The Fenton method is an effective technology for the removal of organic materials from wastewater.In this work,an induced catalyst Fe_(3)O_(4) was synthesized by a hydrothermal method,and the modulation of the chemica...The Fenton method is an effective technology for the removal of organic materials from wastewater.In this work,an induced catalyst Fe_(3)O_(4) was synthesized by a hydrothermal method,and the modulation of the chemical composition of Fe_(3)O_(4) crystals was achieved under the microwave shock method with the same effect as that of calcination treatment.Fe_(3)O_(4) catalyst for the removal of the dye Rhodamine B (Rh B) from polluted wastewater under microwave (MW),H_(2)O_(2) system.The results showed that Fe_(3)O_(4) nanomicrospheres prepared by microwave shock exhibited superior catalytic activity under the conditions of 500 W,0.4 mol/L H_(2)O_(2) and10 mg/L Rh B,and the removal rate of Rh B reached 98.5%after 10 min.The Fe_(3)O_(4) catalysts also exhibited good stability and degradation efficiency.Electron paramagnetic resonance experiments confirmed that·OH plays a major role in the rapid degradation of Rh B.Under microwave action,the catalyst produces electron-hole pairs,in which the holes react with OH-produced by water ionisation to form·OH,and the microwave-treated Fe_(3)O_(4) produces more active species.Fe^(3+)and Fe^(2+)serve as microwave catalytic activity centers and Fenton catalytic activity centers,respectively.This research demonstrates that optimizing the Fe^(2+)/Fe^(3+) ratio significantly enhances the degradation efficiency of Rh B.This study presents novel views regarding the mechanism of microwave synergistic catalyst-induced Fenton.展开更多
Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was des...Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.展开更多
Bamboo charcoal（BC） was used as starting material to prepare iron-modified bamboo charcoal（Fe-MBC） by its impregnation in FeCl 3 and HNO 3 solutions simultaneously,followed by microwave heating.The material can be...Bamboo charcoal（BC） was used as starting material to prepare iron-modified bamboo charcoal（Fe-MBC） by its impregnation in FeCl 3 and HNO 3 solutions simultaneously,followed by microwave heating.The material can be used as an adsorbent for Pb（Ⅱ） contaminants removal in water.The composites were prepared with Fe molar concentration of 0.5,1.0 and 2.0 mol/L and characterized by means of N 2 adsorption-desorption isotherms,X-ray diffraction spectroscopy（XRD）,scanning electron microscopy coupled with energy dispersive X-ray spectrometry（SEM-EDS）,Fourier transform infrared（FT-IR） and point of zero charge（pH pzc） measurements.Nitrogen adsorption analyses showed that the BET specific surface area and total pore volume increased with iron impregnation.The adsorbent with Fe molar concentration of 2 mol/L（2Fe-MBC） exhibited the highest surface area and produced the best pore structure.The Pb（Ⅱ） adsorption process of 2Fe-MBC and BC were evaluated in batch experiments and 2Fe-MBC showed an excellent adsorption capability for removal Pb（Ⅱ）.The adsorption of Pb（Ⅱ） strongly depended on solution pH,with maximum values at pH 5.0.The ionic strength had a significant effect on the adsorption at pH 〈 6.0.The adsorption isotherms followed the Langmuir isotherm model well,and the maximum adsorption capacity for Pb（Ⅱ） was 200.38 mg/g for 2Fe-MBC.The adsorption processes were well fitted by a pseudo second-order kinetic model.Thermodynamic parameters showed that the adsorption of Pb（Ⅱ） onto Fe-MBC was feasible,spontaneous,and exothermic under the studied conditions,and the ion exchange mechanism played an significant role.These results have important implications for the design of low-cost and effective adsorbents in the removal of Pb（Ⅱ） from wastewater.展开更多
In this paper,the Pt/SnO2 nanostructures were prepared via a facile one-step microwave assisted hydrothermal route.The structure of the introduced Pt/SnO2 and its gas-sensing properties toward CO were investigated.The...In this paper,the Pt/SnO2 nanostructures were prepared via a facile one-step microwave assisted hydrothermal route.The structure of the introduced Pt/SnO2 and its gas-sensing properties toward CO were investigated.The results from the TEM test reveal that Pt grows on the SnO2 nanostructure,which was not found for bulk in this situ method,constructing Pt/SnO2.The results indicated that the sensor using 3.0 wt%Pt/SnO2 to 100 ppm carbon monoxide performed a superior sensing properties compared to 1.5 wt%and 4.5 wt%Pt/SnO2 at 225℃.The response time of 3.0 wt%sensor is 16 s to 100 ppm CO at225℃.Such enhanced gas sensing performances could be attributed to the chemical and electrical factors.In view of chemical factors,the presence of Pt facilitates the surface reaction,which will improve the gas sensing properties.With respect to the electrical factors,the Pt/SnO2 plays roles in increasing the sensor’s response due to its characteristic configuration.In addition,the one-step in situ microwave assisted process provides a promising and versatile choice for the preparation of gas sensing materials.展开更多
Process parameters of microwave assisted extraction （MAE） of the polysaccharides from pumpkin viz. extraction temperature, time and liquid-solid ratio were studied by using single factor and response surface methodo...Process parameters of microwave assisted extraction （MAE） of the polysaccharides from pumpkin viz. extraction temperature, time and liquid-solid ratio were studied by using single factor and response surface methodology method. The results showed that the liquid-solid ratio was the most important factor in polysaccharides yield, followed the extraction temperature was the least important factor. The optimum microwave assisted extraction co by ndi extraction time, and tions for the highest polysaccharides yield from pumpkin （16.76%-4-0.38%） were obtained by using the response surface methodology with extraction time of 29 min, an extraction temperature of 79 ℃ and a liquid-solid ratio of 22 mL·g^-1. Validation experiment result well agreed with predicted value.展开更多
