在强光照射下,CdS量子点易发生光腐蚀现象,通过金属掺杂和复合的方式可以提高CdS的光催化性能和光稳定性。采用水热法合成了Zn掺杂CdS/g-C_(3)N_(4)复合纳米材料(Zn-CdS/g-C_(3)N_(4))。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、...在强光照射下,CdS量子点易发生光腐蚀现象,通过金属掺杂和复合的方式可以提高CdS的光催化性能和光稳定性。采用水热法合成了Zn掺杂CdS/g-C_(3)N_(4)复合纳米材料(Zn-CdS/g-C_(3)N_(4))。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和傅里叶变换红外光谱(FT-IR)等手段对Zn-CdS/g-C_(3)N_(4)复合材料的形貌、结构和组成等进行了表征。结果表明,Zn-CdS纳米颗粒附着在g-C_(3)N_(4)表面上,从而形成Zn-CdS/g-C_(3)N_(4)复合材料,且复合后材料带隙减小,光生电子-空穴复合率降低。在500 W Xe灯照射下,研究了Zn-CdS/g-C_(3)N_(4)对罗丹明B(RhB)的光催化降解性能。在最优条件下,光照40 min后,所制备的Zn-CdS/g-C_(3)N_(4)对RhB的光催化降解效率达99%。此外,所合成的Zn-CdS/g-C_(3)N_(4)复合材料光稳定性较高、可再生性好。这归因于Zn和Cd的协同作用以及与g-C_(3)N_(4)的复合,促进了光生载流子的分离和转移。展开更多
A capillary electrophoresis (CE) method has been firstly used for the separation of the therapeutically important xanthones from Securidaca inappendiculata. The separation of the nine xanthones was systematically opt...A capillary electrophoresis (CE) method has been firstly used for the separation of the therapeutically important xanthones from Securidaca inappendiculata. The separation of the nine xanthones was systematically optimized with respect to pH, concentration of running buffers, addition of sulfated b-CD, applied voltage and column temperature. Baseline separation was achieved for the nine xanthones in less than 15 minutes using a background electrolyte consisting of 200 mmol/L borate (pH 9.5) and 10 mmol/L sulfated b-CD.展开更多
In the present method a new,simple and rapid spectophotometric FI technique for the accurate and determination of Cd(Ⅱ) in waste water has been developed.The method is based on the decrease of absorbance intensity of...In the present method a new,simple and rapid spectophotometric FI technique for the accurate and determination of Cd(Ⅱ) in waste water has been developed.The method is based on the decrease of absorbance intensity of iodide-butylrhodamine B(BRB+) due to the complexation with Cd(Ⅱ),which is found useful for sensitivity in arabin and OP-emulsion media.The absorption peak of the complexation,which is increased linearly by addition of Cd(Ⅱ),occurs at 608nm.Optimization of chemical and FI variables has been made. Under the optimized conditions,the calibration curve obtained were linear over the range 5μg/L^160μg/L,the detection limit was 2μg/L,and the precision(RSD=0.65%,n=10) was found quite satisfactory.Application of the method to the analysis of Cd(Ⅱ) in tap water,steam water added and waste water resulted a good agreement between the expected and found values.展开更多
文摘在强光照射下,CdS量子点易发生光腐蚀现象,通过金属掺杂和复合的方式可以提高CdS的光催化性能和光稳定性。采用水热法合成了Zn掺杂CdS/g-C_(3)N_(4)复合纳米材料(Zn-CdS/g-C_(3)N_(4))。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和傅里叶变换红外光谱(FT-IR)等手段对Zn-CdS/g-C_(3)N_(4)复合材料的形貌、结构和组成等进行了表征。结果表明,Zn-CdS纳米颗粒附着在g-C_(3)N_(4)表面上,从而形成Zn-CdS/g-C_(3)N_(4)复合材料,且复合后材料带隙减小,光生电子-空穴复合率降低。在500 W Xe灯照射下,研究了Zn-CdS/g-C_(3)N_(4)对罗丹明B(RhB)的光催化降解性能。在最优条件下,光照40 min后,所制备的Zn-CdS/g-C_(3)N_(4)对RhB的光催化降解效率达99%。此外,所合成的Zn-CdS/g-C_(3)N_(4)复合材料光稳定性较高、可再生性好。这归因于Zn和Cd的协同作用以及与g-C_(3)N_(4)的复合,促进了光生载流子的分离和转移。
基金The authors would like to acknowledge Agilent Technologies for providing the capillary electrophoresis system and Bioanalytical System for present of sulfated b-CD. The study is supported by NSFC Grant No. 29875001.
文摘A capillary electrophoresis (CE) method has been firstly used for the separation of the therapeutically important xanthones from Securidaca inappendiculata. The separation of the nine xanthones was systematically optimized with respect to pH, concentration of running buffers, addition of sulfated b-CD, applied voltage and column temperature. Baseline separation was achieved for the nine xanthones in less than 15 minutes using a background electrolyte consisting of 200 mmol/L borate (pH 9.5) and 10 mmol/L sulfated b-CD.
文摘In the present method a new,simple and rapid spectophotometric FI technique for the accurate and determination of Cd(Ⅱ) in waste water has been developed.The method is based on the decrease of absorbance intensity of iodide-butylrhodamine B(BRB+) due to the complexation with Cd(Ⅱ),which is found useful for sensitivity in arabin and OP-emulsion media.The absorption peak of the complexation,which is increased linearly by addition of Cd(Ⅱ),occurs at 608nm.Optimization of chemical and FI variables has been made. Under the optimized conditions,the calibration curve obtained were linear over the range 5μg/L^160μg/L,the detection limit was 2μg/L,and the precision(RSD=0.65%,n=10) was found quite satisfactory.Application of the method to the analysis of Cd(Ⅱ) in tap water,steam water added and waste water resulted a good agreement between the expected and found values.
