Synthetic resin, Amberlite XAD-4 was linked covalently with the third generation supramolecule, octa-O-methoxy resorcin [4] arene through -N=N-group to form chelating resin, which has been characterized and effectivel...Synthetic resin, Amberlite XAD-4 was linked covalently with the third generation supramolecule, octa-O-methoxy resorcin [4] arene through -N=N-group to form chelating resin, which has been characterized and effectively used for the separation and preconcentration of metal ions such as Ni(II), Cu(II), Zn(II) and Cd(II). Critical parameters such as pH, flow rate, sorption capacity, breakthrough studies, distribution coefficient, preconcentration factor, concentration of eluting agents responsible for quantitative extraction of metal ions were optimized. The synthesized resin showed good binding affinity towards Ni(II), Cu(II), Zn(II) and Cd(II) under selective pH conditions. Good breakthrough capacity and fast exchange kinetics of the resin lead to effective separation of metal ions from their binary and ternary mixture by column method on the basis of pH and eluting agents. The resin could be reused for about 8 -10 cycles. The proposed method having the analytical data with the relative standard deviation (RSD) 2% and with recoveries of analytes higher than 98%, reflects upon the reproducibility and reliability of the method which has been successfully applied in the separation and determination of Ni(II), Cu(II), Zn(II) and Cd(II) ions in synthetic, natural and ground water samples.展开更多
Scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) and X-ray diffraction (XRD) systems were used to demonstrate the overgrowth of soot to fractal like structure and its subsequent coalescence with...Scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) and X-ray diffraction (XRD) systems were used to demonstrate the overgrowth of soot to fractal like structure and its subsequent coalescence with crystal shaped silicate particles. Sample was obtained from a very clean area of Delhi at a height of 16 m from ground with the help of a five stage cascade impactor in the winters of 2006. Impactor collects particles in five different size ranges (i.e. ≥10.9, 10.9 - 5.4, 5.4 - 1.6, 1.6 - 0.7 and ≤0.7 μm). In the present investigation only the particles collected in the size range 1.6 - 0.7 μm (D50 = 0.980 μm) have been considered. It has clearly been observed that the soot particles tend to grow or rather agglomerate in a fractal like structure. During this process they incorporate other chemically and structurally different particles (crystal silicate in the present investigation) to make multi phase and multi chemical amorphous aggregates. These aggregates are formed during/after its collection on the sampling substrate and may be as many as hundred times more than the expected size interval (D50 or cut off range).展开更多
A simple and quick method for the synthesis of water dispersible stable silver nanoparticles has been developed. Calix[4]pyrrole octahydrazide （CPOH）, has been successfully used as a reducing as well as stabilizing ...A simple and quick method for the synthesis of water dispersible stable silver nanoparticles has been developed. Calix[4]pyrrole octahydrazide （CPOH）, has been successfully used as a reducing as well as stabilizing agent for the synthesis of silver nanoparticles. CPOH-AgNps have been duly characterized by SPR, PSA, TEM and EDX-ray. The ability of CPOH-AgNps as selective and sensitive sensor for various ions （Pb（Ⅱ）, Cd（II）, Mn（Ⅱ）, Fe（Ⅲ）, Ni（Ⅱ）, Zn（Ⅱ）, Hg（Ⅱ）, Co（Ⅱ）, Cu（Ⅱ）） by colorimetry and spectrofluorimetry has been explored. CPOH-AgNps were found to be selective only for Hg（Ⅱ） ions. Nanomolar concentration of Hg（Ⅱ） ions can also be determined by spectrofluorimetry by increase in fluorescence intensity. Linear range of detection of Hg（Ⅱ） ions in water was found to be from 1nmol/L to mol/L. The method has been successfully applied for determination of Hg（Ⅱ） ions in ground water and industrial effluent waste water samples.展开更多
文摘Synthetic resin, Amberlite XAD-4 was linked covalently with the third generation supramolecule, octa-O-methoxy resorcin [4] arene through -N=N-group to form chelating resin, which has been characterized and effectively used for the separation and preconcentration of metal ions such as Ni(II), Cu(II), Zn(II) and Cd(II). Critical parameters such as pH, flow rate, sorption capacity, breakthrough studies, distribution coefficient, preconcentration factor, concentration of eluting agents responsible for quantitative extraction of metal ions were optimized. The synthesized resin showed good binding affinity towards Ni(II), Cu(II), Zn(II) and Cd(II) under selective pH conditions. Good breakthrough capacity and fast exchange kinetics of the resin lead to effective separation of metal ions from their binary and ternary mixture by column method on the basis of pH and eluting agents. The resin could be reused for about 8 -10 cycles. The proposed method having the analytical data with the relative standard deviation (RSD) 2% and with recoveries of analytes higher than 98%, reflects upon the reproducibility and reliability of the method which has been successfully applied in the separation and determination of Ni(II), Cu(II), Zn(II) and Cd(II) ions in synthetic, natural and ground water samples.
文摘Scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) and X-ray diffraction (XRD) systems were used to demonstrate the overgrowth of soot to fractal like structure and its subsequent coalescence with crystal shaped silicate particles. Sample was obtained from a very clean area of Delhi at a height of 16 m from ground with the help of a five stage cascade impactor in the winters of 2006. Impactor collects particles in five different size ranges (i.e. ≥10.9, 10.9 - 5.4, 5.4 - 1.6, 1.6 - 0.7 and ≤0.7 μm). In the present investigation only the particles collected in the size range 1.6 - 0.7 μm (D50 = 0.980 μm) have been considered. It has clearly been observed that the soot particles tend to grow or rather agglomerate in a fractal like structure. During this process they incorporate other chemically and structurally different particles (crystal silicate in the present investigation) to make multi phase and multi chemical amorphous aggregates. These aggregates are formed during/after its collection on the sampling substrate and may be as many as hundred times more than the expected size interval (D50 or cut off range).
基金financial assistance provided by University Grants Commission (New Delhi. India), GUJCOST (Gandhinagar, India)
文摘A simple and quick method for the synthesis of water dispersible stable silver nanoparticles has been developed. Calix[4]pyrrole octahydrazide （CPOH）, has been successfully used as a reducing as well as stabilizing agent for the synthesis of silver nanoparticles. CPOH-AgNps have been duly characterized by SPR, PSA, TEM and EDX-ray. The ability of CPOH-AgNps as selective and sensitive sensor for various ions （Pb（Ⅱ）, Cd（II）, Mn（Ⅱ）, Fe（Ⅲ）, Ni（Ⅱ）, Zn（Ⅱ）, Hg（Ⅱ）, Co（Ⅱ）, Cu（Ⅱ）） by colorimetry and spectrofluorimetry has been explored. CPOH-AgNps were found to be selective only for Hg（Ⅱ） ions. Nanomolar concentration of Hg（Ⅱ） ions can also be determined by spectrofluorimetry by increase in fluorescence intensity. Linear range of detection of Hg（Ⅱ） ions in water was found to be from 1nmol/L to mol/L. The method has been successfully applied for determination of Hg（Ⅱ） ions in ground water and industrial effluent waste water samples.
