Phenolic compounds are widely present in domestic and industrial sewage and have serious environmental hazards.Electrochemical oxidation(EO)is one of the most promising methods for sewage degradation because of its hi...Phenolic compounds are widely present in domestic and industrial sewage and have serious environmental hazards.Electrochemical oxidation(EO)is one of the most promising methods for sewage degradation because of its high efficiency,environmental compatibility,and safety.In this work,we present an in-depth overview of the mechanism and factors affecting the degradation of phenolic compounds by EO.In particular,the effects of treatment of phenolic compounds with different anode materials are discussed in detail.The non-active anode shows higher degradation efficiency,less intermediate accumulation,and lower energy consumption than the active anode.EO combined with other treatment methods(biological,photo,and Fenton)presents advantages,such as low energy consumption and high degradation rate.Mean-while,the remaining drawbacks of the EO process in the phenolic compound treatment system have been discussed.Furthermore,future re-search directions are put forward to improve the feasibility of the practical application of EO technology.展开更多
Soil and land degradation in the tropics can be identified and described in terms of physical,chemical,and biological changes from its pristine state brought about by natural and anthropogenic influences.A characteris...Soil and land degradation in the tropics can be identified and described in terms of physical,chemical,and biological changes from its pristine state brought about by natural and anthropogenic influences.A characteristic of these ecosystems is their capacity to recycle nutrients through soil organic matter(SOM). Following disturbance through changed land management.SOM is rapidly mineralized and there is a cor responding decline in fertility and the variable charge component of the cation exchange capacity.As these ecosystems are strongly dependent on SOM for their functionality,changed land use can have irreversible impacts on the productivity of these systems.The paper focuses on quantifying chemical degradation throughbenchmaking using data from paried sites in tropical China and Thailand using surface charge finger printing.Using values taken from the fingerprint of an undistubed soil,an index of chemical degradation from ideality was calculated.Various management stratgeies that attempt to reverse degradative trends or improve poor quality soils in their natural condition are discussed.such as the ddition of natural clays and silicated materials.Results are present to whow the effect of each of the aforementional strategies on surface charge characteristics and associated increases in plant productivity.展开更多
The paper deals with the influence of anode material on the efficiency of degradation for organic pollutants in water system.The electrochemical performance of fluorine ion doped lead dioxide(F--PbO2) electrode for th...The paper deals with the influence of anode material on the efficiency of degradation for organic pollutants in water system.The electrochemical performance of fluorine ion doped lead dioxide(F--PbO2) electrode for the degradation of aniline was compared with that of undoped lead dioxide(PbO2) electrode by ultraviolet-visible(UV-Vis) spectroscopy,linear voltammetry and other analytical methods,such as the measurement by chemical oxygen demand analyzer,high performance liquid chromatography and scanning electron micrography.It was shown that both PbO2 electrode and F--PbO2 electrode could make aniline be mineralized completely and have the same degradation course,but F--PbO2 electrode has much higher electrocatalytic activity than undoped PbO2 electrode for the electrochemical degradation of aniline.The experimental results confirm that F--PbO2 electrode has much higher potential for oxygen evolution than undoped PbO2 electrode.展开更多
Ultrasonic irradiation was found to accelerate the rate of hydrolysis of omethoate in aqueous solution over the pH range of 2—12 Process parameters studied include pH, steady state temperature, concentration, and the...Ultrasonic irradiation was found to accelerate the rate of hydrolysis of omethoate in aqueous solution over the pH range of 2—12 Process parameters studied include pH, steady state temperature, concentration, and the type of gases. Greater than 96% hydrolysis was observed in 30 minutes through this process and the rate of destruction increased with the help of more soluble and low thermal inert gas. So with Krypton, omethoate was found to undergo rapid destruction as compared with Argon. In the presence of ultrasound, the observed first order rate of hydrolysis of omethoate is found to be independent of pH. The formation of transient supercritical water(SCW) appears to be an important factor in the acceleration of chemical reactions in the presence of ultrasound. A detailed chemical reaction mechanism for omethoate destruction in water was formulated. Experimental results and theoretical kinetic mechanism demonstrated that the most of the omethoate undergo destruction inside the cavitating holes. A very less effect of temperature on the degradation of omethoate within a temperature range of 20—70℃ proves that a small quantity of omethoate undergoes secondary destruction in the bulk liquid.展开更多
