In this study,an efficient stabilizer material for cadmium(Cd^(2+))treatment was successfully prepared by simply co-milling olivine with magnesite.Several analyticalmethods including XRD,TEM,SEM and FTIR,combined with...In this study,an efficient stabilizer material for cadmium(Cd^(2+))treatment was successfully prepared by simply co-milling olivine with magnesite.Several analyticalmethods including XRD,TEM,SEM and FTIR,combined with theoretical calculations(DFT),were used to investigate mechanochemical interfacial reaction between twominerals,and the reaction mechanism of Cd removal,with ion exchange between Cd^(2+)and Mg^(2+)as the main pathway.A fixation capacity of Cd^(2+)as high as 270.61 mg/g,much higher than that of the pristine minerals and even the individual/physical mixture of milled olivine and magnesite,has been obtained at optimized conditions,with a neutral pH value of the solution after treatment to allow its direct discharge.The as-proposed Mg-based stabilizer with various advantages such as cost benefits,green feature etc.,will boosts the utilization efficiency of naturalminerals over the elaborately prepared adsorbents.展开更多
Polydopamine-based melanin-like materials have been widely used in the fields of ultraviolet(UV)shielding,solar desalination and anti-inflammatory treatment owing to their unique physical properties.The well-establish...Polydopamine-based melanin-like materials have been widely used in the fields of ultraviolet(UV)shielding,solar desalination and anti-inflammatory treatment owing to their unique physical properties.The well-established synthesis of polydopamine nanoparticles involves the oxidative polymerization of dopamine-derived monomers,resulting in cross-linked nanostructures with high complexity and heterogeneity.Therefore,the controlled synthesis of polydopamine-based melanin-like materials with well-defined structures and predictable properties remains challenging.Herein,we propose a mechanochemical Suzuki polymerization approach for the synthesis of linear melanin-like polymers with tunable physical properties.Compared with polydopamine nanoparticles,the mechanochemical approach offers a more flexible chain-like structure,thereby enhancing its antioxidant performance.Furthermore,this approach also enables the preparation of a melanin-like alternating copolymer that exhibits green fluorescence owing to itsπ-conjugated structure.This study not only offers opportunities for exploring novel synthetic melanin materials,but also provides new insights into the structure-function relationships of polydopamine-based materials.展开更多
Recently,researchers have explored the use of precipitation strengthening and finer microstructures with high-density dislocations in additive manufacturing to produce high-entropy alloys(HEAs)with adjustable properti...Recently,researchers have explored the use of precipitation strengthening and finer microstructures with high-density dislocations in additive manufacturing to produce high-entropy alloys(HEAs)with adjustable properties.However,the inherent surface roughness and lack of machinability research in AMed HEAs limit their engineering applications.In this study,we systematically investigated the microstructural characteristics,mechanical properties,and machinability of Fe_(29.3)Co_(28.7)Ni_(28.6)Al_(6.8)Ti_(6.6)(at.%)HEAs with three different structures:single FCC phase cellular(SPC),dual precipitation-strengthened(DPS),and single precipitation-strengthened(SPS).These structures were fabricated by selective laser melting and isothermally annealing at 780 and 940℃.Compared to SPC HEA,DPS HEA exhibits a significant increase in yield strength and ultimate tensile strength but with a dramatic sacrifice in ductility.SPS HEA exhibits similar mechanical properties to SPC HEA due to the pronounced coarsening of L21 precipitates.The ultraprecision machining micro-cutting test showed that SPC HEA had a significant mechanochem-ical effect,as evidenced by a sharp drop in cutting force for inked workpieces,but not DPS HEA.An abnormal finding was that the negligible reflection of cutting force for SPS HEAs suggested a negative mechanochemical effect,even though SPS HEA had equally excellent plasticity like SPC HEA.It was found that nanocrystallization-induced strength enhancement and ductility reduction of SPS HEA lead to chips’deformation dominated by shear avalanche rather than chip folding of SPC HEA,which involves the reduction of surface energy and friction of chips’interfaces.Overall,these results and our research findings may guide the machining of AMed precipitation-strengthened HEAs and accelerate their engineering ap-plication.展开更多
Photocatalytic oxidation technology is a promising green technology for degrading volatile organic compounds(VOCs)due to its non-toxic,environmentally friendly,energy-saving and affordable characteristics.In this pape...Photocatalytic oxidation technology is a promising green technology for degrading volatile organic compounds(VOCs)due to its non-toxic,environmentally friendly,energy-saving and affordable characteristics.In this paper,Ag/TiO_(2)@PANI-MC with high stability and activity was synthesized by the mechanochemical method.The designed Ag/TiO_(2)@PANI-MC were of high specific surface area,light absorption capacity and low recombination rate of electronehole pairs,which was demonstrated by various characterizations.When applied in photocatalytic toluene oxidation,the conversion is 17%at 20℃under 100 W high-pressure mercury lamp.This photocatalytic performance is with less temperature sensitivity and significantly improved compared with Ag/TiO_(2)or TiO_(2)catalysts.Furthermore,the reaction routine was also confirmed by gas chromatography-mass spectrometry and toluene was mineralized to CO_(2).More importantly,the Ag/TiO_(2)@PANI-MC indicated good reusability after three cycles,which was verified by the Fourier transform-infrared spectroscopy comparison with fresh and used catalysts.Our work proves a potential way of constructing nanocomposites based on mechanochemical synthesis for enhanced toluene photocatalytic degradation.展开更多
