The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
P V Chuong - One of the best experts on this subject based on the ideXlab platform.
-
rice seedling establishment as affected by cultivar seed coating with Calcium Peroxide sowing depth and water level
Field Crops Research, 1995Co-Authors: M Yamauchi, P V ChuongAbstract:Abstract Inconsistent seedling establishment is a constraint to the adoption of direct seeding of lowland rice (Oryza sativa L.) in the tropics. Rice cultivars with superior seedling establishment in flooded soil have been recently identified. The establishment of these tolerant cultivars was compared with a control cultivar with and without Calcium Peroxide-coated seed under various combinations of water level and sowing depth. Water level had little effect on seedling establishment when seed were sown on the soil surface, but establishment was reduced by raising the water level when seed were sown below the soil surface. Calcium Peroxide-coated seed established better than the tolerant cultivars at 13- and 25-mm sowing depths, but their seedlings were shorter and less vigorous than those of tolerant cultivars. Tolerant cultivars and coated seed had longer mesocotyls than controls. Sowing tolerant cultivars beneath a flooded soil surface at less than 13 mm assists achievement of consistent seedling establishment in lowland rice production.
M Yamauchi - One of the best experts on this subject based on the ideXlab platform.
-
rice seedling establishment as affected by cultivar seed coating with Calcium Peroxide sowing depth and water level
Field Crops Research, 1995Co-Authors: M Yamauchi, P V ChuongAbstract:Abstract Inconsistent seedling establishment is a constraint to the adoption of direct seeding of lowland rice (Oryza sativa L.) in the tropics. Rice cultivars with superior seedling establishment in flooded soil have been recently identified. The establishment of these tolerant cultivars was compared with a control cultivar with and without Calcium Peroxide-coated seed under various combinations of water level and sowing depth. Water level had little effect on seedling establishment when seed were sown on the soil surface, but establishment was reduced by raising the water level when seed were sown below the soil surface. Calcium Peroxide-coated seed established better than the tolerant cultivars at 13- and 25-mm sowing depths, but their seedlings were shorter and less vigorous than those of tolerant cultivars. Tolerant cultivars and coated seed had longer mesocotyls than controls. Sowing tolerant cultivars beneath a flooded soil surface at less than 13 mm assists achievement of consistent seedling establishment in lowland rice production.
Xiang Zhang - One of the best experts on this subject based on the ideXlab platform.
-
application of ascorbic acid to enhance trichloroethene degradation by fe iii activated Calcium Peroxide
Chemical Engineering Journal, 2017Co-Authors: Xiang Zhang, Shuguang Lu, Xiaogang Gu, Minhui Xu, Mark L Brusseau, Xiaori FuAbstract:Abstract The enhancement effect of an environmentally friendly reducing agent, ascorbic acid (AA), on trichloroethene (TCE) degradation by Fe(III)-activated Calcium Peroxide (CP) was evaluated. The addition of AA accelerated the transformation of Fe(III) to Fe(II), and the complexation of Fe(III)/Fe(II) with AA and its products alleviated the precipitation of dissolved iron. These impacts enhanced the generation of reactive oxygen species (ROSs). Investigation of ROSs using chemical probe tests, electron paramagnetic resonance (EPR) tests, and radical scavenger tests strongly confirm large production of hydroxyl radicals (HO ) that is responsible for TCE degradation. The generation of Cl − from the degraded TCE was complete in the enhanced CP/Fe(III)/AA system. The investigation of solution matrix effects showed that the TCE degradation rate decreases with the increase in solution pH, while Cl − , SO 4 2− and NO 3 − anions have minor impact. Conversely, HCO 3 − significantly inhibited TCE degradation due to pH elevation and HO scavenging. The results of experiments performed using actual groundwater indicated that an increase in reagent doses are required for effective TCE removal. In summary, the potential effectiveness of the CP/Fe(III)/AA oxidation system for remediation of TCE contaminated groundwater has been demonstrated. Additional research is needed to develop the system for practical implementation.
