Thermogravimetry was used to study the non-isothermal decomposition kinetics and the stability of porphyrin copper-sodium from ephedra. The kinetic equation for the second step can be expressed as . The kinetic compe...Thermogravimetry was used to study the non-isothermal decomposition kinetics and the stability of porphyrin copper-sodium from ephedra. The kinetic equation for the second step can be expressed as . The kinetic compensation effect is found to be: InA=0. 2468E a ?8. 0513.Ea is 206. 61 kJ/mol. The results show that porphyrin copper-sodium has a high activation energy and good stability.展开更多
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
The formation of undersaturated lead or iodide ions and I_(2) on the perovskite surface can decrease the performance and stability of perovskite solar cells(PSCs).Additionally,the leakage of noxious lead limits the ap...The formation of undersaturated lead or iodide ions and I_(2) on the perovskite surface can decrease the performance and stability of perovskite solar cells(PSCs).Additionally,the leakage of noxious lead limits the application of PSCs.Here,we develop a strategy for molecular modulation of a perovskite surface using thiol copper(Ⅱ)porphyrin(CuP)to post-treat the perovskite film.展开更多
Acid mine drainage is wastewater from a mine having a low pH and an elevated level of dissolved heavy metals. These metals are harmful to aquatic, animal and human life. This paper looks at the removal of copper from ...Acid mine drainage is wastewater from a mine having a low pH and an elevated level of dissolved heavy metals. These metals are harmful to aquatic, animal and human life. This paper looks at the removal of copper from acid mine drainage using ion exchange to less than 1 mg/l. A weak acidic cation resin was used. Spectrophotometric determination of copper with sodium diethyldithiocarbamate was used to determine the copper concentrations in the treated water. Using regression analysis, the experimental results gave a correlation coefficient of 0.977 and a coefficient of determination of 99.5%. Results indicated that the higher the flows rate the shorter the period after which the copper concentration in the treated water reaches 1 mg/l. At pH 3.85 and 5.09, the resin performed better and at pH above 6.62 and between pH 3.0 and below the resin’s does not perform well. The higher the resin height the greater is the resin exchange capacity and the longer it takes for the copper concentration to reach 1 mg/l in the treated water. The higher the wastewater copper concentration the shorter the time it takes the resin to reach 1 mg/l. The results for this experiment indicated that acid mine drainage can be treated well by ion exchange resins, but it is also very important to establish suitable operating conditions.展开更多
Spectrophotometry usually has a high sensitivity in determining the complexation of TAPP with metal ions. Therefore, as an excellent color-producing reagent, TAPP has already been used for the spectrophotometric deter...Spectrophotometry usually has a high sensitivity in determining the complexation of TAPP with metal ions. Therefore, as an excellent color-producing reagent, TAPP has already been used for the spectrophotometric determination of trace amounts of mercury (Ⅱ), cobalt (Ⅱ), manganese(Ⅱ), zinc (Ⅱ) and cadmium (Ⅱ)etc..展开更多
A novel kinetic procedure for determination of trace copper was proposed based on the catalytic effect of Cu 2+ on the aerial oxidation of gallocyanine (GC), by which GC was oxidized and a colourless product was ...A novel kinetic procedure for determination of trace copper was proposed based on the catalytic effect of Cu 2+ on the aerial oxidation of gallocyanine (GC), by which GC was oxidized and a colourless product was produced. The reaction was monitored spectrophotometrically in hexamethylene tetramine hydrochloric acid buffer solution. The calibration graph is linear for 0.05～0.5 μg/ml, and the detection limit is 0 02 μg/ml (Cu 2+ ). The selectivity for copper is satisfied as the interferences of Fe 3+ and Al 3+ could be easily and effectively eliminated by the addition of NH 4HF 2. The method was applied to the determination of copper in soil, tap water and simulated water samples, and the results were satisfactory.展开更多
The present paper describes the preparation of new organic reagent 2-[2-（6-chloro benzothiazolyl） azo]-resorcinol （6-CIBTAR = LH2） and used for the spectrophotometric determination of traces microgram amount of ni...The present paper describes the preparation of new organic reagent 2-[2-（6-chloro benzothiazolyl） azo]-resorcinol （6-CIBTAR = LH2） and used for the spectrophotometric determination of traces microgram amount of nickel （II） and copper （II） was found to form Ni（II）-CIBTAR at pH 7.5 giving a green coloured complex with maximum absorption at wavelength 636 nm and copper （II） was found to from Cu（II）-CIBTAR at pH 6.5 giving green bluish coloured complex with maximum absorption at wavelength 648 nm. The molar absorptivity （~） of the complexes are 0.3695 ~ 104 L.moll-cml and 0.3933 ~ 154 L＇mol＇l.cm1 for Ni（II） and Cu（II） respectively. Calibration curves for the determination of nickel（II） and copper （II） conformed to beers law over the concentration rang of （1-20） μg.mL-1. The DL （detection limit）, RSD （relative standard deviations）, RE （relative errors） and recovery for Ni（II） and Cu（II） complexes were found to be D.L = 0.45, 0.61; R.S.D% = 1.81, 2.04; Erei% = 1.3, 0.86 and Re% = 98.7, 99.14 respectively. The analytical data show the metal to reagent ratio （mole ratio method; M：L） in Ni（II） and Cu（II） complexes are 1：2.展开更多