Industrial-use VOx-based catalysts usually have a higher active temperature window (>250-300℃),which becomes a“bottleneck”for the practical application of PCDD/Fs catalytic degradation technology.In this work,VO...Industrial-use VOx-based catalysts usually have a higher active temperature window (>250-300℃),which becomes a“bottleneck”for the practical application of PCDD/Fs catalytic degradation technology.In this work,VO_(x)-FeO_(x)/TiO_(2) catalyst prepared via mechanochemically method was investigated for the catalytic removal of PCDD/Fs.The removal efficiency of 1,2-DCBz,pure PCDD/Fs gas generated in the lab,PCDD/Fs from actual fue gas,long-term were studied,and the degradation mechanism was explored using FTIR and TOFMS.The degradation efficiency of 1,2-DCBz and PCDD/Fs on VO_(x)-FeO_(x)/TiO_(2) were higher than that of VO_(x)/TiO_(2)catalyst,and the optimal FeOx addition ratio was 3 wt.%.The characterization results show that the addition of FeOx can effectively improve the pore structure,surface acidity,and VOx dispersion of the catalyst,thus contributing to increasing the V^(5+)content and surface-active oxygen,which is conducive to the improvement of adsorption and redox performance of the catalyst.Under the actual MSWI (municipal solid waste incineration)fue gas,the PCDD/Fs removal efficiency over VTi-3Fe-MC maintained long-term stability,higher than 85%for 240 min.This result was not significantly reduced compared with the data obtained in the laboratory.According to the analysis results of intermediate products by FTIR and GC-TOFMS,it can be inferred that the epoxidation fracture of benzene ring is the rate-limiting step of dioxin catalytic degradation reaction.This work gives an in-depth view into the PCDD/Fs removal over VO_(x)-FeO_(x)/TiO_(2) catalysts and could provide guidelines for the rational design of reliable catalysts for industrial applications.展开更多
Through the mechanochemical method,sulfamic acid(SA)is successfully introduced into UiO-66-NH_(2)to form SA@UiO-66-NH_(2).In SA@UiO-66-NH_(2),the acidic cationic sulfiliminium(—S=NH_(2)^(+))moiety formed by the bridg...Through the mechanochemical method,sulfamic acid(SA)is successfully introduced into UiO-66-NH_(2)to form SA@UiO-66-NH_(2).In SA@UiO-66-NH_(2),the acidic cationic sulfiliminium(—S=NH_(2)^(+))moiety formed by the bridging bidentate binding mode between SA and the zirconium metal center can release protons,and SA actively participates in the construction of hydrogen-bonded network,thereby accelerating the proton conduction.At 95%RH(relative humidity)and 358 K,the proton conductivity of SA@UiO-66-NH_(2)can reach 1.42×10^(-2)S·cm^(-1),which is four orders of magnitude higher than that of the parent framework UiO-66-NH_(2).Meanwhile,this high proton conductivity can be maintained for at least 90 h.展开更多
The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hyd...The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hydroxyapatite of high crystallinity powder including trace Ca 10 (PO 4) 6CO 3(OH) and Ca 9HPO 4(PO 4) 6OH can be synthesized by mechanical activation without further thermal treatment at a high temperature. The synthesis reaction during the grinding process was almost completed within 1h. The as-ground powder exhibits a particle distribution of 20-100nm in size with a spherical or rodlike morphology. The composition and degree of crystallinity of the mechanochemical synthesized hydroxyapatite powders were coincident with the cement-type hydroxyapatite.展开更多
The mechanochemical dechlorination of pentachlorophenol （PCP） was studied using CaO and SiO2 powder as additives. The effects of the milling time and additives on the dechlorination rate were investigated. The resul...The mechanochemical dechlorination of pentachlorophenol （PCP） was studied using CaO and SiO2 powder as additives. The effects of the milling time and additives on the dechlorination rate were investigated. The resulting product was characterized by X-ray diffraction （XRD）, Fourier transform infrared spectra （FT-IR）, thermogravimetric analysis （TG） and ion chromatography （IC）. It is found that grinding operation could dechlorinate PCP, with the formation of inorganic chloride and amorphous carbon. The addition of quartz to the grinding mixture facilitated dechlorination. On the basis of the experimental results, the decomposition mechanism was proposed. Decomposition predominantly proceeds through rupture of C-Cl bond in PCP molecule, followed by the formation of inorganic chlorides.展开更多
Al2O3-CeO2 supports containing 1-10 wt%Ce were prepared mechanochemically by milling aluminum and/or cerium nitrates with NH4HCO3.Heteropolymolybdate,（NH4）4NiMo6O（24）,was used as the precursor of the Ni and Mo to ...Al2O3-CeO2 supports containing 1-10 wt%Ce were prepared mechanochemically by milling aluminum and/or cerium nitrates with NH4HCO3.Heteropolymolybdate,（NH4）4NiMo6O（24）,was used as the precursor of the Ni and Mo to prepare NiMo6/Al2O3-CeO2 components in catalysts by impregnation method.The physicochemical properties of the catalysts were determined using chemical analysis,X-ray diffraction,temperature-programmed H2 reduction,temperature-programmed NH3 desorption,X-ray photoelectron spectroscopy（XPS）,and the Brunauer-Emmett-Teller method.The catalyst acidity decreased with increasing Ce concentration in the support.XPS showed that the NiS/MoS ratio decreased two-fold for the Ce-modified alumina support.NiMo6/Al2O3,which had the highest acidity,showed the highest activity in hydrodesulfurization of 1-benzothiophene（normalized per weight of catalyst）.The concentration of surface MoOxSy species（which is equal to the concentration of Mo^（5＋）） gradually decreased to zero for catalysts with Ce concentrations 10 wt%.However,the activities of all the catalysts prepared mechanochemically from Al2O3 and Al2O3-CeO2supports significantly exceeded that of a reference NiMo6/Al2O3 catalyst prepared by impregnation method using the same precursor and with the same composition.展开更多
Mechanochemical sulfidization of a mixed sulfide/oxide copper ore by co-grinding with sulfur and additives including Mg(NO3)2 and Fe(NO3)3 salts and iron,aluminum and magnesium powders was investigated for the first t...Mechanochemical sulfidization of a mixed sulfide/oxide copper ore by co-grinding with sulfur and additives including Mg(NO3)2 and Fe(NO3)3 salts and iron,aluminum and magnesium powders was investigated for the first time.Also,the influence of sulfidization during the wet-milling process was examined on the separation efficiency and recovery of copper in detail.The results demonstrated that co-grinding with sulfur solely had the best flotation performance at the value of 0.5 wt.%and it was attributed to the possible existence of S\\O bonding on copper oxides surfaces.In addition,adding magnesium nitrate salt,magnesium powder,iron nitrate salt and aluminum powder as additive associated with 0.5 wt%sulfur into ball milling caused the flotation improvement at the amounts of 0.2 wt%,0.2 wt%,0.5 wt%and 0.5 wt%,respectively.Also,the effect of grinding time and sulfidization pH with 0.5 wt%sulfur solely was determined and pH s of 7.5 to 8.5 gave the best results.The highest recovery(75.76%)and separation efficiency(63.44%)were achieved at pH of 7.5 and 8.5,respectively.展开更多
