The kinetics of aniline degradation by persulfate processes with iron（Ⅱ） activation at ambient temperature was investigated in this study.With iron（Ⅱ） as initiator,the oxidation reactions were found to follow a ...The kinetics of aniline degradation by persulfate processes with iron（Ⅱ） activation at ambient temperature was investigated in this study.With iron（Ⅱ） as initiator,the oxidation reactions were found to follow a biphasic rate phenomenon：a rapid transformation followed by a slow but sustained oxidation process.In the first 30 s,the reaction mainly relies on the persulfate-Fe^（2＋） reaction in which aniline is oxidized rapidly.After 30 s,the aniline was still oxidized but the rate of reaction tended to be slower and the rates were clearly linear-proportional.After the initial fast oxidation,the reactions appeared to follow a pseudo-first-order model.展开更多
Many studies have successfully built iron-mediatedmaterials to activate or catalyze Fentonlike reactions,with applications in water and wastewater treatment being investigated.However,the developed materials are rarel...Many studies have successfully built iron-mediatedmaterials to activate or catalyze Fentonlike reactions,with applications in water and wastewater treatment being investigated.However,the developed materials are rarely compared with each other regarding their performance of organic contaminant removal.In this review,the recent advances of Fentonlike processes in homogeneous and heterogeneous ways are summarized,especially the performance and mechanism of activators including ferrous iron,zero valent iron,iron oxides,iron-loaded carbon,zeolite,and metal organic framework materials.Also,this work mainly compares three O-O bond containing oxidants including hydrogen dioxide,persulfate,and percarbonate,which are environmental-friendly oxidants and feasible for in-situ chemical oxidation.The influence of reaction conditions,catalyst properties and benefits are analyzed and compared.In addition,the challenges and strategies of these oxidants in applications and the major mechanisms of the oxidation process have been discussed.This work can help understand the mechanistic insights of variable Fenton-like reactions,the role of emerging iron-based materials,and provide guidance for choosing appropriate technologies when facing real-world water and wastewater applications.展开更多
Anode material for lithium ion battery is prepared by chemical oxidation of natural graphite. After oxidation, the properties of natural graphite are modified, such as surface structure, the content of graphite phases...Anode material for lithium ion battery is prepared by chemical oxidation of natural graphite. After oxidation, the properties of natural graphite are modified, such as surface structure, the content of graphite phases, the number of micropores and its stability. thus the modified natural graphite can be used as anode material for commercial lithium ion battery. The reversible capacity is increased from 100 mAh/g to above 300 mAh/g, and its cycling properly is also satisfactory.展开更多
Acidic black 10B dye wastewater was treated by chemical oxidation and adsorption of activated carbon fixed bed and all kinds of influential factors of removal CODcr were discussed. When the initial concentration of th...Acidic black 10B dye wastewater was treated by chemical oxidation and adsorption of activated carbon fixed bed and all kinds of influential factors of removal CODcr were discussed. When the initial concentration of the dye was 150 mg/L, CODer was 432 mg/L and chrome was 2800 times, the appropriate conditions determined by the experiment were as follows： r（NaC10）--4.84 g/L, 25 min, pH=6, height of activated carbon fixed bed was 10 cm. Under these conditions, the decolorizing rate can come up to about 100% and total removed rate of CODer reached at 89.6%. Comparison of UV-Vis adsorption spectrums before and after treatment showed that decomposition effects of chemical oxidation and adsorption of activated carbon fixed bed on acidic black 10B dye wastewater were satisfactory.展开更多
Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for converting ethane to ethylene.In the current study MeO/LaCoO_(3)(MeO=Fe_(2)O_(3),NiO or Co_(2)O_(3))composite metal oxides w...Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for converting ethane to ethylene.In the current study MeO/LaCoO_(3)(MeO=Fe_(2)O_(3),NiO or Co_(2)O_(3))composite metal oxides were prepared via citrate gel and impregnation methods,and used as oxygen carriers for CL-ODH.X-ray diffraction results indicated that all oxygen carriers had a perovskite structure even after eight redox cycles.Under a reaction temperature of 650°C,a reaction pressure of 0.1 MPa,and a weight hourly space velocity(WHSV)of 7500 mL/(g·h),ethane conversion over Co_(2)O_(3)/LaCoO_(3) reached 100%and ethylene selectivity reached 60%,both of which were better than corresponding values attained over Fe_(2)O_(3)/LaCoO_(3) and NiO/LaCoO_(3).Ethylene selectivity remained stable for 80 cycles over Co_(2)O_(3)/LaCoO_(3),then decreased gradually after 80 cycles.X-ray photoelectron spectroscopy results and evaluation results indicated that lattice oxygen and O_(2)2-had a direct relationship with ethane conversion and ethylene selectivity.Co_(2)O_(3)/LaCoO_(3) exhibited a strong capacity to release and absorb oxygen,mainly due to interaction between Co_(2)O_(3) and LaCoO_(3).展开更多
Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for ethylene preparation.Fe_(2)O_(3)/MgO oxygen carrier was prepared using the co-precipitation method.The influence of added Ni...Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for ethylene preparation.Fe_(2)O_(3)/MgO oxygen carrier was prepared using the co-precipitation method.The influence of added NiO and its different loadings on Fe_(2)O_(3)/MgO were investigated.Then,a series of oxygen carriers were applied in the CL-ODH of the ethane cycle system.Brunauer-Emmett-Teller(BET),X-ray diffractometry(XRD),X-ray photoelection spectroscopy(XPS),and H2-temperature programmed reduction(TPR)were used to characterize the physicochemical properties of these oxygen carriers.It was confirmed that an interaction between NiO and Fe_(2)O_(3) occurred based on the XPS and H2-TPR results.Based on the CL-ODH activity performance tests conducted in a fixed-bed reactor,it was revealed that ethylene selectivity was significantly improved after NiO addition.Fe_(2)O_(3)-10%NiO/MgO showed the best activity performance with 93%ethane conversion and 50%ethylene selectivity at a reaction temperature of 650℃,atmospheric pressure,and space velocity of 7500 mL/(g·h).展开更多
The kinetics of heat-facilitated persulfate oxidation of p-chloroaniline（PCA） in aqueous solutions was measured at five different temperature conditions and at four different oxidant concentrations.The PCA degradati...The kinetics of heat-facilitated persulfate oxidation of p-chloroaniline（PCA） in aqueous solutions was measured at five different temperature conditions and at four different oxidant concentrations.The PCA degradation was found to follow a pseudo-first-order decay model when the persulfate was excessive.The pseudo-first-order rate constants of PCA degradation by persulfate（50 mmol/ L） at pH 7.0 are 0.12×10^-4,0.28×10^-4,0.43×10^-4,0.83×10^-4,1.32×10^-4 s^-1 at 10,20,30,40 and 50℃,respectively. Under the above reaction conditions,the reaction has activation energy of 49.97 kJ/mol.The observed rate was found to be function of temperature and oxidant concentration.Raising temperature and increasing persulfate concentration can significantly accelerate the PCA degradation.展开更多
Fenton and ozone treatment was investigated at laboratory scale for the degradation of aqueous solutions of nitrobenzene （NB）. Effects of reactants concentration （O3, H2O2, and Fe（Ⅱ））, temperature, and pH on NB...Fenton and ozone treatment was investigated at laboratory scale for the degradation of aqueous solutions of nitrobenzene （NB）. Effects of reactants concentration （O3, H2O2, and Fe（Ⅱ））, temperature, and pH on NB degradation were monitored. Reaction kinetic of these processes was also assessed. A rapid reaction took place for Fenton process at higher initial concentration of H2O2, higher temperatures, and more acidic conditions （pH 3）. Similarly, ozonation reaction exhibited rapid rates for higher ozone dose, higher temperatures, and more basic conditions （pH 11）. Complete NB degradation in 65 min was achieved using Fenton process. The conditions of complete elimination of 100 mg/L of initial NB concentration, were 250 mg/L of H202 concentration, pH 3, and 10 mg/L of Fe（Ⅱ） concentration. Under these conditions, 55% organic carbon elimination was achieved. Total organic carbon mineralization was attained in 240 rain reaction time by Fenton process with 900 mg/L of H202 concentration, and 30 mg/L of Fe（Ⅱ） concentration. Fenton reaction showed a pseudo-first order kinetic; the reaction rate constant was ranged from 0.0226 to 0.0658 min^-1. Complete NB degradation was also achieved for an ozone dose of the order of 2.5 g/L. The ozonation was studied at different ozone doses, different initial pH （7-11） and at different temperatures （15-35℃）. NB ozonation kinetic was represented by a bi-molecular kinetic model which was reduced to pseudo-first order kinetic. The pseudo-first order reaction rate constant was determined to increase at 20℃ from 0.004 to 0.020 min^-1 as the used ozone increased from 0.4 to 1.9 g/L.展开更多
Decoloration of acidic scarlet GR by pyrolusite is studied in this paper. The effects of pH in solution, dosage and granularity of pyrolusite, reaction temperature, and vibration speed on decoloration efficiency are d...Decoloration of acidic scarlet GR by pyrolusite is studied in this paper. The effects of pH in solution, dosage and granularity of pyrolusite, reaction temperature, and vibration speed on decoloration efficiency are discussed. According to experiment results, the decoloration efficiency may exceed 95% for 40 mg/L GR solution by pyrolusite, pH is most important among all factors which impact the decoloration of acidic scarlet GR. Dosage and granularity of pyrolusite, reaction temperature, and vibration speed have a little benitfit on decoloration. The high decoloration efficiency and low removal efficiency of COD as well as FT-IR spectra of products between pyrolusite and acidic scarlet GR indicate that acidic scarlet GR undergoes the redox reaction on the interface of mineral and its chromophore is oxidated and decolored, but it is not removed thoroughly by oxidation.展开更多
Nicotinic acid was synthesized from 3 methylpyridine with potassium dichromate as the oxidant. The reaction conditions, the product separation and analysis were studied. The results indicate that under the certain re...Nicotinic acid was synthesized from 3 methylpyridine with potassium dichromate as the oxidant. The reaction conditions, the product separation and analysis were studied. The results indicate that under the certain reaction conditions, the yield of nicotinic acid can reach 67.4%, the conversion can reach 99.7% and the selectivity can be as high as 99.8%. The final product has a high purity.展开更多
An in situ characterization technique called electrochemical noise（ECN） was used to investigate the bioleaching of natural pyrite.ECN experiments were conducted in four active systems（sulfuric acid,ferric-ion,9k cu...An in situ characterization technique called electrochemical noise（ECN） was used to investigate the bioleaching of natural pyrite.ECN experiments were conducted in four active systems（sulfuric acid,ferric-ion,9k culture medium,and bioleaching solutions）.The ECN data were analyzed in both the time and frequency domains.Spectral noise impedance spectra obtained from power spectral density（PSD）plots for different systems were compared.A reaction mechanism was also proposed on the basis of the experimental data analysis.The bioleaching system exhibits the lowest noise resistance of 0.101 MΩ The bioleaching of natural pyrite is considered to be a bio-battery reaction,which distinguishes it from chemical oxidation reactions in ferric-ion and culture-medium（9k） solutions.The corrosion of pyrite becomes more severe over time after the long-term testing of bioleaching.展开更多
