Nanoparticles of Fe<sub>3</sub>O<sub>4</sub> and Fe are chemically synthesized by reduction of Fe(acac)<sub>3</sub> using ascorbic acid in controlled condition. It was observed that...Nanoparticles of Fe<sub>3</sub>O<sub>4</sub> and Fe are chemically synthesized by reduction of Fe(acac)<sub>3</sub> using ascorbic acid in controlled condition. It was observed that addition of water during the chemical synthesis process yields Fe3O4 nanoparticles, whereas if the reaction is carried out in absence of water yields Fe nanoparticles—which get oxidized upon exposure to air atmosphere. Fe<sub>3</sub>O<sub>4</sub> (15 ± 5 nm) and Fe/iron oxide nanoparticles (7 ± 1 nm) were successfully synthesized in the comparative study reported herewith. Mechanism for formation/synthesis of Fe<sub>3</sub>O<sub>4</sub> and Fe/iron oxide nanoparticles is proposed herewith in which added water acts as an oxygen supplier. Physico-chemical characterization done by SEM, TEM, EDAX, and XPS supports the proposed mechanism.展开更多
Nitrous oxide is not an environmentally regulated species in the U.S., but it does participate in the stratospheric ozone chemistry and contributes to the greenhouse effect. Nitrous oxide has been found to be a by-pro...Nitrous oxide is not an environmentally regulated species in the U.S., but it does participate in the stratospheric ozone chemistry and contributes to the greenhouse effect. Nitrous oxide has been found to be a by-product of the selective non-catalytic reduction process. Chemical kinetic calculations demonstrated that the formation of nitrous oxide in the urea-based selective non-catalytic reduction process is linked to the conversion of NO by cyano species released from the process parent compounds. This conversion occurs within in temperature window between 850 and 1050℃. With urea injection, nitrous oxide emissions represent up to 20 percent conversion of the NOx reduced. The amount of nitrous oxide formed depends primarily on the process temperature, the amount of chemical injected, the initial NOx level, and the carbon monoxide level in the gas stream. These observations, which were based on the chemical kinetics of the process, should be considered in designing selective non-catalytic reduction systems to minimize nitrous oxide by- product formation.展开更多
Photoelectrocatalysis(PEC)is a promising approach that can convert renewable solar energy into chemical energy,while most concern is concentrated on PEC water splitting to obtain high‐value‐added fuel—hydrogen.In p...Photoelectrocatalysis(PEC)is a promising approach that can convert renewable solar energy into chemical energy,while most concern is concentrated on PEC water splitting to obtain high‐value‐added fuel—hydrogen.In practice,more economic benefits can be produced based on PEC technique,such as H_(2)O oxidative H_(2)O_(2) synthesis,organic selective oxidation,organic pollutants degradation and CO_(2) reduction.Although there are plenty of excellent reviews focusing on the PEC water splitting system,the production of various high‐value‐added chemicals in PEC systems has not been discussed synthetically.This Account will focus on the production process of various high‐value‐added chemicals through PEC technology.The photoelectrode design,reaction environment and working mechanisms of PEC systems are also discussed in detail.We believe that this comprehensive Account of the expanded application of photoelectrocatalysis can add an inestimable impetus to the follow‐up development of this technology.展开更多
Simultaneous functionalization and reduction of graphene oxide （GO） is realized by refluxing of GO suspension with polyetheramine （D2000） followed by thermal treatment at 120℃. Compared to GO, the D2000-treated ...Simultaneous functionalization and reduction of graphene oxide （GO） is realized by refluxing of GO suspension with polyetheramine （D2000） followed by thermal treatment at 120℃. Compared to GO, the D2000-treated GO （GO- D2000） becomes hydrophobic, thermally stable and highly conductive with an electrical conductivity of 11 S/m, which is almost 8 orders of magnitude higher than that of GO. Due to the high conductivity and improved dispersion of GO-D2000, its epoxy nanocomposites exhibit a sharp transition from electrically insulating to conducting with a low percolation threshold of 0.71 vol%. With 3.6 wt% GO-D2000, the glass transition temperature of the epoxy nanocomposite is 27 K higher than that of neat epoxy.展开更多
