Chemical engineering is a broad field in terms of the scope of practice but the discipline has been united by a few intellectually coherent principles. Among them, thermodynamics, reaction kinetics and transport pheno...Chemical engineering is a broad field in terms of the scope of practice but the discipline has been united by a few intellectually coherent principles. Among them, thermodynamics, reaction kinetics and transport phenomena are often considered as the cornerstones, providing support for the design and operation of diverse chemical processes for power generation and production of industrial goods such as plastics, gasoline and ammonia. Traditionally, these industrial processes use fossil fuels as the raw materials and are responsible for significant greenhouse gas emissions. As fossil-energy-based processes are deemed phasing out , development of alternative routes with renewable energy and sustainable feedstock is calling for the expansion of the knowledge base such that eco-friendly chemical processes can be quantified, controlled and optimized with high precision. This article offers some perspectives on possible engineering developments to accelerate the paradigm shift from fossil fuels to renewable energy.展开更多
A hybrid gas/liquid pulsed discharge plasma reactor using a porous ceramic tube is proposed for dye wastewater treatment. High voltage pulsed discharge plasma was generated in the gas phase and simultaneously the plas...A hybrid gas/liquid pulsed discharge plasma reactor using a porous ceramic tube is proposed for dye wastewater treatment. High voltage pulsed discharge plasma was generated in the gas phase and simultaneously the plasma channel was permeated through the tiny holes of the ceramic tube into the water phase accompanied by gas bubbles. The porous ceramic tube not only separated the gas phase and liquid phase but also offered an effective plasma spreading channel. The effects of the peak pulse voltage, additive gas varieties, gas bubbling rate, solution conductivity and TiO2 addition were investigated. The results showed that this reactor was effective for dye wastewater treatment. The decoloration efficiency of Acid Orange II was enhanced with an increase in the power supplied. Under the studied conditions, 97% of Acid Orange II in aqueous solution was effectively decolored with additive oxygen gas, which was 51% higher than that with argon gas, and the increasing 02 bubbling rate also benefited the decoloration of dye wastewater. Water conductivity had a small effect on the level of decoloration. Catalysis of TiO2 could be induced by the pulsed discharge plasma and addition of TiO2 aided the decoloration of Acid Orange II.展开更多
Systematic optimization of the photocatalyst and investigation of the role of each component is important to maximizing catalytic activity and comprehending the photocatalytic conversion of CO_(2) reduction to solar f...Systematic optimization of the photocatalyst and investigation of the role of each component is important to maximizing catalytic activity and comprehending the photocatalytic conversion of CO_(2) reduction to solar fuels.A surface-modified Ag@Ru-P25 photocatalyst with H_(2)O_(2) treatment was designed in this study to convert CO_(2) and H_(2)O vapor into highly selective CH4.Ru doping followed by Ag nanoparticles(NPs)cocatalyst deposition on P25(TiO_(2))enhances visible light absorption and charge separation,whereas H_(2)O_(2) treatment modifies the surface of the photocatalyst with hydroxyl(–OH)groups and promotes CO_(2) adsorption.High-resonance transmission electron microscopy,X-ray photoelectron spectroscopy,X-ray absorption near-edge structure,and extended X-ray absorption fine structure techniques were used to analyze the surface and chemical composition of the photocatalyst,while thermogravimetric analysis,CO_(2) adsorption isotherm,and temperature programmed desorption study were performed to examine the significance of H_(2)O_(2) treatment in increasing CO_(2) reduction activity.The optimized Ag1.0@Ru1.0-P25 photocatalyst performed excellent CO_(2) reduction activity into CO,CH4,and C2H6 with a~95%selectivity of CH4,where the activity was~135 times higher than that of pristine TiO_(2)(P25).For the first time,this work explored the effect of H_(2)O_(2) treatment on the photocatalyst that dramatically increases CO_(2) reduction activity.展开更多
This simulation-based comparative assessment aims to quantify the environmental and human-health impacts of greener hydrogen(H2)production via three glycerol-based technologies,including:supercritical water reforming(...This simulation-based comparative assessment aims to quantify the environmental and human-health impacts of greener hydrogen(H2)production via three glycerol-based technologies,including:supercritical water reforming(SCWR),aqueous-phase reforming(APR)and autothermal reforming(ATR).The GaBi(2018 edition)life-cycle assessment(LCA)platform is used to develop cradle-to-gate product system models for these technologies and the TRACI 2.1 methodology is used to quantify their midpoint impact categories.Aspen HYSYS(v11)process-simulation software is used to generate the life-cycle inventory(LCI)primary data required to produce 1 kg of H2 via each of