Ultrasound (US)-induced cavitation is an effective way in oxidizing organic contaminants in wastewater either as the independent operation unit or in combination with other oxidation methods. In this paper, black liqu...Ultrasound (US)-induced cavitation is an effective way in oxidizing organic contaminants in wastewater either as the independent operation unit or in combination with other oxidation methods. In this paper, black liquor and filtrate after acidifying and settling were sonicated. The effect of working parameters on ultrasonic degradation of black liquor, such as different combination methods, frequency, power supply, initial concentration, pH, duration time, ionic strength and catalyst were studied. The results were as follows: (1) At the conditions of 40kHz, 100W, 4h, pH at 6 and temperature 30?℃, utilizing US/US-H2O2/US-Fenton, weak-orange filtrate turned to colloid with the increase of time and little sediment produced after settling. Especially filtrate came to be milk white collides and upper water approached to nearly achromatic by US-Fenton. Compared with the US, US-H2O2/US-Fenton COD (Chemical oxidation demand) removal ratio can increase 15%, 30% respectively. Because of more hydroxyl radicals produced in the reaction process; (2) At the condition of 100W and 4h, the degradation efficiency of black liquor was better at 40kHz over at 20kHz. Moreover black liquor can be biodegraded easily. Those based on that the big molecule of contaminants in aqueous solution can be changed into the little molecule with ultrasound (3) At the condition of 40kHz and 4h, the COD removal ratio of black liquor was more higher at 60W than at 80W, while the removal ratio of COD at 60W was nearly close to the ratio at 100W; (4) The initial concentration of black liquor influenced the effect of sonochemical degradation; (5) The variation of pH had no effect on degradation; (6) The longer the duration time, the greater the removal ratio of COD. But this ratio increased slowly after 4h; (7) Adding 0.2g/L NaCl to change the ionic strength of the black liquor, the COD removal ratio can increase 10%; (8) The degradation rates increased by the coexistent catalysts of TiO2, Co2+ and Ag+.展开更多
The features of organic pollutants degradation mainly characterized by bio-flocculation for step-A of adsorption-biodegredation（AB） process were studied. By investigating the relationship of extracellular polymeric ...The features of organic pollutants degradation mainly characterized by bio-flocculation for step-A of adsorption-biodegredation（AB） process were studied. By investigating the relationship of extracellular polymeric substances（EPS） with bioflocculation and introducing kinetic model of organic pollutant degradation into EPS, the kinetic model of organic pollutant degradation for step-A hioflocculation was deducted. And through the experiments, the kinetic constants were calculated as follows： k1 =0. 005 3; kc1 =1 710.7 and vmax1=10 min^-1.展开更多
Thermal catalytic degradation of organic pollutants conducted in the dark at room temperature under atmospheric pressure without the need of external chemicals and energy sources has attracted a lot of attention over ...Thermal catalytic degradation of organic pollutants conducted in the dark at room temperature under atmospheric pressure without the need of external chemicals and energy sources has attracted a lot of attention over the last two decades. It provides unparalleled advantages over other advanced oxidation processes (AOPs) in treating domestic and industrial contaminated wastewater from the viewpoint of energy/chemical conservation and ease of operation. Rich knowledge has been accumulated in terms of the synthesis and application of thermal catalysts though controversies remain regarding their underlying mechanisms. This review sheds light on the proposed thermo- catalysis mechanism for the first time and presents the development of thermal catalysts under dark ambient conditions with a focus on catalyst materials, catalytic activity, and mechanism. The present review aims to provide mechanistic insights into the rational design of novel and efficient catalysts, and their underlying mechanisms as well as the emerging challenges and perspectives in thermo-catalysis under dark ambient conditions used for the practical and efficient treatment of contaminated wastewater.展开更多
In this paper, the characteristics of integrated biological aerated filter (IBAF) applied to municipal wastewater treatment were studied in a pilot scale experiment. The experimental results showed that IBAF has high ...In this paper, the characteristics of integrated biological aerated filter (IBAF) applied to municipal wastewater treatment were studied in a pilot scale experiment. The experimental results showed that IBAF has high efficiencies in removing organic pollutants, such as CODCr and SS, in municipal wastewater. The removal rates of CODCr and SS can reach over 90% and 80%, respectively, when COD and SS in the influent are 234 mg L1 and 112 mg L1, hydraulic retention time (HRT) is 8 h, and the aerated intensity is in the range of (0.5 to 0.6) L m2 s1.展开更多
The intensity of Magnetic field by 200, 300 and 400 gaos were selective to study their impacts on bacteria Bacillus, Pseudomonas and yeasts Candida dubliniensis, Candida glabrata, lssatchenkia orientalis and Rhodotoru...The intensity of Magnetic field by 200, 300 and 400 gaos were selective to study their impacts on bacteria Bacillus, Pseudomonas and yeasts Candida dubliniensis, Candida glabrata, lssatchenkia orientalis and Rhodotorula mucilaginosa growth and to reduce organic pollutants in wastewater by COD, TOC, TN and TP in concentrations of 180, 75, 52 and 84 ppm in pH 7.6 and treatment periods of 2, 4, 6 and 18 h in batch system. Results showed that magnetic field 300 gaos had higher ability to increase bacterial and yeasts growth by 400-600% in 18 h and reduced COD, TOC, TN and TP by 88, 85, 90 and 98.5% in same period treatment. While, the intensity of magnetic field 200 and 400 gaos have no effect on microorganisms growth and reducing organic pollutants. This study is first record for showing and explaining the positive effective of magnetic field on microorganisms growth.展开更多