Sairme mineral water, one of the famous mineral waters in Georgia, is renowned for its exceptional healing properties. The distinctiveness and therapeutic benefits of the naturally sourced mineral water, known as “Sa...Sairme mineral water, one of the famous mineral waters in Georgia, is renowned for its exceptional healing properties. The distinctiveness and therapeutic benefits of the naturally sourced mineral water, known as “Sairme”, stem from its rich array of microelements, notably including iron and manganese. Since 1948, the bottling of Sairme mineral water has been a prominent activity. Named after the Sairme deposit, this mineral water is packaged in various formats to cater to diverse consumer preferences. The bottling process involves transporting the mineral water from wells to the bottling plant through pipelines. Prior to bottling, the mineral water undergoes meticulous processing stages in adherence to current Georgian and international regulations. This process ensures that the concentration of trace elements in the bottled water is minimized, maintaining its purity and quality. Given the importance of preserving the microelements present in bottled mineral water, our research is dedicated to optimizing the technological process. Our objective is to safeguard the valuable microelements while ensuring the highest standards of quality and safety in the final product.展开更多
Following consideration of the characteristics of high temperature,high pressure and high in-situ stress in ultradeep sedimentary basins,together with the existence of hydrocarbon phase state transformation,hydrocarbo...Following consideration of the characteristics of high temperature,high pressure and high in-situ stress in ultradeep sedimentary basins,together with the existence of hydrocarbon phase state transformation,hydrocarbon-water-rock interaction and rock mechanical property transition at those depths,the evaluation index system for hydrocarbon preservation was established.The physical leakage evaluation indexes can be divided into three categories:the dynamic efficiency indexes of micro-sealing,caprock integrity and natural gas diffusion.The chemical loss evaluation indexes can be divided into two categories:the thermochemical sulfate reduction(TSR)index in marine gypsum-bearing carbonate strata and the thermochemical oxidation of hydrocarbons(TOH)index in clastic strata.The slippage angle and overconsolidation ratio(OCR)are the key evaluation indexes in the evaluation of the integrity of shale caprocks.TSR intensity can be quantitatively calculated by use of the Zn PVT state parameter method.The TOH strength can be used to estimate the degree of hydrocarbon chemical loss,based on the TOH-related authigenic calcite cement content or the degree of negativeδ^(13)C of authigenic calcite.For the evaluation of ultra-deep preservation in specific areas,key indexes can be selected according to the local geological conditions,instead of all indexes needing to be evaluated for every scenario.展开更多
Coal,a carbon-rich mineral with plentiful reserves,serves not only as a fuel but also as a raw material,presenting lower pollution emissions in the latter use.From a materials chemistry standpoint,coal is a viable raw...Coal,a carbon-rich mineral with plentiful reserves,serves not only as a fuel but also as a raw material,presenting lower pollution emissions in the latter use.From a materials chemistry standpoint,coal is a viable raw material for graphene production.This study develops a promising and sustainable method to convert coal into graphene,leveraging its unique macromolecular aromatic struc-ture and high carbon content.The investigation includes an analysis of the lateral size,morphology,and chemical composition of coal-derived graphene using techniques such as X-ray diffraction,Raman spectroscopy,X-ray photoelectron spectroscopy,and op-tical microscopy.Results confirm that coal can effectively replace natural graphite flakes in graphene production,with the derived graphene featuring three to six exfoliated layers and an oxygen content below 5.5%.While the graphene from coal shares a similar morphology to that derived from graphite,it exhibits more structural defects.Interestingly,the macroscopic size of the coal does not influence the microscopic composition and structure of the graphene.However,the thermal reduction method for oxidized graphene proves more effective at repairing structural defects than chemical reduction.Employing coal-derived graphene as a supercapacitor electrode demonstrates excellent cycling stability and ultra-high capacitance storage capacity.The H-CG-325 shows the highest dis-charge area-specific capacitance across various current densities.At an increased current density of 10 A/g,the H-CG-325 maintains 80.6%of its initial capacitance of 79 F/g observed at 1 A/g.Electrochemical tests reveal that coal-based graphene holds significant potential as a supercapacitor material,indicating promising applications in energy storage and conversion.展开更多
