In this study, the effect of activated peroxydisulfate(PDS) by dielectric barrier discharge(DBD) plasma and activated carbon(HGAC) on the removal of acid orange Ⅱ(AOⅡ) was investigated. The effects of applied voltag...In this study, the effect of activated peroxydisulfate(PDS) by dielectric barrier discharge(DBD) plasma and activated carbon(HGAC) on the removal of acid orange Ⅱ(AOⅡ) was investigated. The effects of applied voltage, PDS dosage, HGAC dosage, initial pH value, and inorganic anions on the removal rate of AOⅡ were discussed. The main free radicals degrading azo dyes during the experiment were also studied. Experimental results show that the removal rate of AOⅡ in DBD/HGAC/PDS synergistic system is much higher than that in the single system. With the applied voltage of 16 kV, HGAC dosage of 1 g l-1, PDS and AOⅡ molar ratio of 200:1, initial pH value of 5.4 and concentration of AOⅡ solution of 20 mg l-1, the removal rate of AOⅡ reached 97.6% in DBD/HGAC/PDS process after 28 min of reaction.Acidic and neutral conditions are beneficial for AOⅡ removal. Sulfate and hydroxyl radicals play an important role in the removal of AOⅡ. Inorganic anions are not conducive to the removal of AOⅡ.展开更多
Many sub-products of pulsed discharge,such as ultraviolet light,strong electric fields,shock waves and active species,are effective in treating wastewater.To improve the efficiency of the discharge plasma technology i...Many sub-products of pulsed discharge,such as ultraviolet light,strong electric fields,shock waves and active species,are effective in treating wastewater.To improve the efficiency of the discharge plasma technology in removing pollutants,adding TiO2 photo-catalyst to pulsed discharges could help.A negative-pulsed-discharge system,which has nozzle discharge electrodes with or without TiO2 coating,is used to degrade azo dye Acid Orange Ⅱ,and the effects of several key conditions(maximum pulse voltage,pulse repetition frequency,initial mass concentration of Acid Orange Ⅱ initial solution pH,treatment duration,the phase of discharge,and the existence of TiO2) on the degradation are experimentally investigated.The degradation of Acid Orange Ⅱ increases with maximum pulse voltage,pulse repetition frequency,and treatment duration,and it is larger when putting the discharge electrode on the solution surface than in air or inside the solution,i.e.the discharge in gas phase is more effective than that in gas-liquid phase or liquid phase.The degradation decreases as the initial mass concentration of the solution increases.It also relates to pH and is higher at acidic conditions than at neutral or alkaline conditions.Compared to treatments without TiO2,the ones using the nozzle discharge electrode with TiO2 coated increase the degradation of Acid Orange Ⅱ by 5 %.It is concluded that the proposed system with TiO2 added in can remove Acid Orange Ⅱ from wastewater effectively.展开更多
Some problems including low treatment capacity,agglomeration and clogging phenomena,and short working life,limit the application of pre-treatment methods involving zero-valent iron （ZVI）.In this article,ZVI was froz...Some problems including low treatment capacity,agglomeration and clogging phenomena,and short working life,limit the application of pre-treatment methods involving zero-valent iron （ZVI）.In this article,ZVI was frozen in an amorphous state through a melt-spinning technique,and the decolorization effect of amorphous ZVI on Acid Orange II solution was investigated under varied conditions of experimental variables such as reaction temperature,ribbon dosage,and initial pH.Batch experiments suggested that the decolorization rate was enhanced with the increase of reaction temperature and ribbon dosage,but decreased with increasing initial solution pH.Kinetic analyses indicated that the decolorization process followed a first order exponential kinetic model,and the surface-normalized decolorization rate could reach 2.09 L/（m^2 ·min） at room temperature,which was about ten times larger than any previously reported under similar conditions.Recycling experiments also proved that the ribbons could be reused at least four times without obvious decay of decolorization rate and efficiency.This study suggests a tremendous application potential for amorphous ZVI in remediation of groundwater or wastewater contaminated with azo dyes.展开更多
