Slickwater fracturing fluids are widely used in the development of unconventional oil and gas resources due to the advantages of low cost,low formation damage and high drag reduction performance.However,their performa...Slickwater fracturing fluids are widely used in the development of unconventional oil and gas resources due to the advantages of low cost,low formation damage and high drag reduction performance.However,their performance is severely affected at high temperatures.Drag reducing agent is the key to determine the drag reducing performance of slickwater.In this work,in order to further improve the temperature resistance of slickwater,a temperature-resistant polymeric drag reducing agent(PDRA)was synthesized and used as the basis for preparing the temperature-resistant slickwater.The slickwater system was prepared with the compositions of 0.2 wt%PDRA,0.05 wt%drainage aid nonylphenol polyoxyethylene ether phosphate(NPEP)and 0.5 wt%anti-expansion agent polyepichlorohydrindimethylamine(PDM).The drag reduction ability,rheology properties,temperature and shear resistance ability,and core damage property of slickwater were systematically studied and evaluated.In contrast to on-site drag reducing agent(DRA)and HPAM,the temperature-resistant slickwater demonstrates enhanced drag reduction efficacy at 90℃,exhibiting superior temperature and shear resistance ability.Notably,the drag reduction retention rate for the slickwater achieved an impressive 90.52%after a 30-min shearing period.Additionally,the core damage is only 5.53%.We expect that this study can broaden the application of slickwater in high-temperature reservoirs and provide a theoretical basis for field applications.展开更多
Due to the low water-cement ratio of ultra-high-performance concrete(UHPC),fluidity and shrinkage cracking are key aspects determining the performance and durability of this type of concrete.In this study,the effects ...Due to the low water-cement ratio of ultra-high-performance concrete(UHPC),fluidity and shrinkage cracking are key aspects determining the performance and durability of this type of concrete.In this study,the effects of different types of cementitious materials,chemical shrinkage-reducing agents(SRA)and steel fiber(SF)were assessed.Compared with M2-UHPC and M3-UHPC,M1-UHPC was found to have better fluidity and shrinkage cracking performance.Moreover,different SRA incorporation methods,dosage and different SF types and aspect ratios were implemented.The incorporation of SRA and SF led to a decrease in the fluidity of UHPC.SRA internal content of 1%(NSRA-1%),SRA external content of 1%(WSRA-1%),STS-0.22 and STE-0.7 decreased the fluidity of UHPC by 3.3%,8.3%,9.2%and 25%,respectively.However,SRA and SF improved the UHPC shrinkage cracking performance.NSRA-1%and STE-0.7 reduced the shrinkage value of UHPC by 40%and 60%,respectively,and increased the crack resistance by 338%and 175%,respectively.In addition,the addition of SF was observed to make the microstructure of UHPC more compact,and the compressive strength and flexural strength of 28 d were increased by 26.9%and 19.9%,respectively.展开更多
The effect of reducing agents and surfactants on controlling the silver nanoplates was studied. Two reducing agents, trisodium citrate dehydrate (TSC) and potassium tartrate, were used to reduce the AgNO3 solution. In...The effect of reducing agents and surfactants on controlling the silver nanoplates was studied. Two reducing agents, trisodium citrate dehydrate (TSC) and potassium tartrate, were used to reduce the AgNO3 solution. In this redox system, polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS) and arabic gum were served as surfactants. The results showed that reducing agents and surfactants both act as the capping agent adhering to the certain facets of silver seeds to block this surface to grow. The relative intensity of reducing agents also takes an active part in influencing the growth rate and direction of silver seeds. It was also found that halides can accelerate the speed of Ostwald ripening by adding Cl?, Br? and I?into the aqueous and have some effects on the morphology of the nanoplates.展开更多
Beach titanomagnetite(TTM)provides a cheap alternative source of Fe and Ti,but this ore is difficult to process to make suitable concentrates for the blast furnace.Recently studies showed that it is feasible to separa...Beach titanomagnetite(TTM)provides a cheap alternative source of Fe and Ti,but this ore is difficult to process to make suitable concentrates for the blast furnace.Recently studies showed that it is feasible to separate Fe and Ti by coal-based direct reduction.In this study,beach TTM was selected as the research object,the effects of reducing agents on reducing atmosphere in coal-based direct reduction of beach TTM were analyzed,and the role of volatiles was also studied.The results showed that when bitumite and coke were used as reducing agents of TTM,the CO produced from volatiles was involved in the reduction reaction,and the generated CO_(2) provided the raw material for the reaction of TTM.The reduction effect of bitumite was better than that of coke.The reason is that bitumite+TTM had a higher gas generation rate and produced a higher CO partial pressure,while coke+TTM had a lower gas generation rate and produced a lower CO partial pressure.When graphite was used as a reducing agent,there was a solid-solid reaction in the early stage in the reaction.With the continuous accumulation of CO_(2),the Boudouad reaction started and accelerated.Graphite+TTM also produced a higher CO partial pressure.展开更多