The goal of this topic is a synthesis of the main characteristics of iron in groundwater and the oxidation process used to remove it. Indeed, the kinetics of chemical oxidation of iron (II) was examined with reconstit...The goal of this topic is a synthesis of the main characteristics of iron in groundwater and the oxidation process used to remove it. Indeed, the kinetics of chemical oxidation of iron (II) was examined with reconstituted water (distilled water + iron sulphate) and proceeded to the application in the groundwater samples taken from <em><strong>South Pout</strong></em> (Senegal) precisely in the drilling <strong>PS2</strong>. The sources of iron are natural or anthropogenic. In Senegalese waters, its content is variable and sometimes exceeds the standards of potability. Despite the diversification of iron removal process, chemical oxidation is the most used solution in drinking water treatment plants in Senegalese rural areas. Applied oxidation processes such as aeration and chlorination, however, are insufficient to produce drinking water with an iron concentration in accordance with standards of potability.展开更多
In this study,water-dispersible graphitic carbon nitride(g-C_(3)N_(4))photocatalysts were successively prepared through the chemically oxidative etching of bulk g-C_(3)N_(4) that was polymerized thermally in different...In this study,water-dispersible graphitic carbon nitride(g-C_(3)N_(4))photocatalysts were successively prepared through the chemically oxidative etching of bulk g-C_(3)N_(4) that was polymerized thermally in different calcination atmospheres such as air,CO_(2),and N_(2).The different calcination atmospheres directly influenced the physicochemical and optical properties of both bulk and water-dispersible g-C_(3)N_(4),changing the photocatalytic degradation behavior of methylene blue(MB)and tetracycline hydrochloride(TCHCl)for water-dispersible g-C_(3)N_(4).The bubble-burst process in the thermal polymerization of thiourea produced defective edges containing C=O groups that preferred substituting the C-NHx groups over bulk g-C_(3)N_(4).In the oxygen-free N_(2) atmosphere among the different calcination atmospheres,more C=O functional groups were generated on the defective edges of bulk g-C_(3)N_(4),resulting in the highest N vacancy of the tri-s-triazine structure.During the successive chemical oxidation,S-or O-containing functional groups were introduced onto water-dispersible g-C_(3)N_(4).The water-dispersible g-C_(3)N_(4) photocatalyst from the oxygen-free N_(2) atmosphere(NTw)contained the most O-and S-functional groups on the g-C_(3)N_(4) surface.Consequently,NTw exhibited the highest photocatalytic activity in the MB and TC-HCl photodegradation because of its slowest recombination process,which was ascribed to the unique surface properties of NTw such as abundant functional groups on the defective edges and N-deficient property.展开更多
The effect of chemically reduced graphene oxide （CRGO） on the phase separation behavior of poly（methyl methacrylate）/poly（styrene-co-acrylonitrile） （PMMA/SAN） blends and the simultaneous response of rheologica...The effect of chemically reduced graphene oxide （CRGO） on the phase separation behavior of poly（methyl methacrylate）/poly（styrene-co-acrylonitrile） （PMMA/SAN） blends and the simultaneous response of rheological and conductive behavior of PMMA/SAN/CRGO nanocomposites upon annealing above the phase-separation temperatures were investigated. The introduction of CRGO causes the decrease of binodal temperature and the increase of spinodal temperature for PMMA/SAN blends and then enlarges their metastable regime. During annealing, the well-dispersed CRGO in the homogeneous blend matrix tends to be selectively located in the SAN-rich phase with the evolution of phase separation and then the CRGO further agglomerates effectively in the SAN-rich phase to form the conductive pathway. Thermal-induced dynamic percolation is observed for both the resistivity p and dynamic storage modulus G＇ as a function of annealing time. The resistivity variation is ascribed to the agglomeration of CRGO in the SAN-rich phase, while the modulus evolution is attributed to the combined contribution of phase separation for blend matrix and the agglomeration of CRGO in the SAN-rich phase.展开更多
Birnessite-type MnO2 （δ-MnO2） nano-sheets were successfully synthesized by an interracial synthesis method in this work. The properties and electrochemical performance of the as-prepared δ-MnO2 were analyzed and e...Birnessite-type MnO2 （δ-MnO2） nano-sheets were successfully synthesized by an interracial synthesis method in this work. The properties and electrochemical performance of the as-prepared δ-MnO2 were analyzed and evaluated by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, nitrogen adsorption measurement and electrochemical tests. This facile synthesis method enables δ-MnO2 nanosheets to show a large specific surface area （257.5 m^2 g^-1）. The electrochemical test results show that the specific capacitance is 272 F g^-1 and the specific capacitance retention is over 96.7% after 1000 cycles at a scan rate of 10 mV s^-1. All results demonstrate that δ-MnO2 has a great potential application in high- performance electrochemical capacitors, and this interracial synthesis method will be a very promising method to synthesize highly active MnO2 materials in a large scale.展开更多