A Pt/graphene‐TiO2catalyst was prepared by a microwave‐assisted solvothermal method and was characterized by X‐ray diffraction,scanning electron microscopy,transmission electron microscopy,cyclic voltammetry,and li...A Pt/graphene‐TiO2catalyst was prepared by a microwave‐assisted solvothermal method and was characterized by X‐ray diffraction,scanning electron microscopy,transmission electron microscopy,cyclic voltammetry,and linear sweep voltammetry.The cubic TiO2particles were approximately60nm in size and were distributed on the graphene sheets.The Pt nanoparticles were uniformly distributed between the TiO2particles and the graphene sheet.The catalyst exhibited a significant improvement in activity and stability towards the oxygen reduction reaction compared with Pt/C,which resulted from the high electronic conductivity of graphene and strong metal‐support interactions.展开更多
Pomegranate pomace is the solid waste of the pomegranate juice industry which accounts for approximately 50%of the quantity of the fruits,which is processed into juice and is a good raw material for production of high...Pomegranate pomace is the solid waste of the pomegranate juice industry which accounts for approximately 50%of the quantity of the fruits,which is processed into juice and is a good raw material for production of high added value products with diverse uses.Pomegranate pomace is rich in polyphenols and flavonoids which could substitute the potentially hazardous synthetic antioxidants/antimicrobials used in agro-food and cosmetics sectors.In this work,eco-friendly aqueous microwave assisted extraction of pomegranate pomace was investigated and optimized in order to produce effectively novel natural antioxidant/antimicrobial extracts.A three-factorial response surface optimization methodology with centered Box&Behnken experimental design was used to obtain the predictive models and the maximum values of total polyphenols,total flavonoids and total antioxidant capacity(TAC).The three optimization factors involved were:(a)water/solid ratio;(b)extraction temperature;(c)extraction time and the effectiveness and robustness of the three models were statistically verified by ANOVA.展开更多
The ligand free coupling reaction of phenyl urea with different functionalized aryl halides in the presence of air stable Cu_2O and t-BuOK as a base gives symmetrical and unsymmetrical diarylureas in relatively high y...The ligand free coupling reaction of phenyl urea with different functionalized aryl halides in the presence of air stable Cu_2O and t-BuOK as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields.This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligand.展开更多
Orange pomace is the solid waste of the orange juice industry which accounts for approximately 50%of the quantity of the fruits processed into juice and is a good raw material for production of high added value produc...Orange pomace is the solid waste of the orange juice industry which accounts for approximately 50%of the quantity of the fruits processed into juice and is a good raw material for production of high added value products with diverse uses.Orange pomace is rich in polyphenols and flavonoids which can substitute the potentially hazardous or less desirable chemical antioxidants/antimicrobials used in agro-food and cosmetics industry.In this work,an eco-friendly aqueous microwave assisted extraction of orange pomace was investigated and optimized in order to produce aqueous bioactive antioxidant/antimicrobial extracts.A three factorial Response Surface Optimization methodology with centered Box&Behnken experimental design was used to obtain optimum values of total polyphenols and total flavonoids and build predictive models for their optimal extraction conditions.The three optimization factors in terms of applied process parameters were(a)water/solid ratio,(b)extraction temperature and(c)extraction time.The effectiveness and statistical soundness of the two corresponding models regarding optimal total polyphenols and flavonoids were verified by Analysis of Variance(ANOVA).展开更多
To analyze the chemical constituents of volatile oils from the fruit of Periploca forrestii Schltr.which were collected in Guizhou province.This volatile oils were extracted by simultaneous distillation extraction (SD...To analyze the chemical constituents of volatile oils from the fruit of Periploca forrestii Schltr.which were collected in Guizhou province.This volatile oils were extracted by simultaneous distillation extraction (SDE)and microwave assistant extraction(MAE) method,and ananlyzed by gas chromatography-mass spectrometry(GC-MS)method.The main chemical compounds were methyl salicylate,β-amyrin and β-amyrin acetate etc.The compounds from the volatile oils extracted with SDE and MAE are quite different.The results provide scientific proof for the further development and utilization of Periploca forrestii Schltr.展开更多
In this study,the holey graphene was prepared by microwave-assisted chemical etching.The three-dimensional(3D)holey graphene hydrogel was obtained through hydrothermal self-assembly method,followed by the introduction...In this study,the holey graphene was prepared by microwave-assisted chemical etching.The three-dimensional(3D)holey graphene hydrogel was obtained through hydrothermal self-assembly method,followed by the introduction of FeCo_(2)S_(4)particles.The resulting holey graphene hydrogel,characterized by high specific surface area and abundant pores combined with FeCo_(2)S_(4)with high pseudocapacitance by interfacial interaction,shortened the mass transport path and enhanced the specific capacitance.The findings reveal that the holey graphene hydrogel/FeCo_(2)S_(4)(FeCo_(2)S_(4)/HGH)composite exhibits high specific capacitance and impressive rate capability(413.4 F·g^(-1)at 1 A·g^(-1),300.4 F·g^(-1)at 6 A·g^(-1)).The symmetric supercapacitor operated within a stable potential window of 0.1-1.6 V,achieving specific capacitance of 127.5 F·g^(-1)at 1 A·g^(-1),and can deliver 37.1 Wh·kg^(-1)at a power density of 1499 W·kg^(-1).Besides,under the current density of 3 A·g^(-1),the supercapacitor retained 90.8%of its capacitance after 5000 cycles,demonstrating exceptional cycle stability.This study presents an efficient method for fabricating advanced integrated supercapacitors electrodes with enhanced energy density.展开更多
