Combined with the practical experience of wastewater treatment plant, the chemical coagulants have inhibition effects on microorganism activity, with the influence degree of PAC (polyaluminium chloride) > AlCl3>...Combined with the practical experience of wastewater treatment plant, the chemical coagulants have inhibition effects on microorganism activity, with the influence degree of PAC (polyaluminium chloride) > AlCl3> Fe2(SO4)3. In synchronization dephosphorization, the inhibition rates of PAC in 10 ppm and 20 ppm are 11.9% and 33% respectively;while the inhibition rates of AlCl3 and Fe2(SO4)3 in 20 ppm are 15.8% and 8.5% respectively, compared with 9.6% and 5.4% in 10 ppm. Backwash wastewater from sand filter after adding coagulants has no direct inhibition effect on microorganism, but it results in inorganic components increase in active sludge. By taking North STP as an example, the VSS/SS ratio reduced from 0.65 after coagulants application to 0.54.展开更多
Hospital wastewater represents an infectious and toxic risk to human health and the environment due to its contents. Most hospitals in developing countries, including Benin, do not have a wastewater treatment plant. I...Hospital wastewater represents an infectious and toxic risk to human health and the environment due to its contents. Most hospitals in developing countries, including Benin, do not have a wastewater treatment plant. In this study, the wastewater from two hospitals in northern Benin was characterized and then treated with Azadirachta indica leaves, Moringa oleifera and Luffa cylindrica seeds by coagulation/flocculation process. The wastewater characteristics showed that the collected samples are greatly polluted by organic matter and fecal bacteria such as Escherichia coli, Enterococcus fecal and Total coliforms. Jar-test results revealed that 95.74%, 78%, 49.19% of turbidity, 51.35%, 38.32%, 22.19% of COD, 93.16%, 85.26%, 83.30% against Escherichia coli, 92.11%, 90.93%, 94.60% against total Coliforms and 99.37%, 91%, 99%, 55.07% against Enterococcus were removed from hospital wastewater using Moringa oleifera, Luffa cylindrica seed and Azadirachta indica leaves respectively at dose of 100 mg/L. The results highlighted that the natural coagulants could be successfully used for the removal of turbidity and fecal bacteria from hospital wastewater.展开更多
The treatment of wastewater from pulp\|paper plants in China by horseradish peroxidase was investigated in this study. The effects of horseradish peroxidase and coagulants were discussed in detail. The results indicat...The treatment of wastewater from pulp\|paper plants in China by horseradish peroxidase was investigated in this study. The effects of horseradish peroxidase and coagulants were discussed in detail. The results indicated that enzymes might improve the removal of AOX, TOC and colour for pulp\|paper wastewater and modified chitosan is far more effective than Al\-2(SO\-4)\-3 to remove AOX, TOC and colour.展开更多
In order to remove the low turbidity present in surface water, a novel metal-polysilicate coagulant was used to treat the raw water taken from Tanjiang River in Guangdong Province. This study on the effects of A1/Fe m...In order to remove the low turbidity present in surface water, a novel metal-polysilicate coagulant was used to treat the raw water taken from Tanjiang River in Guangdong Province. This study on the effects of A1/Fe molar ratio on the performance of a complex compound formed by polysilicic acid, aluminium and ferric salt (PAFS) showed that PAFS with A1/Fe ratio of 10:3 seemed to have the best coagulation performance in removing turbidity and color. Experimental results showed that under the conditions of polymerization time of 15 d, sedimentation time of 12 min, and pH of 6-8,PAFS with A1/Fe molar ratio of 10:3 had the best coagulation efficiency and lowest residual A1 concentration. The turbidity decreased from 23.8 NTU to 3.23 NTU and the residual A1 concentration was only 0.165 mg/L in the product water. It could be speculated that colloidal impurities and particulate A1 were removed by adsorption bridging and electrical neutralization of long chain inorganic polymer coagulants.展开更多