Jincheng orange(Citrus sinensis Osbeck)is widely grown in Chongqing,China,and is commonly consumed because of its characteristic aroma contributed by the presence of diverse volatile compounds.The changes in aroma dur...Jincheng orange(Citrus sinensis Osbeck)is widely grown in Chongqing,China,and is commonly consumed because of its characteristic aroma contributed by the presence of diverse volatile compounds.The changes in aroma during the development and maturation of fruit are indicators for ripening and harvest time.However,the influence of growth stages on the volatile compounds in Jincheng orange remains unclear.In addition,volatiles originate from fatty acids,most of which are the precursors of volatile substances.On this basis,gas chromatography-mass spectrometry(GC-MS)was performed to elaborate the changes in volatile constituents and fatty acids as precursors.This study tested proximately 60 volatiles and 8 fatty acids at 9 growth and development stages(AF1-AF9).Of those compounds,more than 92.00%of total volatiles and 87.50%of fatty acids were terpenoid and saturated fatty acids,respectively.As shown in the PCA plot,the AF5,AF6,and AF9 stages were confirmed as completely segregated and appeared different.In addition,most of the volatiles and fatty acids first increased at the beginning of the development stage,then decreased from the AF6 development stage,and finally increased at the AF9 maturity stage.Moreover,the highest contents of terpenoid,alcohols,aldehydes,ketones,and saturated fatty acids in Jincheng orange peel oil were d-limonene,linalool,octanal,cyclohexanone,and stearic acid during development stages,respectively.Our results found that the growth stages significantly affected the volatile constituents and precursors in Jincheng orange peel oil.展开更多
Inclusion complex of Orange II with β-Cyclodextrin (β-CD) and the anti-photolysis effect under UV-light were investigated. The molar ratio of inclusion complex of β-Cyclodextrin and Orange Ⅱ is 1∶1. The formation...Inclusion complex of Orange II with β-Cyclodextrin (β-CD) and the anti-photolysis effect under UV-light were investigated. The molar ratio of inclusion complex of β-Cyclodextrin and Orange Ⅱ is 1∶1. The formation constant K=1.236×10 3 L/mol was determined by the UV and Fluorescence spectra respectively, which was quite in accordance with the calculation with a modified Benesi-Hildbrand equation. The inclusion complex was characterized by the IR spectra and the molar ratio of inclusion complex is 1∶1 too. The formation constant K=1.266×10 3 L/mol was determined by 1 H NMR analysis and was nearly the same by UV and fluorescence spectra. The photocatalytic decolorization rate of Orange Ⅱ solutions containing β-CD and TiO_ 2 was smaller by 51.9% than that of the Orange Ⅱ solutions only containing TiO_ 2 , while in the case of direct photolysis of Orange Ⅱ solutions, β-CD can lower the photolysis rate by 48.1% under UV-light. This result indicates β-CD can inhibit the photolysis and photocatalytic decolorization of Orange Ⅱ under UV-light. The β-CD inclusion complex was found to be persistent to UV-light photolysis.展开更多
Silicotungstic acid and phosphotungstic acid were prepared and characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD). The results showed that the prepared catalysts possess classi...Silicotungstic acid and phosphotungstic acid were prepared and characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD). The results showed that the prepared catalysts possess classical Keggin structure. The factors on the degradation of methyl orange, such as the kind of catalyst, the amount of catalyst, the original concentration of dye and illumination time were investigated under metal halide lamp. The degradation of methyl orange is up to 93.6% with phosphotungstic acid at the best reaction conditions at 8.89 g/L concentration of phosphotungstic acid, 5.56 mg/L concentration of methyl orange and 80 min illumination time.展开更多
In this paper, a pulsed discharge plasma （PDP） system with a multi-needle-to-plate electrodes geometry was set up to investigate the regeneration of acid orange 7 （AO7） exhausted granular activated carbon （GAC）....In this paper, a pulsed discharge plasma （PDP） system with a multi-needle-to-plate electrodes geometry was set up to investigate the regeneration of acid orange 7 （AO7） exhausted granular activated carbon （GAC）. Regeneration of GAC was studied under different conditions of peak pulse discharge voltage and water pH, as well as the modification effect of GAC by the pulse discharge process, to figure out the regeneration efficiency and the change of the GAC structure by the PDP treatment. The obtained results showed that there was an appropriate peak pulse voltage and an optimal initial pH value of the solution for GAC regeneration. Analyses of scanning electron microscope （SEM）, Boehm titration, Brunauer-Emmett-Teller （BET）, Horvath-Kawazoe （HK）, and X-ray Diffraction （XRD） showed that there were more mesopore and macropore in the regenerated GAC and the structure turned smoother with the increase of discharge voltage; the amount of acidic functional groups on the GAC surface increased while the amount of basic functional groups decreased after the regeneration process. From the result of the XRD analysis, there were no new substances produced on the GAC after PDP treatment.展开更多