-
Application of Calcium Peroxide in water and soil treatment: A review
Journal of Hazardous Materials, 2017Co-Authors: Shuguang Lu, Xiang Zhang, Yunfei XueAbstract:Calcium Peroxide (CP) has been progressively applied in terms of environmental protection due to its certain physical and chemical properties. This review focuses on the latest progresses in the applications of CP in water and soil treatment, including wastewater treatment, surface water restoration and groundwater and soil remediation. The stability of CP makes it an effective solid phase to supply H2O2 and O2 for aerobic biodegradation and chemical degradation of contaminants in water and soil. CP has exerted great performance in the removal of dyes, chlorinated hydrocarbons, petroleum hydrocarbons, pesticides, heavy metals and various other contaminants. The research progress in the encapsulation technologies of CP with other materials and the preparation of CP nanoparticles were also presented in this review. Based on the summarized research progresses, the perspective of CP application in the future was proposed.
-
the destruction of benzene by Calcium Peroxide activated with fe ii in water
Chemical Engineering Journal, 2016Co-Authors: Xiaogang Gu, Shuguang Lu, Zhouwei Miao, Minhui Xu, Xiaori Fu, Mark L Brusseau, Xiang ZhangAbstract:Abstract The ability of Fe(II)-activated Calcium Peroxide (CaO 2 ) to remove benzene is examined with a series of batch experiments. The results showed that benzene concentrations were reduced by 20–100% within 30 min. The magnitude of removal was dependent on the CaO 2 /Fe(II)/Benzene molar ratio, with much greater destruction observed for ratios of 4/4/1 or greater. An empirical equation was developed to quantify the destruction rate dependence on reagent composition. The presence of oxidative hydroxyl radicals (HO ) and reductive radicals (primarily O 2 − ) was identified by probe compound testing and electron paramagnetic resonance (EPR) tests. The results of the EPR tests indicated that the application of CaO 2 /Fe(II) enabled the radical intensity to remain steady for a relatively long time. The effect of initial solution pH was also investigated, and CaO 2 /Fe(II) enabled benzene removal over a wide pH range of 3.0–9.0. The results of radical scavenging tests showed that benzene removal occurred primarily by HO oxidation in the CaO 2 /Fe(II) system, although reductive radicals also contributed. The intermediates in benzene destruction were identified to be phenol and biphenyl. The results indicate that Fe(II)-activated CaO 2 is a feasible approach for treatment of benzene in contaminated groundwater remediation.
-
application of Calcium Peroxide activated with fe ii edds complex in trichloroethylene degradation
Chemosphere, 2016Co-Authors: Xiang Zhang, Shuguang Lu, Xiaogang Gu, Zhouwei Miao, Minhui Xu, Xiaori FuAbstract:Abstract This study was conducted to assess the application of Calcium Peroxide (CP) activated with Fe(II) chelated by ( S,S )-ethylenediamine-N,N′-disuccinic acid (EDDS) to enhance trichloroethylene (TCE) degradation in aqueous solution. It was indicated that EDDS prevented soluble iron from precipitation, and the optimum molar ratio of Fe(II)/EDDS to accelerate TCE degradation was 1/1. The influences of initial TCE, CP and Fe(II)-EDDS concentration were also investigated. The combination of CP and Fe(II)-EDDS complex rendered the efficient degradation of TCE at near neutral pH range. Chemical probe and scavenger tests identified that TCE degradation mainly owed to the oxidation of HO while O 2 − promoted HO generation. Cl − , HCO 3 − and humic acid were found to inhibit CP/Fe(II)-EDDS performance on different levels. In conclusion, the application of CP activated with Fe(II)-EDDS complex is a promising technology in chemical remediation of groundwater, while further research in practical implementation is needed.
-
enhanced degradation of trichloroethene by Calcium Peroxide activated with fe iii in the presence of citric acid
Frontiers of Environmental Science & Engineering in China, 2016Co-Authors: Xiang Zhang, Shuguang Lu, Xiaogang Gu, Zhouwei Miao, Minhui Xu, Xiaori Fu, Muhammad Danish, Mark L BrusseauAbstract:Trichloroethene (TCE) degradation by Fe(III)- activated Calcium Peroxide (CP) in the presence of citric acid (CA) in aqueous solution was investigated. The results demonstrated that the presence of CA enhanced TCE degradation significantly by increasing the concentration of soluble Fe(III) and promoting H2O2 generation. The generation of HO• and O 2 – • in both the CP/Fe(III) and CP/Fe(III)/CA systems was confirmed with chemical probes. The results of radical scavenging tests showed that TCE degradation was due predominantly to direct oxidation by HO•, while O 2 – • strengthened the generation of HO• by promoting Fe(III) transformation in the CP/Fe (III)/CA system. Acidic pH conditions were favorable for TCE degradation, and the TCE degradation rate decreased with increasing pH. The presence of Cl–, HCO 3 – , and humic acid (HA) inhibited TCE degradation to different extents for the CP/Fe(III)/CA system. Analysis of Cl–production suggested that TCE degradation in the CP/Fe (III)/CA system occurred through a dechlorination process. In summary, this study provided detailed information for the application of CA-enhanced Fe(III)-activated Calcium Peroxide for treating TCE contaminated groundwater.