The 1,3-dipolar cycloaddition reaction of cis-[Co(N_(3))_(2)(en)_(2)]NO_(3)1 with different organonitriles(NCR)under focussed microwave irradiation produced bis-tetrazolate complexes[Co(N_(4)CR)_(2)(en)_(2)](NO_(3)).I...The 1,3-dipolar cycloaddition reaction of cis-[Co(N_(3))_(2)(en)_(2)]NO_(3)1 with different organonitriles(NCR)under focussed microwave irradiation produced bis-tetrazolate complexes[Co(N_(4)CR)_(2)(en)_(2)](NO_(3)).Interestingly,in the case of 3-cyano pyridine the reaction produced both cis-and trans-isomers(cis-2 and trans-2),whereas for 4-cyano pyridine the compound obtained was exclusively cis(cis-3)and for 4-bromobenzonitrile it was only the trans-(trans-4)compound which was isolated.This indicates a probable role of remote substitution of the phenyl ring in dictating the formation of the preferential isomer.When starting from the trans-isomer of the diazido complex(trans-[Co(N_(3))_(2)(en)_(2)]ClO_(4),1a),upon reacting with different nitriles a mixture of cis-and trans-isomers of[Co(N_(4)CR)_(2)(en)_(2)]ClO_(4)was produced in each case,with a greater preference towards cis-geometry[R=4-NC_(5)H_(4)(cis-5 and trans-5),4-BrC_(6)H_(4)(cis-6 and trans-6)and C_(6)H_(5)(cis-7 and trans-7)].The preferential formation of the cis-analogue of compound trans-4 when starting from the trans-precursor was quite curious.A theoretical investigation of compounds trans-4 and cis-6 reveals that the greater stability of the trans-complex 4 may arise from additional van der Waals interactions in the solid state because of the presence of an extra DMF molecule as solvent of crystallization.However,an interacting counter-anion and a probable halogen–halogen interaction may also contribute to the formation of preferential isomers for cycloaddition complexes,even in the solution state.展开更多
NiCo_(2)O_(4)nanoflowers were synthesized through a microwave-assisted hydrothermal method and used as a type support for Ni(OH)_(2)nanoparticles.In the three-dimensional NiCo_(2)O_(4)nanoflowers,twodimensional ultrat...NiCo_(2)O_(4)nanoflowers were synthesized through a microwave-assisted hydrothermal method and used as a type support for Ni(OH)_(2)nanoparticles.In the three-dimensional NiCo_(2)O_(4)nanoflowers,twodimensional ultrathin nanosheets supported the Ni(OH)_(2)nanoparticles by homogeneous precipitation.The materials were characterized by field-emission scanning electron microscopy,transmission electron microscopy,X-ray photoelectron spectroscopy,and Raman spectroscopy.The electrochemical oxidation of methanol was probed through the NiCo_(2)O_(4)/Ni(OH)_(2)modification on a glassy carbon electrode in an alkaline medium by employing cyclic voltammetry(CV)and chronoamperometry(CA).The current density of the NiCo_(2)O_(4)/Ni(OH)_(2)electrode in 1 M KOH with 0.5 M methanol ascends to 92.3 A g^(-1)and restores to 94.6%of the primitive value through the replacement with a new solution after a long-term CV cycling(500 cycles).Therefore,the compounds further corroborate their excellent electrocatalytic activity and superb perennial stability for methanol oxidation.This study demonstrates that NiCo_(2)O_(4)/Ni(OH)_(2)is a peculiar material with an outstanding performance in direct methanol fuel cells.展开更多
Defective engineering is crucial for developing extremely effective electrocatalysts for the hydrogen evolution reaction(HER).Herein,low-content platinum(Pt)loaded onto cerium dioxide(CeO₂)cubes with oxygen vacancies(...Defective engineering is crucial for developing extremely effective electrocatalysts for the hydrogen evolution reaction(HER).Herein,low-content platinum(Pt)loaded onto cerium dioxide(CeO₂)cubes with oxygen vacancies(Oᵥ)was developed via an ultrafast microwave quasi-solid-state approach(Pt/CeO₂-Oᵥ)within 60 s.The turnover frequency(TOF)and mass activity verify that the Pt/CeO₂-Oᵥsample demonstrates favorable HER activity owing to the generated Oᵥand the introduction of Pt,which reduce electrical resistance and enhance metal–support electronic interactions.The as-synthesized Pt/CeO₂-Oᵥsample demonstrates a low overpotential of 10 mV to reach 10 mA cm⁻²coupled with a small Tafel slope of 25.6 mV dec⁻¹in 0.5 M H₂SO₄,while also exhibiting remarkable long-term stability.This research paves the way for developing catalysts with exceptional catalytic activity and stability,holding promise in advanced green energy conversion through defect engineering and strong electronic interaction.展开更多
Cerium dioxide(CeO_(2))octahedra were synthesized by a facile microwave-assisted hydrothermal method.The structure and morphology were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and trans...Cerium dioxide(CeO_(2))octahedra were synthesized by a facile microwave-assisted hydrothermal method.The structure and morphology were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The results showed that octahedra were enclosed by eight(111)facets with an edge length of 180 nm.展开更多
