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Industrial & Engineering Chemistry Research 01/2012; 51:12310–12320. · 2.24 Impact Factor
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ABSTRACT: The selectivity of nanoporous manganese oxides for some alkali and transition metals over calcium and magnesium was studied. Two tunnel-structured oxides (OMS-1 and OMS-2) were synthesized by means of a hydrothermal route. Competitive uptake of metals and acid was studied using batch kinetic measurements at different metal ion concentrations. The experimental data were correlated with a dynamic model. The results show that the studied OMS materials selectively adsorb Cu, Ni and Cd in the presence of Ca and Mg. It was also found that the exchange rates were reasonably high due to the small particle dimensions. Both materials are stable in the studied conditions and their maximum Cu uptake capacity was 0.9-1.3 mmol/g. The results indicate that both materials have potential for environmental applications involving the uptake of harmful metal ions.
Journal of hazardous materials 08/2010; 180(1-3):234-40. · 4.14 Impact Factor
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ABSTRACT: Use of the chelating adsorbent CuWRAM® in the copper removal step of hydrometallurgical zinc process has been studied. This adsorbent contains 2-(aminomethyl)pyridine groups anchored on a polyamine–silica composite and it binds copper and other transition metals by a chelating adsorption mechanism. Equilibrium binding capacity of metal sulfates and sulfuric acid from synthetic and authentic ZnSO4 process solution was determined at 25–90 °C using batch adsorption measurements. The copper removal efficiency was tested using a laboratory-scale fixed-bed column.Results of the equilibrium measurements show that the selectivity of CuWRAM® is sufficient for feasible separation of copper in the presence of 250-fold zinc excess. Increasing the operation temperature from 25 °C to 60 °C affects only slightly the binding capacity of copper and at the same time decreases the capacity of zinc. In column separation, increasing temperature substantially improves copper removal efficiency from the ZnSO4 process solution. The improvement is mainly due to enhanced intra-particle mass transport. The positive effect is further amplified by marked decrease in viscosity of the feed solution. The optimum temperature for copper removal appears to be around 60 °C. According to the results of this study, copper can be separated from the authentic ZnSO4 solution by the chelating adsorbent, while nickel, cobalt and cadmium must be separated by means of conventional methods like cementation with zinc dust. A process scheme is proposed for the solution purification step in the zinc process.
Hydrometallurgy 104(1):14-19. · 2.03 Impact Factor