the indicated glycerol-reforming technologies.Per ISO 14040:2006 reporting requirements for the LCA results interpretation step,three base case(BC)scenarios and four sensitivity scenarios(SS)are developed and quantified to compare the effects of different process electricity sources(US grid mix versus wind power)and thermal energy sources(natural gas versus biogas)on the LCA results.The high operating pressure(viz.240 bar)of SCWR enabled assessment of the impact of in situ electricity generation to offset some of electricity required for this technology.The major insights from this research are as follows:(i)per 1 kg of produced H2,APR reduces CO_(2) emissions by≈95%compared to ATR and by≈92%compared to SCWR,(ii)for BC scenarios,the primary energy consumption(in MJ/kg of produced H2)is in the following order from highest to lowest:ATR>SCWR>APR and(iii)H2 production via glycerol APR is more environmentally sustainable than SCWR and ATR,and thus offers a promising path for greener H2 production.Future environmental sustainability studies should focus on expanding the scope of this study to include H2 production via water electrolysis using renewable electricity sources and via solar and nuclear-driven thermochemical water splitting.展开更多
In this paper,we discuss the previous advances,current challenges,and future opportunities for the research of catalytic reduction of water pollutants.We present five case studies on the development of palladium-based...In this paper,we discuss the previous advances,current challenges,and future opportunities for the research of catalytic reduction of water pollutants.We present five case studies on the development of palladium-based catalysts for nitrate,chlorate,and perchlorate reduction with hydrogen gas under ambient conditions.We emphasize the realization of new functionalities through the screening and design of catalytic metal sites,including(i)platinum group metal(PGM)nanoparticles,(ii)the secondary metals for improving the reaction rate and product selectivity of nitrate reduction,(iii)oxygen-atom-transfer metal oxides for chlorate and perchlorate reduction,and(iv)ligand-enhanced coordination complexes for substantial activity enhancement.We also highlight the facile catalyst preparation approach that brought significant convenience to catalyst optimization.Based on our own studies,we then discuss directions of the catalyst research effort that are not immediately necessary or desirable,including(1)systematic study on the downstream aspects of under-developed catalysts,(2)random integration with hot concepts without a clear rationale,and(3)excessive and decorative experiments.We further address some general concerns regarding using H2 and PGMs in the catalytic system.Finally,we recommend future catalyst development in both“fundamental”and“applied”aspects.The purpose of this perspective is to remove major misconceptions about reductive catalysis research and bring back significant innovations for both scientific advancements and engineering applications to benefit environmental protection.展开更多
Defects in materials significantly alter their electronic and structural properties,which affect the per-formance of electronic devices,structural alloys,and functional materials.However,calculating all the possible d...Defects in materials significantly alter their electronic and structural properties,which affect the per-formance of electronic devices,structural alloys,and functional materials.However,calculating all the possible defects in complex materials with conventional Density Functional Theory(DFT)can be compu-tationally prohibitive.To enhance the efficiency of these calculations,we interfaced Density Functional Tight Binding(DFTB)with the Clusters Approach to Statistical Mechanics(CASM)software package for the first time.Using SiC and ZnO as representative examples,we show that DFTB gives accurate results and can be used as an efficient computational approach for calculating and pre-screening formation ener-gies/convex hulls.Our DFTB+CASM implementation allows for an efficient exploration(up to an order of magnitude faster than DFT)of formation energies and convex hulls,which researchers can use to probe other complex systems.展开更多
文摘Chemical engineering is a broad field in terms of the scope of practice but the discipline has been united by a few intellectually coherent principles. Among them, thermodynamics, reaction kinetics and transport phenomena are often considered as the cornerstones, providing support for the design and operation of diverse chemical processes for power generation and production of industrial goods such as plastics, gasoline and ammonia. Traditionally, these industrial processes use fossil fuels as the raw materials and are responsible for significant greenhouse gas emissions. As fossil-energy-based processes are deemed phasing out , development of alternative routes with renewable energy and sustainable feedstock is calling for the expansion of the knowledge base such that eco-friendly chemical processes can be quantified, controlled and optimized with high precision. This article offers some perspectives on possible engineering developments to accelerate the paradigm shift from fossil fuels to renewable energy.
