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
The oxidation rate of ferrous sulfate was investigated in the preparation of polyferric sulfate(PFS) coagulant. It was proved that this reaction is zero order with respect to Fe 2+ , first order with respect to NO\-2(...The oxidation rate of ferrous sulfate was investigated in the preparation of polyferric sulfate(PFS) coagulant. It was proved that this reaction is zero order with respect to Fe 2+ , first order with respect to NO\-2(g) and first order with respect to the interface area between gas phase and liquid phase. If the partial pressure of NO\-2(g) in gas phase is increased or the interface area is increased, the time needed to complete the reaction will be decreased.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
The purpose of this work is the study the ability of the plant material Aloe vera to act as natural coagulant using raw water obtained from a drinking water treatment plant(Mila,Algeria).Different solvents such as:NaC...The purpose of this work is the study the ability of the plant material Aloe vera to act as natural coagulant using raw water obtained from a drinking water treatment plant(Mila,Algeria).Different solvents such as:NaCl;NaOH and HCl were used as chemical activators to extract the active components from the Aloe vera plant,and different coagulation-flocculation experiments were conducted in a jar test apparatus to evaluate the perfor-mance of the extracted coagulant.Also,the effect of coagulant dose on some water parameters such as turbidity,pH,total alkalinity and organic matter were investigated.The results showed that the use of coagulants obtained by using different solvents increases the coagulation efficiency compared to the coagulant obtained from the raw material,for example the maximum turbidity removal efficiency was 28.23,78.07,83.46 and 85.15%when using powdered Aloe vera(raw material),AV-NaCl(0.5 M),AV-NaOH(0.05 M)and AV-HCl(0.05 M),respectively.The results defined,that the residual turbidity obtained in this work,where the Aloe vera was used(after treat-ment by solvents)produced a turbidity lower than the Algerian standard(5 NTU)with initial turbidity(13 NTU).In this study,the infrared spectrum study and analysis has revealed the presence of different functional groups,which are responsible for the coagulation process.展开更多
The efficiency of using tapioca starch as a natural coagulant on semiconductor wastewater treatment was investigated. The silica content in the wastewater was pH dependent and it was found that the reduction of COD an...The efficiency of using tapioca starch as a natural coagulant on semiconductor wastewater treatment was investigated. The silica content in the wastewater was pH dependent and it was found that the reduction of COD and turbidity occurred at pH between 12 and 14 with measurements below 100 mg/L and 100 NTU respectively. A three-level factorial design experiment in the Response Surface Methodology (RSM) was applied to determine the influence of retention time and dosage of the tapioca starch. The parameters studied were chemical oxygen demand (COD), turbidity and total suspended solids (TSS). The R2 for turbidity, COD and TSS were 0.92, 0.92 and 0.77 respectively. Results indicate that the dosage of the tapioca starch has a higher influence on COD and turbidity reduction. Tapioca starch as a natural coagulant has shown that the optimum turbidity reduction was 99% at a settling time of 30 minutes with dosage of 0.1 g/L. The COD reduction was achieved at 87% after 60 min of retention time and 0.1 g/L of dosage while higher coagulant dosages reduced the TSS concentration to 10.9 mg/L at retention time between 50 to 60 minutes.展开更多
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
In Chihuahua, north Mexico, the berries of Solanum elaeagnifolium (trompillo or silverleaf nightshade) have been used in the manufacture of artisanal filata-type asadero cheese. Solanum elaeagnifolium is a wild plant ...In Chihuahua, north Mexico, the berries of Solanum elaeagnifolium (trompillo or silverleaf nightshade) have been used in the manufacture of artisanal filata-type asadero cheese. Solanum elaeagnifolium is a wild plant that possesses proteases in its fruit;those enzymes exhibit general proteolytic activities, which are useful in traditional asadero cheesemaking as a rennet substitute. These type of cheese is softer than those made with rennin or chymosin due to their water content and proteolysis. Thus, the aim of this work was to explore microbiological susceptibility of asadero cheese made with an extract from ripe berries and compared with those elaborated with commercial rennet. Crude extract of such fruit was obtained by salting out with ammonium sulfate (40%). Cheeses were obtained by a standardized process only changing the enzyme, packaged in plastic