The use of Fenton＇s reagent （Fe^2＋/H2O2） and Fenton-like reagents containing transition metals of Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ）, and Mn（Ⅱ） for an alum sludge conditioning to improve its dewaterability was invest...The use of Fenton＇s reagent （Fe^2＋/H2O2） and Fenton-like reagents containing transition metals of Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ）, and Mn（Ⅱ） for an alum sludge conditioning to improve its dewaterability was investigated. The results obtained were compared with those obtained from conditioning the same alum sludge using cationic and anionic polymers. Experimental results show that Fenton＇s reagent was the best among the Fenton and Fenton-like reagents for the alum sludge conditioning. A considerable effectiveness of capillary suction time （CST） reduction efficiency of 47% can be achieved under test conditions of Fe^2＋/H2O2 = 20/125 mg/g DS （dry solid） and pH 6.0. The observation of floc-like particles after Fenton＇s reagent conditioning of alum sludge suggested that the mechanism of Fenton＇s reagent conditioning was different from that of polymer conditioning. In spite of the lower efficiency in the CST reduction of Fenton＇s reagent in alum sludge conditioning compared to that of polymer conditioning, Fenton＇s reagent offers a more environmentally safe option. Tiffs study provided an example of proactive treatment engineering, which is aimed at seeking a safe alternative to the use of polymers in sludge conditioning towards achieving a more sustainable sludge management strategy.展开更多
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
4-Chlorophenol (4-CP) solution was treated by dual-frequency ultrasound inconjunction with Fenton reagent, and obvious improvement in the 4-CP degradation rate was observedin this advanced oxidation process. Experimen...4-Chlorophenol (4-CP) solution was treated by dual-frequency ultrasound inconjunction with Fenton reagent, and obvious improvement in the 4-CP degradation rate was observedin this advanced oxidation process. Experimental results showed that ultrasonic intensity,saturating gas and pH value affected greatly the 4-CP removal rate. Among four different saturatinggases (Ar, O_2, air and N_2), 4-CP degradation with Ar-saturated solution was the best. However, inthe view of practical wastewater treatment, using oxygen as the saturating gas would be moreeconomical. The addition of Fenton reagent followed the first-order kinetics and increased the 4-CPdegradation rate. The 4-CP removal rate increased by around 126% within 15 min treatment. Thesynergetic effect of dual-frequency ultrasound with Fenton reagent on 4-CP degradation was obviouslyobserved.展开更多
The degradation of ortho-chlorophenol using Fenton＇s reagent was studied by chemiluminescence （CL）. Without a special CL reagent, a weak CL emission from the mixture of ferrous ion and hydrogen peroxide was observe...The degradation of ortho-chlorophenol using Fenton＇s reagent was studied by chemiluminescence （CL）. Without a special CL reagent, a weak CL emission from the mixture of ferrous ion and hydrogen peroxide was observed at room temperature. The CL intensity was increased by the addition of ortho-chlorophenol into the mixed solution. When the temperature was raised to 65°C, the CL intensity was enhanced strongly. The CL mechanisms for the system H2O2-Fe2＋ with and without ortho-chlorophenol were studied by examining the CL spectrum, gas chromatography-mass spectrometry and electron spin resonance spectrum. The effects of various free radical scavengers, surfactants and fluorescence compounds on the CL intensity were also investigated. A self-catalytic oxidation mechanism was proposed. The results showed that singlet oxygen was the main emitter for the system H2O2-Fe2＋. The strong CL from the system H2O2-Fe2＋-ortho-chlorophenol was due to singlet oxygen and electronically excited quinone. The benzenediol-like intermediate product formed during the phenol oxidation process greatly promoted the Fenton＇s reaction and led to higher CL intensity. Chemiluninescence is a novel approach for the investigation of the oxidation of some organic pollutants by Fenton＇s reagent.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
The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation w...The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.展开更多