Nitric oxide（NO）,a bioactive signaling molecule,serves as an antioxidant and anti-stress agent under abiotic stress.A hydroponics experiment was conducted to investigate the effects of sodium nitroprusside（SNP）,a ...Nitric oxide（NO）,a bioactive signaling molecule,serves as an antioxidant and anti-stress agent under abiotic stress.A hydroponics experiment was conducted to investigate the effects of sodium nitroprusside（SNP）,a NO donor,on tomato seedlings exposed to 50 μmol L-1CuCl 2.The results show that copper is primarily stored in the soluble cell sap fraction in the roots,especially after treatment with Cu＋SNP treatment,which accounted for 66.2% of the total copper content.The copper concentration gradually decreased from the roots to the leaves.In the leaves,exogenous NO induces the storage of excess copper in the cell walls.Copper stress decreases the proportion of copper integrated with pectates and proteins,but exogenous NO remarkably reverses this trend.The alleviating effect of NO is blocked by hemoglobin.Thus,exogenous NO is likely involved in the regulation of the subcellular copper concentrations and its chemical forms under copper stress.Although exogenous NO inhibited the absorption and transport of excess copper to some extent,the copper accumulation in tomato seedlings significantly increased under copper stress.The use of exogenous NO to enhance copper tolerance in some plants is a promising method for copper remediation.展开更多
The hydrophobic films of TixOy-CmHn. deposited from mixture gases of titanium isopropoxide （TTIP） and oxygen by plasma enhanced chemical vapor deposition （PECVD） were investigated. The films were investigated by s...The hydrophobic films of TixOy-CmHn. deposited from mixture gases of titanium isopropoxide （TTIP） and oxygen by plasma enhanced chemical vapor deposition （PECVD） were investigated. The films were investigated by scanning electron microscope （ SEM ）, transmission electron microscope （ TEM ）, Fourier transform infrared spectrometer （ FTIR）, X-Ray diffraction （ XRD ）, element analysis （ EA ）, ultraviolet visible spectrometer （ UV-Vis）, and water contact angle （WCA）. The results reveal that the surface of the films is formed by mierosized papillaes aggregated by inorganic and organic phases of complex nanoparticles with size from 50 nm to 200 nm when the discharge power is increased from 40 W to 150 W. All fdms demonstrate the strong broad of Ti-O-Ti stretching vibration at 400 -800cm-1, -CH bending vibration at 1 388 cm -1, and broadening -OH stretching vibration at 3 000-3500 cm-1 With the increase of the discharge power, the asdeposited film changes from amorphous to crystallization. The WCA of the film can be as high as 160°, indicating the hydrophobicity. The films show a similar ultraviolet absorption property as the bulk TiO2 film. The composition of the composition of film deposited at 150 W can be formulated as Tio.302-C1.5H3. Therefore, the composition formula of this hydrophobic film could be expressed as TiO2-C5H10O4.7. It is believed that the complex micro/nano structures of TiO2 and C5H10O4.7 residues are responsible for the observed hydrophobicity and the ultraviolet absorption property of the film.展开更多
Chemical oxidation was applied to an artificially contaminated soil with naphthalene(NAP).Evaluation of NAP distribution and mass reduction in soil,water and air phases was carried out through mass balance.Evaluation ...Chemical oxidation was applied to an artificially contaminated soil with naphthalene(NAP).Evaluation of NAP distribution and mass reduction in soil,water and air phases was carried out through mass balance.Evaluation of NAP distribution and mass reduction in soil,water and air phases was carried out through mass balance.The importance of the air phase analysis was emphasized by demonstrating how NAP behaves in a sealed system over a 4 hr reaction period.Design of Experiments method was applied to the following variables:sodium persulfate concentration[SP],ferrous sulfate concentration[FeS04],and pH.The system operated with a prefixed solid to liquid ratio of 1:2.The following conditions resulted in optimum NAP removal[SP]=18.37 g/L,[FeSO4]=4.25 g/L and pH=3.00.At the end of the 4 hr reaction,62%of NAP was degraded.In the soil phase,the chemical oxidation reduced the NAP concentration thus achieving levels which comply with Brazilian and USA environmental legislations.Besides the NAP partitioning view,the monitoring of each phase allowed the variabilities assessment over the process,refining the knowledge of mass reduction.Based on NAP distribution in the system,this study demonstrates the importance of evaluating the presence of semi-volatile and volatile organic compounds in the air phase during remediation,so that there is greater control of the system as to the distribution and presence of the contaminant in the environment.The results highlight the importance of treating the contaminant in all its phases at the contaminated site.展开更多
A PANI/TiO2 composite film deposited on the glass surface was successfully prepared using sol-gel dip-coating technique and chemical oxidation method. The film was characterized using XRD, AFM, and UV. The result show...A PANI/TiO2 composite film deposited on the glass surface was successfully prepared using sol-gel dip-coating technique and chemical oxidation method. The film was characterized using XRD, AFM, and UV. The result showed that the TiO2 film consists of both cuboid-shaped and anatase-phased TiO2 nanoparticles. The average grain size of TiO2 in the film was approximately 20 nm. After coating with PANI, the particle was changed into irregular spherical-shaped and the size was increased up to approximately 35 nm in diameter. UV-Vis spectroscopy analysis indicated that the coating of TiO2 with PANI would result in an enhancement of photocatalytic efficiency and an extension of the photoresponse of TiO2. The band gap of the PANI/TiO2 film was 3.18 eV. The photocatalytic property of the film was evaluated by the degradation of rhodamine-B. It was found that 67.1% and 83.2% of rhodamine-B could be degraded under sunlight and UV irradiation within 120 min using the PANI/TiO2 composite t-tim as photocatalyst.展开更多