文摘Nanoparticles of Fe<sub>3</sub>O<sub>4</sub> and Fe are chemically synthesized by reduction of Fe(acac)<sub>3</sub> using ascorbic acid in controlled condition. It was observed that addition of water during the chemical synthesis process yields Fe3O4 nanoparticles, whereas if the reaction is carried out in absence of water yields Fe nanoparticles—which get oxidized upon exposure to air atmosphere. Fe<sub>3</sub>O<sub>4</sub> (15 ± 5 nm) and Fe/iron oxide nanoparticles (7 ± 1 nm) were successfully synthesized in the comparative study reported herewith. Mechanism for formation/synthesis of Fe<sub>3</sub>O<sub>4</sub> and Fe/iron oxide nanoparticles is proposed herewith in which added water acts as an oxygen supplier. Physico-chemical characterization done by SEM, TEM, EDAX, and XPS supports the proposed mechanism.
文摘Nitrous oxide is not an environmentally regulated species in the U.S., but it does participate in the stratospheric ozone chemistry and contributes to the greenhouse effect. Nitrous oxide has been found to be a by-product of the selective non-catalytic reduction process. Chemical kinetic calculations demonstrated that the formation of nitrous oxide in the urea-based selective non-catalytic reduction process is linked to the conversion of NO by cyano species released from the process parent compounds. This conversion occurs within in temperature window between 850 and 1050℃. With urea injection, nitrous oxide emissions represent up to 20 percent conversion of the NOx reduced. The amount of nitrous oxide formed depends primarily on the process temperature, the amount of chemical injected, the initial NOx level, and the carbon monoxide level in the gas stream. These observations, which were based on the chemical kinetics of the process, should be considered in designing selective non-catalytic reduction systems to minimize nitrous oxide by- product formation.
文摘Photoelectrocatalysis(PEC)is a promising approach that can convert renewable solar energy into chemical energy,while most concern is concentrated on PEC water splitting to obtain high‐value‐added fuel—hydrogen.In practice,more economic benefits can be produced based on PEC technique,such as H_(2)O oxidative H_(2)O_(2) synthesis,organic selective oxidation,organic pollutants degradation and CO_(2) reduction.Although there are plenty of excellent reviews focusing on the PEC water splitting system,the production of various high‐value‐added chemicals in PEC systems has not been discussed synthetically.This Account will focus on the production process of various high‐value‐added chemicals through PEC technology.The photoelectrode design,reaction environment and working mechanisms of PEC systems are also discussed in detail.We believe that this comprehensive Account of the expanded application of photoelectrocatalysis can add an inestimable impetus to the follow‐up development of this technology.
基金financially supported by the National Natural Science Foundation of China(Nos.51125010 and 51221002)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20100010110006)
文摘Simultaneous functionalization and reduction of graphene oxide （GO） is realized by refluxing of GO suspension with polyetheramine （D2000） followed by thermal treatment at 120℃. Compared to GO, the D2000-treated GO （GO- D2000） becomes hydrophobic, thermally stable and highly conductive with an electrical conductivity of 11 S/m, which is almost 8 orders of magnitude higher than that of GO. Due to the high conductivity and improved dispersion of GO-D2000, its epoxy nanocomposites exhibit a sharp transition from electrically insulating to conducting with a low percolation threshold of 0.71 vol%. With 3.6 wt% GO-D2000, the glass transition temperature of the epoxy nanocomposite is 27 K higher than that of neat epoxy.