Aim: The objective of this study is to review all the reported outcomes of heparin application in amniotic fluid embolism (AFE) so far and to find out why, when and how heparin or other anticoagulants should be used i...Aim: The objective of this study is to review all the reported outcomes of heparin application in amniotic fluid embolism (AFE) so far and to find out why, when and how heparin or other anticoagulants should be used in AFE. Material and methods: We searched Medline (from 1969 to 2011), using two key words: 1) amniotic fluid embolism;2) amniotic fluid embolism and heparin. The search for the former produced 1127 replies, of which 208 were case reports of AFE. In response to the other key word, there were 94 articles. We looked through all the articles, selecting those relevant for our study. Results: In the years 1969-2011, 208 AFE cases were reported. Heparin (unfractionated heparin) or low molecular weight heparin (LMWH) was applied in 20 cases (9.6%), being the main drug in 11 cases (5.3%) and in 6 cases as a component of spectacular treatment of AFE (surgical treatment and extracorporal membrane oxygenation). In one of these cases anithrombin (AT) with LMWH was used. In one patient heparin therapy was considered to be unsuccessful and hence recombinant plasminogen activator (rt-PA) was instituted. All the patients survived. Conclusions: 1) The attempts to use heparin in AFE could be defined as promising, although the number of treated patients is too small for conclusion;2) The postulate to use heparin at the very onset of AFE (a bolus of 10,000 U followed by monitored intravenous infusion) has serious justification: one of the pathways of AFE is the target for heparin (coagulation pathway).展开更多
Membranes for gas separation have developed significantly in the last twenty years,however,there is still a need for high temperature and chemically resistant membranes that exhibit good selectivity and gas permeabili...Membranes for gas separation have developed significantly in the last twenty years,however,there is still a need for high temperature and chemically resistant membranes that exhibit good selectivity and gas permeability.Our study examines the fundamental properties of polyetherketone (PEK,a thermally stable and chemically resistant polymer) membranes prepared using concentrated sulphuric acid (98% H_2SO_4) as the solvent.Non-solvents used in the work included acetic acid,ethanol,methanol,glycerol,and wat...展开更多
Objective To establish and evaluate a hypercoagulable animal model for the assessment of anticoagulants. Methods Forty mice, thirty-two rats, and twenty-four rabbits were randomly and equally divided into control grou...Objective To establish and evaluate a hypercoagulable animal model for the assessment of anticoagulants. Methods Forty mice, thirty-two rats, and twenty-four rabbits were randomly and equally divided into control group (saline) and three ellagic acid (EA)-treated groups (low, middle, and high doses). In the mice, bleeding time (BT) was estimated with tail transaction, and clotting time (CT) with template method. Prothrombin time (PT) and the activated partial thromboplastin time (APTT) in rats and rabbits were measured by means of Quick's one-stage assay and modified APTT assay respectively. In addition, thrombin activity was estimated in rats with PT assay using a hemagglutination analyzer. The circulating platelet aggregates were de- tected in rabbits through platelet counting and presented as the circulating platelet aggregate ratio (CPAR). Results EA shortened BT and CT in mice, PT and APTT in rats, and increased thrombin activity and CPAR, all in a dose-dependent manner. EA also brought reduction of PT and APTT in rabbits in dose- and time-dependent manners. Conclusion EA could induce hypercoagulable state through activating coagulation system and platelets in mice, rats, and rabbits.展开更多
This study investigated the floc aggregation, average floc size, floc size variance and floc growth velocity when ferric chloride （FeCl3） and polyferric chloride （PFC） were used to treat the simulated water sample...This study investigated the floc aggregation, average floc size, floc size variance and floc growth velocity when ferric chloride （FeCl3） and polyferric chloride （PFC） were used to treat the simulated water samples. The factors including coagulant dose, ionic strength and solution pH, which affect the floc aggregation, were studied. Experiments were carried out in a bench-scale reactor using photometric dispersion analyzer （PDA）. Results showed that there were great differences between the floc aggregation of PFC and FeCl3. The average floc size and floc growth velocity of PFC were much larger than those of FeCl3. Compared with FeCl3, PFC gave a better coagulation performance in wider range of pH, dosage and ionic strength. It was also found that the coagulation efficiency of PFC did not depend on average floc size but on floc growth velocity.展开更多
