The characteristic and mechanism of parachlorophenol(4-CP) degradation in an internal electrolysis system were investigated. The degradation rate of 4-CP was higher in acid solution than that of in neutral or alkaline...The characteristic and mechanism of parachlorophenol(4-CP) degradation in an internal electrolysis system were investigated. The degradation rate of 4-CP was higher in acid solution than that of in neutral or alkaline solution. Addition of activated carbon could make 4-CP easier be degraded by the surface contact catalysis. The dissolved oxygen in solution could take part in the electrode reaction and intensify the degradation of 4-CP. By the analysis of intermediates of degradation of 4-CP, it could be conferred that 4-CP was broken through the bond beside hydroxy firstly, then the bond beside chloride was broken and the chloride was dechlorinated simultaneously. Most intermediate products were glycerine, ethane diacid and acetic acid, while very few 1,4-butanedial and alcohols were found.展开更多
The reduction of nitrate using internal circulation micro-electrolysis te chnology(ICE)was investigated.The effect of the reaction time,initial pH,Fe/C ratio,and aeration rate on the nitrate reduction was investigated...The reduction of nitrate using internal circulation micro-electrolysis te chnology(ICE)was investigated.The effect of the reaction time,initial pH,Fe/C ratio,and aeration rate on the nitrate reduction was investigated using a single factor experiment.Based on the results of the single factor experiment,a response surface methodology(RSM)was applied to optimize the N2 generation selectivity.The effects and interactions of three independent variables were estimated using a Box-Behnken design.Using the RSM analysis,a quadratic polynomial model with optimal conditions at pH=8.8,Fe/C=1:1,and an aeration rate of 30 L·min-1 was developed by means of the regre ssion analysis of the experimental data.Using the RSM optimization,the optimal conditions yielded a N2 generation selectivity of 72.0%,which is in good agreement with experimental result(73.2%±0.5%)and falls within the 95%confidence interval(IC:66.8%-77.3%)of the model results.This indicates that the model obtained in this study effectively predicts the N2 generation selectivity for nitrate reduction by the ICE process,thus providing a theoretical basis for process design.展开更多
It is generally recognized that internal-loop reactors are well-developed mass and heat-transfer multiphase flow reactors. However, the internal flow field in the internal-loop reactor is influenced by the structure p...It is generally recognized that internal-loop reactors are well-developed mass and heat-transfer multiphase flow reactors. However, the internal flow field in the internal-loop reactor is influenced by the structure parameter of the reactor, which has a great effect on the reaction efficiency. In this study, the computational fluid dynamics simulation method was used to determine the influence of reactor structure on flow field, and a volume-offluid model was employed to simulate the gas–liquid, two-phase flow of the internal-loop micro-electrolysis reactor. Hydrodynamic factors were optimized when the height-to-diameter ratio was 4:1, diameter ratio was9:1, draft-tube axial height was 90 mm. Three-dimensional simulations for the water distributor were carried out, and the results suggested that the optimal conditions are as follows: the number of water distribution pipes was four, and an inhomogeneous water distribution was used. According to the results of the simulation,the suitable structure can be used to achieve good fluid mechanical properties, such as the good liquid circulation velocity and gas holdup, which provides a good theoretical foundation for the application of the reactor.展开更多
The formation of multiple oxygen intermediates supporting efficient oxygen evolution reaction(OER)are affinitive with hydroxyl adsorption.However,ability of the catalyst to capture hydroxyl and maintain the continuous...The formation of multiple oxygen intermediates supporting efficient oxygen evolution reaction(OER)are affinitive with hydroxyl adsorption.However,ability of the catalyst to capture hydroxyl and maintain the continuous supply at active sits remains a tremendous challenge.Herein,an affordable Ni2P/FeP2 heterostructure is presented to form the internal polarization field(IPF),arising hydroxyl spillover(HOSo)during OER.Facilitated by IPF,the oriented HOSo from FeP2 to Ni2P can activate the Ni site with a new hydroxyl transmission channel and build the optimized reaction path of oxygen intermediates for lower adsorption energy,boosting the OER activity(242 mV vs.RHE at 100 mA cm-2)for least 100 h.More interestingly,for the anion exchange membrane water electrolyzer(AEMWE)with low concentration electrolyte,the advantage of HOSo effect is significantly amplified,delivering 1 A cm^(-2)at a low cell voltage of 1.88 V with excellent stability for over 50 h.展开更多