The mechanochemical treatment of fly ash generated from a medical waste incinerator was subjected to grinding for 2 hr at 400 r/min in a planetary ball mill. The treated fly ash was characterized by a suite of analyti...The mechanochemical treatment of fly ash generated from a medical waste incinerator was subjected to grinding for 2 hr at 400 r/min in a planetary ball mill. The treated fly ash was characterized by a suite of analytical methods including High Resolution Gas Chromatograph/High Resolution Mass Spectrometer, Mastersizer 2000 Particle Size Analyzer, QUADRASORBTM SI Surface Area Analyzer, Scanning Electron Microscopy and X-ray diffraction. Results showed that abatement efficiency of polychlorinated dibenzo- p-dioxins and polychlorinated dibenzofurans （PCDDs/Fs） in terms of total concentration averagely amount to 76% which was relatively higher than that of I-TEQ concentration averagely amount to 56%; the most concentration of toxic congeners as well as isomers of PCDDs/Fs decreased after mechanochemical treatment. The treated fly ash was characterized by a more homogeneous distribution of concaves as well as the significant decreasing in overall particle size and great enlargement in surface area. The major crystallization phases or intensities were considerably changed by mechanochemical treatment, of which a new phase containing chlorine formed may be a possible factor suggesting chlorination reaction occurring on the crystalline surface.展开更多
The kinetics of isothermal reduction of Ag2O with graphite under argon atmosphere for a non-activated sample and mechanically activated sample was investigated.It is found that Johnson-Mehl-Avrami model appropriately ...The kinetics of isothermal reduction of Ag2O with graphite under argon atmosphere for a non-activated sample and mechanically activated sample was investigated.It is found that Johnson-Mehl-Avrami model appropriately explained the thermal and mechanochemical synthesis of Ag from Ag2O＋ghraphite mixture.The process kinetics was investigated using the same approach for milled and unmilled samples.The results show that the Avrami exponent of mechanochemical reduction is higher than that of high temperature thermal reduction.Also,the mechanisms of nuclei growth in thermal and mechanochemical reduction are diffusion controlled and interface controlled,respectively.展开更多
Mechanochemical reaction involves simultaneous chemical reaction and particle crushing;the latter increases the effective reaction area and improves the reactivity,thus enhancing its kinetics.The classical shrinking c...Mechanochemical reaction involves simultaneous chemical reaction and particle crushing;the latter increases the effective reaction area and improves the reactivity,thus enhancing its kinetics.The classical shrinking core model was used to model the kinetics of bastnaesite mechanochemical decomposition in NaOH solution,which shows a questionable result.Mechanochemical reaction is a dynamic process,where the particle shape and concentration in reaction interface undergo constant change.Thus,a physically consistent model was applied to describe the kinetics.The variations in OH^-concentration and particle shape were considered in the revision of model.Considering the variation in OH^-concentration in solution with time,the model with varying OH^-concentration agrees better with the experimental data,improving the regression coefficients to between 0.936 and 0.992.By introducing fractal geometry to deal with the irregular system,the model was further optimized,and the regression coefficients increase to between 0.940 and 0.997.All these models considere shrinking particle approaches and controlling mechanisms for the diffusion and chemical reaction.Finally,the fractal model with varying OH^-concentration was selected to describe the mechanochemical decomposition of bastnaesite,which indicates that the process is controlled by chemical reaction.展开更多
A mechanochemical method with SiO_(2)as the grinding aid was used to enhance the leaching efficiencies of Co and Li from spent lithium batteries(LIBs).Experiment results show that the optimal leaching efficiencies of ...A mechanochemical method with SiO_(2)as the grinding aid was used to enhance the leaching efficiencies of Co and Li from spent lithium batteries(LIBs).Experiment results show that the optimal leaching efficiencies of 94.91%for Co and 97.22%for Li were obtained under the parameters of SiO_(2)/LiCoO_(2)mass ratio of 1:1,grinding speed of 500 r/min and grinding time of 30 min in citric acid.Characterization results indicate that the surficial properties of LiCoO_(2)were changed after mechanochemical grinding treatment due to the newly generated surfaces on LiCoO_(2).Meanwhile,the incompletely coordinated atomic structure and defective lattice structure lead to the activation of LiCoO_(2).The reduction effect of carbon black on Co^(3+)under the action of mechanical forces increases its leaching efficiencies in the citric acid solution.The proposed process was found efficiently to recover Co and Li from LiCoO_(2).展开更多
In this study,we present the characterization of the carbon fibers recovered from the mechanochemical-enhanced recycling of carbon fiber reinforced fibers.The objectives of the study were to investigate the effect of ...In this study,we present the characterization of the carbon fibers recovered from the mechanochemical-enhanced recycling of carbon fiber reinforced fibers.The objectives of the study were to investigate the effect of our modified recycling method on the interfacial properties of recovered fibers.The reinforced plastics were recycled;the recycling efficiency was determined and the recovered fibers were sized using 1 wt%and 3 wt%concentration of(3-aminopropyl)triethoxysilane.We characterized the morphologies utilizing the electron spectroscopy for chemical analysis(ESCA),atomic force microscopy(AFM),FTIR-attenuated total reflection(ATR)spectroscopy and scanning electron microscopy(SEM).Although the surface of the fibers had no cracks,there was evidence of contaminations which affected the interfacial properties and the quality of the fibers.Results showed that the trends in the recovered and virgin fibers were similar with an increase in sizing concentration.The results highlighted the perspectives of increasing the quality of recovered fibers after the recycling process.展开更多