The bioconversion of the hydrophobic and volatile limonene to perillic acid, a potential anticancer agent, by the yeast Yarrowia lipolytica was studied in two steps. Firstly, experimental design was used for process o...The bioconversion of the hydrophobic and volatile limonene to perillic acid, a potential anticancer agent, by the yeast Yarrowia lipolytica was studied in two steps. Firstly, experimental design was used for process optimization using high-purity limonene as substrate and secondly orange essential oil containing 89.1% limonene was used as substrate under the previously optimized conditions. Limonene concentration and pH were identified by fractional factorial design as significant factors and were optimized by central composite design. Under optimized process conditions (0.16% (v/v) limonene;pH 6.9), the 24 h biotransformation process resulted in the accumulation of 0.368 g·L-1 of perillic acid corresponding to a molar yield of 23.1%. A subsequent substrate addition under the same reaction conditions doubled perillic acid concentration to 0.793 g·L-1 and a molar yield of 24.2%. The use of orange essential oil under the optimized reaction conditions increased both perillic acid accumulation and yield to 0.872 g·L-1 and 29.7%, respectively. The robustness of Y. lipolytica allowed the efficient biotransformation of a crude by-product of the citrus industry into a valuable fine chemical.展开更多
Bottom ash. a power plant waste, was used to adsorb acid orange 7. The adsorption of acid orange 7 in aqueous solutions onto bottom ash was studied as functions of particle size. dosage, initial concentration and agit...Bottom ash. a power plant waste, was used to adsorb acid orange 7. The adsorption of acid orange 7 in aqueous solutions onto bottom ash was studied as functions of particle size. dosage, initial concentration and agitation time by batch experiments. Under conditions of bottom ash dosage of 1.5 g/50 ml and 5 g/50 ml for 〈0.074 mm and 0.074 mm-0.2 mm of bottom ash, respectively, it could achieve 99.1% and 87.6% dye removal efficiency. The adsorption isotherms for the bottom ash could be well described by both Freundlich and Langmuir isotherms. The calculated dye adsorption capacities of bottom ash for the particle size of 0.074 mm -0.2 mm and 〈0.074 mm were 2.78 mg/g and 10.21 mg/g, respectively. The results indicated that the dye uptake process fitted to the pseudo-first-order kinetic model better than the pseudo-second-order. The data were also fitted to intraparticle diffusion model by two adsorption stages, due to the difference in rate of mass transfer in the initial and final stages of adsorption. Significant variations were observed in the FTIR spectra and Stem photographs of bottom ash after adsorption. The column parameters were calculated by breakthrough curves at different flow rates and bed depths.展开更多
基金National Natural Science Foundation Youth Project of China(No.51707093).
文摘In this study, the effect of activated peroxydisulfate(PDS) by dielectric barrier discharge(DBD) plasma and activated carbon(HGAC) on the removal of acid orange Ⅱ(AOⅡ) was investigated. The effects of applied voltage, PDS dosage, HGAC dosage, initial pH value, and inorganic anions on the removal rate of AOⅡ were discussed. The main free radicals degrading azo dyes during the experiment were also studied. Experimental results show that the removal rate of AOⅡ in DBD/HGAC/PDS synergistic system is much higher than that in the single system. With the applied voltage of 16 kV, HGAC dosage of 1 g l-1, PDS and AOⅡ molar ratio of 200:1, initial pH value of 5.4 and concentration of AOⅡ solution of 20 mg l-1, the removal rate of AOⅡ reached 97.6% in DBD/HGAC/PDS process after 28 min of reaction.Acidic and neutral conditions are beneficial for AOⅡ removal. Sulfate and hydroxyl radicals play an important role in the removal of AOⅡ. Inorganic anions are not conducive to the removal of AOⅡ.
基金Project supported by National Natural Science Foundation of China （51207089）, Shang- hai Maritime University （20120097）.