The experimental degradation of a water soluble dye, potassium indigo tetrasulfonate salt, has been studied using stand-alone ozonation and photocatalytic oxidation process. Progress of the dye oxidation was followed ...The experimental degradation of a water soluble dye, potassium indigo tetrasulfonate salt, has been studied using stand-alone ozonation and photocatalytic oxidation process. Progress of the dye oxidation was followed by UV-VIS spectrophotometric measurements at controlled operating conditions. The organic content of reaction samples was measured to verify the process efficiency in dye mineralization. According to current results, almost complete color removal was obtained for ozonation within about 1 h reaction time. The reduction of the organic load was almost 80% from its original while initial sulphur content decreased to 32.5%. Dye conversion of 100% was obtained by means of a photocatalytic process using TiO2 as catalyst at 294 nm irradiated UV light. This complete color removal for the catalytic process was observed within 7 min of reaction time. The calculated initial rate of reaction of photocatalysis treatment was 8 times faster than that of ozonolysis. However, the remaining organic load of photocatalysis was almost 88% from its original while the final sulphur content was 27.3%. This contrasting behavior of the performance of the type of oxidation process stressed importance of physicochemical phenomena and intermediates molecules present during dye degradation. An insightful and mechanistic aspect of the dye oxidation was developed by performing quantumchemical calculations.展开更多
Photochemical degradation of crude oil in seawater is an important issue in marine environ- mental protection and is studied in this work. Results showed that petroleum hydrocarbons could be ef- fectively degraded by ...Photochemical degradation of crude oil in seawater is an important issue in marine environ- mental protection and is studied in this work. Results showed that petroleum hydrocarbons could be ef- fectively degraded by the irradiation of high-pressure mercury light or natural sunlight. Photochemical reaction was controlled by various factors including light source, aquatic medium, heavy metal ion and photo-sensitizer. The rate of photo-degradation was fast at the initial stage of exposure, exhibiting a first-order reaction kinetic behavior. However, after irradiation for a few hours, the concentration of wa- ter-soluble fraction (WSF) of petroleum hydrocarbons stabilized. For all experimental conditions, the range of the photo-degradation rate is from 0.001 3 to 0.005 7/min.展开更多
The electrochemical degradation of p-nitrophenol(PNP) under different conditions was investigated.The electrochemical behavior of PNP and its reduction product p-aminophenol(PAP) on stainless steel cathode and Ti/Pt a...The electrochemical degradation of p-nitrophenol(PNP) under different conditions was investigated.The electrochemical behavior of PNP and its reduction product p-aminophenol(PAP) on stainless steel cathode and Ti/Pt anode through cyclic voltammetry were observed.Electrochemical degradation process was performed in an undivided cell and 92% PNP was removed corresponding to a 22% total organic carbon removal.A divided cell was also used and it was found that PNP degradation was mainly attributed to cathodic reduction,while anodic oxidation was responsible for PNP removal due to the reaction with hydroxyl radicals and surface oxide generated on the anode.The sequential electrolytic processes,reduction-oxidation and oxidation-reduction,were compared in the divided cell.In the case of reduction-oxidation process,the total organic carbon removal reached 40%,but PNP removal was the same with the undivided cell.A black deposit was found in the effluent and identified by Fourier transform infrared spectroscopy as a polymer of PAP produced by the 1,4-addition reaction of quinoneimine.Intermediates left in the solution such as hydroquinone,p-benzoquinone and PAP were determined by high performance liquid chromatography.Whereas,the oxidation-reduction process proved unsatisfying.展开更多
The photochemical degradation of triadimefon in seawater was investigated under different reaction conditions in this study. The results showed that triadimefon could be effectively degraded by the irradiation of a hi...The photochemical degradation of triadimefon in seawater was investigated under different reaction conditions in this study. The results showed that triadimefon could be effectively degraded by the irradiation of a high-pressure mercury lamp and the photodegradation rates were influenced by aquatic media, heavy metal ions and photosensitizers. The photochemical degradation of triadimefon followed the first-order reaction kinetic behavior, with the rate constants ranging from 0.0027 to 0.0128 min-1 under the studied conditions. The photolysis of triadimefon was slower in natural seawater than in distilled water or synthetic seawater. All the heavy metal ions studied in this paper had inhibition effects on the photolysis of triadimefon. Acetone, as a common photosensitizer, could accelerate the photolysis of triadimefon. Three photoproducts were identified by GC-MS analysis. Our study confirmed that photochemical degradation is an effective pathway to remove triadimefon in seawater.展开更多
Chlorsulfuron (ChS) which is a nonbiodegradable herbicide was effectively removed using an electrochemical method at the Ti/IrO2-Pt anode. The influences of current density, initial ChS concentration, initial solution...Chlorsulfuron (ChS) which is a nonbiodegradable herbicide was effectively removed using an electrochemical method at the Ti/IrO2-Pt anode. The influences of current density, initial ChS concentration, initial solution pH and different NaCl dosages on electrochemical degradation of ChS were investigated. HOCl formed during electrolysis and quickly generated .OH radicals would likely play an important role in the electrochemical degradation of ChS with the presence of NaCl. At current density of 20 mA?cm–2, ChS concentration decreased from 1 mg.L–1 to 0 mg.L–1 after 10 min electrolysis with 0.2 g?L–1 NaCl dosage. It was found that the ChS removal rate increased with increasing current density and the ChS degradation was similar at different initial pH values, which means that Ti/IrO2-Pt anode can be used in a wide pH range. The electrochemical performance of Ti/IrO2-Pt anode for degradation of ChS will not decrease after serviced for a long time. These results reveal that an electrochemical approach would be a novel treatment method for effective and rapid degradation of ChS herbicide from aqueous solution.展开更多