bag or vacuum bag and storage at 4℃ -?6℃. The study included the analysis of spoilage bacteria (total aerobic count, yeasts and molds), indicators of hygiene (total coliforms and E. coli) and fecal contamination (fecal coliforms) after 1, 7, 14, 21 and 28 days of production. Although cheese made with S. elaeagnifolium had lower microbial growth, the aerobic count and yeasts and molds count of all cheese samples showing a 28 days shelf life. Total coliforms, in limits beyond the established ones by the Mexican legislation for human consumption with no effect of the enzyme type used for production, as well as for fecal coliforms. Differences were detected just for packaged method, suggesting that good manufacturing practices take place not the plant coagulant.展开更多
A comprehensive method was applied to evaluate the anticoagulant activity of a novel anticoagulant peptide(NAESLRK)derived from oyster(Crassostrea gigas).The anticoagulant peptide drastically reduced the extrinsic clo...A comprehensive method was applied to evaluate the anticoagulant activity of a novel anticoagulant peptide(NAESLRK)derived from oyster(Crassostrea gigas).The anticoagulant peptide drastically reduced the extrinsic clotting activity and also impaired the intrinsic clotting activity slightly.Consistent with clotting data,the thrombin peak height was reduced to 84.7 nmol/L from 123.4 nmol/L,and thrombin generation time was delayed to 4.67 min from 4.42 min when the extrinsic trigger was applied.The inhibitory kinetics of FⅪa,FⅨa,FⅩa,FⅡa,and APC in a purified component system rationally explained the reduction of extrinsic clotting activity and impairment of thrombin generation.Besides the inhibition of FⅩa and FⅡa activity,the activation processes of FⅩand FⅡby intrinsic/extrinsic tenase complex and prothrombinase were also damaged.The anticoagulant activity in the plasma system was the result of comprehensive inhibition of various factors.The research provided a novel method for anticoagulant evaluation and inhibitory mechanism of bioactive peptides from food products.展开更多
The ability of seed extracts of Trigonella foenum-graecum (T. foenum-graecum) and Cuminum cyminum (C. cyminum) to act as natural coagulants was tested using natural turbid water. Seed extracts were prepared using dist...The ability of seed extracts of Trigonella foenum-graecum (T. foenum-graecum) and Cuminum cyminum (C. cyminum) to act as natural coagulants was tested using natural turbid water. Seed extracts were prepared using distilled water and NaCl (0.5 M and 1.0 M) solution. Only 1.0 M NaCl extract of T. foenum-graecum had coagulation capability and did not depend on pH values. Further it showed that natural coagulant obtained from T. foenum-graecum is temperature (upto 100?C) and pH stable (pH 4.0 - 10.0). Extract of C. cyminum had very minimal (16 ± 2) coagulation property. The seed extract of T. foenum-graecum showed about 80% coagulation properties, where as the best known natural coagulants such as Strychnos potatorum and Moringa oleifera, and chemical coagulant such as Al2(SO4)3 showed around 90%, 65% and 95% respectively, which are used as standards for the present study. When compared with pond water, T. foenum-graecum extract treated water shows decrease in alkalinity, turbidity, KMnO4 demand and total coli-form. This study reveals that seed extract of T. foenum-graecum can be used as natural water coagulant.展开更多
Coagulation-Flocculation plays a significant role in drinking water treatment. Laboratory experiments were carried out in order to assess the effectiveness of using Conocarpus Leaves Solution (CLS) as a natural coagul...Coagulation-Flocculation plays a significant role in drinking water treatment. Laboratory experiments were carried out in order to assess the effectiveness of using Conocarpus Leaves Solution (CLS) as a natural coagulant in conjunction with the synthetic chemical represented by Alum in the water purification. Biological test was carried out to confirm that these leaves are not toxic, followed by optimizing the dosage of alum and then Alum and CLS were applied to the turbid water whose turbidity level has two ranges, (20 - 35) NTU and (90 - 120) NTU, using the JAR Test. The parameters determined before and after coagulation were turbidity, pH and temperature. The experiments showed that the optimum dose of alum coagulant (individually) for high turbid water is about 18 mg/l with PH = 7 and 24 mg/l f with PH = 5 and 9. In addition, for the low turbidity water, the optimum dose of alum was lower than in the high turbid water. In terms of using Alum in conjunction with CLS, at high range of turbidity, the results show that at 33% ratio of leaves solution to alum coagulant, there are 50% and 75% turbidity reduction performed for the PH equal to 5 and 9 respectively. Although about 62% and 65% turbidity reduction were achieved at PH = 7 and PH = 9 in the low range level. However, low reduction in turbidity has occurred when the water PH = 5. The amount of leaves solution added to the water in the water treatment plant is highly important, hence it decreases the amount of using the synthetic chemicals by about 33% of the quantity that required for water treatment and that will help both, the water industry and the human health. More studies need to be achieved in particular different concentration of the Conocarpus leaves solution in order to improve the percentage of using the natural material as a coagulant.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
