The pretreatment of refractory polyvinyl-alcohol （PVA） wastewater with low value of CODcr by Fenton＇s reagent was investigated to enhance the biodegradabilily. The effects of operating conditions such as pH of the ...The pretreatment of refractory polyvinyl-alcohol （PVA） wastewater with low value of CODcr by Fenton＇s reagent was investigated to enhance the biodegradabilily. The effects of operating conditions such as pH of the solution, Fe2＋ dosage, H2O2 dosage, reaction time and initial PVA concentration on the removal efficiency of CODCr were discussed. It is demonstrated that the optimum value of pH for removal of CODcr is 5 and the most suitable dosages of H2O2 （2%） and FeSO4 （10 mg/L） are 5% and 8.0%, respectively. When the initial CODcr value of the PVA water is 760 mg/L, the favorable reaction time is 110 min. Under these optimum conditions, the removal ratio of CODcr is 58.6% 61.4%, and the value of biodegradability （CODB/CODcr） increases markedly from 8.9% 9.7% to 62.6% 68.3%.展开更多
Fenton's reagent was employed to treat the wastewater containing RDX.The effects of FeSO4 concentration,H2O2 concentration,pH value,reaction time,temperature and initial COD of wastewater on residual COD of wastew...Fenton's reagent was employed to treat the wastewater containing RDX.The effects of FeSO4 concentration,H2O2 concentration,pH value,reaction time,temperature and initial COD of wastewater on residual COD of wastewater were investigated.The results show that the optimum FeSO4 concentration and pH are 700 mg/L and 2.5,respectively,and the residual COD of wastewater decreases with the rise in H2O2 concentration,but increases with the rise in temperature.After Fenton's reagent treatment,the initial COD of less than 874 mg/L wastewater can meet effluent standard.Under conditions of 100 mg/L H2O2,437 mg/L initial COD and 15 ℃ temperature,the lowest residual COD is obtained at 83.80 mg/L in 5 min.展开更多
Gaskets are applied in PEMFCs（proton exchange membrane fuel cells） to keep reactant gases and liquid within their respective regions, which are of great significance for the both sealing and electrochemical performa...Gaskets are applied in PEMFCs（proton exchange membrane fuel cells） to keep reactant gases and liquid within their respective regions, which are of great significance for the both sealing and electrochemical performance of fuel cells during the long-term operation. In this study, the degradation of silicone rubbers, often selected as seals in PEMFCs, in Fenton＇s reagents with different H_2O_2 concentrations was investigated. The changes in chemical properties, mechanical behavior and surface morphology of the samples were studied before and after exposure to the test environment over time. It is found that increasing H_2O_2 concentration will degrade the rubbers more severely. The experimental results elucidate the degradation mechanism of silicone rubbers in Fenton＇s reagents and the influence of H_2O_2 in the degradation process.展开更多
A novel, simple and convenient method for the determination of hydroxyl radicals isestablished. Hydroxyl radicals produced by Fenton reaction is trapped by spin trap reagent phenyl-t-butyl nitrone (PBN), and the free ...A novel, simple and convenient method for the determination of hydroxyl radicals isestablished. Hydroxyl radicals produced by Fenton reaction is trapped by spin trap reagent phenyl-t-butyl nitrone (PBN), and the free radical adduct of PBN can be detected by single sweeposcillopolarography, with its second order derivative cathodic wave at -0.52V vs SCE. Theoptimum experimental conditions for the detemination is discussed, and the scavenging effects ofsome compounds on OH was also studied.展开更多
Ethylenediaminetetraacetic acid (EDTA) is a chelating agent that has been used for decontamination purposes in nuclear industry. The presence of EDTA in decontamination wastes can cause complexation of the cations res...Ethylenediaminetetraacetic acid (EDTA) is a chelating agent that has been used for decontamination purposes in nuclear industry. The presence of EDTA in decontamination wastes can cause complexation of the cations resulting into interferences in their removal by various treatment processes such as chemical precipitation, ion exchange etc. Further, it might also impart elevated leachability of cationic contaminants from the conditioned wastes immobilized in cement or other matrices and can negatively influence the quality of the final form of waste. In the present study, kinetics of degradation of EDTA (20,000 mg/l) by employing either Photo-Fenton process using UV (15 W λmax = 253.7 nm) or Sono-Fenton process using ultrasound at 130 KHz or simultaneous Sono-Photo Fenton process has been investigated. EDTA is effectively degraded by the synergistic effect of both Photo Fenton and Sono Fenton process. All the above mentioned processes were found to follow a first order kinetics reaction. From the observed pH changes during the oxidation processes, it can be concluded that there is a loss of chelating ability of EDTA. Formation of amides was con- firmed during the degradation processes.展开更多
The experiments focused on the Fenton treatment of humic substances(HS) in concentrated landfill leachate rejected by reverse osmosis(RO).The changes in dissolved organic matter by oxidation/coagulation were assessed ...The experiments focused on the Fenton treatment of humic substances(HS) in concentrated landfill leachate rejected by reverse osmosis(RO).The changes in dissolved organic matter by oxidation/coagulation were assessed by using gross organic parameters such as chemical oxygen demand(COD),total organic carbon(TOC),UV254 and COD/TOC molar ratio during the treatment with Fenton reagent.The results demonstrated that the humic substances removal efficiency(from 11.9% to 89.5%) was higher than that of COD(from 9.6% to 75.2%) and there was a good correlation between humic substances degradation and COD removal.This study showed that the oxidation efficiency controlled the coagulation efficiency,so high oxidation efficiency may cause relatively low coagulation.The change of(COD/TOC)oxid indicated that the oxidation reaction was ultimate degradation under the condition of pH= 2.0—4.0,>80 mmol·L-1,= 40—160 mmol·L-1,reaction time 2 h.The changes of(COD/TOC)coag illustrated that the oxidation state of the organic matter removed by coagulation was significantly higher than in the fresh landfill leachate under the above reaction conditions.展开更多
基金Project(08JCYBJC02600) supported by the Natural Science Foundation of Tianjin,ChinaProject(2008ZX07314-005-011) supported by the National Major Technological Program of China
文摘The pretreatment of refractory polyvinyl-alcohol （PVA） wastewater with low value of CODcr by Fenton＇s reagent was investigated to enhance the biodegradabilily. The effects of operating conditions such as pH of the solution, Fe2＋ dosage, H2O2 dosage, reaction time and initial PVA concentration on the removal efficiency of CODCr were discussed. It is demonstrated that the optimum value of pH for removal of CODcr is 5 and the most suitable dosages of H2O2 （2%） and FeSO4 （10 mg/L） are 5% and 8.0%, respectively. When the initial CODcr value of the PVA water is 760 mg/L, the favorable reaction time is 110 min. Under these optimum conditions, the removal ratio of CODcr is 58.6% 61.4%, and the value of biodegradability （CODB/CODcr） increases markedly from 8.9% 9.7% to 62.6% 68.3%.