The mechanochemical effect on the microcutting of AA6061 alloy is studied through characterization on the microgroove surface.There is a reduction in cutting and thrust forces with the application of ink during microc...The mechanochemical effect on the microcutting of AA6061 alloy is studied through characterization on the microgroove surface.There is a reduction in cutting and thrust forces with the application of ink during microcutting.Moreover,the microhardness of the ink-affected microgroove is lower than that of the ink-free microgroove.Numerous substructured grains exist in the ink-affected microgroove zone whilst deformed grains dominate in the ink-free microgroove zone produced by microcutting.Furthermore,the mechanochemical effect can facilitate the nucleation of precipitates in the microgroove zone and induce the formation of subgrains with multiple orientations.According to the analysis and calculation,the main texture components of the ink-affected sample are Goss{110}<001>and R{124}<211>,and that of the ink-free sample are Brass{110}<112>,Copper{112}<111>and S{123}<634>.Besides,a clear difference of slip systems is found between the ink-free and ink-affected microgrooves,and the results show that R texture is easier to form on the ink-affected microgroove.展开更多
A technology of mechanochemical treatment (MCT) is introduced to modify nanodiamond (ND) surface aiming to obtaining a stable suspension with well-dispersed ND particles in aqueous medium. ND investigated in this pape...A technology of mechanochemical treatment (MCT) is introduced to modify nanodiamond (ND) surface aiming to obtaining a stable suspension with well-dispersed ND particles in aqueous medium. ND investigated in this paper is a purified product of nanometer-sized diamond synthesized by explosive detonation. As obvious aggregation and sediment were observed when the sample was added into deionized water, it is crucial to conduct deaggregation and dispersion investigations. Amid a series of mechanical treatments, i.e. grinding, stirring, ultrasonic and classification, some reagents are introduced to modify the newly created surface during aggregates comminution. For the co-effects of mechanical forces and surfactants, the mean size of particles was reduced and a stable system containing ND with narrow size distribution was prepared. Mechanism of surface reaction and modification are discussed, while AFM, Zetasizer3000HS, XRD, XPS and FTIR are utilized for the analysis. The functional chemical structure of ND particle surface and surface electrical property changed during the modification processes, and the dispersion character and stability of suspension can consequently be improved.展开更多
Activated carbon was prepared from bamboo by mechanochemical process with phosphoric acid as activating agent.The effects of milling time on the adsorption property and porous structure of the obtained activated car-b...Activated carbon was prepared from bamboo by mechanochemical process with phosphoric acid as activating agent.The effects of milling time on the adsorption property and porous structure of the obtained activated car-bon were discussed.The results showed that phosphoric acid activation assisted by mechanochemical process can slightly improve the adsorption performance of the prepared activated carbon.The iodine,methylene blue adsorption value and the specific surface area of the prepared activated carbons increased from 840.16 mg/g,168 mg/g and 1229.246 m/g to 947.51 mg/g,195 mg/g,and 1265.373 m2/g,respectively.Compared with conventional phosphoric acid activation,the activated carbon produced by mechanochemical process has greater adsorption capacity.展开更多
The mechanical decomposing and mechanochemical reductions of silver oxide for preparation of nanocrystalline silver powders by high planetary ball mill was investigated. XRD and HRSEM techniques were used to character...The mechanical decomposing and mechanochemical reductions of silver oxide for preparation of nanocrystalline silver powders by high planetary ball mill was investigated. XRD and HRSEM techniques were used to characterize the structural evolution and morphological changes of products. The results show that the nanostructured silver with an average crystallite size of 14 nm and internal strain of 0.75% is synthesized by mechanical decomposing of Ag2O after 95 h milling. While, the product of mechanochemical reduction of silver oxide using graphite after 22 h milling is nanostructured silver with an average crystallite size of 28 nm and internal strain of 0.44%.展开更多
This study aimed to introduce a new cost-effective methodology for increasing the leaching efficiency of chalcopyrite concentrates at ambient temperature and pressure. Mechanical activation was employed during the lea...This study aimed to introduce a new cost-effective methodology for increasing the leaching efficiency of chalcopyrite concentrates at ambient temperature and pressure. Mechanical activation was employed during the leaching（mechanochemical leaching） of chalcopyrite concentrates in a sulfuric acid medium at room temperature and atmospheric pressure. High energy ball milling process was used during the leaching to provide the mechanochemical leaching condition, and atomic absorption spectroscopy and cyclic voltammetry were used to determine the leaching behavior of chalcopyrite. Moreover, X-ray diffraction and scanning electron microscopy were used to characterize the chalcopyrite powder before and after leaching. The results demonstrated that mechanochemical leaching was effective; the extraction of copper increased significantly and continuously. Although the leaching efficiency of chalcopyrite was very low at ambient temperature, the percentages of copper dissolved in the presence of hydrogen peroxide（H2O2） and ferric sulfate（Fe2（SO4）3） after 20 h of mechanochemical leaching reached 28% and 33%, respectively. Given the efficiency of the developed method and the facts that it does not require the use of an autoclave and can be conducted at room temperature and atmospheric pressure, it represents an economical and easy-to-use method for the leaching industry.展开更多
基金supported by the Key 491 R&D Programof Hubei Province(No.2022BCA083).