This paper explores a new compounding coagulant for decolourization, which can decolour wastewater containing soluble dyestuffs (especially reactive and acidic dyestuffs). The best prescription and condition of this d...This paper explores a new compounding coagulant for decolourization, which can decolour wastewater containing soluble dyestuffs (especially reactive and acidic dyestuffs). The best prescription and condition of this decolourizing process are discussed and the mechanism is studied. Experimental results show that the treatment efficiency of decolourization is very high by using the new coagulant. Both the colour and pH of the effluent meet the required standards. The synergism of chemical and physico-chemical actions among the coagulant components has also been found. This effect determines the superiority of the new coagulant to other single component ones.展开更多
A new ternary coagulant polysilicate ferromanganese(PSFM),composed of Fe,Mn and Si,was designed.Its coagulation performance for dye removal was investigated systematically together with the impact of several key opera...A new ternary coagulant polysilicate ferromanganese(PSFM),composed of Fe,Mn and Si,was designed.Its coagulation performance for dye removal was investigated systematically together with the impact of several key operational parameters.The experimental results indicate that an excellent coagulation efficiency with higher than 95%color removal and higher than 94%total organic carbon(TOC)removal can be obtained at an optimized molar ratio of Si∶Fe∶Mn(5∶5∶1).The coagulation performance of PSFM coagulant was studied comparatively with other conventional coagulants,e.g.poly aluminium chloride(PAC),Al_(2)(SO_(4))_(3)and FeCl_(3).Additionally,various characterization techniques were applied to get detailed morphological and compositional information of PSFM coagulants.Furthermore,the underlying mechanism for improved coagulant performance was proposed based on these results.These results have exemplified quantitatively that PSFM coagulant exhibits a great potential as a promising material for application in various environmental fields.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
<b><span style="font-family:;" "="">Introduction<span>:</span></span></b><span><i><span style="font-family:;" "=""&g...<b><span style="font-family:;" "="">Introduction<span>:</span></span></b><span><i><span style="font-family:;" "=""> Pergularia tomentosa</span></i></span><span><span style="font-family:;" "=""> is a saharan spontaneous plant belonging to <i>Asclepiadacea </i>family. It has several medicinal properties and uses in the human food as an auxiliary in cheese-making. The purpose of this study is the extraction of the coagulant enzymatic system (C.E.S) from the plant dried leaves and its use in the preparation of fresh cheese. <b>Materials & Methods</b></span></span><span><b><span style="font-family:;" "="">: </span></b></span><span><span style="font-family:;" "="">The determination of the coagulant activity was carried out on a skimmed</span></span><span><span style="font-family:;" "=""> milk <span>powder by Berridge’s method. Cow’s milk used for coagulant strength</span> deter<span>mination and cheese-making. Proteolytic activity</span></span></span><span><span style="font-family:;" "="">. </span></span><span><span style="font-family:;" "="">The chemical </span></span><span><span style="font-family:;" "="">determinations <span>of raw milk were carried out according to AFNOR analysis methods. A</span> descriptive sensory evaluation was performed to determine the organoleptic pro<span>perties of the produced cheese. The proteolytic activity was determined b</span>y measuring the aspartyl-protease units. <b>Results:</b> The main results of the phy<span>sico-chemical characterization show that its coagulant activity (R.U mL<sup>-1</sup>)</span> was 97.19 ± 4.67, coagulant strength (SU) was 230.05 ± 0.37, proteolytic activity (μg<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>mL<sup>-1</sup>) was 0.33 ± 0.04 and coagulant activity/proteolytic activity ratio was <span>294.51. For the cheese made, it has presented the following results</span></span></span><span><span style="font-family:;" "=""> </span></span><span><span style="font-family:;" "="">as %</span></span><span><span style="font-family:;" "=""> (g/100g): <span>titrable acidity 0.80 ± 0.005, total dry extract 30.48 ± 1.490, fat 2</span></span></span><span><span style="font-family:;" "="">.