The biosorption characteristics of Cs（I） ions from aqueous solution using exopolymers （PFC02） produced from Pseudomonas fluorescens C-2 were investigated as a function of pH, biosorbent dosage, contact time and in...The biosorption characteristics of Cs（I） ions from aqueous solution using exopolymers （PFC02） produced from Pseudomonas fluorescens C-2 were investigated as a function of pH, biosorbent dosage, contact time and initial concentration. pH played a major role in the adsorption process, and the optimum pH for the removal of Cs（I） was 8.0. Langmuir, Freundlich and Dubinin-Radushkevich （D-R） models were applied to describe the biosorption isotherm of the Cs（I） ions by PFC02. The Lagergren first-order, pseudo second-order kinetic and intraparticle diffusion models were used to test the kinetic data. Langmuir model and D-R model fitted the equilibrium data better than the Freundlich isotherm. The monolayer adsorption capacities of PFC02 as obtained from Langmuir isotherm at 25°C was found to be 32.63 mg/g. From the D-R isotherm model, the mean free energy was calculated as 26.73 kJ/mol, indicating that the biosorption of cesium was chemisorption. The biosorption process was rapid, and the kinetic rates were best fitted to the pseudo second-order model, which indicated the biosorption process operated through chemisorption mechanism. FT-IR analysis of PFC02 showed the possible functional groups responsible for cesium adsorption were hydroxyl, carboxyl, carbonyl and sulphonate groups. SEM analysis showed the porous structure of the material while EDX analysis confirmed the adsorption of Cs（I） on PFC02. Cesium adsorbed onto the PFC02 could be desorbed efficiently using 1 mol/L HNO 3 , and the enrichment factor was 50.0. Furthermore, PFC02 could be reused five times with only about 8.25% regeneration loss. The developed method was successfully utilized for the removal of Cs（I） ions from aqueous solution.展开更多
我们在转基因水稻后代中发现了两个生殖器官发育相关的隐性突变体,暂命名为function of reproductive organ1（fro1）和pistilloid-stamen（ps-2）。fro1突变体内外稃闭合,抽穗但不开花;4轮器官结构及数目近正常,但内外稃片抱合扭曲成...我们在转基因水稻后代中发现了两个生殖器官发育相关的隐性突变体,暂命名为function of reproductive organ1（fro1）和pistilloid-stamen（ps-2）。fro1突变体内外稃闭合,抽穗但不开花;4轮器官结构及数目近正常,但内外稃片抱合扭曲成辣椒状,雌雄蕊发育不完全,无花粉形成,雌蕊不育。ps-2突变体类似Luo等（2006）报道的ps突变体：颖花开裂,内外颖片变窄、变硬,外颖弯曲,但ps只有1-5枚雄蕊转化成雌蕊,而ps-2有5-6枚雄蕊转化成雌蕊,仅有极少数突变颖花留有1枚未转变的雄蕊,突变体雌蕊状结构10个以上,不能结实。通过对突变体fro1和ps-2分别与野生型明恢86正反杂交,与R527、93-11和中花16的杂交后代表型分离规律分析表明：突变体fro1和ps-2是分别由一对隐性基因控制的突变体,其中fro1的F2后代表型分离比均符合3：1,大部分ps-2的F2后代表型分离比偏离3：1。进一步分析fro1和ps-2双突变体的遗传和表型发现：fro1和ps-2基因不等位,是两个独立遗传的基因。植株生活力受纯合ps-2基因的影响,但不受纯合fro1基因的影响。双突变体的内外稃片结构及开裂特征似ps-2,而内外稃包合状与fro1近似,雄蕊仍表现雌化,但数目明显减少。fro1和ps-2双突变体的表型特征暗示了ps-2和fro1间存在一定的互作。展开更多
基金supported by the National Nat- ural Science Foundation of China (No. 30970309)the Natural Science Foundation of He'nan Province (No. 082102220009)the Natural Science Foundation of He'nan Province Education Department (No. 2009A610001)
文摘The biosorption characteristics of Cs（I） ions from aqueous solution using exopolymers （PFC02） produced from Pseudomonas fluorescens C-2 were investigated as a function of pH, biosorbent dosage, contact time and initial concentration. pH played a major role in the adsorption process, and the optimum pH for the removal of Cs（I） was 8.0. Langmuir, Freundlich and Dubinin-Radushkevich （D-R） models were applied to describe the biosorption isotherm of the Cs（I） ions by PFC02. The Lagergren first-order, pseudo second-order kinetic and intraparticle diffusion models were used to test the kinetic data. Langmuir model and D-R model fitted the equilibrium data better than the Freundlich isotherm. The monolayer adsorption capacities of PFC02 as obtained from Langmuir isotherm at 25°C was found to be 32.63 mg/g. From the D-R isotherm model, the mean free energy was calculated as 26.73 kJ/mol, indicating that the biosorption of cesium was chemisorption. The biosorption process was rapid, and the kinetic rates were best fitted to the pseudo second-order model, which indicated the biosorption process operated through chemisorption mechanism. FT-IR analysis of PFC02 showed the possible functional groups responsible for cesium adsorption were hydroxyl, carboxyl, carbonyl and sulphonate groups. SEM analysis showed the porous structure of the material while EDX analysis confirmed the adsorption of Cs（I） on PFC02. Cesium adsorbed onto the PFC02 could be desorbed efficiently using 1 mol/L HNO 3 , and the enrichment factor was 50.0. Furthermore, PFC02 could be reused five times with only about 8.25% regeneration loss. The developed method was successfully utilized for the removal of Cs（I） ions from aqueous solution.
文摘我们在转基因水稻后代中发现了两个生殖器官发育相关的隐性突变体,暂命名为function of reproductive organ1（fro1）和pistilloid-stamen（ps-2）。fro1突变体内外稃闭合,抽穗但不开花;4轮器官结构及数目近正常,但内外稃片抱合扭曲成辣椒状,雌雄蕊发育不完全,无花粉形成,雌蕊不育。ps-2突变体类似Luo等（2006）报道的ps突变体：颖花开裂,内外颖片变窄、变硬,外颖弯曲,但ps只有1-5枚雄蕊转化成雌蕊,而ps-2有5-6枚雄蕊转化成雌蕊,仅有极少数突变颖花留有1枚未转变的雄蕊,突变体雌蕊状结构10个以上,不能结实。通过对突变体fro1和ps-2分别与野生型明恢86正反杂交,与R527、93-11和中花16的杂交后代表型分离规律分析表明：突变体fro1和ps-2是分别由一对隐性基因控制的突变体,其中fro1的F2后代表型分离比均符合3：1,大部分ps-2的F2后代表型分离比偏离3：1。进一步分析fro1和ps-2双突变体的遗传和表型发现：fro1和ps-2基因不等位,是两个独立遗传的基因。植株生活力受纯合ps-2基因的影响,但不受纯合fro1基因的影响。双突变体的内外稃片结构及开裂特征似ps-2,而内外稃包合状与fro1近似,雄蕊仍表现雌化,但数目明显减少。fro1和ps-2双突变体的表型特征暗示了ps-2和fro1间存在一定的互作。
