通过溶液法合成不同钙硅比C-S-H凝胶,并借助X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscopy,SEM)、透射电子显微镜(transmission electron microscopy,TEM)、电感耦合等离子发射光谱(inductively coup...通过溶液法合成不同钙硅比C-S-H凝胶,并借助X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscopy,SEM)、透射电子显微镜(transmission electron microscopy,TEM)、电感耦合等离子发射光谱(inductively coupled plasmaatomic emission spectrometry,ICP-AES)等测试技术,研究了C-S-H凝胶对Pb2+的固化能力及其长期稳定性.研究结果表明:水化液相多种重金属离子共存下C-S-H对Pb2+俘获能力与Pb2+以单一离子存在时有较大差异;且C-S-H钙硅比不同,其对Pb2+俘获机制及俘获能力不同.水化液相中Pb2+的质量分数较低时,C-S-H对Pb2+俘获能力较高;水化液相中Pb2+的质量分数较高时,不同钙硅比C-S-H对Pb2+俘获能力存在明显区别,C-S-H(Ⅰ)对Pb2+俘获能力显著降低;而多种重金属离子共存时,C-S-H对Pb2+俘获能力有所增强.随水化龄期延长(约210 d),不同钙硅比C-S-H对Pb2+俘获能力有不同程度变化.冻融循环作用对低钙硅比C-S-H对Pb2+固化能力有较大影响,且在冻融循环及氯盐侵蚀复合作用下,C-S-H凝胶对Pb2+俘获能力有显著降低.展开更多
The transfer of Pb2+ facilitated by interfacial complexation with 5-(4-phenoxyphenyl)-6H-1,3,4-thiadiazin-2-amine(PPTA) at the polarized water/1,2-dicholoroethane(1,2-DCE) interface was investigated by cyclic voltamme...The transfer of Pb2+ facilitated by interfacial complexation with 5-(4-phenoxyphenyl)-6H-1,3,4-thiadiazin-2-amine(PPTA) at the polarized water/1,2-dicholoroethane(1,2-DCE) interface was investigated by cyclic voltammetry.We synthesized the thiadiazine derivative,PPTA,firstly.The transfer was performed at different metal concentrations and scan rates,and the obtained voltammetric transfer peaks toward Pb2+ ion over other divalent cations(Zn2+,Co2+,Ni2+,Cd2+,Hg2+,and Cu2+) were reversible.The dependence of the half-wave potentials of the Pb2+ ion on the concentration of PPTA in the organic phase indicates that the ion transfer is facilitated by the formation of 1:2(metal:ligand) complex in the organic phase with the association constant(lgβ2) of(17.1±0.2).展开更多
In the present work,we report a label-free fluorescence turn-on approach for the sensitive and selective sensing of Pb2?.Pyrene with one positive charge was used as the fluorescent probe,and thrombin aptamer(TBA),whic...In the present work,we report a label-free fluorescence turn-on approach for the sensitive and selective sensing of Pb2?.Pyrene with one positive charge was used as the fluorescent probe,and thrombin aptamer(TBA),which was a G-rich oligonucleotide,was employed to form G-quadruplex with lead(II).When TBA and Pb2?were mixed with lead(II)in an aqueous solution,it was folded into a stable G-quadruplex.Subsequently,a single-stranded nucleic acid-specific nuclease S1 was added.The G-quadruplex stabilized by Pb2?lead(II)had markedly a significant resistant ability to nuclease S1 digestion.However,in the absence of Pb2?lead(II),no quadruplex or less stable quadruplex was formed and TBA was digested by nuclease S1 in 3 min under the optimized experimental conditions.Finally,pyrene probe was mixed with oligonucleotide in Pb2?lead(II).Electrostatic interactions between oligonucleotide(a polyanion)and the probe induced the aggregation of the probe,which in turn produced strong emission of the strong pyrene excimer emission.The intensity of the induced excimer emission was directly proportional to the amount of Pb2?added.Our approach shows good selectivity and sensitivity for the detection of Pb2?with a limit of detection limit as low as 800 nmol/L.展开更多