Direct electrochemical nitrate reduction to ammonia(NRA)synthesis is an efficient and environmentally friendly production technology.However,the development of highly selective electrocatalysts is still a challenge du...Direct electrochemical nitrate reduction to ammonia(NRA)synthesis is an efficient and environmentally friendly production technology.However,the development of highly selective electrocatalysts is still a challenge due to the nine-proton and eight-electron reduction reaction.High-entropy alloys(HEAs)contain a wide range of elements and have adjustable properties,giving them excellent application potential in multi-step reactions.In this work,we skillfully use the local high temperature and excellent thermal conductivity generated at the reduced graphene oxide(rGO)defect in a microwave process to achieve a rapid quenching process in 10 seconds.This approach overcomes element immiscibility and results in a self-supported,single-phase,non-precious metal and uniform FeCoNiCuSn alloy electrode.The HEAs reach a remarkable NH3 yield of 883.7±11.2μg h^(-1) cm^(-2),maximum faradaic efficiency(FE)of 94.5±1.4%,and highest NH3 selectivity of 90.4±2.7%.Experimental and theoretical calculations reveal that the presence of multiple adjacent elements in HEAs triggers a synergistic catalytic effect,while the excellent mass and charge transfer properties of rGO jointly encourage the performance of the electrochemical NRA.In particular,NO3-favors vertical adsorption at Fe-Fe sites,and the desorption of NH3 is identified as the rate-determining step(RDS)with an extremely smallΔG value of 0.7 eV.展开更多
Regulating interlayer distance is a crucial factor in the development of two‐dimensional(2D)nanomaterials.A 2D metal‐free photocatalyst,such as graphitic carbon nitride(g‐C3N4),exhibits morphology‐and microstruct...Regulating interlayer distance is a crucial factor in the development of two‐dimensional(2D)nanomaterials.A 2D metal‐free photocatalyst,such as graphitic carbon nitride(g‐C3N4),exhibits morphology‐and microstructure‐dependent photocatalytic activity.Herein,we report a straightforward and facile route for the preparation of unique lamellar g‐C3N4,by co‐firing melamine and ammonium chloride via microwave‐assisted heating.Through the decomposition of NH4Cl,the evaporation of NH3 gas can effectively overcome van der Waals forces,expanding the interlayer distance of g‐C3N4,thereby creating a lamellar structure consisting of nanosheets.Compared with bulk g‐C3N4,the NH3‐derived lamellar g‐C3N4 exhibits a larger specific surface area and enhanced optical absorption capability,which increase photocatalytic hydrogen production because of the highly active structure,excellent utilization efficiency of photon energy,and low recombination efficiency of photogenerated charge carriers.This study provides a simple strategy for the regulation of the g‐C3N4 microstructure toward highly efficient photocatalytic applications.展开更多
Adherent nano diamond films were successfully deposited on glass substrate bymicrowave plasma assisted CVD method in H_2-CH_4 and Ar-CH_4 environment. Raman, AFM (Atomic ForceMicroscope), TEM (Transmission Electron Mi...Adherent nano diamond films were successfully deposited on glass substrate bymicrowave plasma assisted CVD method in H_2-CH_4 and Ar-CH_4 environment. Raman, AFM (Atomic ForceMicroscope), TEM (Transmission Electron Microscope), FTIR, and Nano Indentation techniques were usedfor characterization of the obtained nano diamond films. It was found that the average grain sizewas less than 100 nm with a surface roughness value as low as 2 nm. The nano diamond films werefound to have excellent transparency in visible and IR spectrum range, and were as hard as naturaldiamond. Experimental results were presented. Mechanisms for nano diamond film deposition werediscussed.展开更多
In this study the antioxidant activity of barley malt rootlet (BMR) extracts w</span><span style="font-family:"">as</span><span style="font-family:""> evaluated in...In this study the antioxidant activity of barley malt rootlet (BMR) extracts w</span><span style="font-family:"">as</span><span style="font-family:""> evaluated in heat treated corn oil up to 5 hours at 185</span><span style="font-family:"">°</span><span style="font-family:"">C frying temperature. The antioxidant activity </span><span style="font-family:"">of </span><span style="font-family:"">BMR extracts was measured at 25, 50, 100 and 150 ppm concentrations. The free and bound antioxidant phenolics were extracted from BMR using three different extraction methods. Conventional solvent extraction (CSE), microwave assisted extraction (MAE) and autoclave assisted pretreated solvent extraction (APSE). In the present experiment, the total phenolic content and antioxidant activity of the various extracts w</span><span style="font-family:"">ere</span><span style="font-family:""> measured. Thiobarbituric acid reactive substances (TBARS) assay was used to evaluate the ability of the BMR to protect lipid peroxidation in corn oil at 185</span><span style="font-family:"">°</span><span style="font-family:"">C frying temperature. The formation of TBARS at 5 hours of heat treated corn oil ha</span><span style="font-family:"">s</span><span style="font-family:""> shown similar antioxidant levels in 150 ppm butylated hydroxytoluene (BHT) or MAE free phenolic extract added to corn oil. TBARS value for BHT was 1.896 ± 0.013 μg/mL of corn oil and for MAE was 1.896 ± 0.034 μg/mL of corn oil. The highest level of antioxidant activity was found for the free phenolic extracts. The order of inhibition of oxidation was found to be for free phenolics as follows: BHT (100 ppm) > APSE (50 ppm) > MAE (100 ppm) > CSE (100 ppm).展开更多