Actual pharmaceutical wastewater was treatedusing a combined ultrasonic irradiation (US) and iron/cokeinternal electrolysis (Fe/C) technology. A significantsynergetic effect was observed, showing that ultrasonicirradi...Actual pharmaceutical wastewater was treatedusing a combined ultrasonic irradiation (US) and iron/cokeinternal electrolysis (Fe/C) technology. A significantsynergetic effect was observed, showing that ultrasonicirradiation dramatically enhanced the chemical oxygendemand (COD) removal efficiencies by internal electrolysis.The effects of primary operating factors on CODremoval were evaluated systematically. Higher ultrasonicfrequency and lower pH values as well as longer reactiontime were favorable to COD removal. The ratio ofbiochemical oxygen demand (BOD) and COD (B/C) ofthe wastewater increased from 0.21 to 0.32 after US-Fe/Ctreatment. An acute biotoxicity assay measuring theinhibition of bioluminescence indicated that the wastewaterwith overall toxicity of 4.3 mg-Zn^(2+)·L^(-1) wasreduced to 0.5 mg-Zn^(2+)·L^(-1) after treatment. Both the rawand the treated wastewater samples were separated andidentified. The types of compounds suggested that theincreased biodegradability and reduced biotoxicityresulted mainly from the destruction of N,N-2 dimethylformamide and aromatic compounds in the pharmaceuticalwastewater.展开更多
The internal-electrolysis (IE) process can be used as pretreatment to improve the biodegradability of yeast wastewater. The water before and after IE pretreatment was analyzed by UV, GPC, GC-MS to determine the change...The internal-electrolysis (IE) process can be used as pretreatment to improve the biodegradability of yeast wastewater. The water before and after IE pretreatment was analyzed by UV, GPC, GC-MS to determine the changes in its chemical composition. The mechanism on the improvement of biodegradability by the IE process was discussed in two aspects according to the changes of chemical composition. (i) Some reactions occurred during the IE process, such as hydrolytic reaction, cracking, and redox reaction. Thus, the cyclic structure opened and changed into chains, and the macromolecular compounds were spilt to small molecule substances. All these reactions tended to simplify the structure of molecules and increase the donating electron groups so as to improve the biodegradability. (ii) The small molecule acids and alcohols in raw water or produced by the internal electrolysis process could be removed through volatilization and electrochemical adhesion, which was conducive to the removal of COD and the improvement of biodegradability of yeast wastewater.展开更多
文摘The characteristic and mechanism of parachlorophenol(4-CP) degradation in an internal electrolysis system were investigated. The degradation rate of 4-CP was higher in acid solution than that of in neutral or alkaline solution. Addition of activated carbon could make 4-CP easier be degraded by the surface contact catalysis. The dissolved oxygen in solution could take part in the electrode reaction and intensify the degradation of 4-CP. By the analysis of intermediates of degradation of 4-CP, it could be conferred that 4-CP was broken through the bond beside hydroxy firstly, then the bond beside chloride was broken and the chloride was dechlorinated simultaneously. Most intermediate products were glycerine, ethane diacid and acetic acid, while very few 1,4-butanedial and alcohols were found.
基金Supported by the National Natural Science Foundation of China(21677018)the Joint Fund of the Beijing Natural Science Foundation and Beijing Municipal Education Commission(KZ201810017024).
文摘The reduction of nitrate using internal circulation micro-electrolysis te chnology(ICE)was investigated.The effect of the reaction time,initial pH,Fe/C ratio,and aeration rate on the nitrate reduction was investigated using a single factor experiment.Based on the results of the single factor experiment,a response surface methodology(RSM)was applied to optimize the N2 generation selectivity.The effects and interactions of three independent variables were estimated using a Box-Behnken design.Using the RSM analysis,a quadratic polynomial model with optimal conditions at pH=8.8,Fe/C=1:1,and an aeration rate of 30 L·min-1 was developed by means of the regre ssion analysis of the experimental data.Using the RSM optimization,the optimal conditions yielded a N2 generation selectivity of 72.0%,which is in good agreement with experimental result(73.2%±0.5%)and falls within the 95%confidence interval(IC:66.8%-77.3%)of the model results.This indicates that the model obtained in this study effectively predicts the N2 generation selectivity for nitrate reduction by the ICE process,thus providing a theoretical basis for process design.