</span></span><span><span style="font-family:;" "="">32 ± 0.02, fresh </span></span><span><span style="font-family:;" "="">yield 11.5 ± 0</span></span><span><span style="font-family:;" "="">.</span></span><span><span style="font-family:;" "="">09, dry yield 30.06 ± 0.05. Moreover, sensory analysis results<span> showed that fresh cheese prepared from <i>Pergularia tomentosa</i> dried</span> <span>leaves diluted enzymatic extract filtrate was characterized by whitish color</span><span>, smooth texture, with acceptable and satisfying lactic taste. <b>Conclusion:</b> The plant enzymatic system studied could be added to the list of plant rennet substitutes and, thus, contribute</span></span></span><span><span style="font-family:;" "="">s</span></span><span><span style="font-family:;" "=""> to the manufacture of enzymatic coagula</span></span><span><span style="font-family:;" "="">tion cheese.</span></span><span></span><span style="font-family:;" "=""></span>展开更多
An environment-friendly composite coagulant for treating drinking water was prepared by using [Al 2 (OH) n Cl 6-n ]m?[Fe2 (OH) NCl6-N ]M (PAFC), chitosan (CTS) and modified starch (MS). It is called PCS. Results indic...An environment-friendly composite coagulant for treating drinking water was prepared by using [Al 2 (OH) n Cl 6-n ]m?[Fe2 (OH) NCl6-N ]M (PAFC), chitosan (CTS) and modified starch (MS). It is called PCS. Results indicated that the best proportion of this coagulant was V (0.1%wt PAFC): V (0.001%wt CTS): V (3%wt modified starch) = 25:6:8. If compared with using traditional coagulant such as PAC, adding the novel coagulant, turbidity and the mass concentration of Al3+ in the water were decreased by 5.17% and 51.1% respectively. Rapid and slow stirring speed in Jar test were evaluated and they were founded to be slight influence. And neutral pH and room temperature allow up to 97.2% turbidity removal. Low coagulant doses reached high turbidity removal percentage, so this coagulant has obvious economic and environmental benefits.展开更多
This study was performed in laboratory scale and consisted of the using of aqueous Opuntia dillenii solution for the clarification of very turbid surface water (Turbidities varying between 186 NTU and 418 NTU). This p...This study was performed in laboratory scale and consisted of the using of aqueous Opuntia dillenii solution for the clarification of very turbid surface water (Turbidities varying between 186 NTU and 418 NTU). This plant from Cactaceae family was used as a natural coagulant for the different clarification tests. The preliminary phytochemical Screening of the powder of this plant showed that it contains tanins, saponins and mucilages. Flocculation and coagulation tests showed that Opuntia dillenii can be used in highly turbid water treatment. The removal efficiency varied from 89% to 93% for the turbidity and suspended solids, and from 4% to 15% for the obvious color in water when we used the optimum values of this natural coagulant (1 mL to 10 mL). The successive addition of this natural coagulant and the lime, gave a better elimination of turbidity and suspended solids, and a good reduction for the color. The removal efficiency of the turbidity and suspended solids became more than 95% and the one of the color between 67% and 94%.展开更多
Inflammation and coagulation are so tightly linked that the cytokine storm which accompanies the development of sepsis initiates thrombin activation and the development of an intravascular coagulopathy. This review ex...Inflammation and coagulation are so tightly linked that the cytokine storm which accompanies the development of sepsis initiates thrombin activation and the development of an intravascular coagulopathy. This review examines the interaction between the inflammatory and coagulation cascades, as well as the role of endogenous anticoagulants in regulating this interaction and dampening the activity of both pathways. Clinical trials attempting to improve outcomes in patients with severe sepsis by inhibiting thrombin generation with heparin and or endogenous anticoagulants are reviewed. In general, these trials have failed to demonstrate that anticoagulant therapy is associated with improvement in mortality or morbidity. While it is possible that selective patients who are severelyill with a high expected mortality may be shown to benefit from such therapy, at the present time none of these anticoagulants are neither approved nor can they be recommended for the treatment of sepsis.展开更多
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.