The increasing consumption of plastics inevitably results in increasing amounts of waste plastics. Because of their long degradation periods, these wastes negatively affect the natural environment. Numerous studies ha...The increasing consumption of plastics inevitably results in increasing amounts of waste plastics. Because of their long degradation periods, these wastes negatively affect the natural environment. Numerous studies have been conducted to recycle and eliminate waste plastics. The potential for recycling waste plastics in the iron and steel industry has been underestimated; the high C and H contents of plastics may make them suitable as alternative reductants in the reduction process of iron ore. This study aims to substitute plastic wastes for coal in reduction melting process and to investigate their performance during reduction at high temperature. We used a common type of waste plastic, polyethylene terephthalate （PET）, because of its high carbon and hydrogen contents. Composite pellets containing PET wastes, coke, and magnetite iron ore were reduced at selected temperatures of 1400 and 1450℃ for reduction time from 2 to 10 min to investigate the reduction melting behavior of these pellets. The results showed that an increased temperature and reduction time increased the reduction ratio of the pellets. The optimum experimental conditions for obtaining metallic iron （iron nuggets） were reduction at 1450℃ for 10 min using composite pellets containing 60% PET and 40% coke.展开更多
A new chitosan-supported borohydride reducing reagent (CBER) was prepared by treatment of KBH4 with the resin of chitosan derivative, which was first synthesized from: the reaction of cross-linked chitosan microsphere...A new chitosan-supported borohydride reducing reagent (CBER) was prepared by treatment of KBH4 with the resin of chitosan derivative, which was first synthesized from: the reaction of cross-linked chitosan microsphere with glycidyl trimethylammonium chloride. CBER could reduce aromatic carbonyl compound to corresponding alcohol.展开更多
The effects of Na_(2)MoO_(4) and Na_(2)B_(4)O_(7) on corrosion behavior of Q235 steel in resistance reducing agent(RRA)containing sodium bentonite were studied by mass loss,scanning electron microscopy and electrochem...The effects of Na_(2)MoO_(4) and Na_(2)B_(4)O_(7) on corrosion behavior of Q235 steel in resistance reducing agent(RRA)containing sodium bentonite were studied by mass loss,scanning electron microscopy and electrochemical measurement.The results showed that both the independent and mixed additions of Na_(2)MoO_(4) and/or Na_(2)B_(4)O_(7),can reduce the corrosion rate of Q235 steel in RRA containing sodium bentonite.And the inhibition effect of Na_(2)MoO_(4) and/or Na_(2)B_(4)O_(7)increased with their dosage increase.With the same dosage,the inhibition efficiency of the mixed addition of Na_(2)MoO_(4) and Na_(2)B_(4)O_(7),was higher than that of their independent addition.The passivation effect of Q235 steel was easy to obtain in the RRA with the mixed addition of Na_(2)MoO_(4) and Na_(2)B_(4)O_(7).The optimized inhibitor for the RRA containing sodium bentonite was the mixture of Na_(2)B_(4)O_(7) and Na_(2)MoO_(4) with a total concentration of 1.5 wt.%.Furthermore,the increase in corrosion potential E_(corr) and the decrease in corrosion current density i_(cor) in carbon steel were one of the important criteria for the formation of passivation film.展开更多
Magnetic-silver nanostructures were synthesized via optimized chemical conditions, and their characteristics and cytotoxicity were compared as candidates for the magnetic delivery of silver nanoparticles toward cancer...Magnetic-silver nanostructures were synthesized via optimized chemical conditions, and their characteristics and cytotoxicity were compared as candidates for the magnetic delivery of silver nanoparticles toward cancer cells. Magnetic-silver nanostructures were prepared through the reduction of silver ions in the presence of iron oxide nanoparticles using three different reducing agents （glucose, maltose and sodium citrate）. Their physicochemical characteristics were determined using ultraviolet-visible spectroscopy, X-ray diffraction analysis, transmission electron microscopy, selected area electron diffraction analysis, Fourier transformed infrared spectroscopy, atomic absorption spectroscopy, vibrating sample magnetometry and differential scanning calorimetry. Cytotoxic activities were evaluated against a human liver hepatocellular carcinoma cell line. Fabricated nanostructures, which exhibit differences in size, silver content, magnetic saturation value and cytotoxicity, represent sufficient superparamagnetic properties and considerable cytotoxicity to be suggested as effective tools in magnetic targeting of silver nanoparticles as an approach to cancer therapy.展开更多