文摘Sairme mineral water, one of the famous mineral waters in Georgia, is renowned for its exceptional healing properties. The distinctiveness and therapeutic benefits of the naturally sourced mineral water, known as “Sairme”, stem from its rich array of microelements, notably including iron and manganese. Since 1948, the bottling of Sairme mineral water has been a prominent activity. Named after the Sairme deposit, this mineral water is packaged in various formats to cater to diverse consumer preferences. The bottling process involves transporting the mineral water from wells to the bottling plant through pipelines. Prior to bottling, the mineral water undergoes meticulous processing stages in adherence to current Georgian and international regulations. This process ensures that the concentration of trace elements in the bottled water is minimized, maintaining its purity and quality. Given the importance of preserving the microelements present in bottled mineral water, our research is dedicated to optimizing the technological process. Our objective is to safeguard the valuable microelements while ensuring the highest standards of quality and safety in the final product.
基金financially supported by the National Key R&D Program of China(Grant No.2017YFC0603105)。
文摘Following consideration of the characteristics of high temperature,high pressure and high in-situ stress in ultradeep sedimentary basins,together with the existence of hydrocarbon phase state transformation,hydrocarbon-water-rock interaction and rock mechanical property transition at those depths,the evaluation index system for hydrocarbon preservation was established.The physical leakage evaluation indexes can be divided into three categories:the dynamic efficiency indexes of micro-sealing,caprock integrity and natural gas diffusion.The chemical loss evaluation indexes can be divided into two categories:the thermochemical sulfate reduction(TSR)index in marine gypsum-bearing carbonate strata and the thermochemical oxidation of hydrocarbons(TOH)index in clastic strata.The slippage angle and overconsolidation ratio(OCR)are the key evaluation indexes in the evaluation of the integrity of shale caprocks.TSR intensity can be quantitatively calculated by use of the Zn PVT state parameter method.The TOH strength can be used to estimate the degree of hydrocarbon chemical loss,based on the TOH-related authigenic calcite cement content or the degree of negativeδ^(13)C of authigenic calcite.For the evaluation of ultra-deep preservation in specific areas,key indexes can be selected according to the local geological conditions,instead of all indexes needing to be evaluated for every scenario.
基金sponsored by the China Energy Investment Corporation under grant no.GJNY-21-85.
文摘Coal,a carbon-rich mineral with plentiful reserves,serves not only as a fuel but also as a raw material,presenting lower pollution emissions in the latter use.From a materials chemistry standpoint,coal is a viable raw material for graphene production.This study develops a promising and sustainable method to convert coal into graphene,leveraging its unique macromolecular aromatic struc-ture and high carbon content.The investigation includes an analysis of the lateral size,morphology,and chemical composition of coal-derived graphene using techniques such as X-ray diffraction,Raman spectroscopy,X-ray photoelectron spectroscopy,and op-tical microscopy.Results confirm that coal can effectively replace natural graphite flakes in graphene production,with the derived graphene featuring three to six exfoliated layers and an oxygen content below 5.5%.While the graphene from coal shares a similar morphology to that derived from graphite,it exhibits more structural defects.Interestingly,the macroscopic size of the coal does not influence the microscopic composition and structure of the graphene.However,the thermal reduction method for oxidized graphene proves more effective at repairing structural defects than chemical reduction.Employing coal-derived graphene as a supercapacitor electrode demonstrates excellent cycling stability and ultra-high capacitance storage capacity.The H-CG-325 shows the highest dis-charge area-specific capacitance across various current densities.At an increased current density of 10 A/g,the H-CG-325 maintains 80.6%of its initial capacitance of 79 F/g observed at 1 A/g.Electrochemical tests reveal that coal-based graphene holds significant potential as a supercapacitor material,indicating promising applications in energy storage and conversion.
