thermo-hydromechanical problem and cracking process in saturated porous media in the context of deep geological disposal of radioactive waste.The fundamental background of thermo-poro-elastoplasticity theory is first summarized.The emphasis is put on the effect of pore fluid pressure on plastic deformation.A micromechanics-based elastoplastic model is then presented for a class of clayey rocks considered as host rock.Based on linear and nonlinear homogenization techniques,the proposed model is able to systematically account for the influences of porosity and mineral composition on macroscopic elastic properties and plastic yield strength.The initial anisotropy and time-dependent deformation are also taken into account.The induced cracking process is described by using a non-local damage model.A specific hybrid formulation is proposed,able to conveniently capture tensile,shear and mixed cracks.In particular,the influences of pore pressure and confining stress on the shear cracking mechanism are taken into account.The proposed model is applied to investigating thermo-hydromechanical responses and induced damage evolution in laboratory tests at the sample scale.In the last part,an in situ heating experiment is analyzed by using the proposed model.Numerical results are compared with experimental data and field measurements in terms of temperature variation,pore fluid pressure change and induced damaged zone.展开更多
A fully coupled thermo-hydro-mechano-chemical（THMC） formulation is described in this paper.Special attention is paid to phenomena likely to be encountered in clay barriers used as engineered barriers in the disposal...A fully coupled thermo-hydro-mechano-chemical（THMC） formulation is described in this paper.Special attention is paid to phenomena likely to be encountered in clay barriers used as engineered barriers in the disposal of nuclear radioactive waste.The types of processes considered in the chemical formulation include hydrolysis,complex formation,oxidation/reduction reactions,acid/base reactions,precipitation/dissolution of minerals and cation exchange.Both kinetics-and equilibrium-controlled reactions are incorporated.The formulation is implemented in a numerical code.An application is presented concerning the performance of a large-scale in-situ heating test simulating high-level radioactive waste repository conditions.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22572141,22178266)Talent Program Fund of Tianjin University(Nos.0701321039,0903074107)supported by a grant from the Key Laboratory of Recycling and Eco-Treatment of Waste Biomass of Zhejiang Province(No.2024HZYB02)。
文摘Photocatalytic C-N coupling reactions using waste plastic-and biomass-based feedstocks with nitrogen-containing species have emerged as a promising route for the synthesis of high-value chemicals such as amides and amino acids.However,the complexity of multistep reaction routes and the presence of competing side reactions pose significant challenges,often leading to low yield and poor selectivity of target products.To substantially enhance the efficiency and selectivity of C-N coupling reactions,it is imperative to gain a thorough understanding of the underlying reaction mechanisms and to develop highly active photocatalysts.Such catalysts must be capable of effectively activating diverse substrates while maintaining an appropriate balance between the adsorption and desorption of carbon-and nitrogen-containing intermediates or radical species.In this review,we systematically summarize recent advances in photocatalytic C-N coupling for the production of amides and amino acids from waste plastic-and biomass-based feedstocks,with particular focus on catalyst selection,process design,control of reaction intermediates,and catalytic mechanisms.Furthermore,the technoeconomic feasibility and environmental impact of these C-N coupling reactions are evaluated using technoeconomic analysis and life-cycle assessment.Lastly,the current challenges and future prospects in this field are also discussed.This review aims to provide valuable insights for the development of high-efficiency photocatalytic C-N coupling reactions and to deepen the understanding of their catalytic mechanisms.
基金Funding was provided by the U.S.Department of Energy,Office of Nuclear Energy,Spent Fuel and Waste Disposition,under Contract Number DE-AC02-05CH11231 with Lawrence Berkeley National Laboratory(LBNL).
文摘An important challenge in ensuring the long-term effectiveness of geological nuclear waste disposal is predicting the transportation of decay heat and gases released from nuclear waste canisters.In this study,thermo-hydromechanical(THM)coupled simulations were conducted using the TOUGH + FLAC3D simulator to predict the THM behaviors of a generic nuclear waste repository over 100,000 years following closure.The designed engineered barrier system(EBS)consists of the waste canister,backfill,and concrete liner.The objective of this study is to evaluate the long-term performance of the repository in the presence of continued hydrogen(H_(2))and heat release around the canister.The simulation results show that thermal pressurization and gas accumulation significantly raise the pore pressure within the EBS and surrounding host rock,while the peak pore pressure is not likely to exceed the lithostatic stress so that there is no risk of widespread hydro-fracturing in the host rock.However,tension failure and fracturing can occur at the tunnel scale because of internal gas buildup.Meanwhile,the generated H_(2) continuously migrates outward and tends to accumulate in the concrete liner and excavation disturbed zone surrounding the tunnel because of lower capillary pressure.Nevertheless,the fluids that may contain radionuclides will not leach into the confining units over a 100,000-year time frame.Our analysis indicates that for the assumed disposal system in Opalinus Clay,the generated heat and gas can gradually be transported through the host rock without significantly disturbing the isolation characteristics of the repository.