PBO materials possess super mechanical properties and high thermal and chemical resistance due to their special rigid-rod backbones with heterocyclic chemical structure and supermolecular microstructure. But these str...PBO materials possess super mechanical properties and high thermal and chemical resistance due to their special rigid-rod backbones with heterocyclic chemical structure and supermolecular microstructure. But these structures may be affected by a series of preparing technologies, among which the coagulant is even more important. In this paper the chemical and microstructure changes of PBO materials coagulated with different solvents were investigated. Analyses of molecular weight and chemical structure of PBO coagulated indicate that the heterocyclic ring of PBO will experience cleavage in coagulation and in this stage water plays an important role. The final structure of PBO materials may involve several intermediate structures lying between benzoxazole and the open ring. Wide-angle X-ray diffraction (WAXD) 2θ scans and scanning probe microscope (SPM) show that the microstructure of PBO materials coagulated in solvents with different properties will change a lot and those coagulants with the smaller rate of diffusion like methanol can cause more ordered molecule alignment containing fewer voids.展开更多
The coagulation process is a widely applied technology in water and wastewater treatment.Novel composite polyferric mag-nesium-silicate-sulfate(PFMS)coagulants were synthesized using Na_(2)SiO_(3)·9H_(2)O,Fe_(2)(...The coagulation process is a widely applied technology in water and wastewater treatment.Novel composite polyferric mag-nesium-silicate-sulfate(PFMS)coagulants were synthesized using Na_(2)SiO_(3)·9H_(2)O,Fe_(2)(SO_(4))_(3),and MgSO_(4) as raw materials in this paper.The effects of aging time,Fe:Si:Mg,and OH:M molar ratios(M represents the metal ions)on the coagulation performance of the as-pre-pared PFMS were systematically investigated to obtain optimum coagulants.The results showed that PFMS coagulant exhibited good co-agulation properties in the treatment of simulated humic acid-kaolin surface water and reactive dye wastewater.When the molar ratio was controlled at Fe:Si:Mg=2:2:1 and OH:M=0.32,the obtained PFMS presented excellent stability and a high coagulation efficiency.The removal efficiency of ultraviolet UV254 was 99.81%,and the residual turbidity of the surface water reached 0.56 NTU at a dosage of 30 mg·L^(-1).After standing the coagulant for 120 d in the laboratory,the removal efficiency of UV254 and residual turbidity of the surface wa-ter were 88.12%and 0.68 NTU,respectively,which accord with the surface water treatment requirements.In addition,the coagulation performance in the treatment of reactive dye wastewater was greatly improved by combining the advantages of magnesium and iron salts.Compared with polyferric silicate-sulfate(PFS)and polymagnesium silicate-sulfate(PMS),the PFMS coagulant played a better decolor-ization role within the pH range of 7-13.展开更多
文摘Combined with the practical experience of wastewater treatment plant, the chemical coagulants have inhibition effects on microorganism activity, with the influence degree of PAC (polyaluminium chloride) > AlCl3> Fe2(SO4)3. In synchronization dephosphorization, the inhibition rates of PAC in 10 ppm and 20 ppm are 11.9% and 33% respectively;while the inhibition rates of AlCl3 and Fe2(SO4)3 in 20 ppm are 15.8% and 8.5% respectively, compared with 9.6% and 5.4% in 10 ppm. Backwash wastewater from sand filter after adding coagulants has no direct inhibition effect on microorganism, but it results in inorganic components increase in active sludge. By taking North STP as an example, the VSS/SS ratio reduced from 0.65 after coagulants application to 0.54.
文摘Hospital wastewater represents an infectious and toxic risk to human health and the environment due to its contents. Most hospitals in developing countries, including Benin, do not have a wastewater treatment plant. In this study, the wastewater from two hospitals in northern Benin was characterized and then treated with Azadirachta indica leaves, Moringa oleifera and Luffa cylindrica seeds by coagulation/flocculation process. The wastewater characteristics showed that the collected samples are greatly polluted by organic matter and fecal bacteria such as Escherichia coli, Enterococcus fecal and Total coliforms. Jar-test results revealed that 95.74%, 78%, 49.19% of turbidity, 51.35%, 38.32%, 22.19% of COD, 93.16%, 85.26%, 83.30% against Escherichia coli, 92.11%, 90.93%, 94.60% against total Coliforms and 99.37%, 91%, 99%, 55.07% against Enterococcus were removed from hospital wastewater using Moringa oleifera, Luffa cylindrica seed and Azadirachta indica leaves respectively at dose of 100 mg/L. The results highlighted that the natural coagulants could be successfully used for the removal of turbidity and fecal bacteria from hospital wastewater.