为了有效去除水中的铅离子,实验制备以MnO2为吸附表面的磁性Fe/Mn纳米复合吸附剂,并进行了吸附实验研究,分析pH、温度等参数对吸附的影响.结果发现,从298 K Langmuir等温吸附曲线可以计算出Fe/Mn复合吸附剂对Pb2+的饱和吸附量(Q0=118.06...为了有效去除水中的铅离子,实验制备以MnO2为吸附表面的磁性Fe/Mn纳米复合吸附剂,并进行了吸附实验研究,分析pH、温度等参数对吸附的影响.结果发现,从298 K Langmuir等温吸附曲线可以计算出Fe/Mn复合吸附剂对Pb2+的饱和吸附量(Q0=118.06 mg/L).复合吸附剂对Pb2+的吸附总量正比于pH(1.5～5)和温度(303～323 K).在研究纳米复合材料对铅离子的吸附动力学实验中发现,纳米复合材料和铅离子之间的吸附动力学符合假二级模型,通过相关热力学研究计算得到纳米材料和铅离子之间为吸热反应.展开更多
基金supported by the Scientific Research Fund of Selcuk University, Turkey (BAP-07201027)
文摘The transfer of Pb2+ facilitated by interfacial complexation with 5-(4-phenoxyphenyl)-6H-1,3,4-thiadiazin-2-amine(PPTA) at the polarized water/1,2-dicholoroethane(1,2-DCE) interface was investigated by cyclic voltammetry.We synthesized the thiadiazine derivative,PPTA,firstly.The transfer was performed at different metal concentrations and scan rates,and the obtained voltammetric transfer peaks toward Pb2+ ion over other divalent cations(Zn2+,Co2+,Ni2+,Cd2+,Hg2+,and Cu2+) were reversible.The dependence of the half-wave potentials of the Pb2+ ion on the concentration of PPTA in the organic phase indicates that the ion transfer is facilitated by the formation of 1:2(metal:ligand) complex in the organic phase with the association constant(lgβ2) of(17.1±0.2).
基金supported by the National Natural Science Foundation of China(50905071)National Science & Technology Pillar Programme(2009156)
文摘In the present work,we report a label-free fluorescence turn-on approach for the sensitive and selective sensing of Pb2?.Pyrene with one positive charge was used as the fluorescent probe,and thrombin aptamer(TBA),which was a G-rich oligonucleotide,was employed to form G-quadruplex with lead(II).When TBA and Pb2?were mixed with lead(II)in an aqueous solution,it was folded into a stable G-quadruplex.Subsequently,a single-stranded nucleic acid-specific nuclease S1 was added.The G-quadruplex stabilized by Pb2?lead(II)had markedly a significant resistant ability to nuclease S1 digestion.However,in the absence of Pb2?lead(II),no quadruplex or less stable quadruplex was formed and TBA was digested by nuclease S1 in 3 min under the optimized experimental conditions.Finally,pyrene probe was mixed with oligonucleotide in Pb2?lead(II).Electrostatic interactions between oligonucleotide(a polyanion)and the probe induced the aggregation of the probe,which in turn produced strong emission of the strong pyrene excimer emission.The intensity of the induced excimer emission was directly proportional to the amount of Pb2?added.Our approach shows good selectivity and sensitivity for the detection of Pb2?with a limit of detection limit as low as 800 nmol/L.
文摘为了有效去除水中的铅离子,实验制备以MnO2为吸附表面的磁性Fe/Mn纳米复合吸附剂,并进行了吸附实验研究,分析pH、温度等参数对吸附的影响.结果发现,从298 K Langmuir等温吸附曲线可以计算出Fe/Mn复合吸附剂对Pb2+的饱和吸附量(Q0=118.06 mg/L).复合吸附剂对Pb2+的吸附总量正比于pH(1.5～5)和温度(303～323 K).在研究纳米复合材料对铅离子的吸附动力学实验中发现,纳米复合材料和铅离子之间的吸附动力学符合假二级模型,通过相关热力学研究计算得到纳米材料和铅离子之间为吸热反应.