基金supported financially by the Program for Liaoning Excellent Talents in University,China (No.2009R09)National Natural Science Foundation of China (No.40901150)863 Program of China (No.2009AA064101-4)
文摘A hybrid gas/liquid pulsed discharge plasma reactor using a porous ceramic tube is proposed for dye wastewater treatment. High voltage pulsed discharge plasma was generated in the gas phase and simultaneously the plasma channel was permeated through the tiny holes of the ceramic tube into the water phase accompanied by gas bubbles. The porous ceramic tube not only separated the gas phase and liquid phase but also offered an effective plasma spreading channel. The effects of the peak pulse voltage, additive gas varieties, gas bubbling rate, solution conductivity and TiO2 addition were investigated. The results showed that this reactor was effective for dye wastewater treatment. The decoloration efficiency of Acid Orange II was enhanced with an increase in the power supplied. Under the studied conditions, 97% of Acid Orange II in aqueous solution was effectively decolored with additive oxygen gas, which was 51% higher than that with argon gas, and the increasing 02 bubbling rate also benefited the decoloration of dye wastewater. Water conductivity had a small effect on the level of decoloration. Catalysis of TiO2 could be induced by the pulsed discharge plasma and addition of TiO2 aided the decoloration of Acid Orange II.
基金supported by the Ministry of Science and ICT in Korea(2021R1A2C2009459)X-ray absorption spectra were obtained from Pohang Accelerator Laboratory(PAL)10C beamlinesupported by the US Department of Energy,Office of Science,Office of Advanced Scientific Computing Research,and Scientific Discovery through Advanced Computing(SciDAC)program under Award Number DE-SC0022209.
文摘Systematic optimization of the photocatalyst and investigation of the role of each component is important to maximizing catalytic activity and comprehending the photocatalytic conversion of CO_(2) reduction to solar fuels.A surface-modified Ag@Ru-P25 photocatalyst with H_(2)O_(2) treatment was designed in this study to convert CO_(2) and H_(2)O vapor into highly selective CH4.Ru doping followed by Ag nanoparticles(NPs)cocatalyst deposition on P25(TiO_(2))enhances visible light absorption and charge separation,whereas H_(2)O_(2) treatment modifies the surface of the photocatalyst with hydroxyl(–OH)groups and promotes CO_(2) adsorption.High-resonance transmission electron microscopy,X-ray photoelectron spectroscopy,X-ray absorption near-edge structure,and extended X-ray absorption fine structure techniques were used to analyze the surface and chemical composition of the photocatalyst,while thermogravimetric analysis,CO_(2) adsorption isotherm,and temperature programmed desorption study were performed to examine the significance of H_(2)O_(2) treatment in increasing CO_(2) reduction activity.The optimized Ag1.0@Ru1.0-P25 photocatalyst performed excellent CO_(2) reduction activity into CO,CH4,and C2H6 with a~95%selectivity of CH4,where the activity was~135 times higher than that of pristine TiO_(2)(P25).For the first time,this work explored the effect of H_(2)O_(2) treatment on the photocatalyst that dramatically increases CO_(2) reduction activity.
