A novel inorganic polymer flocculant,poly-ferric sulfate（BPFS） was prepared by oxidation of ferrous sulfate using domestic Thiobacillus ferrooxidans（T·f） under acid condition.The optimal conditions for the pr...A novel inorganic polymer flocculant,poly-ferric sulfate（BPFS） was prepared by oxidation of ferrous sulfate using domestic Thiobacillus ferrooxidans（T·f） under acid condition.The optimal conditions for the preparation were pH value of 1.5,（NH4）2SO4 dosage of 0.5 g/L,initial Fe2＋ concentration of 45g/L,inoculum 10%,rotating speed of 120 r/min,reaction time of 5-6 d and reaction temperature of 30 ℃.Under the optimal conditions,the BPFS product with pH value of 1.5-2.2,basicity of 17.5%-22.7% and total iron content of 43.87-45.24 g/L was obtained.The application of the BPFS to three wastewaters was carried out,and the removal efficiencies of COD,decolorization and Zn2＋ by BPFS can be reached 70%,90% and 99%,respectively.The result suggests that the BPFS is an excellent flocculant for water treatment.展开更多
Flotation tailings were successfully flocculated in the presence of cationic polyacrylamide and silica gel.The effects of various parameters such as polymer weight,charge density,and pH on the rate of flocculation wer...Flotation tailings were successfully flocculated in the presence of cationic polyacrylamide and silica gel.The effects of various parameters such as polymer weight,charge density,and pH on the rate of flocculation were also investigated in the current study.The flocculation mechanism of the flocculant on tailings was investigated using zeta potential and Fourier transform infrared(FTIR)measurements.The results obtained reveal that 1)sodium silicate gel,used as a binder for the consolidation of tailings form primary flocs,acts as an anchor and the adsorption of polymer flocculant on these anchors results in the formation of larger flocs and,consequently,enhanced settling rate;2)flocculation in the presence of silica gel and polymer has a faster settling rate than single-polymer flocculation owing to the mechanisms of charge neutralization and bridging as identified using zeta potential and FTIR measurements.A pilot level study was conducted to investigate the influence of processed water on the flotation of scheelite.The results show that the proposed tailing disposal method could improve scheelite recovery by 2%(approximately)and could reduce the daily operation costs of the plant by approximately 108.57 USD.展开更多
The biopolymer flocculant （named PS-2） producing by Pseudomonas fluorescens was investigated. The PS-2 had high efficiency with small dosage, when dealing with kaolin suspension, formed larger floc, with big sedimen...The biopolymer flocculant （named PS-2） producing by Pseudomonas fluorescens was investigated. The PS-2 had high efficiency with small dosage, when dealing with kaolin suspension, formed larger floc, with big sedimentation rate, over a wide range of temperatures. Distributing of flocculating activity test showed that the biopolymer flocculant was an extracellular product. The composition analysis of purified biopolymer flocculant showed that it composed mainly of polysaccharide and nucleic acid. The content of polysaccharide was 86. 7%, which determined by using phenol-vitriol method, and the content of nucleic acid was 7.8%, which determined by UV absorption method. The biopolymer flocculant as a powder form showed much better stability than that as a supernatant. The character of biopolymer flocculant was stable even it was heated to 100℃ when it in acidic condition. The optimal conditions to flocculate kaolin suspension were as follows： pH 8-12, flocculant dosage lmL/L, and Ca^2＋ as the optimal cation.展开更多
A strain secreting a strongly acidic polysaccharide flocculating agent was isolated from activated sludge, and identified as Bacillus brevis. The bioflocculant was produced by RL-2 during the late logarithmic growth i...A strain secreting a strongly acidic polysaccharide flocculating agent was isolated from activated sludge, and identified as Bacillus brevis. The bioflocculant was produced by RL-2 during the late logarithmic growth in the batch culture and was recovered from supernatant by ethanol precipitation. The bioflocculant is thermo-stable as its activity remains stable after heated at 100 °C for 45 min. Its flocculating activity with kaolin suspensions was stimulated by the addition of Ca2+, Al3+ and Cu2+. The flocculant consists of glucose, mannose, and galacturonic acid. Its average molecular mass was estimated to be approximately 2.86×105 by the method of viscosity. The flocculant aggregates various inorganic and organic compounds in solution.展开更多