An investigation of photoelectrochemical degradation of pentachlorophenol (PCP) on a TiO2 film electrode was presented. The TiO2 film electrode was prepared by anodisation of titanium metal in sulfuric acid solution a...An investigation of photoelectrochemical degradation of pentachlorophenol (PCP) on a TiO2 film electrode was presented. The TiO2 film electrode was prepared by anodisation of titanium metal in sulfuric acid solution and its photoelectrocatalystic performance was studied. The destruction of PCP follows approximately the first-order kinetics. The reaction constant decreases slightly from 2.6×10-5 s-1 to 2.0×10-5 s-1 as the initial PCP concentration is increased from 0.1 mmol/L to 1.0 mmol/L under the experimental condition.展开更多
Environmentally persistent and bioaccumulative perfluorooctanic acid (PFOA) was difficult to be decomposed under the irradiation of 254 nm UV light.However,in the presence of 80μmol/L Fe(Ⅲ),80% of PFOA with initial ...Environmentally persistent and bioaccumulative perfluorooctanic acid (PFOA) was difficult to be decomposed under the irradiation of 254 nm UV light.However,in the presence of 80μmol/L Fe(Ⅲ),80% of PFOA with initial concentration of 48μmol/L (20 rag/L) was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction.Shorter chain perfluorocarboxylic acids bearing C_3-C_7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution.It was proposed that complexes of PFOA with Fe(Ⅲ) initiated degradation of PFOA irradiated with 254 nm UV light.展开更多
Polychlorinated biphenyl (PCB) is a kind of persistent and dangerous environmental pollutants. This paper presented the research result of sonochemical degradation of 2-chloro- biphenyl (2-CBP), 4-chlorobiphenyl (4-CB...Polychlorinated biphenyl (PCB) is a kind of persistent and dangerous environmental pollutants. This paper presented the research result of sonochemical degradation of 2-chloro- biphenyl (2-CBP), 4-chlorobiphenyl (4-CBP) and 4,4-dichlorobiphenyl (4,4-CBP)in water. The ultrasonic degradation kinetics of 2-CBP, 4-CBP and 4,4-CBP in water were found to be first-order and the degradation rate coefficients are 3.69?0-2, 3.19?0-2 and 2.06?0-2 at 25?C for 2-CBP, 4-CBP and 4,4-CBP respectively. The influence of initial concentrations, reaction temperature on the ultrasonic decomposition of 2-CBP were also investigated.展开更多
Machine learning-based methods have emerged as a promising solution to accurate battery capacity estimation for battery management systems.However,they are generally developed in a supervised manner which requires a c...Machine learning-based methods have emerged as a promising solution to accurate battery capacity estimation for battery management systems.However,they are generally developed in a supervised manner which requires a considerable number of input features and corresponding capacities,leading to prohibitive costs and efforts for data collection.In response to this issue,this study proposes a convolutional neural network(CNN)based method to perform end-to-end capacity estimation by taking only raw impedance spectra as input.More importantly,an input reconstruction module is devised to effectively exploit impedance spectra without corresponding capacities in the training process,thereby significantly alleviating the cost of collecting training data.Two large battery degradation datasets encompassing over 4700 impedance spectra are developed to validate the proposed method.The results show that accurate capacity estimation can be achieved when substantial training samples with measured capacities are given.However,the estimation performance of supervised machine learning algorithms sharply deteriorates when fewer samples with measured capacities are available.In this case,the proposed method outperforms supervised benchmarks and can reduce the root mean square error by up to 50.66%.A further validation under different current rates and states of charge confirms the effectiveness of the proposed method.Our method provides a flexible approach to take advantage of unlabelled samples for developing data-driven models and is promising to be generalised to other battery management tasks.展开更多
Polyethylene glycol(PEG)was added at different concentrations to the blend of poly(L-lactic acid)(PLLA)and poly(D,L-lactic acid)(PDLLA)to tailor the properties.The differential scanning calorimetry(DSC)measurement sho...Polyethylene glycol(PEG)was added at different concentrations to the blend of poly(L-lactic acid)(PLLA)and poly(D,L-lactic acid)(PDLLA)to tailor the properties.The differential scanning calorimetry(DSC)measurement showed that all blends were miscible due to shifting a single glass transition temperature into a lower temperature for increasing PEG content.The DSC,FTIR,and XRD results implied the crystallinity enhancement for PEG content until 8 wt%,then decreased at 12 wt%PEG.The XRD result indicated the homo crystalline phase formation in all blends and no stereocomplex crystal.The in vitro degradation study indicated that PEG content is proportional to the degradation rate.The highest weight loss after 28 days was achieved at 12 wt%PEG.The FTIR analysis showed a structural evolution overview during hydrolytic degradation,viz.increasing and decreasing crystallinity during 14 days for the blend without and with PEG,respectively.In conclusion,the PEG addition increased crystallinity and degradation rate of the PLLA/PDLLA mixture,but PEG higher amounts led to a decrease in crystallinity,and the weight loss was intensified.This can be useful for tuning PLA-based biomaterials with the desired physicochemical properties and appropriate degradation rates for applications in drug delivery/tissue engineering.展开更多