基金Sponsored by National Nature Science Foundation of China (20476010)
文摘Fenton's reagent was employed to treat the wastewater containing RDX.The effects of FeSO4 concentration,H2O2 concentration,pH value,reaction time,temperature and initial COD of wastewater on residual COD of wastewater were investigated.The results show that the optimum FeSO4 concentration and pH are 700 mg/L and 2.5,respectively,and the residual COD of wastewater decreases with the rise in H2O2 concentration,but increases with the rise in temperature.After Fenton's reagent treatment,the initial COD of less than 874 mg/L wastewater can meet effluent standard.Under conditions of 100 mg/L H2O2,437 mg/L initial COD and 15 ℃ temperature,the lowest residual COD is obtained at 83.80 mg/L in 5 min.
基金the Natural Science Foundation of China(No.21476178)the Fundamental Research Funds for the Central Universities(WUT:2015IVA059)
文摘Gaskets are applied in PEMFCs（proton exchange membrane fuel cells） to keep reactant gases and liquid within their respective regions, which are of great significance for the both sealing and electrochemical performance of fuel cells during the long-term operation. In this study, the degradation of silicone rubbers, often selected as seals in PEMFCs, in Fenton＇s reagents with different H_2O_2 concentrations was investigated. The changes in chemical properties, mechanical behavior and surface morphology of the samples were studied before and after exposure to the test environment over time. It is found that increasing H_2O_2 concentration will degrade the rubbers more severely. The experimental results elucidate the degradation mechanism of silicone rubbers in Fenton＇s reagents and the influence of H_2O_2 in the degradation process.
文摘A novel, simple and convenient method for the determination of hydroxyl radicals isestablished. Hydroxyl radicals produced by Fenton reaction is trapped by spin trap reagent phenyl-t-butyl nitrone (PBN), and the free radical adduct of PBN can be detected by single sweeposcillopolarography, with its second order derivative cathodic wave at -0.52V vs SCE. Theoptimum experimental conditions for the detemination is discussed, and the scavenging effects ofsome compounds on OH was also studied.
文摘Ethylenediaminetetraacetic acid (EDTA) is a chelating agent that has been used for decontamination purposes in nuclear industry. The presence of EDTA in decontamination wastes can cause complexation of the cations resulting into interferences in their removal by various treatment processes such as chemical precipitation, ion exchange etc. Further, it might also impart elevated leachability of cationic contaminants from the conditioned wastes immobilized in cement or other matrices and can negatively influence the quality of the final form of waste. In the present study, kinetics of degradation of EDTA (20,000 mg/l) by employing either Photo-Fenton process using UV (15 W λmax = 253.7 nm) or Sono-Fenton process using ultrasound at 130 KHz or simultaneous Sono-Photo Fenton process has been investigated. EDTA is effectively degraded by the synergistic effect of both Photo Fenton and Sono Fenton process. All the above mentioned processes were found to follow a first order kinetics reaction. From the observed pH changes during the oxidation processes, it can be concluded that there is a loss of chelating ability of EDTA. Formation of amides was con- firmed during the degradation processes.
文摘The experiments focused on the Fenton treatment of humic substances(HS) in concentrated landfill leachate rejected by reverse osmosis(RO).The changes in dissolved organic matter by oxidation/coagulation were assessed by using gross organic parameters such as chemical oxygen demand(COD),total organic carbon(TOC),UV254 and COD/TOC molar ratio during the treatment with Fenton reagent.The results demonstrated that the humic substances removal efficiency(from 11.9% to 89.5%) was higher than that of COD(from 9.6% to 75.2%) and there was a good correlation between humic substances degradation and COD removal.This study showed that the oxidation efficiency controlled the coagulation efficiency,so high oxidation efficiency may cause relatively low coagulation.The change of(COD/TOC)oxid indicated that the oxidation reaction was ultimate degradation under the condition of pH= 2.0—4.0,>80 mmol·L-1,= 40—160 mmol·L-1,reaction time 2 h.The changes of(COD/TOC)coag illustrated that the oxidation state of the organic matter removed by coagulation was significantly higher than in the fresh landfill leachate under the above reaction conditions.