Triphenylphosphine （TPP） was used as reducing agent to continuously generate the Cu（I） activator in copper（II）- catalyzed activators generated by electron transfer atom transfer radical polymerization （AGET ATR...Triphenylphosphine （TPP） was used as reducing agent to continuously generate the Cu（I） activator in copper（II）- catalyzed activators generated by electron transfer atom transfer radical polymerization （AGET ATRP）. For example, the polymers prepared with a molar ratio of [MMA]0/[EBiB]0/[CuC12]o/[PMDETA]0/[TPP]o = 500/1/0.1/0.5/0.5 had controlled molecular weights and low molecular weight distribution （Mw/Mn） values （-1.2）. TPP as a commercial reducing agent provides a convenient copper-catalyzed AGET ATRP procedure for the preparation of well-defined polymers.展开更多
Ovalbumin-stabilized gold nanoclusters （OVA@AuNCs） were prepared with ascorbic acid as a reducing agent. This strategy could realize the synthesis of water-soluble OVA@AuNCs within 20 min. The asprepared fluorescent...Ovalbumin-stabilized gold nanoclusters （OVA@AuNCs） were prepared with ascorbic acid as a reducing agent. This strategy could realize the synthesis of water-soluble OVA@AuNCs within 20 min. The asprepared fluorescent probe showed a red fluorescence emission at 630 nm. Moreover, the properties of the OVA@AuNCs were characterized by transmission electron microscope, dynamic light scattering, ultraviolet-visible spectroscopy, fluorescent spectroscopy. Based on the surface electron density decrease-induced fluorescence quenching mechanism, the OVA@AuNCs provided high sensitivity and selectivity for sensing copper ions. A good linear relationship was obtained between the fluorescence intensity of OVA@AuNCs and the concentration of copper ions in the range of 5.0-100.0pumol/L （R2z0.999） with a detection limit of 640 nmol/L. Furthermore, the rat serum copper contents were determined by using the OVA@AuNCs based assay, indicating great potential of fluorescent probes for application in biological and clinical analysis.展开更多
Electroless deposition has been used to deposit Ni-P films on glass slides using the reducing agent sodium hypophosphite. This has been done with a purpose to use Ni-P films as back contact for silicon carbide radiati...Electroless deposition has been used to deposit Ni-P films on glass slides using the reducing agent sodium hypophosphite. This has been done with a purpose to use Ni-P films as back contact for silicon carbide radiation detectors. By keeping deposition time, temperature, pH and concentration of the precursor solution constant, the film deposition has been done. XPS studies were done to analyze the composition and stoichiometry of Ni-P thin films.展开更多
Cu2O@Cu2O core-shell nanoparticles (NPs) were prepared by using solution phase strategy. It was found that Cu2O@Cu2O NPs were easily converted to Cu2O@Cu NPs with the help of polyvinylpyrrolidine (PVP) and excessive a...Cu2O@Cu2O core-shell nanoparticles (NPs) were prepared by using solution phase strategy. It was found that Cu2O@Cu2O NPs were easily converted to Cu2O@Cu NPs with the help of polyvinylpyrrolidine (PVP) and excessive ascorbic acid (AA) in air at room temperature, which was an interesting phenomenon. The features of the two kinds of NPs were characterized by XRD, TEM and extinction spectra. Cu2O@Cu NPs with different shell thicknesses showed wide tunable optical properties for the localized surface plasmon (LSP) in metallic Cu. But Cu2O@Cu2O NPs did not indicate this feature. FTIR results reveal that Cu+ ions on the surface of Cu2O shell coordinate with N and O atoms in PVP and are further reduced to metallic Cu by excessive AA and then form a nucleation site on the surface of Cu2O nanocrystalline. PVP binds onto different sites to proceed with the reduction utill all the Cu sources in Cu2O shell are completely assumed.展开更多
As one of the most important components of the vanadium redox flow battery （VRFB）, the electrolyte can impose a significant impact on cell properties, performance and capital cost. In particular, the electrolyte com...As one of the most important components of the vanadium redox flow battery （VRFB）, the electrolyte can impose a significant impact on cell properties, performance and capital cost. In particular, the electrolyte composition will influence energy density, operating temperature range and the practical applications of the VRFB. Various approaches to increase the energy density and operating temperature range have been proposed. The presence of electrolyte impurities, or the addition of a small amount of other chemical species into the vanadium solution can alter the stability of the electrolyte and influence cell perfor- mance, operating temperature range, energy density, electrochemical kinetics and cost effectiveness. This review provides a detailed overview of research on electrolyte additives including stabilizing agents, im- mobilizing agents, kinetic enhancers, as well as electrolyte impurities and chemical reductants that can be used for different purposes in the VRFBs.展开更多
Two different kinds of black liquor from the papermaking industry were treated by acidification and reuse. The experimental parameters and conditions were discussed in detail. The experimental results indicated that t...Two different kinds of black liquor from the papermaking industry were treated by acidification and reuse. The experimental parameters and conditions were discussed in detail. The experimental results indicated that the treatment process mentioned in this article is an effective process for the treatment of black liquor from the papermaking industry. By the treatment, the solid materials in black liquor are transferred into two by products and the other components are reused or evaporated. Thus, no wastewater except some condensation water would be discharged in pulping process and the problem of pollution of black liquor would be effectively solved.展开更多