文摘The oxidation rate of ferrous sulfate was investigated in the preparation of polyferric sulfate(PFS) coagulant. It was proved that this reaction is zero order with respect to Fe 2+ , first order with respect to NO\-2(g) and first order with respect to the interface area between gas phase and liquid phase. If the partial pressure of NO\-2(g) in gas phase is increased or the interface area is increased, the time needed to complete the reaction will be decreased.
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.
文摘The purpose of this work is the study the ability of the plant material Aloe vera to act as natural coagulant using raw water obtained from a drinking water treatment plant(Mila,Algeria).Different solvents such as:NaCl;NaOH and HCl were used as chemical activators to extract the active components from the Aloe vera plant,and different coagulation-flocculation experiments were conducted in a jar test apparatus to evaluate the perfor-mance of the extracted coagulant.Also,the effect of coagulant dose on some water parameters such as turbidity,pH,total alkalinity and organic matter were investigated.The results showed that the use of coagulants obtained by using different solvents increases the coagulation efficiency compared to the coagulant obtained from the raw material,for example the maximum turbidity removal efficiency was 28.23,78.07,83.46 and 85.15%when using powdered Aloe vera(raw material),AV-NaCl(0.5 M),AV-NaOH(0.05 M)and AV-HCl(0.05 M),respectively.The results defined,that the residual turbidity obtained in this work,where the Aloe vera was used(after treat-ment by solvents)produced a turbidity lower than the Algerian standard(5 NTU)with initial turbidity(13 NTU).In this study,the infrared spectrum study and analysis has revealed the presence of different functional groups,which are responsible for the coagulation process.
文摘The efficiency of using tapioca starch as a natural coagulant on semiconductor wastewater treatment was investigated. The silica content in the wastewater was pH dependent and it was found that the reduction of COD and turbidity occurred at pH between 12 and 14 with measurements below 100 mg/L and 100 NTU respectively. A three-level factorial design experiment in the Response Surface Methodology (RSM) was applied to determine the influence of retention time and dosage of the tapioca starch. The parameters studied were chemical oxygen demand (COD), turbidity and total suspended solids (TSS). The R2 for turbidity, COD and TSS were 0.92, 0.92 and 0.77 respectively. Results indicate that the dosage of the tapioca starch has a higher influence on COD and turbidity reduction. Tapioca starch as a natural coagulant has shown that the optimum turbidity reduction was 99% at a settling time of 30 minutes with dosage of 0.1 g/L. The COD reduction was achieved at 87% after 60 min of retention time and 0.1 g/L of dosage while higher coagulant dosages reduced the TSS concentration to 10.9 mg/L at retention time between 50 to 60 minutes.