Yuyou Li - One of the best experts on this subject based on the ideXlab platform.
-
Calcium Peroxide pretreatment of waste activated sludge for enhancement of short chain fatty acids extraction from fermentation liquid by layered double hydroxides
Journal of Cleaner Production, 2020Co-Authors: Liang Sheng, Yuyou LiAbstract:Abstract In the present study, Calcium Peroxide (CaO2) pretreatment of waste activated sludge (WAS) was proposed to enhance the extraction efficiency of short chain fatty acids (SCFAs) from anaerobic fermentation liquid (AFL) via in situ synthesis of layered double hydroxides (LDHs). The experimental results showed that the SCFAs concentration in the AFL of the WAS with CaO2 pretreatment was significantly enhanced to 7471.7 mg chemical oxygen demand (COD)/L, which was much higher than that of the control (4982.0 mg COD/L). At the same time, phosphate and carbonate ions were simultaneously removed by Calcium ions with removal rates of 85.3% and 90.8% compared with the control, respectively. With the help of a higher SCFAs concentration and the removal of interfering anions, the SCFAs content in the synthesized SCFAs-LDHs-CaO2 could be enhanced to 26.6 mg COD/g LDH, which was 39.3% higher than that of the control. The economic analysis for future applications revealed that the expense of using SCFAs-LDHs-CaO2 as an external carbon source was 0.9 Renminbi/m3, which resulted in a savings of approximately 57.0% compared with that of the SCFAs-LDHs-Control.
Shuguang Lu - One of the best experts on this subject based on the ideXlab platform.
-
application of ascorbic acid to enhance trichloroethene degradation by fe iii activated Calcium Peroxide
Chemical Engineering Journal, 2017Co-Authors: Xiang Zhang, Shuguang Lu, Xiaogang Gu, Minhui Xu, Mark L Brusseau, Xiaori FuAbstract:Abstract The enhancement effect of an environmentally friendly reducing agent, ascorbic acid (AA), on trichloroethene (TCE) degradation by Fe(III)-activated Calcium Peroxide (CP) was evaluated. The addition of AA accelerated the transformation of Fe(III) to Fe(II), and the complexation of Fe(III)/Fe(II) with AA and its products alleviated the precipitation of dissolved iron. These impacts enhanced the generation of reactive oxygen species (ROSs). Investigation of ROSs using chemical probe tests, electron paramagnetic resonance (EPR) tests, and radical scavenger tests strongly confirm large production of hydroxyl radicals (HO ) that is responsible for TCE degradation. The generation of Cl − from the degraded TCE was complete in the enhanced CP/Fe(III)/AA system. The investigation of solution matrix effects showed that the TCE degradation rate decreases with the increase in solution pH, while Cl − , SO 4 2− and NO 3 − anions have minor impact. Conversely, HCO 3 − significantly inhibited TCE degradation due to pH elevation and HO scavenging. The results of experiments performed using actual groundwater indicated that an increase in reagent doses are required for effective TCE removal. In summary, the potential effectiveness of the CP/Fe(III)/AA oxidation system for remediation of TCE contaminated groundwater has been demonstrated. Additional research is needed to develop the system for practical implementation.
-
Application of Calcium Peroxide in water and soil treatment: A review
Journal of Hazardous Materials, 2017Co-Authors: Shuguang Lu, Xiang Zhang, Yunfei XueAbstract:Calcium Peroxide (CP) has been progressively applied in terms of environmental protection due to its certain physical and chemical properties. This review focuses on the latest progresses in the applications of CP in water and soil treatment, including wastewater treatment, surface water restoration and groundwater and soil remediation. The stability of CP makes it an effective solid phase to supply H2O2 and O2 for aerobic biodegradation and chemical degradation of contaminants in water and soil. CP has exerted great performance in the removal of dyes, chlorinated hydrocarbons, petroleum hydrocarbons, pesticides, heavy metals and various other contaminants. The research progress in the encapsulation technologies of CP with other materials and the preparation of CP nanoparticles were also presented in this review. Based on the summarized research progresses, the perspective of CP application in the future was proposed.