Microwave-assisted ignition(MAI)is a promising technology to improve the ignition stability in internal combustion engines under lean conditions.To investigate the interplay between the microwave pulses and the electr...Microwave-assisted ignition(MAI)is a promising technology to improve the ignition stability in internal combustion engines under lean conditions.To investigate the interplay between the microwave pulses and the electrical characteristics of ignition plasma,the high-time-resolved electrical characteristics of MAI are measured based on the discharge voltage and current profiles with microwave power varying from 0 to 1000 W.The effects of microwave pulse on the electrical characteristics in the breakdown and glow discharge phases are discussed respectively.The results show that the microwave-induced-voltage-decline(MIVD)occurs during the glow discharge phase,which originates from the increment of free electrons and the additional microwave field.However,this voltage decline is insignificant in the breakdown phase.Moreover,as the free electron number reaches a critical value,a shining plasma can be observed between the gap of electrodes and the voltage decline is stabilized to a"saturated voltage curve".Ultimately,the effect of microwave plasma on the enhancement of ignition kernel area is explored.The result indicates that the enhancement effect increases with plasma duration rising.Those enhancements of earlier-generated plasmas are more significant than those of subsequent plasmas due to the distance limit of the plasma propulsive effect.展开更多
基金supported by Beijing Natural Science Foundation(No.2232062)the Fundamental Research Funds for the Central Universities (No.2652022006)。
文摘The Fenton method is an effective technology for the removal of organic materials from wastewater.In this work,an induced catalyst Fe_(3)O_(4) was synthesized by a hydrothermal method,and the modulation of the chemical composition of Fe_(3)O_(4) crystals was achieved under the microwave shock method with the same effect as that of calcination treatment.Fe_(3)O_(4) catalyst for the removal of the dye Rhodamine B (Rh B) from polluted wastewater under microwave (MW),H_(2)O_(2) system.The results showed that Fe_(3)O_(4) nanomicrospheres prepared by microwave shock exhibited superior catalytic activity under the conditions of 500 W,0.4 mol/L H_(2)O_(2) and10 mg/L Rh B,and the removal rate of Rh B reached 98.5%after 10 min.The Fe_(3)O_(4) catalysts also exhibited good stability and degradation efficiency.Electron paramagnetic resonance experiments confirmed that·OH plays a major role in the rapid degradation of Rh B.Under microwave action,the catalyst produces electron-hole pairs,in which the holes react with OH-produced by water ionisation to form·OH,and the microwave-treated Fe_(3)O_(4) produces more active species.Fe^(3+)and Fe^(2+)serve as microwave catalytic activity centers and Fenton catalytic activity centers,respectively.This research demonstrates that optimizing the Fe^(2+)/Fe^(3+) ratio significantly enhances the degradation efficiency of Rh B.This study presents novel views regarding the mechanism of microwave synergistic catalyst-induced Fenton.
文摘Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.
基金supported by the National Key Technology R&D Program of China (No. 2012BAJ21B01)
文摘Bamboo charcoal（BC） was used as starting material to prepare iron-modified bamboo charcoal（Fe-MBC） by its impregnation in FeCl 3 and HNO 3 solutions simultaneously,followed by microwave heating.The material can be used as an adsorbent for Pb（Ⅱ） contaminants removal in water.The composites were prepared with Fe molar concentration of 0.5,1.0 and 2.0 mol/L and characterized by means of N 2 adsorption-desorption isotherms,X-ray diffraction spectroscopy（XRD）,scanning electron microscopy coupled with energy dispersive X-ray spectrometry（SEM-EDS）,Fourier transform infrared（FT-IR） and point of zero charge（pH pzc） measurements.Nitrogen adsorption analyses showed that the BET specific surface area and total pore volume increased with iron impregnation.The adsorbent with Fe molar concentration of 2 mol/L（2Fe-MBC） exhibited the highest surface area and produced the best pore structure.The Pb（Ⅱ） adsorption process of 2Fe-MBC and BC were evaluated in batch experiments and 2Fe-MBC showed an excellent adsorption capability for removal Pb（Ⅱ）.The adsorption of Pb（Ⅱ） strongly depended on solution pH,with maximum values at pH 5.0.The ionic strength had a significant effect on the adsorption at pH 〈 6.0.The adsorption isotherms followed the Langmuir isotherm model well,and the maximum adsorption capacity for Pb（Ⅱ） was 200.38 mg/g for 2Fe-MBC.The adsorption processes were well fitted by a pseudo second-order kinetic model.Thermodynamic parameters showed that the adsorption of Pb（Ⅱ） onto Fe-MBC was feasible,spontaneous,and exothermic under the studied conditions,and the ion exchange mechanism played an significant role.These results have important implications for the design of low-cost and effective adsorbents in the removal of Pb（Ⅱ） from wastewater.
基金supported by the National Natural Science Foundation of China (No.61803172)the Start-up Research Foundation of Hainan University (No.KYQD(ZR)1910)。
文摘In this paper,the Pt/SnO2 nanostructures were prepared via a facile one-step microwave assisted hydrothermal route.The structure of the introduced Pt/SnO2 and its gas-sensing properties toward CO were investigated.The results from the TEM test reveal that Pt grows on the SnO2 nanostructure,which was not found for bulk in this situ method,constructing Pt/SnO2.The results indicated that the sensor using 3.0 wt%Pt/SnO2 to 100 ppm carbon monoxide performed a superior sensing properties compared to 1.5 wt%and 4.5 wt%Pt/SnO2 at 225℃.The response time of 3.0 wt%sensor is 16 s to 100 ppm CO at225℃.Such enhanced gas sensing performances could be attributed to the chemical and electrical factors.In view of chemical factors,the presence of Pt facilitates the surface reaction,which will improve the gas sensing properties.With respect to the electrical factors,the Pt/SnO2 plays roles in increasing the sensor’s response due to its characteristic configuration.In addition,the one-step in situ microwave assisted process provides a promising and versatile choice for the preparation of gas sensing materials.