This paper is intended to explore soil organic matter and carbon isotope fractionation at three locations of the Passaic River to determine if microbial degradation of organic contaminants in soil is correlated to the...This paper is intended to explore soil organic matter and carbon isotope fractionation at three locations of the Passaic River to determine if microbial degradation of organic contaminants in soil is correlated to the surrounding physical environment. Microbial degradation of organic contaminants is important for the detoxification of toxic substances thereby minimizing stagnation in the environment and accumulating in the food chain. Since organic contaminants are not easily dissolved in water, they will penetrate sediment and end up enriching the adjacent soil. The hypothesis that we are testing is microbial activity and carbon isotope fractionation will be greater in preserved soils than urban soils. The reason why this is expected to be the case is the expectation of higher microbial activity in preserved environments due to less exposure to pollutants, better soil structure, higher organic matter content, and more favorable conditions for microbial growth. This is contrasted with urban soils, which are impacted by pollutants and disturbances, potentially inhibiting microbial activity. We wish to collect soil samples adjacent to the Passaic River at a pristine location, Great Swamp Wildlife Refuge, a suburban location, Goffle Brook Park, Hawthorne NJ, and an urban location, Paterson NJ. These soil samples will be weighed for soil organic matter (SOM) and weighed for isotope ratio mass spectrometry (IRMS) to test organic carbon isotopes. High SOM and δ13C depletion activity indicate microbial growth based on the characteristics of the soil horizon rather than the location of the soil sample which results in degradation of organic compounds.展开更多
SR-AOP(sulfate radical advanced oxidation process)is a novel water treatment method able to eliminate refractory organic pollutants.Hydrodynamic cavitation(HC)is a novel green technology,that can effectively produce s...SR-AOP(sulfate radical advanced oxidation process)is a novel water treatment method able to eliminate refractory organic pollutants.Hydrodynamic cavitation(HC)is a novel green technology,that can effectively produce strong oxidizing sulfate radicals.This paper presents a comprehensive review of the research advancements in these fields and a critical discussion of the principal factors influencing HC-enhanced SR-AOP and the mechanisms of synergistic degradation.Furthermore,some insights into the industrial application of HC/PS are also provided.Current research shows that this technology is feasible at the laboratory stage,but its application on larger scales requires further understanding and exploration.In this review,some attention is also paid to the design of the hydrodynamic cavitation reactor and the related operating parameters.展开更多
The degradation of Mg alloys relates to the service performance of Mg alloy biodegradable implants.In order to investigate the degradation behavior of Mg alloys as vascular stent materials in the near service environm...The degradation of Mg alloys relates to the service performance of Mg alloy biodegradable implants.In order to investigate the degradation behavior of Mg alloys as vascular stent materials in the near service environment,the hot-extruded fine-grained Mg-Zn-Y-Nd alloy microtubes,which are employed to manufacture vascular stents,were tested under radial compressive stress in the dynamic Hanks'Balanced Salt Solution(HBSS).The results revealed that the high flow rate accelerates the degradation of Mg alloy microtubes and its degradation is sensitive to radial compressive stress.These results contribute to understanding the service performance of Mg alloys as vascular stent materials.展开更多
The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater.Herein,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)...The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater.Herein,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)degradation.The electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of CDs.Finally,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry technique.This research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.展开更多
Walnut oil is a functional wood oil known to researchers that may potentially be a large source of Chinese edible oils.There are various extraction methods for walnut oil,including traditional(pressing,solvent-and enz...Walnut oil is a functional wood oil known to researchers that may potentially be a large source of Chinese edible oils.There are various extraction methods for walnut oil,including traditional(pressing,solvent-and enzymeassisted extraction)and novel methods(microwave,ultrasound,supercritical CO_(2),subcritical and other extraction technologies).Walnut oil is rich in nutrients,including phytosterols,tocopherols,polyphenols,squalene and minerals.It provides many health benefits,such as antioxidant,antitumor,anti-inflammatory,antidiabetic and lipid metabolism-related functions.In addition,the authentication of walnut oil has received much research attention.The present review provides detailed research on walnut oil extraction,composition,health benefits and adulteration identification methods.The path toward further walnut oil improvement in the context of the market value of walnut oil is also discussed.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52025041 and 51974021)the Fundamental Research Funds for the Central Universities(No.FRF-TP-19-004B2Z),and the Beijing Excellent Talents Foundation.