文摘This simulation-based comparative assessment aims to quantify the environmental and human-health impacts of greener hydrogen(H2)production via three glycerol-based technologies,including:supercritical water reforming(SCWR),aqueous-phase reforming(APR)and autothermal reforming(ATR).The GaBi(2018 edition)life-cycle assessment(LCA)platform is used to develop cradle-to-gate product system models for these technologies and the TRACI 2.1 methodology is used to quantify their midpoint impact categories.Aspen HYSYS(v11)process-simulation software is used to generate the life-cycle inventory(LCI)primary data required to produce 1 kg of H2 via each of the indicated glycerol-reforming technologies.Per ISO 14040:2006 reporting requirements for the LCA results interpretation step,three base case(BC)scenarios and four sensitivity scenarios(SS)are developed and quantified to compare the effects of different process electricity sources(US grid mix versus wind power)and thermal energy sources(natural gas versus biogas)on the LCA results.The high operating pressure(viz.240 bar)of SCWR enabled assessment of the impact of in situ electricity generation to offset some of electricity required for this technology.The major insights from this research are as follows:(i)per 1 kg of produced H2,APR reduces CO_(2) emissions by≈95%compared to ATR and by≈92%compared to SCWR,(ii)for BC scenarios,the primary energy consumption(in MJ/kg of produced H2)is in the following order from highest to lowest:ATR>SCWR>APR and(iii)H2 production via glycerol APR is more environmentally sustainable than SCWR and ATR,and thus offers a promising path for greener H2 production.Future environmental sustainability studies should focus on expanding the scope of this study to include H2 production via water electrolysis using renewable electricity sources and via solar and nuclear-driven thermochemical water splitting.
基金Financial support was provided by the U.S. National Science Foundation (CBET-1932942).
文摘In this paper,we discuss the previous advances,current challenges,and future opportunities for the research of catalytic reduction of water pollutants.We present five case studies on the development of palladium-based catalysts for nitrate,chlorate,and perchlorate reduction with hydrogen gas under ambient conditions.We emphasize the realization of new functionalities through the screening and design of catalytic metal sites,including(i)platinum group metal(PGM)nanoparticles,(ii)the secondary metals for improving the reaction rate and product selectivity of nitrate reduction,(iii)oxygen-atom-transfer metal oxides for chlorate and perchlorate reduction,and(iv)ligand-enhanced coordination complexes for substantial activity enhancement.We also highlight the facile catalyst preparation approach that brought significant convenience to catalyst optimization.Based on our own studies,we then discuss directions of the catalyst research effort that are not immediately necessary or desirable,including(1)systematic study on the downstream aspects of under-developed catalysts,(2)random integration with hot concepts without a clear rationale,and(3)excessive and decorative experiments.We further address some general concerns regarding using H2 and PGMs in the catalytic system.Finally,we recommend future catalyst development in both“fundamental”and“applied”aspects.The purpose of this perspective is to remove major misconceptions about reductive catalysis research and bring back significant innovations for both scientific advancements and engineering applications to benefit environmental protection.
基金supported by the U.S.Department of Energy,Na-tional Energy Technology Laboratory(NETL),under Award No.DE-FE0030582.
文摘Defects in materials significantly alter their electronic and structural properties,which affect the per-formance of electronic devices,structural alloys,and functional materials.However,calculating all the possible defects in complex materials with conventional Density Functional Theory(DFT)can be compu-tationally prohibitive.To enhance the efficiency of these calculations,we interfaced Density Functional Tight Binding(DFTB)with the Clusters Approach to Statistical Mechanics(CASM)software package for the first time.Using SiC and ZnO as representative examples,we show that DFTB gives accurate results and can be used as an efficient computational approach for calculating and pre-screening formation ener-gies/convex hulls.Our DFTB+CASM implementation allows for an efficient exploration(up to an order of magnitude faster than DFT)of formation energies and convex hulls,which researchers can use to probe other complex systems.