文摘In this study,an efficient stabilizer material for cadmium(Cd^(2+))treatment was successfully prepared by simply co-milling olivine with magnesite.Several analyticalmethods including XRD,TEM,SEM and FTIR,combined with theoretical calculations(DFT),were used to investigate mechanochemical interfacial reaction between twominerals,and the reaction mechanism of Cd removal,with ion exchange between Cd^(2+)and Mg^(2+)as the main pathway.A fixation capacity of Cd^(2+)as high as 270.61 mg/g,much higher than that of the pristine minerals and even the individual/physical mixture of milled olivine and magnesite,has been obtained at optimized conditions,with a neutral pH value of the solution after treatment to allow its direct discharge.The as-proposed Mg-based stabilizer with various advantages such as cost benefits,green feature etc.,will boosts the utilization efficiency of naturalminerals over the elaborately prepared adsorbents.
基金supported by the National Natural Science Foundation of China(Nos.22471185 and 52225311)Science and Technology Program of Suzhou(No.ZXL2022480)+1 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Program of Innovative Research Team of Soochow University。
文摘Polydopamine-based melanin-like materials have been widely used in the fields of ultraviolet(UV)shielding,solar desalination and anti-inflammatory treatment owing to their unique physical properties.The well-established synthesis of polydopamine nanoparticles involves the oxidative polymerization of dopamine-derived monomers,resulting in cross-linked nanostructures with high complexity and heterogeneity.Therefore,the controlled synthesis of polydopamine-based melanin-like materials with well-defined structures and predictable properties remains challenging.Herein,we propose a mechanochemical Suzuki polymerization approach for the synthesis of linear melanin-like polymers with tunable physical properties.Compared with polydopamine nanoparticles,the mechanochemical approach offers a more flexible chain-like structure,thereby enhancing its antioxidant performance.Furthermore,this approach also enables the preparation of a melanin-like alternating copolymer that exhibits green fluorescence owing to itsπ-conjugated structure.This study not only offers opportunities for exploring novel synthetic melanin materials,but also provides new insights into the structure-function relationships of polydopamine-based materials.
基金the National Natural Science Foundation of China(Nos.52271149,51971123,and 51925103)the Innovation Program of Shanghai Municipal Edu-cation Commission(No.2021-01-07-00-09-E00114)+4 种基金the financial support from Program 173(No.2020-JCIQ-ZD-186-01)111project(No.D16002)the Space Utilization System of China Manned Space Engineering(No.KJZ-YY-NCL08)the Singapore Ministry of Education Academic Research Funds(Grant Nos.MOE-T2EP50120-0010,MOE-T2EP50220-0010,and A-8001225-00-00)Long Xu thanks the China Scholarship Council(CSC)Scholarship,China(CSC No.202106890047).
文摘Recently,researchers have explored the use of precipitation strengthening and finer microstructures with high-density dislocations in additive manufacturing to produce high-entropy alloys(HEAs)with adjustable properties.However,the inherent surface roughness and lack of machinability research in AMed HEAs limit their engineering applications.In this study,we systematically investigated the microstructural characteristics,mechanical properties,and machinability of Fe_(29.3)Co_(28.7)Ni_(28.6)Al_(6.8)Ti_(6.6)(at.%)HEAs with three different structures:single FCC phase cellular(SPC),dual precipitation-strengthened(DPS),and single precipitation-strengthened(SPS).These structures were fabricated by selective laser melting and isothermally annealing at 780 and 940℃.Compared to SPC HEA,DPS HEA exhibits a significant increase in yield strength and ultimate tensile strength but with a dramatic sacrifice in ductility.SPS HEA exhibits similar mechanical properties to SPC HEA due to the pronounced coarsening of L21 precipitates.The ultraprecision machining micro-cutting test showed that SPC HEA had a significant mechanochem-ical effect,as evidenced by a sharp drop in cutting force for inked workpieces,but not DPS HEA.An abnormal finding was that the negligible reflection of cutting force for SPS HEAs suggested a negative mechanochemical effect,even though SPS HEA had equally excellent plasticity like SPC HEA.It was found that nanocrystallization-induced strength enhancement and ductility reduction of SPS HEA lead to chips’deformation dominated by shear avalanche rather than chip folding of SPC HEA,which involves the reduction of surface energy and friction of chips’interfaces.Overall,these results and our research findings may guide the machining of AMed precipitation-strengthened HEAs and accelerate their engineering ap-plication.
基金supported by the National Key Research and Development Program(2022YFC3702003)the Key Research and Development Projects in Zhejiang Province(2024C03114).
文摘Photocatalytic oxidation technology is a promising green technology for degrading volatile organic compounds(VOCs)due to its non-toxic,environmentally friendly,energy-saving and affordable characteristics.In this paper,Ag/TiO_(2)@PANI-MC with high stability and activity was synthesized by the mechanochemical method.The designed Ag/TiO_(2)@PANI-MC were of high specific surface area,light absorption capacity and low recombination rate of electronehole pairs,which was demonstrated by various characterizations.When applied in photocatalytic toluene oxidation,the conversion is 17%at 20℃under 100 W high-pressure mercury lamp.This photocatalytic performance is with less temperature sensitivity and significantly improved compared with Ag/TiO_(2)or TiO_(2)catalysts.Furthermore,the reaction routine was also confirmed by gas chromatography-mass spectrometry and toluene was mineralized to CO_(2).More importantly,the Ag/TiO_(2)@PANI-MC indicated good reusability after three cycles,which was verified by the Fourier transform-infrared spectroscopy comparison with fresh and used catalysts.Our work proves a potential way of constructing nanocomposites based on mechanochemical synthesis for enhanced toluene photocatalytic degradation.