The present research was conducted to extract keratin protein from chicken feathers. Protein is an important nutrient needed by our body to maintain body structures and is an important ingredient for cosmetic products...The present research was conducted to extract keratin protein from chicken feathers. Protein is an important nutrient needed by our body to maintain body structures and is an important ingredient for cosmetic products. Chicken feathers have high level of keratin protein content and can become a suitable protein source. The main processes involved are first dissolving chicken feathers using different reducing agents and later on separating the protein from chemicals. Reducing agents used are potassium cyanide, thioglycolic acid and sodium sulphide. Once the feathers are dissolved using reducing agents, ammonium sulfate solution is added to the solution for the precipitation of protein. The precipitated protein is washed with water several times and sodium hydroxide solution is used to obtain protein back in the solution form. Out of three different reducing agents used, sodium sulfide gives the highest efficiency in dissolving chicken feathers since the feathers are dissolved in a very short period of time. The percentage of keratin protein is evaluated by means of biuret test and FTIR analysis. The analysis by FTIR confirmed the presence of carboxyl acid and amino groups in the protein solution. The biuret test helps in determining the concentration of protein obtained from different methods. Thus these two tests confirm the presence of protein in the solution. From this research, it can be concluded that protein can be extracted from chicken feathers. The keratin protein solution can be used for several purposes such as anti-aging cream, shampoo, and conditioner and for medical purposes such as bone replacement and bone graft.展开更多
Aromatic nitro compounds are reduced to correspouding amiues in ethanol by borohydride exchauge resin(BER)in the presence of transition metal Pd,Co,Ni,Cu)compounds as catalysts.
In oilfield fracturing construction, to solve the technical problems such as poor dissolution effect and long dissolution time of polymer drag reducer powder, the rheological regulator, phase transfer agent, organic s...In oilfield fracturing construction, to solve the technical problems such as poor dissolution effect and long dissolution time of polymer drag reducer powder, the rheological regulator, phase transfer agent, organic solvent, and drag reducer powder were compounded to prepare a drag reducer emulsion that was soluble in water. The stability of the drag reducer emulsion was observed at room temperature for 90 days. The effects of the rheological regulator, phase transfer agent, and organic solvent on the stability and solubility of the drag reducer emulsion were studied. The dissolution time, dissolution effect, viscosity of the aqueous solution, and drag reduction performance of the drag reducer emulsion were evaluated. The results show the stability rate of the drag reducer emulsion prepared by MOST-1 rheological regulator, BHJ-8 and BHJ-6 compound phase inversion agent, ethylene glycol ether and 120 - 140 mesh powder can reach 97% at room temperature for 90 days. Compared with the drag reducer powder, when the aqueous solution concentration is 0.1%, the dissolution time is only 28 s, the viscosity can be increased by 30%, and the drag reduction rate can be increased by up to 8%.展开更多
A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-co...A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-cobalt oxide ore was carried out by mixing the sample with sulphuric acid followed by baking of the mixture in a muffle furnace. Baking tests were conducted at different conditions such as temperature, time, and varying amounts of acid. The reacted samples were then subjected to water leaching at room temperature to determine the leachability of copper and cobalt from the baked material. The dissolutions of copper and cobalt were dependent on acid concentration with cobalt showing more sensitivity to the amount of acid. Both copper and cobalt were extracted from the baked material within short leaching times and without the addition of reducing agents. The outcome of this work has shown that the sulphuric acid bake-leach process is a possible alternative to the reductive leaching method for copper-cobalt oxide ores.展开更多