基金Supported by National Natural Science Foundation (31071579)Key Program of Heilongjiang Province Science Foundation (ZP201013)
文摘Process parameters of microwave assisted extraction （MAE） of the polysaccharides from pumpkin viz. extraction temperature, time and liquid-solid ratio were studied by using single factor and response surface methodology method. The results showed that the liquid-solid ratio was the most important factor in polysaccharides yield, followed the extraction temperature was the least important factor. The optimum microwave assisted extraction co by ndi extraction time, and tions for the highest polysaccharides yield from pumpkin （16.76%-4-0.38%） were obtained by using the response surface methodology with extraction time of 29 min, an extraction temperature of 79 ℃ and a liquid-solid ratio of 22 mL·g^-1. Validation experiment result well agreed with predicted value.
基金supported by the National Natural Science Foundation of China(21376113)the Jiangsu Specially Appointed Professor Projectthe Graduate Student Scientific Research Innovation Projects in Jiangsu Province(KYZZ15_0384)~~
文摘A Pt/graphene‐TiO2catalyst was prepared by a microwave‐assisted solvothermal method and was characterized by X‐ray diffraction,scanning electron microscopy,transmission electron microscopy,cyclic voltammetry,and linear sweep voltammetry.The cubic TiO2particles were approximately60nm in size and were distributed on the graphene sheets.The Pt nanoparticles were uniformly distributed between the TiO2particles and the graphene sheet.The catalyst exhibited a significant improvement in activity and stability towards the oxygen reduction reaction compared with Pt/C,which resulted from the high electronic conductivity of graphene and strong metal‐support interactions.
文摘Pomegranate pomace is the solid waste of the pomegranate juice industry which accounts for approximately 50%of the quantity of the fruits,which is processed into juice and is a good raw material for production of high added value products with diverse uses.Pomegranate pomace is rich in polyphenols and flavonoids which could substitute the potentially hazardous synthetic antioxidants/antimicrobials used in agro-food and cosmetics sectors.In this work,eco-friendly aqueous microwave assisted extraction of pomegranate pomace was investigated and optimized in order to produce effectively novel natural antioxidant/antimicrobial extracts.A three-factorial response surface optimization methodology with centered Box&Behnken experimental design was used to obtain the predictive models and the maximum values of total polyphenols,total flavonoids and total antioxidant capacity(TAC).The three optimization factors involved were:(a)water/solid ratio;(b)extraction temperature;(c)extraction time and the effectiveness and robustness of the three models were statistically verified by ANOVA.
文摘The ligand free coupling reaction of phenyl urea with different functionalized aryl halides in the presence of air stable Cu_2O and t-BuOK as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields.This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligand.
基金co-financed by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness,Entrepreneurship and Innovation,under the call Research-Create-Innovate(project code:T1EDK-03942).
文摘Orange pomace is the solid waste of the orange juice industry which accounts for approximately 50%of the quantity of the fruits processed into juice and is a good raw material for production of high added value products with diverse uses.Orange pomace is rich in polyphenols and flavonoids which can substitute the potentially hazardous or less desirable chemical antioxidants/antimicrobials used in agro-food and cosmetics industry.In this work,an eco-friendly aqueous microwave assisted extraction of orange pomace was investigated and optimized in order to produce aqueous bioactive antioxidant/antimicrobial extracts.A three factorial Response Surface Optimization methodology with centered Box&Behnken experimental design was used to obtain optimum values of total polyphenols and total flavonoids and build predictive models for their optimal extraction conditions.The three optimization factors in terms of applied process parameters were(a)water/solid ratio,(b)extraction temperature and(c)extraction time.The effectiveness and statistical soundness of the two corresponding models regarding optimal total polyphenols and flavonoids were verified by Analysis of Variance(ANOVA).
文摘To analyze the chemical constituents of volatile oils from the fruit of Periploca forrestii Schltr.which were collected in Guizhou province.This volatile oils were extracted by simultaneous distillation extraction (SDE)and microwave assistant extraction(MAE) method,and ananlyzed by gas chromatography-mass spectrometry(GC-MS)method.The main chemical compounds were methyl salicylate,β-amyrin and β-amyrin acetate etc.The compounds from the volatile oils extracted with SDE and MAE are quite different.The results provide scientific proof for the further development and utilization of Periploca forrestii Schltr.
基金Funded by the National Natural Science Foundation of China(No.51972242)the National College Students'Innovation and Entrepreneurship Training Program(No.202210488020)+2 种基金the Open Fund of the Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steel making(Wuhan University of Science and Technology)of China(No.KF-20-5)the Research Project of Yingcheng Xinjincheng Environmental Protection Technology Co.,Ltd(No.2023420612000754)the Program(No.BG20210227001)of High-end Foreign Experts of the State of the State Administration of Foreign Experts Affairs(SAFEA)。
文摘In this study,the holey graphene was prepared by microwave-assisted chemical etching.The three-dimensional(3D)holey graphene hydrogel was obtained through hydrothermal self-assembly method,followed by the introduction of FeCo_(2)S_(4)particles.The resulting holey graphene hydrogel,characterized by high specific surface area and abundant pores combined with FeCo_(2)S_(4)with high pseudocapacitance by interfacial interaction,shortened the mass transport path and enhanced the specific capacitance.The findings reveal that the holey graphene hydrogel/FeCo_(2)S_(4)(FeCo_(2)S_(4)/HGH)composite exhibits high specific capacitance and impressive rate capability(413.4 F·g^(-1)at 1 A·g^(-1),300.4 F·g^(-1)at 6 A·g^(-1)).The symmetric supercapacitor operated within a stable potential window of 0.1-1.6 V,achieving specific capacitance of 127.5 F·g^(-1)at 1 A·g^(-1),and can deliver 37.1 Wh·kg^(-1)at a power density of 1499 W·kg^(-1).Besides,under the current density of 3 A·g^(-1),the supercapacitor retained 90.8%of its capacitance after 5000 cycles,demonstrating exceptional cycle stability.This study presents an efficient method for fabricating advanced integrated supercapacitors electrodes with enhanced energy density.