基金supported by the Natural Science Foundation of Zhejiang Province (No. LY21E060007)the National Natural Science Foundation of China (No. 52006191)。
文摘Industrial-use VOx-based catalysts usually have a higher active temperature window (>250-300℃),which becomes a“bottleneck”for the practical application of PCDD/Fs catalytic degradation technology.In this work,VO_(x)-FeO_(x)/TiO_(2) catalyst prepared via mechanochemically method was investigated for the catalytic removal of PCDD/Fs.The removal efficiency of 1,2-DCBz,pure PCDD/Fs gas generated in the lab,PCDD/Fs from actual fue gas,long-term were studied,and the degradation mechanism was explored using FTIR and TOFMS.The degradation efficiency of 1,2-DCBz and PCDD/Fs on VO_(x)-FeO_(x)/TiO_(2) were higher than that of VO_(x)/TiO_(2)catalyst,and the optimal FeOx addition ratio was 3 wt.%.The characterization results show that the addition of FeOx can effectively improve the pore structure,surface acidity,and VOx dispersion of the catalyst,thus contributing to increasing the V^(5+)content and surface-active oxygen,which is conducive to the improvement of adsorption and redox performance of the catalyst.Under the actual MSWI (municipal solid waste incineration)fue gas,the PCDD/Fs removal efficiency over VTi-3Fe-MC maintained long-term stability,higher than 85%for 240 min.This result was not significantly reduced compared with the data obtained in the laboratory.According to the analysis results of intermediate products by FTIR and GC-TOFMS,it can be inferred that the epoxidation fracture of benzene ring is the rate-limiting step of dioxin catalytic degradation reaction.This work gives an in-depth view into the PCDD/Fs removal over VO_(x)-FeO_(x)/TiO_(2) catalysts and could provide guidelines for the rational design of reliable catalysts for industrial applications.
基金supported by the National Natural Science Foundation of China(22071019 and 21872021)the Basic Scientific Research Project of Liaoning Provincial Department of Education(LJKMZ20220968)
文摘Through the mechanochemical method,sulfamic acid(SA)is successfully introduced into UiO-66-NH_(2)to form SA@UiO-66-NH_(2).In SA@UiO-66-NH_(2),the acidic cationic sulfiliminium(—S=NH_(2)^(+))moiety formed by the bridging bidentate binding mode between SA and the zirconium metal center can release protons,and SA actively participates in the construction of hydrogen-bonded network,thereby accelerating the proton conduction.At 95%RH(relative humidity)and 358 K,the proton conductivity of SA@UiO-66-NH_(2)can reach 1.42×10^(-2)S·cm^(-1),which is four orders of magnitude higher than that of the parent framework UiO-66-NH_(2).Meanwhile,this high proton conductivity can be maintained for at least 90 h.
文摘The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hydroxyapatite of high crystallinity powder including trace Ca 10 (PO 4) 6CO 3(OH) and Ca 9HPO 4(PO 4) 6OH can be synthesized by mechanical activation without further thermal treatment at a high temperature. The synthesis reaction during the grinding process was almost completed within 1h. The as-ground powder exhibits a particle distribution of 20-100nm in size with a spherical or rodlike morphology. The composition and degree of crystallinity of the mechanochemical synthesized hydroxyapatite powders were coincident with the cement-type hydroxyapatite.
基金supported by the National Natural Science Foundation of China (No. 50776081)the Doctoral Program of Higher Education (No. 20060335129)the Project on Science and Technology of Zhejiang Province of China (No. 2008C23090)
文摘The mechanochemical dechlorination of pentachlorophenol （PCP） was studied using CaO and SiO2 powder as additives. The effects of the milling time and additives on the dechlorination rate were investigated. The resulting product was characterized by X-ray diffraction （XRD）, Fourier transform infrared spectra （FT-IR）, thermogravimetric analysis （TG） and ion chromatography （IC）. It is found that grinding operation could dechlorinate PCP, with the formation of inorganic chloride and amorphous carbon. The addition of quartz to the grinding mixture facilitated dechlorination. On the basis of the experimental results, the decomposition mechanism was proposed. Decomposition predominantly proceeds through rupture of C-Cl bond in PCP molecule, followed by the formation of inorganic chlorides.
基金Czech Science Foundation(Project P106/11/0902) for financial support
文摘Al2O3-CeO2 supports containing 1-10 wt%Ce were prepared mechanochemically by milling aluminum and/or cerium nitrates with NH4HCO3.Heteropolymolybdate,（NH4）4NiMo6O（24）,was used as the precursor of the Ni and Mo to prepare NiMo6/Al2O3-CeO2 components in catalysts by impregnation method.The physicochemical properties of the catalysts were determined using chemical analysis,X-ray diffraction,temperature-programmed H2 reduction,temperature-programmed NH3 desorption,X-ray photoelectron spectroscopy（XPS）,and the Brunauer-Emmett-Teller method.The catalyst acidity decreased with increasing Ce concentration in the support.XPS showed that the NiS/MoS ratio decreased two-fold for the Ce-modified alumina support.NiMo6/Al2O3,which had the highest acidity,showed the highest activity in hydrodesulfurization of 1-benzothiophene（normalized per weight of catalyst）.The concentration of surface MoOxSy species（which is equal to the concentration of Mo^（5＋）） gradually decreased to zero for catalysts with Ce concentrations 10 wt%.However,the activities of all the catalysts prepared mechanochemically from Al2O3 and Al2O3-CeO2supports significantly exceeded that of a reference NiMo6/Al2O3 catalyst prepared by impregnation method using the same precursor and with the same composition.