文摘Many sub-products of pulsed discharge,such as ultraviolet light,strong electric fields,shock waves and active species,are effective in treating wastewater.To improve the efficiency of the discharge plasma technology in removing pollutants,adding TiO2 photo-catalyst to pulsed discharges could help.A negative-pulsed-discharge system,which has nozzle discharge electrodes with or without TiO2 coating,is used to degrade azo dye Acid Orange Ⅱ,and the effects of several key conditions(maximum pulse voltage,pulse repetition frequency,initial mass concentration of Acid Orange Ⅱ initial solution pH,treatment duration,the phase of discharge,and the existence of TiO2) on the degradation are experimentally investigated.The degradation of Acid Orange Ⅱ increases with maximum pulse voltage,pulse repetition frequency,and treatment duration,and it is larger when putting the discharge electrode on the solution surface than in air or inside the solution,i.e.the discharge in gas phase is more effective than that in gas-liquid phase or liquid phase.The degradation decreases as the initial mass concentration of the solution increases.It also relates to pH and is higher at acidic conditions than at neutral or alkaline conditions.Compared to treatments without TiO2,the ones using the nozzle discharge electrode with TiO2 coated increase the degradation of Acid Orange Ⅱ by 5 %.It is concluded that the proposed system with TiO2 added in can remove Acid Orange Ⅱ from wastewater effectively.
基金the financial support from the Ministry of Science and Technology of China(No. 2011CB606301)the National Natural Science Foundation of China (No. 50825402,51101156)
文摘Some problems including low treatment capacity,agglomeration and clogging phenomena,and short working life,limit the application of pre-treatment methods involving zero-valent iron （ZVI）.In this article,ZVI was frozen in an amorphous state through a melt-spinning technique,and the decolorization effect of amorphous ZVI on Acid Orange II solution was investigated under varied conditions of experimental variables such as reaction temperature,ribbon dosage,and initial pH.Batch experiments suggested that the decolorization rate was enhanced with the increase of reaction temperature and ribbon dosage,but decreased with increasing initial solution pH.Kinetic analyses indicated that the decolorization process followed a first order exponential kinetic model,and the surface-normalized decolorization rate could reach 2.09 L/（m^2 ·min） at room temperature,which was about ten times larger than any previously reported under similar conditions.Recycling experiments also proved that the ribbons could be reused at least four times without obvious decay of decolorization rate and efficiency.This study suggests a tremendous application potential for amorphous ZVI in remediation of groundwater or wastewater contaminated with azo dyes.
基金supported by the Guizhou Provincial Science and Technology Projects,China(ZK[2022]391)the Cultivation Project of National Natural Science Foundation of Guizhou Medical University,China(21NSFCP20).
文摘Jincheng orange(Citrus sinensis Osbeck)is widely grown in Chongqing,China,and is commonly consumed because of its characteristic aroma contributed by the presence of diverse volatile compounds.The changes in aroma during the development and maturation of fruit are indicators for ripening and harvest time.However,the influence of growth stages on the volatile compounds in Jincheng orange remains unclear.In addition,volatiles originate from fatty acids,most of which are the precursors of volatile substances.On this basis,gas chromatography-mass spectrometry(GC-MS)was performed to elaborate the changes in volatile constituents and fatty acids as precursors.This study tested proximately 60 volatiles and 8 fatty acids at 9 growth and development stages(AF1-AF9).Of those compounds,more than 92.00%of total volatiles and 87.50%of fatty acids were terpenoid and saturated fatty acids,respectively.As shown in the PCA plot,the AF5,AF6,and AF9 stages were confirmed as completely segregated and appeared different.In addition,most of the volatiles and fatty acids first increased at the beginning of the development stage,then decreased from the AF6 development stage,and finally increased at the AF9 maturity stage.Moreover,the highest contents of terpenoid,alcohols,aldehydes,ketones,and saturated fatty acids in Jincheng orange peel oil were d-limonene,linalool,octanal,cyclohexanone,and stearic acid during development stages,respectively.Our results found that the growth stages significantly affected the volatile constituents and precursors in Jincheng orange peel oil.
文摘Inclusion complex of Orange II with β-Cyclodextrin (β-CD) and the anti-photolysis effect under UV-light were investigated. The molar ratio of inclusion complex of β-Cyclodextrin and Orange Ⅱ is 1∶1. The formation constant K=1.236×10 3 L/mol was determined by the UV and Fluorescence spectra respectively, which was quite in accordance with the calculation with a modified Benesi-Hildbrand equation. The inclusion complex was characterized by the IR spectra and the molar ratio of inclusion complex is 1∶1 too. The formation constant K=1.266×10 3 L/mol was determined by 1 H NMR analysis and was nearly the same by UV and fluorescence spectra. The photocatalytic decolorization rate of Orange Ⅱ solutions containing β-CD and TiO_ 2 was smaller by 51.9% than that of the Orange Ⅱ solutions only containing TiO_ 2 , while in the case of direct photolysis of Orange Ⅱ solutions, β-CD can lower the photolysis rate by 48.1% under UV-light. This result indicates β-CD can inhibit the photolysis and photocatalytic decolorization of Orange Ⅱ under UV-light. The β-CD inclusion complex was found to be persistent to UV-light photolysis.