A novel chromogenic reaction involving copper（Ⅱ） and bromosulphonazo Ⅲ （Br-SAZⅢ） in hexamethylenetetramine- hydrochloric buffer solution was investigated. The results showed that a blue complex of copper（Ⅱ） ...A novel chromogenic reaction involving copper（Ⅱ） and bromosulphonazo Ⅲ （Br-SAZⅢ） in hexamethylenetetramine- hydrochloric buffer solution was investigated. The results showed that a blue complex of copper（Ⅱ） and bromosulphonazo Ⅲ was formed with a molar ratio of 1：1. The apparent molar absorptivity was 3.3×10^5Lmol-1cm-1 and the maximum absorption peak was at 616.8 nm. The proposed procedure was used for quantitative estimation of Cu（II） in the concentration range of 0-1.024μg/mL with the detection limit （3σ） of 7.03 × 10^-4 μg/mL （n = 20）. The relative standard deviations （RSDs） were 0.56-4.68%. Under the optimized conditions, total copper in the vegetables and tea was successfully determined. 2007 Li Yuan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At ...A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.展开更多
A new pyridine derivative ligand, (E)-(Pyridine-2-ylmethylidene) ({2-(E)-(Pyridine-2-ylmethylidene) amino] ethyl} has been synthesized and kf value of it’s complexes with Cu2+, Ni2+, Cd2+, Zn2+, Co2+, Hg2+ and Ag+ ha...A new pyridine derivative ligand, (E)-(Pyridine-2-ylmethylidene) ({2-(E)-(Pyridine-2-ylmethylidene) amino] ethyl} has been synthesized and kf value of it’s complexes with Cu2+, Ni2+, Cd2+, Zn2+, Co2+, Hg2+ and Ag+ has been determined spectrophometrically. The stability of the complexes to vary in acetonitrile solvent was in the order of Cu2+ > Ni2+ > Cd2+ > Zn2+ > Co2+ > Hg2+ > Ag+, thus because this ligand have good selectivity to copper ion, a simple, reliable and rapid method for preconcentration and determination of the ultratrace amount of copper using octadecyl silica membrane disk modified by this ligand, and determination by flame atomic absorption has been presented. Various parameters including pH of aqueous solution, flow rates, the amount of ligand and the type of stripping reagent were optimized. Under optimum experimental conditions, the breakthrough volume is greater than 2000 ml with an enrichment factor of more than 400 and 0.054 μg×L?1 detection limit. The capacity of the membrane disks modified by 6 mg of the ligand has been found to be330.17 gof copper. The effects of various cationic interferences on the percent recovery of copper ion were studied. The method has been successfully applied for the determination of copper ion in different water samples.展开更多
文摘Thermogravimetry was used to study the non-isothermal decomposition kinetics and the stability of porphyrin copper-sodium from ephedra. The kinetic equation for the second step can be expressed as . The kinetic compensation effect is found to be: InA=0. 2468E a ?8. 0513.Ea is 206. 61 kJ/mol. The results show that porphyrin copper-sodium has a high activation energy and good stability.
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%
基金National Natural Science Foundation of China(no.21801104)and Fundamental Research Funds for the Central Universities(no.lzujbky-2019-sp01).Y.-Y.W.acknowledges funding support from the U.S.Department of Energy(award no.DEFG02-07ER46427).The authors sincerely thank the theoretical calculation support of Prof.Penji Yan from Hexi University of China.
文摘The formation of undersaturated lead or iodide ions and I_(2) on the perovskite surface can decrease the performance and stability of perovskite solar cells(PSCs).Additionally,the leakage of noxious lead limits the application of PSCs.Here,we develop a strategy for molecular modulation of a perovskite surface using thiol copper(Ⅱ)porphyrin(CuP)to post-treat the perovskite film.
文摘Acid mine drainage is wastewater from a mine having a low pH and an elevated level of dissolved heavy metals. These metals are harmful to aquatic, animal and human life. This paper looks at the removal of copper from acid mine drainage using ion exchange to less than 1 mg/l. A weak acidic cation resin was used. Spectrophotometric determination of copper with sodium diethyldithiocarbamate was used to determine the copper concentrations in the treated water. Using regression analysis, the experimental results gave a correlation coefficient of 0.977 and a coefficient of determination of 99.5%. Results indicated that the higher the flows rate the shorter the period after which the copper concentration in the treated water reaches 1 mg/l. At pH 3.85 and 5.09, the resin performed better and at pH above 6.62 and between pH 3.0 and below the resin’s does not perform well. The higher the resin height the greater is the resin exchange capacity and the longer it takes for the copper concentration to reach 1 mg/l in the treated water. The higher the wastewater copper concentration the shorter the time it takes the resin to reach 1 mg/l. The results for this experiment indicated that acid mine drainage can be treated well by ion exchange resins, but it is also very important to establish suitable operating conditions.