文摘Phenolic compounds are widely present in domestic and industrial sewage and have serious environmental hazards.Electrochemical oxidation(EO)is one of the most promising methods for sewage degradation because of its high efficiency,environmental compatibility,and safety.In this work,we present an in-depth overview of the mechanism and factors affecting the degradation of phenolic compounds by EO.In particular,the effects of treatment of phenolic compounds with different anode materials are discussed in detail.The non-active anode shows higher degradation efficiency,less intermediate accumulation,and lower energy consumption than the active anode.EO combined with other treatment methods(biological,photo,and Fenton)presents advantages,such as low energy consumption and high degradation rate.Mean-while,the remaining drawbacks of the EO process in the phenolic compound treatment system have been discussed.Furthermore,future re-search directions are put forward to improve the feasibility of the practical application of EO technology.
基金Project financially supported by the Australian Centre for International Agricultural Research(ACIAR) and the Sugar Research and Development Corporation(SRDC),Australia.
文摘Soil and land degradation in the tropics can be identified and described in terms of physical,chemical,and biological changes from its pristine state brought about by natural and anthropogenic influences.A characteristic of these ecosystems is their capacity to recycle nutrients through soil organic matter(SOM). Following disturbance through changed land management.SOM is rapidly mineralized and there is a cor responding decline in fertility and the variable charge component of the cation exchange capacity.As these ecosystems are strongly dependent on SOM for their functionality,changed land use can have irreversible impacts on the productivity of these systems.The paper focuses on quantifying chemical degradation throughbenchmaking using data from paried sites in tropical China and Thailand using surface charge finger printing.Using values taken from the fingerprint of an undistubed soil,an index of chemical degradation from ideality was calculated.Various management stratgeies that attempt to reverse degradative trends or improve poor quality soils in their natural condition are discussed.such as the ddition of natural clays and silicated materials.Results are present to whow the effect of each of the aforementional strategies on surface charge characteristics and associated increases in plant productivity.
基金Supported by the National Natural Science Foundation of China(No.20873051)the High-tech Research and Development Program of China(No.2006AA06Z321)the Natural Science Foundation of Jiangsu Province,China(No.BK2008555)
文摘The paper deals with the influence of anode material on the efficiency of degradation for organic pollutants in water system.The electrochemical performance of fluorine ion doped lead dioxide(F--PbO2) electrode for the degradation of aniline was compared with that of undoped lead dioxide(PbO2) electrode by ultraviolet-visible(UV-Vis) spectroscopy,linear voltammetry and other analytical methods,such as the measurement by chemical oxygen demand analyzer,high performance liquid chromatography and scanning electron micrography.It was shown that both PbO2 electrode and F--PbO2 electrode could make aniline be mineralized completely and have the same degradation course,but F--PbO2 electrode has much higher electrocatalytic activity than undoped PbO2 electrode for the electrochemical degradation of aniline.The experimental results confirm that F--PbO2 electrode has much higher potential for oxygen evolution than undoped PbO2 electrode.
文摘Ultrasonic irradiation was found to accelerate the rate of hydrolysis of omethoate in aqueous solution over the pH range of 2—12 Process parameters studied include pH, steady state temperature, concentration, and the type of gases. Greater than 96% hydrolysis was observed in 30 minutes through this process and the rate of destruction increased with the help of more soluble and low thermal inert gas. So with Krypton, omethoate was found to undergo rapid destruction as compared with Argon. In the presence of ultrasound, the observed first order rate of hydrolysis of omethoate is found to be independent of pH. The formation of transient supercritical water(SCW) appears to be an important factor in the acceleration of chemical reactions in the presence of ultrasound. A detailed chemical reaction mechanism for omethoate destruction in water was formulated. Experimental results and theoretical kinetic mechanism demonstrated that the most of the omethoate undergo destruction inside the cavitating holes. A very less effect of temperature on the degradation of omethoate within a temperature range of 20—70℃ proves that a small quantity of omethoate undergoes secondary destruction in the bulk liquid.