文摘The treatment of wastewater from pulp\|paper plants in China by horseradish peroxidase was investigated in this study. The effects of horseradish peroxidase and coagulants were discussed in detail. The results indicated that enzymes might improve the removal of AOX, TOC and colour for pulp\|paper wastewater and modified chitosan is far more effective than Al\-2(SO\-4)\-3 to remove AOX, TOC and colour.
基金Project (No. E9825) supported by the Natural Science Foundation of Heilongjiang Province,China
文摘In order to remove the low turbidity present in surface water, a novel metal-polysilicate coagulant was used to treat the raw water taken from Tanjiang River in Guangdong Province. This study on the effects of A1/Fe molar ratio on the performance of a complex compound formed by polysilicic acid, aluminium and ferric salt (PAFS) showed that PAFS with A1/Fe ratio of 10:3 seemed to have the best coagulation performance in removing turbidity and color. Experimental results showed that under the conditions of polymerization time of 15 d, sedimentation time of 12 min, and pH of 6-8,PAFS with A1/Fe molar ratio of 10:3 had the best coagulation efficiency and lowest residual A1 concentration. The turbidity decreased from 23.8 NTU to 3.23 NTU and the residual A1 concentration was only 0.165 mg/L in the product water. It could be speculated that colloidal impurities and particulate A1 were removed by adsorption bridging and electrical neutralization of long chain inorganic polymer coagulants.
文摘Aim: The objective of this study is to review all the reported outcomes of heparin application in amniotic fluid embolism (AFE) so far and to find out why, when and how heparin or other anticoagulants should be used in AFE. Material and methods: We searched Medline (from 1969 to 2011), using two key words: 1) amniotic fluid embolism;2) amniotic fluid embolism and heparin. The search for the former produced 1127 replies, of which 208 were case reports of AFE. In response to the other key word, there were 94 articles. We looked through all the articles, selecting those relevant for our study. Results: In the years 1969-2011, 208 AFE cases were reported. Heparin (unfractionated heparin) or low molecular weight heparin (LMWH) was applied in 20 cases (9.6%), being the main drug in 11 cases (5.3%) and in 6 cases as a component of spectacular treatment of AFE (surgical treatment and extracorporal membrane oxygenation). In one of these cases anithrombin (AT) with LMWH was used. In one patient heparin therapy was considered to be unsuccessful and hence recombinant plasminogen activator (rt-PA) was instituted. All the patients survived. Conclusions: 1) The attempts to use heparin in AFE could be defined as promising, although the number of treated patients is too small for conclusion;2) The postulate to use heparin at the very onset of AFE (a bolus of 10,000 U followed by monitored intravenous infusion) has serious justification: one of the pathways of AFE is the target for heparin (coagulation pathway).
基金the Engineering and Physical Sciences Research Council (EPSRC,No.GR/M56876).
文摘Membranes for gas separation have developed significantly in the last twenty years,however,there is still a need for high temperature and chemically resistant membranes that exhibit good selectivity and gas permeability.Our study examines the fundamental properties of polyetherketone (PEK,a thermally stable and chemically resistant polymer) membranes prepared using concentrated sulphuric acid (98% H_2SO_4) as the solvent.Non-solvents used in the work included acetic acid,ethanol,methanol,glycerol,and wat...