文摘The 1,3-dipolar cycloaddition reaction of cis-[Co(N_(3))_(2)(en)_(2)]NO_(3)1 with different organonitriles(NCR)under focussed microwave irradiation produced bis-tetrazolate complexes[Co(N_(4)CR)_(2)(en)_(2)](NO_(3)).Interestingly,in the case of 3-cyano pyridine the reaction produced both cis-and trans-isomers(cis-2 and trans-2),whereas for 4-cyano pyridine the compound obtained was exclusively cis(cis-3)and for 4-bromobenzonitrile it was only the trans-(trans-4)compound which was isolated.This indicates a probable role of remote substitution of the phenyl ring in dictating the formation of the preferential isomer.When starting from the trans-isomer of the diazido complex(trans-[Co(N_(3))_(2)(en)_(2)]ClO_(4),1a),upon reacting with different nitriles a mixture of cis-and trans-isomers of[Co(N_(4)CR)_(2)(en)_(2)]ClO_(4)was produced in each case,with a greater preference towards cis-geometry[R=4-NC_(5)H_(4)(cis-5 and trans-5),4-BrC_(6)H_(4)(cis-6 and trans-6)and C_(6)H_(5)(cis-7 and trans-7)].The preferential formation of the cis-analogue of compound trans-4 when starting from the trans-precursor was quite curious.A theoretical investigation of compounds trans-4 and cis-6 reveals that the greater stability of the trans-complex 4 may arise from additional van der Waals interactions in the solid state because of the presence of an extra DMF molecule as solvent of crystallization.However,an interacting counter-anion and a probable halogen–halogen interaction may also contribute to the formation of preferential isomers for cycloaddition complexes,even in the solution state.
基金supported by National Natural Science Foundation of China(No.21301042,51361009,and 51461014).
文摘NiCo_(2)O_(4)nanoflowers were synthesized through a microwave-assisted hydrothermal method and used as a type support for Ni(OH)_(2)nanoparticles.In the three-dimensional NiCo_(2)O_(4)nanoflowers,twodimensional ultrathin nanosheets supported the Ni(OH)_(2)nanoparticles by homogeneous precipitation.The materials were characterized by field-emission scanning electron microscopy,transmission electron microscopy,X-ray photoelectron spectroscopy,and Raman spectroscopy.The electrochemical oxidation of methanol was probed through the NiCo_(2)O_(4)/Ni(OH)_(2)modification on a glassy carbon electrode in an alkaline medium by employing cyclic voltammetry(CV)and chronoamperometry(CA).The current density of the NiCo_(2)O_(4)/Ni(OH)_(2)electrode in 1 M KOH with 0.5 M methanol ascends to 92.3 A g^(-1)and restores to 94.6%of the primitive value through the replacement with a new solution after a long-term CV cycling(500 cycles).Therefore,the compounds further corroborate their excellent electrocatalytic activity and superb perennial stability for methanol oxidation.This study demonstrates that NiCo_(2)O_(4)/Ni(OH)_(2)is a peculiar material with an outstanding performance in direct methanol fuel cells.
基金funding support from the National Natural Science Foundation of China(52371227,52272222,52102273 and 52072197)the Taishan Scholar Young Talent Program(tsqn201909114,tsqn202408200)+1 种基金the Shandong Province“Double-Hundred Talent Plan”(WST2020003)the Natural Science Foundation of Shandong Province of China(ZR2021QE081).
文摘Defective engineering is crucial for developing extremely effective electrocatalysts for the hydrogen evolution reaction(HER).Herein,low-content platinum(Pt)loaded onto cerium dioxide(CeO₂)cubes with oxygen vacancies(Oᵥ)was developed via an ultrafast microwave quasi-solid-state approach(Pt/CeO₂-Oᵥ)within 60 s.The turnover frequency(TOF)and mass activity verify that the Pt/CeO₂-Oᵥsample demonstrates favorable HER activity owing to the generated Oᵥand the introduction of Pt,which reduce electrical resistance and enhance metal–support electronic interactions.The as-synthesized Pt/CeO₂-Oᵥsample demonstrates a low overpotential of 10 mV to reach 10 mA cm⁻²coupled with a small Tafel slope of 25.6 mV dec⁻¹in 0.5 M H₂SO₄,while also exhibiting remarkable long-term stability.This research paves the way for developing catalysts with exceptional catalytic activity and stability,holding promise in advanced green energy conversion through defect engineering and strong electronic interaction.
基金supported by the National Natural Science Foundation of China(No:21373010 and No:51602322)the Youth Innovation Promotion Association CAS(No:2015141)+2 种基金the Shanxi Province Science Foundation for Youths(No:201701D211005)the CAS Interdisciplinary Innovation Team(No:BK2018001)the Excellent Youth Scholars of State Key Laboratory of Coal Conversion(No:2016BWZ001)。
文摘Cerium dioxide(CeO_(2))octahedra were synthesized by a facile microwave-assisted hydrothermal method.The structure and morphology were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The results showed that octahedra were enclosed by eight(111)facets with an edge length of 180 nm.
基金supported by the National Natural Science Foundation of China(No.21872034)the Project of the Natural Science Foundation of Fujian Province(No.2019J01746)+1 种基金the Open Fund of Fujian Key Laboratory of Electrochemical Energy Storage Materials,Fuzhou University(No.2021CN01)the Natural Science Foundation of Zhangzhou City(No.ZZ2024J16).