Heterogeneous Fenton reagent, as a strong oxidizer, has been used widely in the treatment ofwastewater. We prepared Fe2O3/γ-Al2O3 catalyst by impregnation method and characterized it by powder X-ray diffraction （XRD...Heterogeneous Fenton reagent, as a strong oxidizer, has been used widely in the treatment ofwastewater. We prepared Fe2O3/γ-Al2O3 catalyst by impregnation method and characterized it by powder X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM）. Test results show that Fe203 crystal was compounded on the γ-Al2O3 carder. We tested and optimized Fe203/γ-Al2O3 /H2O2 and Fe2O3/γ-Al2O3 /H2O2/UV processes to remediate organic material of phenol, using phenol solution with an in. itial concentration of 250 mg/L as a representative of phenolic industrial Wastewater. The preparation conditions were optimized based on performance of Fe2Oa/γ-Al2O3 catalyst and the processes to degrade phenol in aqueous environments. The experimental results showed that the phenol removal perfomance with Fe2O3/γ-Al2O3 /H2O2/UV was more complete than with Fe2O3/γ-Al2O3 /H2O2 and degradation rate of phenol reached 89.4% and 94.7% respectively after reaction for2 h.展开更多
The low biodegradability of polyphenolic compounds typically found in olive processing indicated that biological treatment is not always successful in the treatment of olive oil mill wastewater in term of COD removal....The low biodegradability of polyphenolic compounds typically found in olive processing indicated that biological treatment is not always successful in the treatment of olive oil mill wastewater in term of COD removal. In this study the results of investigations on the applicability of Fenton's reagent in the treatment of this effluent were discussed. The efficiency of this method was determined. 86 % of removal COD was obtained using 5 mol H 2O 2 and 0.4 mol Fe 2+ per liter of crude OMW. The main parameters that govern the complex reactive system, i.e., time, pH, [H 2O 2] and [Fe(II)] were studied.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 selective and new spectrophotometric method is described for determination of five 1,4 dihydropyridine drugs (1,4- DHP);namely nifedipine (NIF), nicardipine (NIC), nimodipine (NIM), felodipine (FEL) and amlodipine (...A selective and new spectrophotometric method is described for determination of five 1,4 dihydropyridine drugs (1,4- DHP);namely nifedipine (NIF), nicardipine (NIC), nimodipine (NIM), felodipine (FEL) and amlodipine (AML). The method is based on a coupling reaction between the cited drugs and vanillin reagent in acidic condition. Under optimized conditions, the red coloured products were measured at 500 nm for NIF, NIC, NIM and FEL or at 479 nm for AML. Molar absorptivities were ranged from 0.575 × 104 - 1.065 × 104 l·mol-1·cm-1, Beer’s law was obeyed at 5 - 70 μg/mL concentration range and the limit of detection was ranged from 0.150 - 1.500 μg/mL. The proposed method was successfully extended to pharmaceutical preparations tablets and capsules and comparison by Student’s t-test and variance ratio F-test showed no significant difference.展开更多
基金The first author would like to appreciate Ministry of Higher Education, Missions Department, Egypt for the fi- nancial support granted through Channel Scheme Mission.
文摘The use of Fenton＇s reagent （Fe^2＋/H2O2） and Fenton-like reagents containing transition metals of Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ）, and Mn（Ⅱ） for an alum sludge conditioning to improve its dewaterability was investigated. The results obtained were compared with those obtained from conditioning the same alum sludge using cationic and anionic polymers. Experimental results show that Fenton＇s reagent was the best among the Fenton and Fenton-like reagents for the alum sludge conditioning. A considerable effectiveness of capillary suction time （CST） reduction efficiency of 47% can be achieved under test conditions of Fe^2＋/H2O2 = 20/125 mg/g DS （dry solid） and pH 6.0. The observation of floc-like particles after Fenton＇s reagent conditioning of alum sludge suggested that the mechanism of Fenton＇s reagent conditioning was different from that of polymer conditioning. In spite of the lower efficiency in the CST reduction of Fenton＇s reagent in alum sludge conditioning compared to that of polymer conditioning, Fenton＇s reagent offers a more environmentally safe option. Tiffs study provided an example of proactive treatment engineering, which is aimed at seeking a safe alternative to the use of polymers in sludge conditioning towards achieving a more sustainable sludge management strategy.
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Partly supported by the National Natural Science Foundation of China (No. 20176053)Academic Foundation of Zhejiang University of Technology (No. 20040004).