基金Supported by the National Natural Science Foundation of China
文摘Spectrophotometry usually has a high sensitivity in determining the complexation of TAPP with metal ions. Therefore, as an excellent color-producing reagent, TAPP has already been used for the spectrophotometric determination of trace amounts of mercury (Ⅱ), cobalt (Ⅱ), manganese(Ⅱ), zinc (Ⅱ) and cadmium (Ⅱ)etc..
文摘A novel kinetic procedure for determination of trace copper was proposed based on the catalytic effect of Cu 2+ on the aerial oxidation of gallocyanine (GC), by which GC was oxidized and a colourless product was produced. The reaction was monitored spectrophotometrically in hexamethylene tetramine hydrochloric acid buffer solution. The calibration graph is linear for 0.05～0.5 μg/ml, and the detection limit is 0 02 μg/ml (Cu 2+ ). The selectivity for copper is satisfied as the interferences of Fe 3+ and Al 3+ could be easily and effectively eliminated by the addition of NH 4HF 2. The method was applied to the determination of copper in soil, tap water and simulated water samples, and the results were satisfactory.
文摘The present paper describes the preparation of new organic reagent 2-[2-（6-chloro benzothiazolyl） azo]-resorcinol （6-CIBTAR = LH2） and used for the spectrophotometric determination of traces microgram amount of nickel （II） and copper （II） was found to form Ni（II）-CIBTAR at pH 7.5 giving a green coloured complex with maximum absorption at wavelength 636 nm and copper （II） was found to from Cu（II）-CIBTAR at pH 6.5 giving green bluish coloured complex with maximum absorption at wavelength 648 nm. The molar absorptivity （~） of the complexes are 0.3695 ~ 104 L.moll-cml and 0.3933 ~ 154 L＇mol＇l.cm1 for Ni（II） and Cu（II） respectively. Calibration curves for the determination of nickel（II） and copper （II） conformed to beers law over the concentration rang of （1-20） μg.mL-1. The DL （detection limit）, RSD （relative standard deviations）, RE （relative errors） and recovery for Ni（II） and Cu（II） complexes were found to be D.L = 0.45, 0.61; R.S.D% = 1.81, 2.04; Erei% = 1.3, 0.86 and Re% = 98.7, 99.14 respectively. The analytical data show the metal to reagent ratio （mole ratio method; M：L） in Ni（II） and Cu（II） complexes are 1：2.
文摘A novel chromogenic reaction involving copper（Ⅱ） and bromosulphonazo Ⅲ （Br-SAZⅢ） in hexamethylenetetramine- hydrochloric buffer solution was investigated. The results showed that a blue complex of copper（Ⅱ） and bromosulphonazo Ⅲ was formed with a molar ratio of 1：1. The apparent molar absorptivity was 3.3×10^5Lmol-1cm-1 and the maximum absorption peak was at 616.8 nm. The proposed procedure was used for quantitative estimation of Cu（II） in the concentration range of 0-1.024μg/mL with the detection limit （3σ） of 7.03 × 10^-4 μg/mL （n = 20）. The relative standard deviations （RSDs） were 0.56-4.68%. Under the optimized conditions, total copper in the vegetables and tea was successfully determined. 2007 Li Yuan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.
文摘A new pyridine derivative ligand, (E)-(Pyridine-2-ylmethylidene) ({2-(E)-(Pyridine-2-ylmethylidene) amino] ethyl} has been synthesized and kf value of it’s complexes with Cu2+, Ni2+, Cd2+, Zn2+, Co2+, Hg2+ and Ag+ has been determined spectrophometrically. The stability of the complexes to vary in acetonitrile solvent was in the order of Cu2+ > Ni2+ > Cd2+ > Zn2+ > Co2+ > Hg2+ > Ag+, thus because this ligand have good selectivity to copper ion, a simple, reliable and rapid method for preconcentration and determination of the ultratrace amount of copper using octadecyl silica membrane disk modified by this ligand, and determination by flame atomic absorption has been presented. Various parameters including pH of aqueous solution, flow rates, the amount of ligand and the type of stripping reagent were optimized. Under optimum experimental conditions, the breakthrough volume is greater than 2000 ml with an enrichment factor of more than 400 and 0.054 μg×L?1 detection limit. The capacity of the membrane disks modified by 6 mg of the ligand has been found to be330.17 gof copper. The effects of various cationic interferences on the percent recovery of copper ion were studied. The method has been successfully applied for the determination of copper ion in different water samples.
