Ruthenium (Ru)‐based catalysts are widely employed in several types of gas‐solid reactions because of their high catalytic activities. This review provides theoretical research on Ru‐based catalysts and an analys...
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Ruthenium (Ru)‐based catalysts are widely employed in several types of gas‐solid reactions because of their high catalytic activities. This review provides theoretical research on Ru‐based catalysts and an analysis of their basic properties and oxidation behavior. There is particular emphasis on Ru‐catalyzed gas‐solid catalytic reactions, including the catalytic oxidation of VOCs, preferential oxidation of CO, synthesis of ammonia, oxidation of HCl and partial oxidation of CH4. Recent litera‐ture on catalysis is summarized and compared. Finally, we describe current challenges in the field and propose approaches for future development of Ru‐based catalysts.
To recover titanium from tionite, a new process consisting of NaOH hydrothermal conversion, water washing, and H2SO4 leaching for TiO2 preparation was developed. The experimental results show that under the optimum ...
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To recover titanium from tionite, a new process consisting of NaOH hydrothermal conversion, water washing, and H2SO4 leaching for TiO2 preparation was developed. The experimental results show that under the optimum hydrothermal conversion conditions, i.e., 50% NaOH (mass fraction) solution, NaOH/tionite mass ratio of 4:1, reaction temperature of 240 ℃reaction time of 1 h and oxygen partial pressure of 0.25 MPa, the titanium was mainly converted into Na2TiO3, and the conversion was 97.2%. The unwanted product Na2TiSiO5 remained stable in water washing, and its formation was prevented by improving NaOH concentration. In water washing process, about 97.6% of Na+ could be recycled by washing the hydrothermal product. The NaOH solutions could be reused after concentration. 96.7% of titanium in the washed product was easily leached in H2SO4 solution at low temperatures, forming titanyl sulfate solution to further prepare TiO2.
Indirect CO2 mineral sequestration that involves two separate steps,with acetic acid as the recycling medium,was limited by a crystallization conversion of only 20% in the second gas-liquid reactive crystallization **...
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Indirect CO2 mineral sequestration that involves two separate steps,with acetic acid as the recycling medium,was limited by a crystallization conversion of only 20% in the second gas-liquid reactive crystallization *** this paper,the second carbonation step was greatly improved by coupling reactive crystallization and solvent extraction with the introduction of an organic solvent,tributyl phosphate(TBP),to the *** effect of the initial concentration of calcium acetate in the aqueous solution on the crystallization conversion was studied *** obtained calcium conversion was above 40%,which was one time higher than that reported in the *** on the mechanism discussion and thermodynamic equilibrium calculation analysis,it can be concluded that adding TBP to the step can consume the produced acetic acid,and it is in favor of the precipitation of calcium *** the challenge presented by the strong interaction between calcium ions and acetate ions for further improving crystallization conversion cannot be solved only by the addition of TBP.
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