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In Chihuahua, north Mexico, the berries of Solanum elaeagnifolium (trompillo or silverleaf nightshade) have been used in the manufacture of artisanal filata-type asadero cheese. Solanum elaeagnifolium is a wild plant that possesses proteases in its fruit;those enzymes exhibit general proteolytic activities, which are useful in traditional asadero cheesemaking as a rennet substitute. These type of cheese is softer than those made with rennin or chymosin due to their water content and proteolysis. Thus, the aim of this work was to explore microbiological susceptibility of asadero cheese made with an extract from ripe berries and compared with those elaborated with commercial rennet. Crude extract of such fruit was obtained by salting out with ammonium sulfate (40%). Cheeses were obtained by a standardized process only changing the enzyme, packaged in plastic bag or vacuum bag and storage at 4℃ -?6℃. The study included the analysis of spoilage bacteria (total aerobic count, yeasts and molds), indicators of hygiene (total coliforms and E. coli) and fecal contamination (fecal coliforms) after 1, 7, 14, 21 and 28 days of production. Although cheese made with S. elaeagnifolium had lower microbial growth, the aerobic count and yeasts and molds count of all cheese samples showing a 28 days shelf life. Total coliforms, in limits beyond the established ones by the Mexican legislation for human consumption with no effect of the enzyme type used for production, as well as for fecal coliforms. Differences were detected just for packaged method, suggesting that good manufacturing practices take place not the plant coagulant.
基金financially supported by the National Natural Science Foundation of China(31771926)the State Key Research and Development Plan“Modern Food Processing and Food Storage and Transportation Technology and Equipment”(No.2017YFD0400201)。
文摘A comprehensive method was applied to evaluate the anticoagulant activity of a novel anticoagulant peptide(NAESLRK)derived from oyster(Crassostrea gigas).The anticoagulant peptide drastically reduced the extrinsic clotting activity and also impaired the intrinsic clotting activity slightly.Consistent with clotting data,the thrombin peak height was reduced to 84.7 nmol/L from 123.4 nmol/L,and thrombin generation time was delayed to 4.67 min from 4.42 min when the extrinsic trigger was applied.The inhibitory kinetics of FⅪa,FⅨa,FⅩa,FⅡa,and APC in a purified component system rationally explained the reduction of extrinsic clotting activity and impairment of thrombin generation.Besides the inhibition of FⅩa and FⅡa activity,the activation processes of FⅩand FⅡby intrinsic/extrinsic tenase complex and prothrombinase were also damaged.The anticoagulant activity in the plasma system was the result of comprehensive inhibition of various factors.The research provided a novel method for anticoagulant evaluation and inhibitory mechanism of bioactive peptides from food products.
文摘The ability of seed extracts of Trigonella foenum-graecum (T. foenum-graecum) and Cuminum cyminum (C. cyminum) to act as natural coagulants was tested using natural turbid water. Seed extracts were prepared using distilled water and NaCl (0.5 M and 1.0 M) solution. Only 1.0 M NaCl extract of T. foenum-graecum had coagulation capability and did not depend on pH values. Further it showed that natural coagulant obtained from T. foenum-graecum is temperature (upto 100?C) and pH stable (pH 4.0 - 10.0). Extract of C. cyminum had very minimal (16 ± 2) coagulation property. The seed extract of T. foenum-graecum showed about 80% coagulation properties, where as the best known natural coagulants such as Strychnos potatorum and Moringa oleifera, and chemical coagulant such as Al2(SO4)3 showed around 90%, 65% and 95% respectively, which are used as standards for the present study. When compared with pond water, T. foenum-graecum extract treated water shows decrease in alkalinity, turbidity, KMnO4 demand and total coli-form. This study reveals that seed extract of T. foenum-graecum can be used as natural water coagulant.