基金Supported by the National Natural Science Foundation of China(21677018)Jointly Projects of Beijing Natural Science Foundation and Beijing Municipal Education Commission(KZ201810017024)
文摘It is generally recognized that internal-loop reactors are well-developed mass and heat-transfer multiphase flow reactors. However, the internal flow field in the internal-loop reactor is influenced by the structure parameter of the reactor, which has a great effect on the reaction efficiency. In this study, the computational fluid dynamics simulation method was used to determine the influence of reactor structure on flow field, and a volume-offluid model was employed to simulate the gas–liquid, two-phase flow of the internal-loop micro-electrolysis reactor. Hydrodynamic factors were optimized when the height-to-diameter ratio was 4:1, diameter ratio was9:1, draft-tube axial height was 90 mm. Three-dimensional simulations for the water distributor were carried out, and the results suggested that the optimal conditions are as follows: the number of water distribution pipes was four, and an inhomogeneous water distribution was used. According to the results of the simulation,the suitable structure can be used to achieve good fluid mechanical properties, such as the good liquid circulation velocity and gas holdup, which provides a good theoretical foundation for the application of the reactor.
基金This work is financially supported by National Natural Science Foundation of China(52174283 and 52274308)Innovation Fund Project for Graduate Student of China University of Petroleum(East China)(22CX04023A)the Fundamental Research Funds for the Central Universities。
文摘The formation of multiple oxygen intermediates supporting efficient oxygen evolution reaction(OER)are affinitive with hydroxyl adsorption.However,ability of the catalyst to capture hydroxyl and maintain the continuous supply at active sits remains a tremendous challenge.Herein,an affordable Ni2P/FeP2 heterostructure is presented to form the internal polarization field(IPF),arising hydroxyl spillover(HOSo)during OER.Facilitated by IPF,the oriented HOSo from FeP2 to Ni2P can activate the Ni site with a new hydroxyl transmission channel and build the optimized reaction path of oxygen intermediates for lower adsorption energy,boosting the OER activity(242 mV vs.RHE at 100 mA cm-2)for least 100 h.More interestingly,for the anion exchange membrane water electrolyzer(AEMWE)with low concentration electrolyte,the advantage of HOSo effect is significantly amplified,delivering 1 A cm^(-2)at a low cell voltage of 1.88 V with excellent stability for over 50 h.
基金This study was supported by the Nation Water Pollution Control and Management of Major Special Science and Technology of China(No.2008ZX07314-001-02)the Key Projects in the National Science&Technology Pillar Program during the“Eleventh Five Year Plan”period(No.2009BAC60B02)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF10013).
文摘Actual pharmaceutical wastewater was treatedusing a combined ultrasonic irradiation (US) and iron/cokeinternal electrolysis (Fe/C) technology. A significantsynergetic effect was observed, showing that ultrasonicirradiation dramatically enhanced the chemical oxygendemand (COD) removal efficiencies by internal electrolysis.The effects of primary operating factors on CODremoval were evaluated systematically. Higher ultrasonicfrequency and lower pH values as well as longer reactiontime were favorable to COD removal. The ratio ofbiochemical oxygen demand (BOD) and COD (B/C) ofthe wastewater increased from 0.21 to 0.32 after US-Fe/Ctreatment. An acute biotoxicity assay measuring theinhibition of bioluminescence indicated that the wastewaterwith overall toxicity of 4.3 mg-Zn^(2+)·L^(-1) wasreduced to 0.5 mg-Zn^(2+)·L^(-1) after treatment. Both the rawand the treated wastewater samples were separated andidentified. The types of compounds suggested that theincreased biodegradability and reduced biotoxicityresulted mainly from the destruction of N,N-2 dimethylformamide and aromatic compounds in the pharmaceuticalwastewater.
基金Supported by the Natural Science Foundation of Hubei Province(Grant No.2005ABA004)
文摘The internal-electrolysis (IE) process can be used as pretreatment to improve the biodegradability of yeast wastewater. The water before and after IE pretreatment was analyzed by UV, GPC, GC-MS to determine the changes in its chemical composition. The mechanism on the improvement of biodegradability by the IE process was discussed in two aspects according to the changes of chemical composition. (i) Some reactions occurred during the IE process, such as hydrolytic reaction, cracking, and redox reaction. Thus, the cyclic structure opened and changed into chains, and the macromolecular compounds were spilt to small molecule substances. All these reactions tended to simplify the structure of molecules and increase the donating electron groups so as to improve the biodegradability. (ii) The small molecule acids and alcohols in raw water or produced by the internal electrolysis process could be removed through volatilization and electrochemical adhesion, which was conducive to the removal of COD and the improvement of biodegradability of yeast wastewater.