基金jointly supported by the National Key Research and Development Program of China (2019YFC1905800)the National Key Research & Development Program of China (2018YFC1903500)+4 种基金the commercial project by Beijing Zhong Dian Hua Yuan Environment Protection Technology Co., Ltd. (E01211200005)the Regional key projects of the science and technology service network program (STS program) of the Chinese Academy of Sciences (KFJ-STS-QYZD-153)the Ningbo Science and Technology Innovation Key Projects (2020Z099, 2022Z028)the Ningbo Municipal Commonweal Key Program (2019C10033)the support of Mineral Resources Analytical and Testing Center, Institute of Process Engineering, Chinese Academy of Science
文摘To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study investigates the features of P and F in PG,and explores the decomposition of PF using hydrofluoric acid(HF)in the sulfuric acid system for K leaching and leaching of P and F in PG.The impact factors such as sulfuric acid concentration,reaction temperature,reaction time,material ratio(PG/PF),liquid–solid ratio,PF particle size,and PF calcination temperature on the leaching of P and K is systematically investigated in this paper.The results show that under optimal conditions,the leaching rate of K and P reach more than 93%and 96%,respectively.Kinetics study using shrinking core model(SCM)indicates two significant stages with internal diffusion predominantly controlling the leaching of K.The apparent activation energies of these two stages are 11.92 kJ·mol^(-1)and 11.55 kJ·mol^(-1),respectively.
基金financially supported by the National Natural Science Foundation of China(Nos.22178181)the Natural Science Fund of Tianjin(No.21JCZDJC00180)the Fundamental Research Funds for the Central Universities(Nankai University(No.63243129)).
文摘Electrocatalysis offers efficient and targeted conversion of monomers derived from waste polyester plastics to chemical products under ambient temperature and pressure conditions.This review provides analysis of research on electrochemical upgrading of monomers derived from waste polyester plastics published from2021 to present.Factors for assessing upgrading of waste polyester plastics include alkaline hydrolysis pretreatment,indices of electrochemical reaction process(activity,stability,and techno-economic a nalysis),separation,and product recovery.Types of depolymerization monomers and their value-added products are summarized along with electrocatalytic mechanisms and reaction pathways.Notably,cathode coupled reactions offer significant value for anodic waste plastic oxidation during electrolysis processes.Development of bifunctional electrocatalysts can reduce the cost of coupled systems and complexity of the electrolyzer.Upgrading and recycling of waste plastic monomers using electrocatalytic technology should undergo downstream processing to form high-value products containing C-N and C-S derived functional groups obtained from depolymerized monomers,Electrochemical conversion and upgrading of monomers derived from waste polyester plastics can contribute to industrialization and global economies and help to realize environmental sustainability.
基金supported by the National Key Research and Development Project(No.2022YFA1505300)National Nature Science Foundation of China(Nos.52202372 and 22304021)Sichuan Science and Technology Program(Nos.2023NSFSC0089 and 2023NSFSC0436).
文摘The management of nitrogenous waste emissions presents significant environmental and health challenges.Efficient and sustainable upcycling strategies are needed to convert waste nitrogen compounds into valuable resources.Electrocatalysis has emerged as a promising solution for waste management,but several challenges remain,including the identification of suitable electrocatalysts and understanding the complex reaction mechanisms.In this review,we focus on the progress in electrocatalytic oxidized nitrogen waste upgrading and utilization,highlighting the application of advanced in situ/operando characterization techniques,including X-ray spectroscopy,scanning electrochemical microscopy and others.These techniques provide valuable insights into the structural and chemical properties of electrocatalysts as well as intermediates during electrochemical reactions,enabling a better understanding of reaction mechanisms and optimization of reaction conditions.The review explores the mechanisms of electrocatalytic upcycling of nitrogenous waste,including nitrate/nitrite reduction,nitric oxide reduction,and carbon dioxide and nitrate co-reduction reactions.Additionally,future research directions and development trends are discussed,offering a relevant guide for the development of sustainable electrocatalytic technologies for waste management and resource recovery.
基金supported by the French National Agency for radioactive waste management(ANDRA).
文摘This work is devoted to numerical analysis of thermo-hydromechanical problem and cracking process in saturated porous media in the context of deep geological disposal of radioactive waste.The fundamental background of thermo-poro-elastoplasticity theory is first summarized.The emphasis is put on the effect of pore fluid pressure on plastic deformation.A micromechanics-based elastoplastic model is then presented for a class of clayey rocks considered as host rock.Based on linear and nonlinear homogenization techniques,the proposed model is able to systematically account for the influences of porosity and mineral composition on macroscopic elastic properties and plastic yield strength.The initial anisotropy and time-dependent deformation are also taken into account.The induced cracking process is described by using a non-local damage model.A specific hybrid formulation is proposed,able to conveniently capture tensile,shear and mixed cracks.In particular,the influences of pore pressure and confining stress on the shear cracking mechanism are taken into account.The proposed model is applied to investigating thermo-hydromechanical responses and induced damage evolution in laboratory tests at the sample scale.In the last part,an in situ heating experiment is analyzed by using the proposed model.Numerical results are compared with experimental data and field measurements in terms of temperature variation,pore fluid pressure change and induced damaged zone.
基金supported by ENRESA and the European Commissionsupport given by CNPq(Conselho Nacional de Desenvolvimento Cientíco e Tecnológico)and the assistance of the Ministerio de Ciencia y Tecnología of Spain through research grant(BIA2008-06537)
文摘A fully coupled thermo-hydro-mechano-chemical（THMC） formulation is described in this paper.Special attention is paid to phenomena likely to be encountered in clay barriers used as engineered barriers in the disposal of nuclear radioactive waste.The types of processes considered in the chemical formulation include hydrolysis,complex formation,oxidation/reduction reactions,acid/base reactions,precipitation/dissolution of minerals and cation exchange.Both kinetics-and equilibrium-controlled reactions are incorporated.The formulation is implemented in a numerical code.An application is presented concerning the performance of a large-scale in-situ heating test simulating high-level radioactive waste repository conditions.