基金Project (2009ZX07212-001-01) supported by the Major Science and Technology Program for Water Pollution Control and Treatment,ChinaProject (50925417) supported by the National Natural Science Foundation for Distinguished Young Scholars of ChinaProjects (50830301,51074191) supported by the National Natural Science Foundation of China
文摘A novel inorganic polymer flocculant,poly-ferric sulfate（BPFS） was prepared by oxidation of ferrous sulfate using domestic Thiobacillus ferrooxidans（T·f） under acid condition.The optimal conditions for the preparation were pH value of 1.5,（NH4）2SO4 dosage of 0.5 g/L,initial Fe2＋ concentration of 45g/L,inoculum 10%,rotating speed of 120 r/min,reaction time of 5-6 d and reaction temperature of 30 ℃.Under the optimal conditions,the BPFS product with pH value of 1.5-2.2,basicity of 17.5%-22.7% and total iron content of 43.87-45.24 g/L was obtained.The application of the BPFS to three wastewaters was carried out,and the removal efficiencies of COD,decolorization and Zn2＋ by BPFS can be reached 70%,90% and 99%,respectively.The result suggests that the BPFS is an excellent flocculant for water treatment.
基金Project(2016zzts109)supported by the Innovation Driven Plan of Central South University,ChinaProject(2015CX005)supported by the Innovation driven Program of National Basic Research Program of ChinaProject(B14034)supported by the Program of Introdution Talents of Discipline to Universities,China(111 Project)
文摘Flotation tailings were successfully flocculated in the presence of cationic polyacrylamide and silica gel.The effects of various parameters such as polymer weight,charge density,and pH on the rate of flocculation were also investigated in the current study.The flocculation mechanism of the flocculant on tailings was investigated using zeta potential and Fourier transform infrared(FTIR)measurements.The results obtained reveal that 1)sodium silicate gel,used as a binder for the consolidation of tailings form primary flocs,acts as an anchor and the adsorption of polymer flocculant on these anchors results in the formation of larger flocs and,consequently,enhanced settling rate;2)flocculation in the presence of silica gel and polymer has a faster settling rate than single-polymer flocculation owing to the mechanisms of charge neutralization and bridging as identified using zeta potential and FTIR measurements.A pilot level study was conducted to investigate the influence of processed water on the flotation of scheelite.The results show that the proposed tailing disposal method could improve scheelite recovery by 2%(approximately)and could reduce the daily operation costs of the plant by approximately 108.57 USD.
文摘The biopolymer flocculant （named PS-2） producing by Pseudomonas fluorescens was investigated. The PS-2 had high efficiency with small dosage, when dealing with kaolin suspension, formed larger floc, with big sedimentation rate, over a wide range of temperatures. Distributing of flocculating activity test showed that the biopolymer flocculant was an extracellular product. The composition analysis of purified biopolymer flocculant showed that it composed mainly of polysaccharide and nucleic acid. The content of polysaccharide was 86. 7%, which determined by using phenol-vitriol method, and the content of nucleic acid was 7.8%, which determined by UV absorption method. The biopolymer flocculant as a powder form showed much better stability than that as a supernatant. The character of biopolymer flocculant was stable even it was heated to 100℃ when it in acidic condition. The optimal conditions to flocculate kaolin suspension were as follows： pH 8-12, flocculant dosage lmL/L, and Ca^2＋ as the optimal cation.
文摘A strain secreting a strongly acidic polysaccharide flocculating agent was isolated from activated sludge, and identified as Bacillus brevis. The bioflocculant was produced by RL-2 during the late logarithmic growth in the batch culture and was recovered from supernatant by ethanol precipitation. The bioflocculant is thermo-stable as its activity remains stable after heated at 100 °C for 45 min. Its flocculating activity with kaolin suspensions was stimulated by the addition of Ca2+, Al3+ and Cu2+. The flocculant consists of glucose, mannose, and galacturonic acid. Its average molecular mass was estimated to be approximately 2.86×105 by the method of viscosity. The flocculant aggregates various inorganic and organic compounds in solution.