A comprehensive investigation on the formation mechanism of gold nanoparticles (AuNPs) in colloidal mixture obtained from the reduction of chloroauric acid (HAuCl4) solution using a single reducing agent (sodium citra...A comprehensive investigation on the formation mechanism of gold nanoparticles (AuNPs) in colloidal mixture obtained from the reduction of chloroauric acid (HAuCl4) solution using a single reducing agent (sodium citrate;process-I), (tannic acid;process-II), and a combination of two reducing agents (sodium citrate plus tannic acid;process-III) is reported. The growth steps at different time intervals during synthesis of colloidal AuNPs were monitored in situ and ex situ using various methods for all the three processes. The measurement of changes in the surface plasmon band position of colloidal AuNPs, along with dynamic light scattering results gave important information for the first assessing of particle size, shape and distribution. Besides, the size and morphological changes at different stages during different processes were also analyzed by transmission electron microscopy. The final Au particles of processes-I & II exhibited different shapes (spherical and nanowires) with particle size and nano wire diameter of 12 nm and 17 nm, respectively. Nevertheless, combination of two reductants (process-III) surprisingly leads to drastically reduced size (ca. 3 nm) with spherical morphology compared to their parent solutions with either of single reducing agent. This result clearly indicates that the combination of reductants has a significant influence on the particle size, morphology and formation mechanism.展开更多
Herein,we have presented a novel and easy to operate seed-mediated system for fabricating gold bipyramids(AuBPs)with 85%yields without any separation/purification processes.The used gold seeds are reduced by tannin an...Herein,we have presented a novel and easy to operate seed-mediated system for fabricating gold bipyramids(AuBPs)with 85%yields without any separation/purification processes.The used gold seeds are reduced by tannin and citrate,two kinds of air stable ligands,and conventio nally employed unstable NaBH4 are thoroughly cast off.In addition,the as-proposed gold seeds can also be employed for AuNRs fabrication with rather larger diameters(22.2-60.3 nm),which is difficult to be achieved by conve ntional seed mediated fabrication system.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52222403,52074333,52120105007)Taishan Scholar Young Expert(No.tsqn202211079)。
文摘Slickwater fracturing fluids are widely used in the development of unconventional oil and gas resources due to the advantages of low cost,low formation damage and high drag reduction performance.However,their performance is severely affected at high temperatures.Drag reducing agent is the key to determine the drag reducing performance of slickwater.In this work,in order to further improve the temperature resistance of slickwater,a temperature-resistant polymeric drag reducing agent(PDRA)was synthesized and used as the basis for preparing the temperature-resistant slickwater.The slickwater system was prepared with the compositions of 0.2 wt%PDRA,0.05 wt%drainage aid nonylphenol polyoxyethylene ether phosphate(NPEP)and 0.5 wt%anti-expansion agent polyepichlorohydrindimethylamine(PDM).The drag reduction ability,rheology properties,temperature and shear resistance ability,and core damage property of slickwater were systematically studied and evaluated.In contrast to on-site drag reducing agent(DRA)and HPAM,the temperature-resistant slickwater demonstrates enhanced drag reduction efficacy at 90℃,exhibiting superior temperature and shear resistance ability.Notably,the drag reduction retention rate for the slickwater achieved an impressive 90.52%after a 30-min shearing period.Additionally,the core damage is only 5.53%.We expect that this study can broaden the application of slickwater in high-temperature reservoirs and provide a theoretical basis for field applications.
基金the Key Research and Development Program of Hubei Province(2022BCA082 and 2022BCA077).
文摘Due to the low water-cement ratio of ultra-high-performance concrete(UHPC),fluidity and shrinkage cracking are key aspects determining the performance and durability of this type of concrete.In this study,the effects of different types of cementitious materials,chemical shrinkage-reducing agents(SRA)and steel fiber(SF)were assessed.Compared with M2-UHPC and M3-UHPC,M1-UHPC was found to have better fluidity and shrinkage cracking performance.Moreover,different SRA incorporation methods,dosage and different SF types and aspect ratios were implemented.The incorporation of SRA and SF led to a decrease in the fluidity of UHPC.SRA internal content of 1%(NSRA-1%),SRA external content of 1%(WSRA-1%),STS-0.22 and STE-0.7 decreased the fluidity of UHPC by 3.3%,8.3%,9.2%and 25%,respectively.However,SRA and SF improved the UHPC shrinkage cracking performance.NSRA-1%and STE-0.7 reduced the shrinkage value of UHPC by 40%and 60%,respectively,and increased the crack resistance by 338%and 175%,respectively.In addition,the addition of SF was observed to make the microstructure of UHPC more compact,and the compressive strength and flexural strength of 28 d were increased by 26.9%and 19.9%,respectively.
基金Project(51373097)supported by The National Natural Science Foundation of China
文摘The effect of reducing agents and surfactants on controlling the silver nanoplates was studied. Two reducing agents, trisodium citrate dehydrate (TSC) and potassium tartrate, were used to reduce the AgNO3 solution. In this redox system, polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS) and arabic gum were served as surfactants. The results showed that reducing agents and surfactants both act as the capping agent adhering to the certain facets of silver seeds to block this surface to grow. The relative intensity of reducing agents also takes an active part in influencing the growth rate and direction of silver seeds. It was also found that halides can accelerate the speed of Ostwald ripening by adding Cl?, Br? and I?into the aqueous and have some effects on the morphology of the nanoplates.
