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
A blended polymer adsorbent prepared using acrylic acid and polyvinylidene fluoride was used to remove copper from aqueous solutions. The polymer was prepared using thermally induced polymerization and phase inversion...A blended polymer adsorbent prepared using acrylic acid and polyvinylidene fluoride was used to remove copper from aqueous solutions. The polymer was prepared using thermally induced polymerization and phase inversion. The blended polymer was characterized by X-ray diffraction analysis （XRD）, environ- mental scanning electron microscopy （ESEM）, X-ray photoelectron spectroscopy （XPS）, and N2 adsorption/desorption experiments. The sorption data was fit to linearized adsorption isotherms of the Langmuir, Freundlich, and Dubinin-Radushkevich （D-R） isotherms models. The batch sorption kinetics was evaluated using pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetic reaction models. △H0 is greater than 0, AGo is lower than 0, and △S0 is greater than 0, which shows that the adsorption of Cu （Ⅱ） by the blended polymer is a spontaneous, endothermic process. The adsorption isotherm fits better to the Freundlich isotherm model and the pseudo-second-order kinetics model gives a better fit to the batch sorption kinetics. The adsorption mechanism is assumed to be ion exchange between the cupric ion and the carboxylic acid functional group of the blended polymer.展开更多
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A blended polymer adsorbent prepared using acrylic acid and polyvinylidene fluoride was used to remove copper from aqueous solutions. The polymer was prepared using thermally induced polymerization and phase inversion. The blended polymer was characterized by X-ray diffraction analysis （XRD）, environ- mental scanning electron microscopy （ESEM）, X-ray photoelectron spectroscopy （XPS）, and N2 adsorption/desorption experiments. The sorption data was fit to linearized adsorption isotherms of the Langmuir, Freundlich, and Dubinin-Radushkevich （D-R） isotherms models. The batch sorption kinetics was evaluated using pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetic reaction models. △H0 is greater than 0, AGo is lower than 0, and △S0 is greater than 0, which shows that the adsorption of Cu （Ⅱ） by the blended polymer is a spontaneous, endothermic process. The adsorption isotherm fits better to the Freundlich isotherm model and the pseudo-second-order kinetics model gives a better fit to the batch sorption kinetics. The adsorption mechanism is assumed to be ion exchange between the cupric ion and the carboxylic acid functional group of the blended polymer.