文摘The experimental degradation of a water soluble dye, potassium indigo tetrasulfonate salt, has been studied using stand-alone ozonation and photocatalytic oxidation process. Progress of the dye oxidation was followed by UV-VIS spectrophotometric measurements at controlled operating conditions. The organic content of reaction samples was measured to verify the process efficiency in dye mineralization. According to current results, almost complete color removal was obtained for ozonation within about 1 h reaction time. The reduction of the organic load was almost 80% from its original while initial sulphur content decreased to 32.5%. Dye conversion of 100% was obtained by means of a photocatalytic process using TiO2 as catalyst at 294 nm irradiated UV light. This complete color removal for the catalytic process was observed within 7 min of reaction time. The calculated initial rate of reaction of photocatalysis treatment was 8 times faster than that of ozonolysis. However, the remaining organic load of photocatalysis was almost 88% from its original while the final sulphur content was 27.3%. This contrasting behavior of the performance of the type of oxidation process stressed importance of physicochemical phenomena and intermediates molecules present during dye degradation. An insightful and mechanistic aspect of the dye oxidation was developed by performing quantumchemical calculations.
基金Supported by NSFC (No. 40176023), the Key Project of Chinese Min-istry of Education (No. 105105) and the Program for New Century Ex-cellent Talents in University (No. NCET-04-0643).
文摘Photochemical degradation of crude oil in seawater is an important issue in marine environ- mental protection and is studied in this work. Results showed that petroleum hydrocarbons could be ef- fectively degraded by the irradiation of high-pressure mercury light or natural sunlight. Photochemical reaction was controlled by various factors including light source, aquatic medium, heavy metal ion and photo-sensitizer. The rate of photo-degradation was fast at the initial stage of exposure, exhibiting a first-order reaction kinetic behavior. However, after irradiation for a few hours, the concentration of wa- ter-soluble fraction (WSF) of petroleum hydrocarbons stabilized. For all experimental conditions, the range of the photo-degradation rate is from 0.001 3 to 0.005 7/min.
基金supported by the National Key Science and Technology Project:Water Pollution Control and Remediation (No.2008ZX07208-004-2)the National Natural Science Foundation of China (No.50808029)
文摘The electrochemical degradation of p-nitrophenol(PNP) under different conditions was investigated.The electrochemical behavior of PNP and its reduction product p-aminophenol(PAP) on stainless steel cathode and Ti/Pt anode through cyclic voltammetry were observed.Electrochemical degradation process was performed in an undivided cell and 92% PNP was removed corresponding to a 22% total organic carbon removal.A divided cell was also used and it was found that PNP degradation was mainly attributed to cathodic reduction,while anodic oxidation was responsible for PNP removal due to the reaction with hydroxyl radicals and surface oxide generated on the anode.The sequential electrolytic processes,reduction-oxidation and oxidation-reduction,were compared in the divided cell.In the case of reduction-oxidation process,the total organic carbon removal reached 40%,but PNP removal was the same with the undivided cell.A black deposit was found in the effluent and identified by Fourier transform infrared spectroscopy as a polymer of PAP produced by the 1,4-addition reaction of quinoneimine.Intermediates left in the solution such as hydroquinone,p-benzoquinone and PAP were determined by high performance liquid chromatography.Whereas,the oxidation-reduction process proved unsatisfying.
文摘The photochemical degradation of triadimefon in seawater was investigated under different reaction conditions in this study. The results showed that triadimefon could be effectively degraded by the irradiation of a high-pressure mercury lamp and the photodegradation rates were influenced by aquatic media, heavy metal ions and photosensitizers. The photochemical degradation of triadimefon followed the first-order reaction kinetic behavior, with the rate constants ranging from 0.0027 to 0.0128 min-1 under the studied conditions. The photolysis of triadimefon was slower in natural seawater than in distilled water or synthetic seawater. All the heavy metal ions studied in this paper had inhibition effects on the photolysis of triadimefon. Acetone, as a common photosensitizer, could accelerate the photolysis of triadimefon. Three photoproducts were identified by GC-MS analysis. Our study confirmed that photochemical degradation is an effective pathway to remove triadimefon in seawater.