文摘Direct electrochemical nitrate reduction to ammonia(NRA)synthesis is an efficient and environmentally friendly production technology.However,the development of highly selective electrocatalysts is still a challenge due to the nine-proton and eight-electron reduction reaction.High-entropy alloys(HEAs)contain a wide range of elements and have adjustable properties,giving them excellent application potential in multi-step reactions.In this work,we skillfully use the local high temperature and excellent thermal conductivity generated at the reduced graphene oxide(rGO)defect in a microwave process to achieve a rapid quenching process in 10 seconds.This approach overcomes element immiscibility and results in a self-supported,single-phase,non-precious metal and uniform FeCoNiCuSn alloy electrode.The HEAs reach a remarkable NH3 yield of 883.7±11.2μg h^(-1) cm^(-2),maximum faradaic efficiency(FE)of 94.5±1.4%,and highest NH3 selectivity of 90.4±2.7%.Experimental and theoretical calculations reveal that the presence of multiple adjacent elements in HEAs triggers a synergistic catalytic effect,while the excellent mass and charge transfer properties of rGO jointly encourage the performance of the electrochemical NRA.In particular,NO3-favors vertical adsorption at Fe-Fe sites,and the desorption of NH3 is identified as the rate-determining step(RDS)with an extremely smallΔG value of 0.7 eV.
文摘Regulating interlayer distance is a crucial factor in the development of two‐dimensional(2D)nanomaterials.A 2D metal‐free photocatalyst,such as graphitic carbon nitride(g‐C3N4),exhibits morphology‐and microstructure‐dependent photocatalytic activity.Herein,we report a straightforward and facile route for the preparation of unique lamellar g‐C3N4,by co‐firing melamine and ammonium chloride via microwave‐assisted heating.Through the decomposition of NH4Cl,the evaporation of NH3 gas can effectively overcome van der Waals forces,expanding the interlayer distance of g‐C3N4,thereby creating a lamellar structure consisting of nanosheets.Compared with bulk g‐C3N4,the NH3‐derived lamellar g‐C3N4 exhibits a larger specific surface area and enhanced optical absorption capability,which increase photocatalytic hydrogen production because of the highly active structure,excellent utilization efficiency of photon energy,and low recombination efficiency of photogenerated charge carriers.This study provides a simple strategy for the regulation of the g‐C3N4 microstructure toward highly efficient photocatalytic applications.
基金This work was financially supported by the National "863" Project of China (No.863-715-Z38-03).
文摘Adherent nano diamond films were successfully deposited on glass substrate bymicrowave plasma assisted CVD method in H_2-CH_4 and Ar-CH_4 environment. Raman, AFM (Atomic ForceMicroscope), TEM (Transmission Electron Microscope), FTIR, and Nano Indentation techniques were usedfor characterization of the obtained nano diamond films. It was found that the average grain sizewas less than 100 nm with a surface roughness value as low as 2 nm. The nano diamond films werefound to have excellent transparency in visible and IR spectrum range, and were as hard as naturaldiamond. Experimental results were presented. Mechanisms for nano diamond film deposition werediscussed.
文摘In this study the antioxidant activity of barley malt rootlet (BMR) extracts w</span><span style="font-family:"">as</span><span style="font-family:""> evaluated in heat treated corn oil up to 5 hours at 185</span><span style="font-family:"">°</span><span style="font-family:"">C frying temperature. The antioxidant activity </span><span style="font-family:"">of </span><span style="font-family:"">BMR extracts was measured at 25, 50, 100 and 150 ppm concentrations. The free and bound antioxidant phenolics were extracted from BMR using three different extraction methods. Conventional solvent extraction (CSE), microwave assisted extraction (MAE) and autoclave assisted pretreated solvent extraction (APSE). In the present experiment, the total phenolic content and antioxidant activity of the various extracts w</span><span style="font-family:"">ere</span><span style="font-family:""> measured. Thiobarbituric acid reactive substances (TBARS) assay was used to evaluate the ability of the BMR to protect lipid peroxidation in corn oil at 185</span><span style="font-family:"">°</span><span style="font-family:"">C frying temperature. The formation of TBARS at 5 hours of heat treated corn oil ha</span><span style="font-family:"">s</span><span style="font-family:""> shown similar antioxidant levels in 150 ppm butylated hydroxytoluene (BHT) or MAE free phenolic extract added to corn oil. TBARS value for BHT was 1.896 ± 0.013 μg/mL of corn oil and for MAE was 1.896 ± 0.034 μg/mL of corn oil. The highest level of antioxidant activity was found for the free phenolic extracts. The order of inhibition of oxidation was found to be for free phenolics as follows: BHT (100 ppm) > APSE (50 ppm) > MAE (100 ppm) > CSE (100 ppm).
文摘Microwave-assisted ignition(MAI)is a promising technology to improve the ignition stability in internal combustion engines under lean conditions.To investigate the interplay between the microwave pulses and the electrical characteristics of ignition plasma,the high-time-resolved electrical characteristics of MAI are measured based on the discharge voltage and current profiles with microwave power varying from 0 to 1000 W.The effects of microwave pulse on the electrical characteristics in the breakdown and glow discharge phases are discussed respectively.The results show that the microwave-induced-voltage-decline(MIVD)occurs during the glow discharge phase,which originates from the increment of free electrons and the additional microwave field.However,this voltage decline is insignificant in the breakdown phase.Moreover,as the free electron number reaches a critical value,a shining plasma can be observed between the gap of electrodes and the voltage decline is stabilized to a"saturated voltage curve".Ultimately,the effect of microwave plasma on the enhancement of ignition kernel area is explored.The result indicates that the enhancement effect increases with plasma duration rising.Those enhancements of earlier-generated plasmas are more significant than those of subsequent plasmas due to the distance limit of the plasma propulsive effect.