基金Project(52104257)supported by the National Natural Science Foundation of China。
文摘Beach titanomagnetite(TTM)provides a cheap alternative source of Fe and Ti,but this ore is difficult to process to make suitable concentrates for the blast furnace.Recently studies showed that it is feasible to separate Fe and Ti by coal-based direct reduction.In this study,beach TTM was selected as the research object,the effects of reducing agents on reducing atmosphere in coal-based direct reduction of beach TTM were analyzed,and the role of volatiles was also studied.The results showed that when bitumite and coke were used as reducing agents of TTM,the CO produced from volatiles was involved in the reduction reaction,and the generated CO_(2) provided the raw material for the reaction of TTM.The reduction effect of bitumite was better than that of coke.The reason is that bitumite+TTM had a higher gas generation rate and produced a higher CO partial pressure,while coke+TTM had a lower gas generation rate and produced a lower CO partial pressure.When graphite was used as a reducing agent,there was a solid-solid reaction in the early stage in the reaction.With the continuous accumulation of CO_(2),the Boudouad reaction started and accelerated.Graphite+TTM also produced a higher CO partial pressure.
基金financially supported by Yildiz Technical University Scientific Research Projects Coordination Department (No. 2011-07-02-KAP02)
文摘The increasing consumption of plastics inevitably results in increasing amounts of waste plastics. Because of their long degradation periods, these wastes negatively affect the natural environment. Numerous studies have been conducted to recycle and eliminate waste plastics. The potential for recycling waste plastics in the iron and steel industry has been underestimated; the high C and H contents of plastics may make them suitable as alternative reductants in the reduction process of iron ore. This study aims to substitute plastic wastes for coal in reduction melting process and to investigate their performance during reduction at high temperature. We used a common type of waste plastic, polyethylene terephthalate （PET）, because of its high carbon and hydrogen contents. Composite pellets containing PET wastes, coke, and magnetite iron ore were reduced at selected temperatures of 1400 and 1450℃ for reduction time from 2 to 10 min to investigate the reduction melting behavior of these pellets. The results showed that an increased temperature and reduction time increased the reduction ratio of the pellets. The optimum experimental conditions for obtaining metallic iron （iron nuggets） were reduction at 1450℃ for 10 min using composite pellets containing 60% PET and 40% coke.
基金the National Natural Science Foundation of China (No.29977014).
文摘A new chitosan-supported borohydride reducing reagent (CBER) was prepared by treatment of KBH4 with the resin of chitosan derivative, which was first synthesized from: the reaction of cross-linked chitosan microsphere with glycidyl trimethylammonium chloride. CBER could reduce aromatic carbonyl compound to corresponding alcohol.
基金support of Foundation of Science and Technology of State Grid(5216AJ20000U)Hunan Provincial Key R&D Program of China(2021GK2008).
文摘The effects of Na_(2)MoO_(4) and Na_(2)B_(4)O_(7) on corrosion behavior of Q235 steel in resistance reducing agent(RRA)containing sodium bentonite were studied by mass loss,scanning electron microscopy and electrochemical measurement.The results showed that both the independent and mixed additions of Na_(2)MoO_(4) and/or Na_(2)B_(4)O_(7),can reduce the corrosion rate of Q235 steel in RRA containing sodium bentonite.And the inhibition effect of Na_(2)MoO_(4) and/or Na_(2)B_(4)O_(7)increased with their dosage increase.With the same dosage,the inhibition efficiency of the mixed addition of Na_(2)MoO_(4) and Na_(2)B_(4)O_(7),was higher than that of their independent addition.The passivation effect of Q235 steel was easy to obtain in the RRA with the mixed addition of Na_(2)MoO_(4) and Na_(2)B_(4)O_(7).The optimized inhibitor for the RRA containing sodium bentonite was the mixture of Na_(2)B_(4)O_(7) and Na_(2)MoO_(4) with a total concentration of 1.5 wt.%.Furthermore,the increase in corrosion potential E_(corr) and the decrease in corrosion current density i_(cor) in carbon steel were one of the important criteria for the formation of passivation film.
基金financially supported by Shiraz University of Medical Sciences,Shiraz,Iran(Grant Number92-6587)
文摘Magnetic-silver nanostructures were synthesized via optimized chemical conditions, and their characteristics and cytotoxicity were compared as candidates for the magnetic delivery of silver nanoparticles toward cancer cells. Magnetic-silver nanostructures were prepared through the reduction of silver ions in the presence of iron oxide nanoparticles using three different reducing agents （glucose, maltose and sodium citrate）. Their physicochemical characteristics were determined using ultraviolet-visible spectroscopy, X-ray diffraction analysis, transmission electron microscopy, selected area electron diffraction analysis, Fourier transformed infrared spectroscopy, atomic absorption spectroscopy, vibrating sample magnetometry and differential scanning calorimetry. Cytotoxic activities were evaluated against a human liver hepatocellular carcinoma cell line. Fabricated nanostructures, which exhibit differences in size, silver content, magnetic saturation value and cytotoxicity, represent sufficient superparamagnetic properties and considerable cytotoxicity to be suggested as effective tools in magnetic targeting of silver nanoparticles as an approach to cancer therapy.