文摘Chlorsulfuron (ChS) which is a nonbiodegradable herbicide was effectively removed using an electrochemical method at the Ti/IrO2-Pt anode. The influences of current density, initial ChS concentration, initial solution pH and different NaCl dosages on electrochemical degradation of ChS were investigated. HOCl formed during electrolysis and quickly generated .OH radicals would likely play an important role in the electrochemical degradation of ChS with the presence of NaCl. At current density of 20 mA?cm–2, ChS concentration decreased from 1 mg.L–1 to 0 mg.L–1 after 10 min electrolysis with 0.2 g?L–1 NaCl dosage. It was found that the ChS removal rate increased with increasing current density and the ChS degradation was similar at different initial pH values, which means that Ti/IrO2-Pt anode can be used in a wide pH range. The electrochemical performance of Ti/IrO2-Pt anode for degradation of ChS will not decrease after serviced for a long time. These results reveal that an electrochemical approach would be a novel treatment method for effective and rapid degradation of ChS herbicide from aqueous solution.
文摘An investigation of photoelectrochemical degradation of pentachlorophenol (PCP) on a TiO2 film electrode was presented. The TiO2 film electrode was prepared by anodisation of titanium metal in sulfuric acid solution and its photoelectrocatalystic performance was studied. The destruction of PCP follows approximately the first-order kinetics. The reaction constant decreases slightly from 2.6×10-5 s-1 to 2.0×10-5 s-1 as the initial PCP concentration is increased from 0.1 mmol/L to 1.0 mmol/L under the experimental condition.
文摘Environmentally persistent and bioaccumulative perfluorooctanic acid (PFOA) was difficult to be decomposed under the irradiation of 254 nm UV light.However,in the presence of 80μmol/L Fe(Ⅲ),80% of PFOA with initial concentration of 48μmol/L (20 rag/L) was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction.Shorter chain perfluorocarboxylic acids bearing C_3-C_7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution.It was proposed that complexes of PFOA with Fe(Ⅲ) initiated degradation of PFOA irradiated with 254 nm UV light.
基金financial support from the Natural Science Foundation of Shandong Province (No. Y98B03022) and the Foundation for University Key Teacher by the Ministry of Education(No. GG-630-11944-1006).
文摘Polychlorinated biphenyl (PCB) is a kind of persistent and dangerous environmental pollutants. This paper presented the research result of sonochemical degradation of 2-chloro- biphenyl (2-CBP), 4-chlorobiphenyl (4-CBP) and 4,4-dichlorobiphenyl (4,4-CBP)in water. The ultrasonic degradation kinetics of 2-CBP, 4-CBP and 4,4-CBP in water were found to be first-order and the degradation rate coefficients are 3.69?0-2, 3.19?0-2 and 2.06?0-2 at 25?C for 2-CBP, 4-CBP and 4,4-CBP respectively. The influence of initial concentrations, reaction temperature on the ultrasonic decomposition of 2-CBP were also investigated.
基金supported by the National Key R&D Program of China(2021YFB2402002)the National Natural Science Foundation of China(51922006 and 51877009)+1 种基金the China Postdoctoral Science Foundation(BX2021035 and 2022M710379)the Beijing Natural Science Foundation(Grant No.L223013)。
文摘Machine learning-based methods have emerged as a promising solution to accurate battery capacity estimation for battery management systems.However,they are generally developed in a supervised manner which requires a considerable number of input features and corresponding capacities,leading to prohibitive costs and efforts for data collection.In response to this issue,this study proposes a convolutional neural network(CNN)based method to perform end-to-end capacity estimation by taking only raw impedance spectra as input.More importantly,an input reconstruction module is devised to effectively exploit impedance spectra without corresponding capacities in the training process,thereby significantly alleviating the cost of collecting training data.Two large battery degradation datasets encompassing over 4700 impedance spectra are developed to validate the proposed method.The results show that accurate capacity estimation can be achieved when substantial training samples with measured capacities are given.However,the estimation performance of supervised machine learning algorithms sharply deteriorates when fewer samples with measured capacities are available.In this case,the proposed method outperforms supervised benchmarks and can reduce the root mean square error by up to 50.66%.A further validation under different current rates and states of charge confirms the effectiveness of the proposed method.Our method provides a flexible approach to take advantage of unlabelled samples for developing data-driven models and is promising to be generalised to other battery management tasks.
基金Funding Statement:This work was supported by Universitas Indonesia under Grant PUTI 2020(No.NKB-4325/UN2.RST/HKP.05.00/2020).