Trichloroethylene （TCE）, as one of the most common chlorinated organic compounds in soils and aquifers at many industrial sites, is carcinogenic and often recalcitrant in environment. TCE degradation in artificially...Trichloroethylene （TCE）, as one of the most common chlorinated organic compounds in soils and aquifers at many industrial sites, is carcinogenic and often recalcitrant in environment. TCE degradation in artificially contaminated soil samples was conducted using Fenton-like processes, i.e., by addition of excess hydrogen peroxide （H2O2）. H2O2 could directly oxidize TCE without addition of ferrous iron in contaminated soil. Under the optimal condition （H2O2 concentration of 300 mg kg^-1, pH at 5.0, and reaction time of 30 rain）, the removal efficiency of TCE in the soil was up to 92.3%. When the initial TCE concentration increased from 30 to 480 mg kg^-1 in soil, the TCE removal rates varied from 89.2% to 86.6%; while the residual TCE in soil ranged from 2.28 to 47.57 mg kg^-1. Results from successive oxidations showed that the TCE removal rate with the TCE concentration of 180 mg kg^-1 increased slightly from 91.6% to 96.2% as the number of successive oxidation cycle increased from one to four. Therefore, increasing the frequency of H2O2 oxidation was perhaps a feasible way to increase TCE removal rate for TCE-contaminated soil.展开更多
基金supported by a grant from E.I.du Pont de Nemours and Company to Rutgers University.Partial funding wasalso provided by the Natural Science Foundation of Guangdong Province(No.9351064101000001)Science and Technology Planning Project of Guangdong Province(No.2007A020100001-13)the Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Higher Education Institutions(China)
文摘The kinetics of aniline degradation by persulfate processes with iron（Ⅱ） activation at ambient temperature was investigated in this study.With iron（Ⅱ） as initiator,the oxidation reactions were found to follow a biphasic rate phenomenon：a rapid transformation followed by a slow but sustained oxidation process.In the first 30 s,the reaction mainly relies on the persulfate-Fe^（2＋） reaction in which aniline is oxidized rapidly.After 30 s,the aniline was still oxidized but the rate of reaction tended to be slower and the rates were clearly linear-proportional.After the initial fast oxidation,the reactions appeared to follow a pseudo-first-order model.
基金This work was supported by the Natural Science Foundation of China(No.52100196)China Key Technologies R&D program(No.2021YFC3200700).
文摘Many studies have successfully built iron-mediatedmaterials to activate or catalyze Fentonlike reactions,with applications in water and wastewater treatment being investigated.However,the developed materials are rarely compared with each other regarding their performance of organic contaminant removal.In this review,the recent advances of Fentonlike processes in homogeneous and heterogeneous ways are summarized,especially the performance and mechanism of activators including ferrous iron,zero valent iron,iron oxides,iron-loaded carbon,zeolite,and metal organic framework materials.Also,this work mainly compares three O-O bond containing oxidants including hydrogen dioxide,persulfate,and percarbonate,which are environmental-friendly oxidants and feasible for in-situ chemical oxidation.The influence of reaction conditions,catalyst properties and benefits are analyzed and compared.In addition,the challenges and strategies of these oxidants in applications and the major mechanisms of the oxidation process have been discussed.This work can help understand the mechanistic insights of variable Fenton-like reactions,the role of emerging iron-based materials,and provide guidance for choosing appropriate technologies when facing real-world water and wastewater applications.
文摘Anode material for lithium ion battery is prepared by chemical oxidation of natural graphite. After oxidation, the properties of natural graphite are modified, such as surface structure, the content of graphite phases, the number of micropores and its stability. thus the modified natural graphite can be used as anode material for commercial lithium ion battery. The reversible capacity is increased from 100 mAh/g to above 300 mAh/g, and its cycling properly is also satisfactory.
文摘Acidic black 10B dye wastewater was treated by chemical oxidation and adsorption of activated carbon fixed bed and all kinds of influential factors of removal CODcr were discussed. When the initial concentration of the dye was 150 mg/L, CODer was 432 mg/L and chrome was 2800 times, the appropriate conditions determined by the experiment were as follows： r（NaC10）--4.84 g/L, 25 min, pH=6, height of activated carbon fixed bed was 10 cm. Under these conditions, the decolorizing rate can come up to about 100% and total removed rate of CODer reached at 89.6%. Comparison of UV-Vis adsorption spectrums before and after treatment showed that decomposition effects of chemical oxidation and adsorption of activated carbon fixed bed on acidic black 10B dye wastewater were satisfactory.
文摘Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for converting ethane to ethylene.In the current study MeO/LaCoO_(3)(MeO=Fe_(2)O_(3),NiO or Co_(2)O_(3))composite metal oxides were prepared via citrate gel and impregnation methods,and used as oxygen carriers for CL-ODH.X-ray diffraction results indicated that all oxygen carriers had a perovskite structure even after eight redox cycles.Under a reaction temperature of 650°C,a reaction pressure of 0.1 MPa,and a weight hourly space velocity(WHSV)of 7500 mL/(g·h),ethane conversion over Co_(2)O_(3)/LaCoO_(3) reached 100%and ethylene selectivity reached 60%,both of which were better than corresponding values attained over Fe_(2)O_(3)/LaCoO_(3) and NiO/LaCoO_(3).Ethylene selectivity remained stable for 80 cycles over Co_(2)O_(3)/LaCoO_(3),then decreased gradually after 80 cycles.X-ray photoelectron spectroscopy results and evaluation results indicated that lattice oxygen and O_(2)2-had a direct relationship with ethane conversion and ethylene selectivity.Co_(2)O_(3)/LaCoO_(3) exhibited a strong capacity to release and absorb oxygen,mainly due to interaction between Co_(2)O_(3) and LaCoO_(3).