文摘4-Chlorophenol (4-CP) solution was treated by dual-frequency ultrasound inconjunction with Fenton reagent, and obvious improvement in the 4-CP degradation rate was observedin this advanced oxidation process. Experimental results showed that ultrasonic intensity,saturating gas and pH value affected greatly the 4-CP removal rate. Among four different saturatinggases (Ar, O_2, air and N_2), 4-CP degradation with Ar-saturated solution was the best. However, inthe view of practical wastewater treatment, using oxygen as the saturating gas would be moreeconomical. The addition of Fenton reagent followed the first-order kinetics and increased the 4-CPdegradation rate. The 4-CP removal rate increased by around 126% within 15 min treatment. Thesynergetic effect of dual-frequency ultrasound with Fenton reagent on 4-CP degradation was obviouslyobserved.
基金supported by the National Key Technology R & D Program of China (No. 2007AA09210107)
文摘The degradation of ortho-chlorophenol using Fenton＇s reagent was studied by chemiluminescence （CL）. Without a special CL reagent, a weak CL emission from the mixture of ferrous ion and hydrogen peroxide was observed at room temperature. The CL intensity was increased by the addition of ortho-chlorophenol into the mixed solution. When the temperature was raised to 65°C, the CL intensity was enhanced strongly. The CL mechanisms for the system H2O2-Fe2＋ with and without ortho-chlorophenol were studied by examining the CL spectrum, gas chromatography-mass spectrometry and electron spin resonance spectrum. The effects of various free radical scavengers, surfactants and fluorescence compounds on the CL intensity were also investigated. A self-catalytic oxidation mechanism was proposed. The results showed that singlet oxygen was the main emitter for the system H2O2-Fe2＋. The strong CL from the system H2O2-Fe2＋-ortho-chlorophenol was due to singlet oxygen and electronically excited quinone. The benzenediol-like intermediate product formed during the phenol oxidation process greatly promoted the Fenton＇s reaction and led to higher CL intensity. Chemiluninescence is a novel approach for the investigation of the oxidation of some organic pollutants by Fenton＇s reagent.
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 Northeast Petroleum University Youth Science Foundation (No. 2019QNL-35)Guiding Science and Technology Plan Project of Daqing (No. zd-2021-39)。
文摘The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.
基金Funded by the Natural Science Foundation of the Education Committee of Heilongjiang Province (No. 12511371)
文摘Heterogeneous Fenton reagent, as a strong oxidizer, has been used widely in the treatment ofwastewater. We prepared Fe2O3/γ-Al2O3 catalyst by impregnation method and characterized it by powder X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM）. Test results show that Fe203 crystal was compounded on the γ-Al2O3 carder. We tested and optimized Fe203/γ-Al2O3 /H2O2 and Fe2O3/γ-Al2O3 /H2O2/UV processes to remediate organic material of phenol, using phenol solution with an in. itial concentration of 250 mg/L as a representative of phenolic industrial Wastewater. The preparation conditions were optimized based on performance of Fe2Oa/γ-Al2O3 catalyst and the processes to degrade phenol in aqueous environments. The experimental results showed that the phenol removal perfomance with Fe2O3/γ-Al2O3 /H2O2/UV was more complete than with Fe2O3/γ-Al2O3 /H2O2 and degradation rate of phenol reached 89.4% and 94.7% respectively after reaction for2 h.
文摘The low biodegradability of polyphenolic compounds typically found in olive processing indicated that biological treatment is not always successful in the treatment of olive oil mill wastewater in term of COD removal. In this study the results of investigations on the applicability of Fenton's reagent in the treatment of this effluent were discussed. The efficiency of this method was determined. 86 % of removal COD was obtained using 5 mol H 2O 2 and 0.4 mol Fe 2+ per liter of crude OMW. The main parameters that govern the complex reactive system, i.e., time, pH, [H 2O 2] and [Fe(II)] were studied.
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 selective and new spectrophotometric method is described for determination of five 1,4 dihydropyridine drugs (1,4- DHP);namely nifedipine (NIF), nicardipine (NIC), nimodipine (NIM), felodipine (FEL) and amlodipine (AML). The method is based on a coupling reaction between the cited drugs and vanillin reagent in acidic condition. Under optimized conditions, the red coloured products were measured at 500 nm for NIF, NIC, NIM and FEL or at 479 nm for AML. Molar absorptivities were ranged from 0.575 × 104 - 1.065 × 104 l·mol-1·cm-1, Beer’s law was obeyed at 5 - 70 μg/mL concentration range and the limit of detection was ranged from 0.150 - 1.500 μg/mL. The proposed method was successfully extended to pharmaceutical preparations tablets and capsules and comparison by Student’s t-test and variance ratio F-test showed no significant difference.
