Alpha-lead dioxide was deposited by anodization of alkaline solution containing HPbO2- anions. Scanning electron microscopy (SEM) results show that the morphology is remarkably affected by the current density, concent...Alpha-lead dioxide was deposited by anodization of alkaline solution containing HPbO2- anions. Scanning electron microscopy (SEM) results show that the morphology is remarkably affected by the current density, concentration of HPbO2- anions, bath temperature and electroplating time. Compact and well adherent layers are possibly obtained under conditions of current densities ≤3 mA/cm2, electrolyte containing 4 mol/L NaOH and 0.12-0.14 mol/L lead (Ⅱ ), bath temperature of 40 ℃, and electroplating time of 2 h. EDS analyses show that the PbO2 deposited in alkaline condition is highly non-stoichiometric at high current density.展开更多
This study investigated the effectiveness of aluminum modified diatomite in removing lead from aqueous solution. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray Fluorescence (XRF) and infrared spect...This study investigated the effectiveness of aluminum modified diatomite in removing lead from aqueous solution. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray Fluorescence (XRF) and infrared spectroscopy were used to characterize the modified absorbents. Effects of several variables like pH, adsorbent dose, initial concentration and the reaction temperature on lead sorption were also investigated. Langmuir and Freundlich isotherm models were applied to describe the equilibrium data. Values of △H, △G and △S illustrated that the adsorption of lead is an endothermic process of nature. Comparing with the natural diatomite, the adsorption efficiency for the lead ions increased from 12.06% to 61.36% which indicated that aluminum modified diatomite can be used as a potential absorbent for lead ions.展开更多
基金Project(20050053) supported by Foundation for the Author of National Excellent Doctoral Dissertation of China
文摘Alpha-lead dioxide was deposited by anodization of alkaline solution containing HPbO2- anions. Scanning electron microscopy (SEM) results show that the morphology is remarkably affected by the current density, concentration of HPbO2- anions, bath temperature and electroplating time. Compact and well adherent layers are possibly obtained under conditions of current densities ≤3 mA/cm2, electrolyte containing 4 mol/L NaOH and 0.12-0.14 mol/L lead (Ⅱ ), bath temperature of 40 ℃, and electroplating time of 2 h. EDS analyses show that the PbO2 deposited in alkaline condition is highly non-stoichiometric at high current density.
文摘This study investigated the effectiveness of aluminum modified diatomite in removing lead from aqueous solution. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray Fluorescence (XRF) and infrared spectroscopy were used to characterize the modified absorbents. Effects of several variables like pH, adsorbent dose, initial concentration and the reaction temperature on lead sorption were also investigated. Langmuir and Freundlich isotherm models were applied to describe the equilibrium data. Values of △H, △G and △S illustrated that the adsorption of lead is an endothermic process of nature. Comparing with the natural diatomite, the adsorption efficiency for the lead ions increased from 12.06% to 61.36% which indicated that aluminum modified diatomite can be used as a potential absorbent for lead ions.