文摘Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for ethylene preparation.Fe_(2)O_(3)/MgO oxygen carrier was prepared using the co-precipitation method.The influence of added NiO and its different loadings on Fe_(2)O_(3)/MgO were investigated.Then,a series of oxygen carriers were applied in the CL-ODH of the ethane cycle system.Brunauer-Emmett-Teller(BET),X-ray diffractometry(XRD),X-ray photoelection spectroscopy(XPS),and H2-temperature programmed reduction(TPR)were used to characterize the physicochemical properties of these oxygen carriers.It was confirmed that an interaction between NiO and Fe_(2)O_(3) occurred based on the XPS and H2-TPR results.Based on the CL-ODH activity performance tests conducted in a fixed-bed reactor,it was revealed that ethylene selectivity was significantly improved after NiO addition.Fe_(2)O_(3)-10%NiO/MgO showed the best activity performance with 93%ethane conversion and 50%ethylene selectivity at a reaction temperature of 650℃,atmospheric pressure,and space velocity of 7500 mL/(g·h).
基金supported financially by the Foundation of Science and Technology Planning Project of Guangdong Province(No2007A020100001-13)the Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Higher Education Institutions(China)
文摘The kinetics of heat-facilitated persulfate oxidation of p-chloroaniline（PCA） in aqueous solutions was measured at five different temperature conditions and at four different oxidant concentrations.The PCA degradation was found to follow a pseudo-first-order decay model when the persulfate was excessive.The pseudo-first-order rate constants of PCA degradation by persulfate（50 mmol/ L） at pH 7.0 are 0.12×10^-4,0.28×10^-4,0.43×10^-4,0.83×10^-4,1.32×10^-4 s^-1 at 10,20,30,40 and 50℃,respectively. Under the above reaction conditions,the reaction has activation energy of 49.97 kJ/mol.The observed rate was found to be function of temperature and oxidant concentration.Raising temperature and increasing persulfate concentration can significantly accelerate the PCA degradation.
文摘Fenton and ozone treatment was investigated at laboratory scale for the degradation of aqueous solutions of nitrobenzene （NB）. Effects of reactants concentration （O3, H2O2, and Fe（Ⅱ））, temperature, and pH on NB degradation were monitored. Reaction kinetic of these processes was also assessed. A rapid reaction took place for Fenton process at higher initial concentration of H2O2, higher temperatures, and more acidic conditions （pH 3）. Similarly, ozonation reaction exhibited rapid rates for higher ozone dose, higher temperatures, and more basic conditions （pH 11）. Complete NB degradation in 65 min was achieved using Fenton process. The conditions of complete elimination of 100 mg/L of initial NB concentration, were 250 mg/L of H202 concentration, pH 3, and 10 mg/L of Fe（Ⅱ） concentration. Under these conditions, 55% organic carbon elimination was achieved. Total organic carbon mineralization was attained in 240 rain reaction time by Fenton process with 900 mg/L of H202 concentration, and 30 mg/L of Fe（Ⅱ） concentration. Fenton reaction showed a pseudo-first order kinetic; the reaction rate constant was ranged from 0.0226 to 0.0658 min^-1. Complete NB degradation was also achieved for an ozone dose of the order of 2.5 g/L. The ozonation was studied at different ozone doses, different initial pH （7-11） and at different temperatures （15-35℃）. NB ozonation kinetic was represented by a bi-molecular kinetic model which was reduced to pseudo-first order kinetic. The pseudo-first order reaction rate constant was determined to increase at 20℃ from 0.004 to 0.020 min^-1 as the used ozone increased from 0.4 to 1.9 g/L.
基金the National Natural Science Foundation of China （40472026）.
文摘Decoloration of acidic scarlet GR by pyrolusite is studied in this paper. The effects of pH in solution, dosage and granularity of pyrolusite, reaction temperature, and vibration speed on decoloration efficiency are discussed. According to experiment results, the decoloration efficiency may exceed 95% for 40 mg/L GR solution by pyrolusite, pH is most important among all factors which impact the decoloration of acidic scarlet GR. Dosage and granularity of pyrolusite, reaction temperature, and vibration speed have a little benitfit on decoloration. The high decoloration efficiency and low removal efficiency of COD as well as FT-IR spectra of products between pyrolusite and acidic scarlet GR indicate that acidic scarlet GR undergoes the redox reaction on the interface of mineral and its chromophore is oxidated and decolored, but it is not removed thoroughly by oxidation.
文摘Nicotinic acid was synthesized from 3 methylpyridine with potassium dichromate as the oxidant. The reaction conditions, the product separation and analysis were studied. The results indicate that under the certain reaction conditions, the yield of nicotinic acid can reach 67.4%, the conversion can reach 99.7% and the selectivity can be as high as 99.8%. The final product has a high purity.
基金supported by the National Natural Science Foundation of China (Nos. 51304047 and 51374066)the Ph.D. Programs Foundation of the Ministry of Education of China (No.20130042120040)
文摘An in situ characterization technique called electrochemical noise（ECN） was used to investigate the bioleaching of natural pyrite.ECN experiments were conducted in four active systems（sulfuric acid,ferric-ion,9k culture medium,and bioleaching solutions）.The ECN data were analyzed in both the time and frequency domains.Spectral noise impedance spectra obtained from power spectral density（PSD）plots for different systems were compared.A reaction mechanism was also proposed on the basis of the experimental data analysis.The bioleaching system exhibits the lowest noise resistance of 0.101 MΩ The bioleaching of natural pyrite is considered to be a bio-battery reaction,which distinguishes it from chemical oxidation reactions in ferric-ion and culture-medium（9k） solutions.The corrosion of pyrite becomes more severe over time after the long-term testing of bioleaching.