基金the AbbasAbad copper mineShahrood University of Technology for their financial support during this research。
文摘Mechanochemical sulfidization of a mixed sulfide/oxide copper ore by co-grinding with sulfur and additives including Mg(NO3)2 and Fe(NO3)3 salts and iron,aluminum and magnesium powders was investigated for the first time.Also,the influence of sulfidization during the wet-milling process was examined on the separation efficiency and recovery of copper in detail.The results demonstrated that co-grinding with sulfur solely had the best flotation performance at the value of 0.5 wt.%and it was attributed to the possible existence of S\\O bonding on copper oxides surfaces.In addition,adding magnesium nitrate salt,magnesium powder,iron nitrate salt and aluminum powder as additive associated with 0.5 wt%sulfur into ball milling caused the flotation improvement at the amounts of 0.2 wt%,0.2 wt%,0.5 wt%and 0.5 wt%,respectively.Also,the effect of grinding time and sulfidization pH with 0.5 wt%sulfur solely was determined and pH s of 7.5 to 8.5 gave the best results.The highest recovery(75.76%)and separation efficiency(63.44%)were achieved at pH of 7.5 and 8.5,respectively.
基金supported by the Zhejiang Province Natural Science Foundation(No.X206955,Z506214)
文摘The mechanochemical treatment of fly ash generated from a medical waste incinerator was subjected to grinding for 2 hr at 400 r/min in a planetary ball mill. The treated fly ash was characterized by a suite of analytical methods including High Resolution Gas Chromatograph/High Resolution Mass Spectrometer, Mastersizer 2000 Particle Size Analyzer, QUADRASORBTM SI Surface Area Analyzer, Scanning Electron Microscopy and X-ray diffraction. Results showed that abatement efficiency of polychlorinated dibenzo- p-dioxins and polychlorinated dibenzofurans （PCDDs/Fs） in terms of total concentration averagely amount to 76% which was relatively higher than that of I-TEQ concentration averagely amount to 56%; the most concentration of toxic congeners as well as isomers of PCDDs/Fs decreased after mechanochemical treatment. The treated fly ash was characterized by a more homogeneous distribution of concaves as well as the significant decreasing in overall particle size and great enlargement in surface area. The major crystallization phases or intensities were considerably changed by mechanochemical treatment, of which a new phase containing chlorine formed may be a possible factor suggesting chlorination reaction occurring on the crystalline surface.
文摘The kinetics of isothermal reduction of Ag2O with graphite under argon atmosphere for a non-activated sample and mechanically activated sample was investigated.It is found that Johnson-Mehl-Avrami model appropriately explained the thermal and mechanochemical synthesis of Ag from Ag2O＋ghraphite mixture.The process kinetics was investigated using the same approach for milled and unmilled samples.The results show that the Avrami exponent of mechanochemical reduction is higher than that of high temperature thermal reduction.Also,the mechanisms of nuclei growth in thermal and mechanochemical reduction are diffusion controlled and interface controlled,respectively.
基金Project supported by the Fundamental Research Funds for the Central Universities(N172506009,N170908001,N182515007,N180725023)National Natural Science Foundation of China(U1508217).
文摘Mechanochemical reaction involves simultaneous chemical reaction and particle crushing;the latter increases the effective reaction area and improves the reactivity,thus enhancing its kinetics.The classical shrinking core model was used to model the kinetics of bastnaesite mechanochemical decomposition in NaOH solution,which shows a questionable result.Mechanochemical reaction is a dynamic process,where the particle shape and concentration in reaction interface undergo constant change.Thus,a physically consistent model was applied to describe the kinetics.The variations in OH^-concentration and particle shape were considered in the revision of model.Considering the variation in OH^-concentration in solution with time,the model with varying OH^-concentration agrees better with the experimental data,improving the regression coefficients to between 0.936 and 0.992.By introducing fractal geometry to deal with the irregular system,the model was further optimized,and the regression coefficients increase to between 0.940 and 0.997.All these models considere shrinking particle approaches and controlling mechanisms for the diffusion and chemical reaction.Finally,the fractal model with varying OH^-concentration was selected to describe the mechanochemical decomposition of bastnaesite,which indicates that the process is controlled by chemical reaction.
基金financially supported by the Key-Area Research and Development Program of Guangdong Province,China(No.2020B090919003)the National Natural Science Foundation of China(Nos.51574234,51904295)+2 种基金the Special Fund(Social Development)Project of Key Research and Development Plan of Jiangsu Province,China(No.BE2019634)the Science Foundation of Jiangsu Province,China(No.BK20180647)the Postdoctoral Science Foundation of China(No.2018M640538)。
文摘A mechanochemical method with SiO_(2)as the grinding aid was used to enhance the leaching efficiencies of Co and Li from spent lithium batteries(LIBs).Experiment results show that the optimal leaching efficiencies of 94.91%for Co and 97.22%for Li were obtained under the parameters of SiO_(2)/LiCoO_(2)mass ratio of 1:1,grinding speed of 500 r/min and grinding time of 30 min in citric acid.Characterization results indicate that the surficial properties of LiCoO_(2)were changed after mechanochemical grinding treatment due to the newly generated surfaces on LiCoO_(2).Meanwhile,the incompletely coordinated atomic structure and defective lattice structure lead to the activation of LiCoO_(2).The reduction effect of carbon black on Co^(3+)under the action of mechanical forces increases its leaching efficiencies in the citric acid solution.The proposed process was found efficiently to recover Co and Li from LiCoO_(2).