基金financially supported by the National Natural Science Foundation of China(Nos.21404051 and 21404052)the Natural Science Foundation of Shandong Province(Nos.ZR2014BQ016 and BS2014CL040)+1 种基金the Talent Introduction Special Funds of Ludong University(Nos.2014012 and 2014017)the Program for Scientific Research Innovation Team in Colleges and Universities of Shandong Province and Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application(Soochow University)
文摘Triphenylphosphine （TPP） was used as reducing agent to continuously generate the Cu（I） activator in copper（II）- catalyzed activators generated by electron transfer atom transfer radical polymerization （AGET ATRP）. For example, the polymers prepared with a molar ratio of [MMA]0/[EBiB]0/[CuC12]o/[PMDETA]0/[TPP]o = 500/1/0.1/0.5/0.5 had controlled molecular weights and low molecular weight distribution （Mw/Mn） values （-1.2）. TPP as a commercial reducing agent provides a convenient copper-catalyzed AGET ATRP procedure for the preparation of well-defined polymers.
基金the financial support from the National Natural Science Foundation of China(Nos. 21575144, 21475137,21375132,21635008,21621062)Chinese Academy of Sciences(No. QYZDJ-SSW-SLH034)
文摘Ovalbumin-stabilized gold nanoclusters （OVA@AuNCs） were prepared with ascorbic acid as a reducing agent. This strategy could realize the synthesis of water-soluble OVA@AuNCs within 20 min. The asprepared fluorescent probe showed a red fluorescence emission at 630 nm. Moreover, the properties of the OVA@AuNCs were characterized by transmission electron microscope, dynamic light scattering, ultraviolet-visible spectroscopy, fluorescent spectroscopy. Based on the surface electron density decrease-induced fluorescence quenching mechanism, the OVA@AuNCs provided high sensitivity and selectivity for sensing copper ions. A good linear relationship was obtained between the fluorescence intensity of OVA@AuNCs and the concentration of copper ions in the range of 5.0-100.0pumol/L （R2z0.999） with a detection limit of 640 nmol/L. Furthermore, the rat serum copper contents were determined by using the OVA@AuNCs based assay, indicating great potential of fluorescent probes for application in biological and clinical analysis.
文摘Electroless deposition has been used to deposit Ni-P films on glass slides using the reducing agent sodium hypophosphite. This has been done with a purpose to use Ni-P films as back contact for silicon carbide radiation detectors. By keeping deposition time, temperature, pH and concentration of the precursor solution constant, the film deposition has been done. XPS studies were done to analyze the composition and stoichiometry of Ni-P thin films.
基金Projects(41172110,61107090)supported by the National Natural Science Foundation of China
文摘Cu2O@Cu2O core-shell nanoparticles (NPs) were prepared by using solution phase strategy. It was found that Cu2O@Cu2O NPs were easily converted to Cu2O@Cu NPs with the help of polyvinylpyrrolidine (PVP) and excessive ascorbic acid (AA) in air at room temperature, which was an interesting phenomenon. The features of the two kinds of NPs were characterized by XRD, TEM and extinction spectra. Cu2O@Cu NPs with different shell thicknesses showed wide tunable optical properties for the localized surface plasmon (LSP) in metallic Cu. But Cu2O@Cu2O NPs did not indicate this feature. FTIR results reveal that Cu+ ions on the surface of Cu2O shell coordinate with N and O atoms in PVP and are further reduced to metallic Cu by excessive AA and then form a nucleation site on the surface of Cu2O nanocrystalline. PVP binds onto different sites to proceed with the reduction utill all the Cu sources in Cu2O shell are completely assumed.
文摘As one of the most important components of the vanadium redox flow battery （VRFB）, the electrolyte can impose a significant impact on cell properties, performance and capital cost. In particular, the electrolyte composition will influence energy density, operating temperature range and the practical applications of the VRFB. Various approaches to increase the energy density and operating temperature range have been proposed. The presence of electrolyte impurities, or the addition of a small amount of other chemical species into the vanadium solution can alter the stability of the electrolyte and influence cell perfor- mance, operating temperature range, energy density, electrochemical kinetics and cost effectiveness. This review provides a detailed overview of research on electrolyte additives including stabilizing agents, im- mobilizing agents, kinetic enhancers, as well as electrolyte impurities and chemical reductants that can be used for different purposes in the VRFBs.
文摘Two different kinds of black liquor from the papermaking industry were treated by acidification and reuse. The experimental parameters and conditions were discussed in detail. The experimental results indicated that the treatment process mentioned in this article is an effective process for the treatment of black liquor from the papermaking industry. By the treatment, the solid materials in black liquor are transferred into two by products and the other components are reused or evaporated. Thus, no wastewater except some condensation water would be discharged in pulping process and the problem of pollution of black liquor would be effectively solved.
