We report on the use of titanium dioxide nanoparticles (NPs) coated with poly-thiophene for the preconcentration of copper and silverions. The NPs were prepared by first modifying the surface of TiO2 NPs with vinyl gr...We report on the use of titanium dioxide nanoparticles (NPs) coated with poly-thiophene for the preconcentration of copper and silverions. The NPs were prepared by first modifying the surface of TiO2 NPs with vinyl groups and then copolymerizing them with vinyl thiophen. The resulting TiO2-polythiophene core-shell NPs were characterized by thermogravimetry, differential thermal analysis, scanning electron microscopy, Fourier transform infrared spectrometry and X-ray diffraction. The experimental conditions such as pH value, adsorption and desorption time, type, concentration and volume of the eluent, break through volume, and effect of potentially interfering ions were optimized. The ions were then desorbed with hydrochloric acid and determined by FAAS. The limits of detection are 0.4 and 1.2 μg·L_1 for Cu(II) and Ag(I), respectively, and recoveries and precisions are >98.0%展开更多
A kinetic procedure for determination of trace silver was established based on the catalytic effect of Ag(Ⅰ) on the ligand substitution reaction between hexacyanoferrate (Ⅱ) and urea in acidic medium under the optim...A kinetic procedure for determination of trace silver was established based on the catalytic effect of Ag(Ⅰ) on the ligand substitution reaction between hexacyanoferrate (Ⅱ) and urea in acidic medium under the optimized conditions of [hexacyanoferrate]=8.0×10 -4 mol·L -1 , [CO(NH 2) 2]=6.0×10 -4 mol·L -1 , [CH 3COOH]=0.12 mol·L -1 , 80℃, 720 nm. The calibration curve is linear for 10～100 ng·ml -1 , and the detection limit is 0.4 ng·ml -1 Ag. The active energy of catalytic reaction is 18.12 kJ·mol -1 . The selectivity of this procedure is much better than that of other kinetic methods. Equal amount of mercury does not interfere with the determination of silver, and its sensitivity was also improved.展开更多
The purpose of the investigation is the study of the physico-chemical properties and electro-catalytic characteristics of the Nafion and MF-4SK membranes with the author’s nanoparticles (A. Revina, 2008) incorporated...The purpose of the investigation is the study of the physico-chemical properties and electro-catalytic characteristics of the Nafion and MF-4SK membranes with the author’s nanoparticles (A. Revina, 2008) incorporated into the perfluoro- sulphonated cationic membranes. An important advance in the creation of new nano-composite materials with poly-functional activity is the inclusion of nanoparticles of various metals (Pd, Pt, Ag) in these membranes. Polymer ion exchange membranes represent widely applicable materials in various areas of modern nanotechnologies. The obtained nanocomposites on the base of included nanoparticles have the perspective properties and polyfunctional activity for the applications.展开更多
Silver Diamine Fluoride (SDF) is colorless and alkaline with a pH of 10. It has been used in Japan and other international countries for decades. The Food and Drug Administration gave approval for it as a means of tre...Silver Diamine Fluoride (SDF) is colorless and alkaline with a pH of 10. It has been used in Japan and other international countries for decades. The Food and Drug Administration gave approval for it as a means of treating hypersensitivity for individuals with chronic teeth pain. SDF is also used as a method to treat and arrest dental caries. SDF application is limited due to its negative esthetic effects, which is a black stain where the cavity was present on the tooth. Topical application of potassium iodide applied immediately after SDF has been shown in studies to reduce the color change caused by SDF. This study used topical application of silver diamine fluoride (SDF) and potassium iodide (KI) treatments on bovine teeth to determine if SDF and KI were efficacious in the treatment for carious lesions. The color change was detected by use of spectrophotometric analysis to determine L, a and b readings that demarcate light and color values following staining. The conclusion was made that the application of SDF followed directly by KI treatment produced L, a and b spectrophotometric values that indicated a significant reduction in teeth staining than the application of SDF alone. Therefore, this study supports the idea that SDF and KI can be used to treat carious lesions on bovine teeth while retaining surface enamel coloration.展开更多
文摘We report on the use of titanium dioxide nanoparticles (NPs) coated with poly-thiophene for the preconcentration of copper and silverions. The NPs were prepared by first modifying the surface of TiO2 NPs with vinyl groups and then copolymerizing them with vinyl thiophen. The resulting TiO2-polythiophene core-shell NPs were characterized by thermogravimetry, differential thermal analysis, scanning electron microscopy, Fourier transform infrared spectrometry and X-ray diffraction. The experimental conditions such as pH value, adsorption and desorption time, type, concentration and volume of the eluent, break through volume, and effect of potentially interfering ions were optimized. The ions were then desorbed with hydrochloric acid and determined by FAAS. The limits of detection are 0.4 and 1.2 μg·L_1 for Cu(II) and Ag(I), respectively, and recoveries and precisions are >98.0%
文摘A kinetic procedure for determination of trace silver was established based on the catalytic effect of Ag(Ⅰ) on the ligand substitution reaction between hexacyanoferrate (Ⅱ) and urea in acidic medium under the optimized conditions of [hexacyanoferrate]=8.0×10 -4 mol·L -1 , [CO(NH 2) 2]=6.0×10 -4 mol·L -1 , [CH 3COOH]=0.12 mol·L -1 , 80℃, 720 nm. The calibration curve is linear for 10～100 ng·ml -1 , and the detection limit is 0.4 ng·ml -1 Ag. The active energy of catalytic reaction is 18.12 kJ·mol -1 . The selectivity of this procedure is much better than that of other kinetic methods. Equal amount of mercury does not interfere with the determination of silver, and its sensitivity was also improved.
文摘The purpose of the investigation is the study of the physico-chemical properties and electro-catalytic characteristics of the Nafion and MF-4SK membranes with the author’s nanoparticles (A. Revina, 2008) incorporated into the perfluoro- sulphonated cationic membranes. An important advance in the creation of new nano-composite materials with poly-functional activity is the inclusion of nanoparticles of various metals (Pd, Pt, Ag) in these membranes. Polymer ion exchange membranes represent widely applicable materials in various areas of modern nanotechnologies. The obtained nanocomposites on the base of included nanoparticles have the perspective properties and polyfunctional activity for the applications.
文摘Silver Diamine Fluoride (SDF) is colorless and alkaline with a pH of 10. It has been used in Japan and other international countries for decades. The Food and Drug Administration gave approval for it as a means of treating hypersensitivity for individuals with chronic teeth pain. SDF is also used as a method to treat and arrest dental caries. SDF application is limited due to its negative esthetic effects, which is a black stain where the cavity was present on the tooth. Topical application of potassium iodide applied immediately after SDF has been shown in studies to reduce the color change caused by SDF. This study used topical application of silver diamine fluoride (SDF) and potassium iodide (KI) treatments on bovine teeth to determine if SDF and KI were efficacious in the treatment for carious lesions. The color change was detected by use of spectrophotometric analysis to determine L, a and b readings that demarcate light and color values following staining. The conclusion was made that the application of SDF followed directly by KI treatment produced L, a and b spectrophotometric values that indicated a significant reduction in teeth staining than the application of SDF alone. Therefore, this study supports the idea that SDF and KI can be used to treat carious lesions on bovine teeth while retaining surface enamel coloration.