文摘Coagulation-Flocculation plays a significant role in drinking water treatment. Laboratory experiments were carried out in order to assess the effectiveness of using Conocarpus Leaves Solution (CLS) as a natural coagulant in conjunction with the synthetic chemical represented by Alum in the water purification. Biological test was carried out to confirm that these leaves are not toxic, followed by optimizing the dosage of alum and then Alum and CLS were applied to the turbid water whose turbidity level has two ranges, (20 - 35) NTU and (90 - 120) NTU, using the JAR Test. The parameters determined before and after coagulation were turbidity, pH and temperature. The experiments showed that the optimum dose of alum coagulant (individually) for high turbid water is about 18 mg/l with PH = 7 and 24 mg/l f with PH = 5 and 9. In addition, for the low turbidity water, the optimum dose of alum was lower than in the high turbid water. In terms of using Alum in conjunction with CLS, at high range of turbidity, the results show that at 33% ratio of leaves solution to alum coagulant, there are 50% and 75% turbidity reduction performed for the PH equal to 5 and 9 respectively. Although about 62% and 65% turbidity reduction were achieved at PH = 7 and PH = 9 in the low range level. However, low reduction in turbidity has occurred when the water PH = 5. The amount of leaves solution added to the water in the water treatment plant is highly important, hence it decreases the amount of using the synthetic chemicals by about 33% of the quantity that required for water treatment and that will help both, the water industry and the human health. More studies need to be achieved in particular different concentration of the Conocarpus leaves solution in order to improve the percentage of using the natural material as a coagulant.
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This paper explores a new compounding coagulant for decolourization, which can decolour wastewater containing soluble dyestuffs (especially reactive and acidic dyestuffs). The best prescription and condition of this decolourizing process are discussed and the mechanism is studied. Experimental results show that the treatment efficiency of decolourization is very high by using the new coagulant. Both the colour and pH of the effluent meet the required standards. The synergism of chemical and physico-chemical actions among the coagulant components has also been found. This effect determines the superiority of the new coagulant to other single component ones.
基金National Natural Science Foundation of China(No.21876025)National Key Research and Development Program of China(No.2019YFC0408304)。
文摘A new ternary coagulant polysilicate ferromanganese(PSFM),composed of Fe,Mn and Si,was designed.Its coagulation performance for dye removal was investigated systematically together with the impact of several key operational parameters.The experimental results indicate that an excellent coagulation efficiency with higher than 95%color removal and higher than 94%total organic carbon(TOC)removal can be obtained at an optimized molar ratio of Si∶Fe∶Mn(5∶5∶1).The coagulation performance of PSFM coagulant was studied comparatively with other conventional coagulants,e.g.poly aluminium chloride(PAC),Al_(2)(SO_(4))_(3)and FeCl_(3).Additionally,various characterization techniques were applied to get detailed morphological and compositional information of PSFM coagulants.Furthermore,the underlying mechanism for improved coagulant performance was proposed based on these results.These results have exemplified quantitatively that PSFM coagulant exhibits a great potential as a promising material for application in various environmental fields.
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<b><span style="font-family:;" "="">Introduction<span>:</span></span></b><span><i><span style="font-family:;" "=""> Pergularia tomentosa</span></i></span><span><span style="font-family:;" "=""> is a saharan spontaneous plant belonging to <i>Asclepiadacea </i>family. It has several medicinal properties and uses in the human food as an auxiliary in cheese-making. The purpose of this study is the extraction of the coagulant enzymatic system (C.E.S) from the plant dried leaves and its use in the preparation of fresh cheese. <b>Materials & Methods</b></span></span><span><b><span style="font-family:;" "="">: </span></b></span><span><span style="font-family:;" "="">The determination of the coagulant activity was carried out on a skimmed</span></span><span><span style="font-family:;" "=""> milk <span>powder by Berridge’s method. Cow’s milk used for coagulant strength</span> deter<span>mination and cheese-making. Proteolytic activity</span></span></span><span><span style="font-family:;" "="">. </span></span><span><span style="font-family:;" "="">The chemical </span></span><span><span style="font-family:;" "="">determinations <span>of raw milk were carried out according to AFNOR analysis methods. A</span> descriptive sensory evaluation was performed to determine the organoleptic pro<span>perties of the produced cheese. The proteolytic activity was determined b</span>y measuring the aspartyl-protease units. <b>Results:</b> The main results of the phy<span>sico-chemical characterization show that its coagulant activity (R.U mL<sup>-1</sup>)</span> was 97.19 ± 4.67, coagulant strength (SU) was 230.05 ± 0.37, proteolytic activity (μg<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>mL<sup>-1</sup>) was 0.33 ± 0.04 and coagulant activity/proteolytic activity ratio was <span>294.51. For the cheese made, it has presented the following results</span></span></span><span><span style="font-family:;" "=""> </span></span><span><span style="font-family:;" "="">as %</span></span><span><span style="font-family:;" "=""> (g/100g): <span>titrable acidity 0.80 ± 0.005, total dry extract 30.48 ± 1.490, fat 2</span></span></span><span><span style="font-family:;" "="">.</span></span><span><span style="font-family:;" "="">32 ± 0.02, fresh </span></span><span><span style="font-family:;" "="">yield 11.5 ± 0</span></span><span><span style="font-family:;" "="">.</span></span><span><span style="font-family:;" "="">09, dry yield 30.06 ± 0.05. Moreover, sensory analysis results<span> showed that fresh cheese prepared from <i>Pergularia tomentosa</i> dried</span> <span>leaves diluted enzymatic extract filtrate was characterized by whitish color</span><span>, smooth texture, with acceptable and satisfying lactic taste. <b>Conclusion:</b> The plant enzymatic system studied could be added to the list of plant rennet substitutes and, thus, contribute</span></span></span><span><span style="font-family:;" "="">s</span></span><span><span style="font-family:;" "=""> to the manufacture of enzymatic coagula</span></span><span><span style="font-family:;" "="">tion cheese.</span></span><span></span><span style="font-family:;" "=""></span>
文摘An environment-friendly composite coagulant for treating drinking water was prepared by using [Al 2 (OH) n Cl 6-n ]m?[Fe2 (OH) NCl6-N ]M (PAFC), chitosan (CTS) and modified starch (MS). It is called PCS. Results indicated that the best proportion of this coagulant was V (0.1%wt PAFC): V (0.001%wt CTS): V (3%wt modified starch) = 25:6:8. If compared with using traditional coagulant such as PAC, adding the novel coagulant, turbidity and the mass concentration of Al3+ in the water were decreased by 5.17% and 51.1% respectively. Rapid and slow stirring speed in Jar test were evaluated and they were founded to be slight influence. And neutral pH and room temperature allow up to 97.2% turbidity removal. Low coagulant doses reached high turbidity removal percentage, so this coagulant has obvious economic and environmental benefits.
文摘This study was performed in laboratory scale and consisted of the using of aqueous Opuntia dillenii solution for the clarification of very turbid surface water (Turbidities varying between 186 NTU and 418 NTU). This plant from Cactaceae family was used as a natural coagulant for the different clarification tests. The preliminary phytochemical Screening of the powder of this plant showed that it contains tanins, saponins and mucilages. Flocculation and coagulation tests showed that Opuntia dillenii can be used in highly turbid water treatment. The removal efficiency varied from 89% to 93% for the turbidity and suspended solids, and from 4% to 15% for the obvious color in water when we used the optimum values of this natural coagulant (1 mL to 10 mL). The successive addition of this natural coagulant and the lime, gave a better elimination of turbidity and suspended solids, and a good reduction for the color. The removal efficiency of the turbidity and suspended solids became more than 95% and the one of the color between 67% and 94%.
文摘Inflammation and coagulation are so tightly linked that the cytokine storm which accompanies the development of sepsis initiates thrombin activation and the development of an intravascular coagulopathy. This review examines the interaction between the inflammatory and coagulation cascades, as well as the role of endogenous anticoagulants in regulating this interaction and dampening the activity of both pathways. Clinical trials attempting to improve outcomes in patients with severe sepsis by inhibiting thrombin generation with heparin and or endogenous anticoagulants are reviewed. In general, these trials have failed to demonstrate that anticoagulant therapy is associated with improvement in mortality or morbidity. While it is possible that selective patients who are severelyill with a high expected mortality may be shown to benefit from such therapy, at the present time none of these anticoagulants are neither approved nor can they be recommended for the treatment of sepsis.