-
the destruction of benzene by Calcium Peroxide activated with fe ii in water
Chemical Engineering Journal, 2016Co-Authors: Xiaogang Gu, Shuguang Lu, Zhouwei Miao, Minhui Xu, Xiaori Fu, Mark L Brusseau, Xiang ZhangAbstract:Abstract The ability of Fe(II)-activated Calcium Peroxide (CaO 2 ) to remove benzene is examined with a series of batch experiments. The results showed that benzene concentrations were reduced by 20–100% within 30 min. The magnitude of removal was dependent on the CaO 2 /Fe(II)/Benzene molar ratio, with much greater destruction observed for ratios of 4/4/1 or greater. An empirical equation was developed to quantify the destruction rate dependence on reagent composition. The presence of oxidative hydroxyl radicals (HO ) and reductive radicals (primarily O 2 − ) was identified by probe compound testing and electron paramagnetic resonance (EPR) tests. The results of the EPR tests indicated that the application of CaO 2 /Fe(II) enabled the radical intensity to remain steady for a relatively long time. The effect of initial solution pH was also investigated, and CaO 2 /Fe(II) enabled benzene removal over a wide pH range of 3.0–9.0. The results of radical scavenging tests showed that benzene removal occurred primarily by HO oxidation in the CaO 2 /Fe(II) system, although reductive radicals also contributed. The intermediates in benzene destruction were identified to be phenol and biphenyl. The results indicate that Fe(II)-activated CaO 2 is a feasible approach for treatment of benzene in contaminated groundwater remediation.
-
application of Calcium Peroxide activated with fe ii edds complex in trichloroethylene degradation
Chemosphere, 2016Co-Authors: Xiang Zhang, Shuguang Lu, Xiaogang Gu, Zhouwei Miao, Minhui Xu, Xiaori FuAbstract:Abstract This study was conducted to assess the application of Calcium Peroxide (CP) activated with Fe(II) chelated by ( S,S )-ethylenediamine-N,N′-disuccinic acid (EDDS) to enhance trichloroethylene (TCE) degradation in aqueous solution. It was indicated that EDDS prevented soluble iron from precipitation, and the optimum molar ratio of Fe(II)/EDDS to accelerate TCE degradation was 1/1. The influences of initial TCE, CP and Fe(II)-EDDS concentration were also investigated. The combination of CP and Fe(II)-EDDS complex rendered the efficient degradation of TCE at near neutral pH range. Chemical probe and scavenger tests identified that TCE degradation mainly owed to the oxidation of HO while O 2 − promoted HO generation. Cl − , HCO 3 − and humic acid were found to inhibit CP/Fe(II)-EDDS performance on different levels. In conclusion, the application of CP activated with Fe(II)-EDDS complex is a promising technology in chemical remediation of groundwater, while further research in practical implementation is needed.
-
enhanced degradation of trichloroethene by Calcium Peroxide activated with fe iii in the presence of citric acid
Frontiers of Environmental Science & Engineering in China, 2016Co-Authors: Xiang Zhang, Shuguang Lu, Xiaogang Gu, Zhouwei Miao, Minhui Xu, Xiaori Fu, Muhammad Danish, Mark L BrusseauAbstract:Trichloroethene (TCE) degradation by Fe(III)- activated Calcium Peroxide (CP) in the presence of citric acid (CA) in aqueous solution was investigated. The results demonstrated that the presence of CA enhanced TCE degradation significantly by increasing the concentration of soluble Fe(III) and promoting H2O2 generation. The generation of HO• and O 2 – • in both the CP/Fe(III) and CP/Fe(III)/CA systems was confirmed with chemical probes. The results of radical scavenging tests showed that TCE degradation was due predominantly to direct oxidation by HO•, while O 2 – • strengthened the generation of HO• by promoting Fe(III) transformation in the CP/Fe (III)/CA system. Acidic pH conditions were favorable for TCE degradation, and the TCE degradation rate decreased with increasing pH. The presence of Cl–, HCO 3 – , and humic acid (HA) inhibited TCE degradation to different extents for the CP/Fe(III)/CA system. Analysis of Cl–production suggested that TCE degradation in the CP/Fe (III)/CA system occurred through a dechlorination process. In summary, this study provided detailed information for the application of CA-enhanced Fe(III)-activated Calcium Peroxide for treating TCE contaminated groundwater.