文摘The goal of this topic is a synthesis of the main characteristics of iron in groundwater and the oxidation process used to remove it. Indeed, the kinetics of chemical oxidation of iron (II) was examined with reconstituted water (distilled water + iron sulphate) and proceeded to the application in the groundwater samples taken from <em><strong>South Pout</strong></em> (Senegal) precisely in the drilling <strong>PS2</strong>. The sources of iron are natural or anthropogenic. In Senegalese waters, its content is variable and sometimes exceeds the standards of potability. Despite the diversification of iron removal process, chemical oxidation is the most used solution in drinking water treatment plants in Senegalese rural areas. Applied oxidation processes such as aeration and chlorination, however, are insufficient to produce drinking water with an iron concentration in accordance with standards of potability.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(Nos.2020R1A4A4079954 and 2021R1A2B5B01001448)。
文摘In this study,water-dispersible graphitic carbon nitride(g-C_(3)N_(4))photocatalysts were successively prepared through the chemically oxidative etching of bulk g-C_(3)N_(4) that was polymerized thermally in different calcination atmospheres such as air,CO_(2),and N_(2).The different calcination atmospheres directly influenced the physicochemical and optical properties of both bulk and water-dispersible g-C_(3)N_(4),changing the photocatalytic degradation behavior of methylene blue(MB)and tetracycline hydrochloride(TCHCl)for water-dispersible g-C_(3)N_(4).The bubble-burst process in the thermal polymerization of thiourea produced defective edges containing C=O groups that preferred substituting the C-NHx groups over bulk g-C_(3)N_(4).In the oxygen-free N_(2) atmosphere among the different calcination atmospheres,more C=O functional groups were generated on the defective edges of bulk g-C_(3)N_(4),resulting in the highest N vacancy of the tri-s-triazine structure.During the successive chemical oxidation,S-or O-containing functional groups were introduced onto water-dispersible g-C_(3)N_(4).The water-dispersible g-C_(3)N_(4) photocatalyst from the oxygen-free N_(2) atmosphere(NTw)contained the most O-and S-functional groups on the g-C_(3)N_(4) surface.Consequently,NTw exhibited the highest photocatalytic activity in the MB and TC-HCl photodegradation because of its slowest recombination process,which was ascribed to the unique surface properties of NTw such as abundant functional groups on the defective edges and N-deficient property.
基金financially supported by the National Natural Science Foundation of China(Nos.51273173 and 51003093)the Research Foundation of Education Bureau of Zhejiang Province(No.Y200908238)
文摘The effect of chemically reduced graphene oxide （CRGO） on the phase separation behavior of poly（methyl methacrylate）/poly（styrene-co-acrylonitrile） （PMMA/SAN） blends and the simultaneous response of rheological and conductive behavior of PMMA/SAN/CRGO nanocomposites upon annealing above the phase-separation temperatures were investigated. The introduction of CRGO causes the decrease of binodal temperature and the increase of spinodal temperature for PMMA/SAN blends and then enlarges their metastable regime. During annealing, the well-dispersed CRGO in the homogeneous blend matrix tends to be selectively located in the SAN-rich phase with the evolution of phase separation and then the CRGO further agglomerates effectively in the SAN-rich phase to form the conductive pathway. Thermal-induced dynamic percolation is observed for both the resistivity p and dynamic storage modulus G＇ as a function of annealing time. The resistivity variation is ascribed to the agglomeration of CRGO in the SAN-rich phase, while the modulus evolution is attributed to the combined contribution of phase separation for blend matrix and the agglomeration of CRGO in the SAN-rich phase.
基金financial support by the One Hundred Talent Program of the Chinese Academy of Sciences and the National Natural Science Foundation of China(No.51302264)
文摘Birnessite-type MnO2 （δ-MnO2） nano-sheets were successfully synthesized by an interracial synthesis method in this work. The properties and electrochemical performance of the as-prepared δ-MnO2 were analyzed and evaluated by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, nitrogen adsorption measurement and electrochemical tests. This facile synthesis method enables δ-MnO2 nanosheets to show a large specific surface area （257.5 m^2 g^-1）. The electrochemical test results show that the specific capacitance is 272 F g^-1 and the specific capacitance retention is over 96.7% after 1000 cycles at a scan rate of 10 mV s^-1. All results demonstrate that δ-MnO2 has a great potential application in high- performance electrochemical capacitors, and this interracial synthesis method will be a very promising method to synthesize highly active MnO2 materials in a large scale.
基金supported partially by the National Natural Science Foundation of China (31201619)Profession Expert Group of Facility Cultivation and Engineering (CARS25-D-03)the Sci-Tech Development Project of Tai’an City, China (32606)
文摘Nitric oxide（NO）,a bioactive signaling molecule,serves as an antioxidant and anti-stress agent under abiotic stress.A hydroponics experiment was conducted to investigate the effects of sodium nitroprusside（SNP）,a NO donor,on tomato seedlings exposed to 50 μmol L-1CuCl 2.The results show that copper is primarily stored in the soluble cell sap fraction in the roots,especially after treatment with Cu＋SNP treatment,which accounted for 66.2% of the total copper content.The copper concentration gradually decreased from the roots to the leaves.In the leaves,exogenous NO induces the storage of excess copper in the cell walls.Copper stress decreases the proportion of copper integrated with pectates and proteins,but exogenous NO remarkably reverses this trend.The alleviating effect of NO is blocked by hemoglobin.Thus,exogenous NO is likely involved in the regulation of the subcellular copper concentrations and its chemical forms under copper stress.Although exogenous NO inhibited the absorption and transport of excess copper to some extent,the copper accumulation in tomato seedlings significantly increased under copper stress.The use of exogenous NO to enhance copper tolerance in some plants is a promising method for copper remediation.