文摘Silicotungstic acid and phosphotungstic acid were prepared and characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD). The results showed that the prepared catalysts possess classical Keggin structure. The factors on the degradation of methyl orange, such as the kind of catalyst, the amount of catalyst, the original concentration of dye and illumination time were investigated under metal halide lamp. The degradation of methyl orange is up to 93.6% with phosphotungstic acid at the best reaction conditions at 8.89 g/L concentration of phosphotungstic acid, 5.56 mg/L concentration of methyl orange and 80 min illumination time.
基金supported by National Natural Science Foundation of China(No.21207052)China Postdoctoral Science Foundation(No.20110491353)Jiangsu Planned Projects for Postdoctoral Research Funds,China(No.1102116C)
文摘In this paper, a pulsed discharge plasma （PDP） system with a multi-needle-to-plate electrodes geometry was set up to investigate the regeneration of acid orange 7 （AO7） exhausted granular activated carbon （GAC）. Regeneration of GAC was studied under different conditions of peak pulse discharge voltage and water pH, as well as the modification effect of GAC by the pulse discharge process, to figure out the regeneration efficiency and the change of the GAC structure by the PDP treatment. The obtained results showed that there was an appropriate peak pulse voltage and an optimal initial pH value of the solution for GAC regeneration. Analyses of scanning electron microscope （SEM）, Boehm titration, Brunauer-Emmett-Teller （BET）, Horvath-Kawazoe （HK）, and X-ray Diffraction （XRD） showed that there were more mesopore and macropore in the regenerated GAC and the structure turned smoother with the increase of discharge voltage; the amount of acidic functional groups on the GAC surface increased while the amount of basic functional groups decreased after the regeneration process. From the result of the XRD analysis, there were no new substances produced on the GAC after PDP treatment.
文摘The bioconversion of the hydrophobic and volatile limonene to perillic acid, a potential anticancer agent, by the yeast Yarrowia lipolytica was studied in two steps. Firstly, experimental design was used for process optimization using high-purity limonene as substrate and secondly orange essential oil containing 89.1% limonene was used as substrate under the previously optimized conditions. Limonene concentration and pH were identified by fractional factorial design as significant factors and were optimized by central composite design. Under optimized process conditions (0.16% (v/v) limonene;pH 6.9), the 24 h biotransformation process resulted in the accumulation of 0.368 g·L-1 of perillic acid corresponding to a molar yield of 23.1%. A subsequent substrate addition under the same reaction conditions doubled perillic acid concentration to 0.793 g·L-1 and a molar yield of 24.2%. The use of orange essential oil under the optimized reaction conditions increased both perillic acid accumulation and yield to 0.872 g·L-1 and 29.7%, respectively. The robustness of Y. lipolytica allowed the efficient biotransformation of a crude by-product of the citrus industry into a valuable fine chemical.
基金Acknowledgements： The study was supported by the National Natural Science Foundation of China （No. 40501063）.
文摘Bottom ash. a power plant waste, was used to adsorb acid orange 7. The adsorption of acid orange 7 in aqueous solutions onto bottom ash was studied as functions of particle size. dosage, initial concentration and agitation time by batch experiments. Under conditions of bottom ash dosage of 1.5 g/50 ml and 5 g/50 ml for 〈0.074 mm and 0.074 mm-0.2 mm of bottom ash, respectively, it could achieve 99.1% and 87.6% dye removal efficiency. The adsorption isotherms for the bottom ash could be well described by both Freundlich and Langmuir isotherms. The calculated dye adsorption capacities of bottom ash for the particle size of 0.074 mm -0.2 mm and 〈0.074 mm were 2.78 mg/g and 10.21 mg/g, respectively. The results indicated that the dye uptake process fitted to the pseudo-first-order kinetic model better than the pseudo-second-order. The data were also fitted to intraparticle diffusion model by two adsorption stages, due to the difference in rate of mass transfer in the initial and final stages of adsorption. Significant variations were observed in the FTIR spectra and Stem photographs of bottom ash after adsorption. The column parameters were calculated by breakthrough curves at different flow rates and bed depths.