文摘Polyethylene glycol(PEG)was added at different concentrations to the blend of poly(L-lactic acid)(PLLA)and poly(D,L-lactic acid)(PDLLA)to tailor the properties.The differential scanning calorimetry(DSC)measurement showed that all blends were miscible due to shifting a single glass transition temperature into a lower temperature for increasing PEG content.The DSC,FTIR,and XRD results implied the crystallinity enhancement for PEG content until 8 wt%,then decreased at 12 wt%PEG.The XRD result indicated the homo crystalline phase formation in all blends and no stereocomplex crystal.The in vitro degradation study indicated that PEG content is proportional to the degradation rate.The highest weight loss after 28 days was achieved at 12 wt%PEG.The FTIR analysis showed a structural evolution overview during hydrolytic degradation,viz.increasing and decreasing crystallinity during 14 days for the blend without and with PEG,respectively.In conclusion,the PEG addition increased crystallinity and degradation rate of the PLLA/PDLLA mixture,but PEG higher amounts led to a decrease in crystallinity,and the weight loss was intensified.This can be useful for tuning PLA-based biomaterials with the desired physicochemical properties and appropriate degradation rates for applications in drug delivery/tissue engineering.
文摘This paper is intended to explore soil organic matter and carbon isotope fractionation at three locations of the Passaic River to determine if microbial degradation of organic contaminants in soil is correlated to the surrounding physical environment. Microbial degradation of organic contaminants is important for the detoxification of toxic substances thereby minimizing stagnation in the environment and accumulating in the food chain. Since organic contaminants are not easily dissolved in water, they will penetrate sediment and end up enriching the adjacent soil. The hypothesis that we are testing is microbial activity and carbon isotope fractionation will be greater in preserved soils than urban soils. The reason why this is expected to be the case is the expectation of higher microbial activity in preserved environments due to less exposure to pollutants, better soil structure, higher organic matter content, and more favorable conditions for microbial growth. This is contrasted with urban soils, which are impacted by pollutants and disturbances, potentially inhibiting microbial activity. We wish to collect soil samples adjacent to the Passaic River at a pristine location, Great Swamp Wildlife Refuge, a suburban location, Goffle Brook Park, Hawthorne NJ, and an urban location, Paterson NJ. These soil samples will be weighed for soil organic matter (SOM) and weighed for isotope ratio mass spectrometry (IRMS) to test organic carbon isotopes. High SOM and δ13C depletion activity indicate microbial growth based on the characteristics of the soil horizon rather than the location of the soil sample which results in degradation of organic compounds.
文摘SR-AOP(sulfate radical advanced oxidation process)is a novel water treatment method able to eliminate refractory organic pollutants.Hydrodynamic cavitation(HC)is a novel green technology,that can effectively produce strong oxidizing sulfate radicals.This paper presents a comprehensive review of the research advancements in these fields and a critical discussion of the principal factors influencing HC-enhanced SR-AOP and the mechanisms of synergistic degradation.Furthermore,some insights into the industrial application of HC/PS are also provided.Current research shows that this technology is feasible at the laboratory stage,but its application on larger scales requires further understanding and exploration.In this review,some attention is also paid to the design of the hydrodynamic cavitation reactor and the related operating parameters.
基金the financial support of the National Key Research and Development Program of China(2018YFC1106703)the Key Projects of the Joint Fund of the National Natural Science Foundation of China(U1804251)。
文摘The degradation of Mg alloys relates to the service performance of Mg alloy biodegradable implants.In order to investigate the degradation behavior of Mg alloys as vascular stent materials in the near service environment,the hot-extruded fine-grained Mg-Zn-Y-Nd alloy microtubes,which are employed to manufacture vascular stents,were tested under radial compressive stress in the dynamic Hanks'Balanced Salt Solution(HBSS).The results revealed that the high flow rate accelerates the degradation of Mg alloy microtubes and its degradation is sensitive to radial compressive stress.These results contribute to understanding the service performance of Mg alloys as vascular stent materials.
基金the funding support from the National Natural Science Foundation of China(21906072,22006057)the Natural Science Foundation of Jiangsu Province(BK20190982)“Doctor of Mass entrepreneurship and innovation”Project in Jiangsu Province。
文摘The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater.Herein,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)degradation.The electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of CDs.Finally,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry technique.This research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.
基金The authors would like to thank the National Natural Science Foundation of China Youth Foud(NO:32201947)Key R&D Program Projects of Shaanxi Province,China(NO:2022NY-003)for the financial support.
文摘Walnut oil is a functional wood oil known to researchers that may potentially be a large source of Chinese edible oils.There are various extraction methods for walnut oil,including traditional(pressing,solvent-and enzymeassisted extraction)and novel methods(microwave,ultrasound,supercritical CO_(2),subcritical and other extraction technologies).Walnut oil is rich in nutrients,including phytosterols,tocopherols,polyphenols,squalene and minerals.It provides many health benefits,such as antioxidant,antitumor,anti-inflammatory,antidiabetic and lipid metabolism-related functions.In addition,the authentication of walnut oil has received much research attention.The present review provides detailed research on walnut oil extraction,composition,health benefits and adulteration identification methods.The path toward further walnut oil improvement in the context of the market value of walnut oil is also discussed.