文摘Objective To establish and evaluate a hypercoagulable animal model for the assessment of anticoagulants. Methods Forty mice, thirty-two rats, and twenty-four rabbits were randomly and equally divided into control group (saline) and three ellagic acid (EA)-treated groups (low, middle, and high doses). In the mice, bleeding time (BT) was estimated with tail transaction, and clotting time (CT) with template method. Prothrombin time (PT) and the activated partial thromboplastin time (APTT) in rats and rabbits were measured by means of Quick's one-stage assay and modified APTT assay respectively. In addition, thrombin activity was estimated in rats with PT assay using a hemagglutination analyzer. The circulating platelet aggregates were de- tected in rabbits through platelet counting and presented as the circulating platelet aggregate ratio (CPAR). Results EA shortened BT and CT in mice, PT and APTT in rats, and increased thrombin activity and CPAR, all in a dose-dependent manner. EA also brought reduction of PT and APTT in rabbits in dose- and time-dependent manners. Conclusion EA could induce hypercoagulable state through activating coagulation system and platelets in mice, rats, and rabbits.
文摘This study investigated the floc aggregation, average floc size, floc size variance and floc growth velocity when ferric chloride （FeCl3） and polyferric chloride （PFC） were used to treat the simulated water samples. The factors including coagulant dose, ionic strength and solution pH, which affect the floc aggregation, were studied. Experiments were carried out in a bench-scale reactor using photometric dispersion analyzer （PDA）. Results showed that there were great differences between the floc aggregation of PFC and FeCl3. The average floc size and floc growth velocity of PFC were much larger than those of FeCl3. Compared with FeCl3, PFC gave a better coagulation performance in wider range of pH, dosage and ionic strength. It was also found that the coagulation efficiency of PFC did not depend on average floc size but on floc growth velocity.
基金Sponsored by the National High Technology Research and Development Program of China(Grant No. 2002AA305109) and Innovational Project in Space Flight Science and Technology(Grant No.2409035).
文摘PBO materials possess super mechanical properties and high thermal and chemical resistance due to their special rigid-rod backbones with heterocyclic chemical structure and supermolecular microstructure. But these structures may be affected by a series of preparing technologies, among which the coagulant is even more important. In this paper the chemical and microstructure changes of PBO materials coagulated with different solvents were investigated. Analyses of molecular weight and chemical structure of PBO coagulated indicate that the heterocyclic ring of PBO will experience cleavage in coagulation and in this stage water plays an important role. The final structure of PBO materials may involve several intermediate structures lying between benzoxazole and the open ring. Wide-angle X-ray diffraction (WAXD) 2θ scans and scanning probe microscope (SPM) show that the microstructure of PBO materials coagulated in solvents with different properties will change a lot and those coagulants with the smaller rate of diffusion like methanol can cause more ordered molecule alignment containing fewer voids.
基金supported by the National Natural Science Foundation of China (No.U1810205).
文摘The coagulation process is a widely applied technology in water and wastewater treatment.Novel composite polyferric mag-nesium-silicate-sulfate(PFMS)coagulants were synthesized using Na_(2)SiO_(3)·9H_(2)O,Fe_(2)(SO_(4))_(3),and MgSO_(4) as raw materials in this paper.The effects of aging time,Fe:Si:Mg,and OH:M molar ratios(M represents the metal ions)on the coagulation performance of the as-pre-pared PFMS were systematically investigated to obtain optimum coagulants.The results showed that PFMS coagulant exhibited good co-agulation properties in the treatment of simulated humic acid-kaolin surface water and reactive dye wastewater.When the molar ratio was controlled at Fe:Si:Mg=2:2:1 and OH:M=0.32,the obtained PFMS presented excellent stability and a high coagulation efficiency.The removal efficiency of ultraviolet UV254 was 99.81%,and the residual turbidity of the surface water reached 0.56 NTU at a dosage of 30 mg·L^(-1).After standing the coagulant for 120 d in the laboratory,the removal efficiency of UV254 and residual turbidity of the surface wa-ter were 88.12%and 0.68 NTU,respectively,which accord with the surface water treatment requirements.In addition,the coagulation performance in the treatment of reactive dye wastewater was greatly improved by combining the advantages of magnesium and iron salts.Compared with polyferric silicate-sulfate(PFS)and polymagnesium silicate-sulfate(PMS),the PFMS coagulant played a better decolor-ization role within the pH range of 7-13.