基金Foundation items: National Natural Science Foundations of China (No.10835004,No.10775031)Science and Technology Commission of Shanghai Municipality,China (No. 10XD1400100)
文摘The hydrophobic films of TixOy-CmHn. deposited from mixture gases of titanium isopropoxide （TTIP） and oxygen by plasma enhanced chemical vapor deposition （PECVD） were investigated. The films were investigated by scanning electron microscope （ SEM ）, transmission electron microscope （ TEM ）, Fourier transform infrared spectrometer （ FTIR）, X-Ray diffraction （ XRD ）, element analysis （ EA ）, ultraviolet visible spectrometer （ UV-Vis）, and water contact angle （WCA）. The results reveal that the surface of the films is formed by mierosized papillaes aggregated by inorganic and organic phases of complex nanoparticles with size from 50 nm to 200 nm when the discharge power is increased from 40 W to 150 W. All fdms demonstrate the strong broad of Ti-O-Ti stretching vibration at 400 -800cm-1, -CH bending vibration at 1 388 cm -1, and broadening -OH stretching vibration at 3 000-3500 cm-1 With the increase of the discharge power, the asdeposited film changes from amorphous to crystallization. The WCA of the film can be as high as 160°, indicating the hydrophobicity. The films show a similar ultraviolet absorption property as the bulk TiO2 film. The composition of the composition of film deposited at 150 W can be formulated as Tio.302-C1.5H3. Therefore, the composition formula of this hydrophobic film could be expressed as TiO2-C5H10O4.7. It is believed that the complex micro/nano structures of TiO2 and C5H10O4.7 residues are responsible for the observed hydrophobicity and the ultraviolet absorption property of the film.
基金the National Council for Scientific and Technological Development(CNPq)the Coordination for the Improvement of Higher Education Personnel(CAPES-Project PROCAD-CAPES No.88881.068433/2014-01)for the financial support
文摘Chemical oxidation was applied to an artificially contaminated soil with naphthalene(NAP).Evaluation of NAP distribution and mass reduction in soil,water and air phases was carried out through mass balance.Evaluation of NAP distribution and mass reduction in soil,water and air phases was carried out through mass balance.The importance of the air phase analysis was emphasized by demonstrating how NAP behaves in a sealed system over a 4 hr reaction period.Design of Experiments method was applied to the following variables:sodium persulfate concentration[SP],ferrous sulfate concentration[FeS04],and pH.The system operated with a prefixed solid to liquid ratio of 1:2.The following conditions resulted in optimum NAP removal[SP]=18.37 g/L,[FeSO4]=4.25 g/L and pH=3.00.At the end of the 4 hr reaction,62%of NAP was degraded.In the soil phase,the chemical oxidation reduced the NAP concentration thus achieving levels which comply with Brazilian and USA environmental legislations.Besides the NAP partitioning view,the monitoring of each phase allowed the variabilities assessment over the process,refining the knowledge of mass reduction.Based on NAP distribution in the system,this study demonstrates the importance of evaluating the presence of semi-volatile and volatile organic compounds in the air phase during remediation,so that there is greater control of the system as to the distribution and presence of the contaminant in the environment.The results highlight the importance of treating the contaminant in all its phases at the contaminated site.
基金This work was financially supported by the Combined Project between the Educational Commission and the Economic Commission of Gansu Province (Nos. 99CX-04, 0310B-08)the Natural Science Foundation of Gansu Province (No. 3ZS041-A25-028)the Invention Project of Science & Technology (No. KJCXGC-01, NWNU), China.
文摘A PANI/TiO2 composite film deposited on the glass surface was successfully prepared using sol-gel dip-coating technique and chemical oxidation method. The film was characterized using XRD, AFM, and UV. The result showed that the TiO2 film consists of both cuboid-shaped and anatase-phased TiO2 nanoparticles. The average grain size of TiO2 in the film was approximately 20 nm. After coating with PANI, the particle was changed into irregular spherical-shaped and the size was increased up to approximately 35 nm in diameter. UV-Vis spectroscopy analysis indicated that the coating of TiO2 with PANI would result in an enhancement of photocatalytic efficiency and an extension of the photoresponse of TiO2. The band gap of the PANI/TiO2 film was 3.18 eV. The photocatalytic property of the film was evaluated by the degradation of rhodamine-B. It was found that 67.1% and 83.2% of rhodamine-B could be degraded under sunlight and UV irradiation within 120 min using the PANI/TiO2 composite t-tim as photocatalyst.
基金Supported by the Ministry of Environmental Protection of China(No.201109020)
文摘Trichloroethylene （TCE）, as one of the most common chlorinated organic compounds in soils and aquifers at many industrial sites, is carcinogenic and often recalcitrant in environment. TCE degradation in artificially contaminated soil samples was conducted using Fenton-like processes, i.e., by addition of excess hydrogen peroxide （H2O2）. H2O2 could directly oxidize TCE without addition of ferrous iron in contaminated soil. Under the optimal condition （H2O2 concentration of 300 mg kg^-1, pH at 5.0, and reaction time of 30 rain）, the removal efficiency of TCE in the soil was up to 92.3%. When the initial TCE concentration increased from 30 to 480 mg kg^-1 in soil, the TCE removal rates varied from 89.2% to 86.6%; while the residual TCE in soil ranged from 2.28 to 47.57 mg kg^-1. Results from successive oxidations showed that the TCE removal rate with the TCE concentration of 180 mg kg^-1 increased slightly from 91.6% to 96.2% as the number of successive oxidation cycle increased from one to four. Therefore, increasing the frequency of H2O2 oxidation was perhaps a feasible way to increase TCE removal rate for TCE-contaminated soil.