文摘Ultrasound (US)-induced cavitation is an effective way in oxidizing organic contaminants in wastewater either as the independent operation unit or in combination with other oxidation methods. In this paper, black liquor and filtrate after acidifying and settling were sonicated. The effect of working parameters on ultrasonic degradation of black liquor, such as different combination methods, frequency, power supply, initial concentration, pH, duration time, ionic strength and catalyst were studied. The results were as follows: (1) At the conditions of 40kHz, 100W, 4h, pH at 6 and temperature 30?℃, utilizing US/US-H2O2/US-Fenton, weak-orange filtrate turned to colloid with the increase of time and little sediment produced after settling. Especially filtrate came to be milk white collides and upper water approached to nearly achromatic by US-Fenton. Compared with the US, US-H2O2/US-Fenton COD (Chemical oxidation demand) removal ratio can increase 15%, 30% respectively. Because of more hydroxyl radicals produced in the reaction process; (2) At the condition of 100W and 4h, the degradation efficiency of black liquor was better at 40kHz over at 20kHz. Moreover black liquor can be biodegraded easily. Those based on that the big molecule of contaminants in aqueous solution can be changed into the little molecule with ultrasound (3) At the condition of 40kHz and 4h, the COD removal ratio of black liquor was more higher at 60W than at 80W, while the removal ratio of COD at 60W was nearly close to the ratio at 100W; (4) The initial concentration of black liquor influenced the effect of sonochemical degradation; (5) The variation of pH had no effect on degradation; (6) The longer the duration time, the greater the removal ratio of COD. But this ratio increased slowly after 4h; (7) Adding 0.2g/L NaCl to change the ionic strength of the black liquor, the COD removal ratio can increase 10%; (8) The degradation rates increased by the coexistent catalysts of TiO2, Co2+ and Ag+.
基金project (2004B4604A01-01) supported by the Mega-projects of Science Research for the 10th Five-Year Plan
文摘The features of organic pollutants degradation mainly characterized by bio-flocculation for step-A of adsorption-biodegredation（AB） process were studied. By investigating the relationship of extracellular polymeric substances（EPS） with bioflocculation and introducing kinetic model of organic pollutant degradation into EPS, the kinetic model of organic pollutant degradation for step-A hioflocculation was deducted. And through the experiments, the kinetic constants were calculated as follows： k1 =0. 005 3; kc1 =1 710.7 and vmax1=10 min^-1.
基金funding support by the National Natural Science Foundation of China (51674091, 51104048)~~
文摘Thermal catalytic degradation of organic pollutants conducted in the dark at room temperature under atmospheric pressure without the need of external chemicals and energy sources has attracted a lot of attention over the last two decades. It provides unparalleled advantages over other advanced oxidation processes (AOPs) in treating domestic and industrial contaminated wastewater from the viewpoint of energy/chemical conservation and ease of operation. Rich knowledge has been accumulated in terms of the synthesis and application of thermal catalysts though controversies remain regarding their underlying mechanisms. This review sheds light on the proposed thermo- catalysis mechanism for the first time and presents the development of thermal catalysts under dark ambient conditions with a focus on catalyst materials, catalytic activity, and mechanism. The present review aims to provide mechanistic insights into the rational design of novel and efficient catalysts, and their underlying mechanisms as well as the emerging challenges and perspectives in thermo-catalysis under dark ambient conditions used for the practical and efficient treatment of contaminated wastewater.
基金Funded by the National Scientific and Technological Project of "the Tenth Five-Year Plan" (No. 2004BA604A01)
文摘In this paper, the characteristics of integrated biological aerated filter (IBAF) applied to municipal wastewater treatment were studied in a pilot scale experiment. The experimental results showed that IBAF has high efficiencies in removing organic pollutants, such as CODCr and SS, in municipal wastewater. The removal rates of CODCr and SS can reach over 90% and 80%, respectively, when COD and SS in the influent are 234 mg L1 and 112 mg L1, hydraulic retention time (HRT) is 8 h, and the aerated intensity is in the range of (0.5 to 0.6) L m2 s1.
文摘The intensity of Magnetic field by 200, 300 and 400 gaos were selective to study their impacts on bacteria Bacillus, Pseudomonas and yeasts Candida dubliniensis, Candida glabrata, lssatchenkia orientalis and Rhodotorula mucilaginosa growth and to reduce organic pollutants in wastewater by COD, TOC, TN and TP in concentrations of 180, 75, 52 and 84 ppm in pH 7.6 and treatment periods of 2, 4, 6 and 18 h in batch system. Results showed that magnetic field 300 gaos had higher ability to increase bacterial and yeasts growth by 400-600% in 18 h and reduced COD, TOC, TN and TP by 88, 85, 90 and 98.5% in same period treatment. While, the intensity of magnetic field 200 and 400 gaos have no effect on microorganisms growth and reducing organic pollutants. This study is first record for showing and explaining the positive effective of magnetic field on microorganisms growth.