文摘The present research was conducted to extract keratin protein from chicken feathers. Protein is an important nutrient needed by our body to maintain body structures and is an important ingredient for cosmetic products. Chicken feathers have high level of keratin protein content and can become a suitable protein source. The main processes involved are first dissolving chicken feathers using different reducing agents and later on separating the protein from chemicals. Reducing agents used are potassium cyanide, thioglycolic acid and sodium sulphide. Once the feathers are dissolved using reducing agents, ammonium sulfate solution is added to the solution for the precipitation of protein. The precipitated protein is washed with water several times and sodium hydroxide solution is used to obtain protein back in the solution form. Out of three different reducing agents used, sodium sulfide gives the highest efficiency in dissolving chicken feathers since the feathers are dissolved in a very short period of time. The percentage of keratin protein is evaluated by means of biuret test and FTIR analysis. The analysis by FTIR confirmed the presence of carboxyl acid and amino groups in the protein solution. The biuret test helps in determining the concentration of protein obtained from different methods. Thus these two tests confirm the presence of protein in the solution. From this research, it can be concluded that protein can be extracted from chicken feathers. The keratin protein solution can be used for several purposes such as anti-aging cream, shampoo, and conditioner and for medical purposes such as bone replacement and bone graft.
文摘Aromatic nitro compounds are reduced to correspouding amiues in ethanol by borohydride exchauge resin(BER)in the presence of transition metal Pd,Co,Ni,Cu)compounds as catalysts.
文摘In oilfield fracturing construction, to solve the technical problems such as poor dissolution effect and long dissolution time of polymer drag reducer powder, the rheological regulator, phase transfer agent, organic solvent, and drag reducer powder were compounded to prepare a drag reducer emulsion that was soluble in water. The stability of the drag reducer emulsion was observed at room temperature for 90 days. The effects of the rheological regulator, phase transfer agent, and organic solvent on the stability and solubility of the drag reducer emulsion were studied. The dissolution time, dissolution effect, viscosity of the aqueous solution, and drag reduction performance of the drag reducer emulsion were evaluated. The results show the stability rate of the drag reducer emulsion prepared by MOST-1 rheological regulator, BHJ-8 and BHJ-6 compound phase inversion agent, ethylene glycol ether and 120 - 140 mesh powder can reach 97% at room temperature for 90 days. Compared with the drag reducer powder, when the aqueous solution concentration is 0.1%, the dissolution time is only 28 s, the viscosity can be increased by 30%, and the drag reduction rate can be increased by up to 8%.
文摘A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-cobalt oxide ore was carried out by mixing the sample with sulphuric acid followed by baking of the mixture in a muffle furnace. Baking tests were conducted at different conditions such as temperature, time, and varying amounts of acid. The reacted samples were then subjected to water leaching at room temperature to determine the leachability of copper and cobalt from the baked material. The dissolutions of copper and cobalt were dependent on acid concentration with cobalt showing more sensitivity to the amount of acid. Both copper and cobalt were extracted from the baked material within short leaching times and without the addition of reducing agents. The outcome of this work has shown that the sulphuric acid bake-leach process is a possible alternative to the reductive leaching method for copper-cobalt oxide ores.
文摘A comprehensive investigation on the formation mechanism of gold nanoparticles (AuNPs) in colloidal mixture obtained from the reduction of chloroauric acid (HAuCl4) solution using a single reducing agent (sodium citrate;process-I), (tannic acid;process-II), and a combination of two reducing agents (sodium citrate plus tannic acid;process-III) is reported. The growth steps at different time intervals during synthesis of colloidal AuNPs were monitored in situ and ex situ using various methods for all the three processes. The measurement of changes in the surface plasmon band position of colloidal AuNPs, along with dynamic light scattering results gave important information for the first assessing of particle size, shape and distribution. Besides, the size and morphological changes at different stages during different processes were also analyzed by transmission electron microscopy. The final Au particles of processes-I & II exhibited different shapes (spherical and nanowires) with particle size and nano wire diameter of 12 nm and 17 nm, respectively. Nevertheless, combination of two reductants (process-III) surprisingly leads to drastically reduced size (ca. 3 nm) with spherical morphology compared to their parent solutions with either of single reducing agent. This result clearly indicates that the combination of reductants has a significant influence on the particle size, morphology and formation mechanism.
基金the National Natural Science Foundation of China(No.21775004)Wanjiang Scholar Program。
文摘Herein,we have presented a novel and easy to operate seed-mediated system for fabricating gold bipyramids(AuBPs)with 85%yields without any separation/purification processes.The used gold seeds are reduced by tannin and citrate,two kinds of air stable ligands,and conventio nally employed unstable NaBH4 are thoroughly cast off.In addition,the as-proposed gold seeds can also be employed for AuNRs fabrication with rather larger diameters(22.2-60.3 nm),which is difficult to be achieved by conve ntional seed mediated fabrication system.