基金Project(S2598445)supported by the Project for Cooperative R&D between Industry,Academy and Research Institute Funded by the Korea Ministry of SME and Startups in 2018
文摘In this study,we present the characterization of the carbon fibers recovered from the mechanochemical-enhanced recycling of carbon fiber reinforced fibers.The objectives of the study were to investigate the effect of our modified recycling method on the interfacial properties of recovered fibers.The reinforced plastics were recycled;the recycling efficiency was determined and the recovered fibers were sized using 1 wt%and 3 wt%concentration of(3-aminopropyl)triethoxysilane.We characterized the morphologies utilizing the electron spectroscopy for chemical analysis(ESCA),atomic force microscopy(AFM),FTIR-attenuated total reflection(ATR)spectroscopy and scanning electron microscopy(SEM).Although the surface of the fibers had no cracks,there was evidence of contaminations which affected the interfacial properties and the quality of the fibers.Results showed that the trends in the recovered and virgin fibers were similar with an increase in sizing concentration.The results highlighted the perspectives of increasing the quality of recovered fibers after the recycling process.
基金the Singapore Ministry of Education Academic Research Fund(R265-000-686-114 and MOE2018-T2-1-140)。
文摘The mechanochemical effect on the microcutting of AA6061 alloy is studied through characterization on the microgroove surface.There is a reduction in cutting and thrust forces with the application of ink during microcutting.Moreover,the microhardness of the ink-affected microgroove is lower than that of the ink-free microgroove.Numerous substructured grains exist in the ink-affected microgroove zone whilst deformed grains dominate in the ink-free microgroove zone produced by microcutting.Furthermore,the mechanochemical effect can facilitate the nucleation of precipitates in the microgroove zone and induce the formation of subgrains with multiple orientations.According to the analysis and calculation,the main texture components of the ink-affected sample are Goss{110}<001>and R{124}<211>,and that of the ink-free sample are Brass{110}<112>,Copper{112}<111>and S{123}<634>.Besides,a clear difference of slip systems is found between the ink-free and ink-affected microgrooves,and the results show that R texture is easier to form on the ink-affected microgroove.
文摘A technology of mechanochemical treatment (MCT) is introduced to modify nanodiamond (ND) surface aiming to obtaining a stable suspension with well-dispersed ND particles in aqueous medium. ND investigated in this paper is a purified product of nanometer-sized diamond synthesized by explosive detonation. As obvious aggregation and sediment were observed when the sample was added into deionized water, it is crucial to conduct deaggregation and dispersion investigations. Amid a series of mechanical treatments, i.e. grinding, stirring, ultrasonic and classification, some reagents are introduced to modify the newly created surface during aggregates comminution. For the co-effects of mechanical forces and surfactants, the mean size of particles was reduced and a stable system containing ND with narrow size distribution was prepared. Mechanism of surface reaction and modification are discussed, while AFM, Zetasizer3000HS, XRD, XPS and FTIR are utilized for the analysis. The functional chemical structure of ND particle surface and surface electrical property changed during the modification processes, and the dispersion character and stability of suspension can consequently be improved.
文摘Activated carbon was prepared from bamboo by mechanochemical process with phosphoric acid as activating agent.The effects of milling time on the adsorption property and porous structure of the obtained activated car-bon were discussed.The results showed that phosphoric acid activation assisted by mechanochemical process can slightly improve the adsorption performance of the prepared activated carbon.The iodine,methylene blue adsorption value and the specific surface area of the prepared activated carbons increased from 840.16 mg/g,168 mg/g and 1229.246 m/g to 947.51 mg/g,195 mg/g,and 1265.373 m2/g,respectively.Compared with conventional phosphoric acid activation,the activated carbon produced by mechanochemical process has greater adsorption capacity.
文摘The mechanical decomposing and mechanochemical reductions of silver oxide for preparation of nanocrystalline silver powders by high planetary ball mill was investigated. XRD and HRSEM techniques were used to characterize the structural evolution and morphological changes of products. The results show that the nanostructured silver with an average crystallite size of 14 nm and internal strain of 0.75% is synthesized by mechanical decomposing of Ag2O after 95 h milling. While, the product of mechanochemical reduction of silver oxide using graphite after 22 h milling is nanostructured silver with an average crystallite size of 28 nm and internal strain of 0.44%.
基金The financial support of the FUM (Ferdowsi University of Mashhad)the Ministry of Science, Research and Technology, Iran
文摘This study aimed to introduce a new cost-effective methodology for increasing the leaching efficiency of chalcopyrite concentrates at ambient temperature and pressure. Mechanical activation was employed during the leaching（mechanochemical leaching） of chalcopyrite concentrates in a sulfuric acid medium at room temperature and atmospheric pressure. High energy ball milling process was used during the leaching to provide the mechanochemical leaching condition, and atomic absorption spectroscopy and cyclic voltammetry were used to determine the leaching behavior of chalcopyrite. Moreover, X-ray diffraction and scanning electron microscopy were used to characterize the chalcopyrite powder before and after leaching. The results demonstrated that mechanochemical leaching was effective; the extraction of copper increased significantly and continuously. Although the leaching efficiency of chalcopyrite was very low at ambient temperature, the percentages of copper dissolved in the presence of hydrogen peroxide（H2O2） and ferric sulfate（Fe2（SO4）3） after 20 h of mechanochemical leaching reached 28% and 33%, respectively. Given the efficiency of the developed method and the facts that it does not require the use of an autoclave and can be conducted at room temperature and atmospheric pressure, it represents an economical and easy-to-use method for the leaching industry.
