1,721,125 research outputs found
“A Real Adsorbed Solution Theory for the adsorbition of PCE and TCE from aqueous solution”
No full text“Natural and industrial porous material as trichloroethylene sorbents for water depuration”
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"Adsorption of metallic ions from aqueous solutions onto activated carbons: a descriptive model"
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A descriptive model for metallic ions adsorption from aqueous solutions onto activated carbons
No full textThe design of adsorber units is mainly dependent on the equilibrium adsorption capacity of the sorbent in the working conditions. At the moment, these data are available in a limited number of experimental conditions and, for the case of activated carbon, there are no predictive models to assess the adsorption capacity as a function of the process parameters. This makes the adsorber design a complex and approximated task. In this work, a model for the description of metallic ions adsorption onto activated carbon is presented. The model starts from an evaluation of ion speciation and it considers the approach of the multi-component Langmuir model to correlate the metal uptake to the ion concentration in solution. The model has been used to analyse available experimental data on the adsorption of As(V), Cd(II), Cr(III) and Cr(VI) ions on activated carbon. A good matching between experimental results and model predictions has been obtained for all the investigated conditions
Investigation of dry reforming of methane over Mo-based catalysts
No full textAn investigation of methane dry reforming over Mo–Ni based catalysts is carried out in a fixed bed catalytic reactor at different temperatures. Two Mo–Ni catalysts supported on alumina are prepared with 20%Mo–10%Ni and 20%Mo–2%Ni, respectively, in which the nickel is used for its highly resistance at high temperature during dry reforming of methane (DRM) reaction. Experimental results shows that an increase in temperature favours the CH4 conversion and determined a higher H2/CO ratio. A small amount of deposited coke is observed because of the abundant presence of CO2 in the reaction medium and only for 2% Ni catalysts. A kinetic model is proposed for the DRM with Mo–Ni based catalysts, in which the reaction mechanism routes and the operating conditions such as the reaction temperature and the CH4/CO2 molar ratio are accounted for. The results of the mathematical model allow a consistent description of the experimental data, in terms of gas outlet composition. The absence of the methane decomposition reaction, responsible of carbon deposition that is known to lead to catalyst deactivation, is the main result that is adequately predicted by the model
Simultaneous absorption of SO2 and NOx from simulated flue-gas exploiting the enhancing oxidative ability of aqueous euchlorine as scrubbing solution
No full textThis paper reports the performances of a pilot-scale Wet Oxidative Scrubber (WOS) in the treatment of a simulated flue-gas containing 500 ppmv SO2 and 1030 ppmv NOx and operated at 60 °C and 1 atm. The scrubber is fed with an oxidizing solution containing NaClO2 at either 0.75 % or 1 % w/w initially at pH > 9 and then acidified to pH down to 3 with HCl, to obtain the additional oxidative contribution given by euchlorine species during the simultaneous absorption. Further experiments of single-component NOx absorption are performed to better understand the role exerted by SO2 in the simultaneous absorption. These experimental tests are carried out to investigate the effect of the acidity of the chlorite-based scrubbing solution on the simultaneous absorption performance of SO2 and NOx, highlighting the intensification with respect to the bare de-NOx system. Experiments also allow determining the optimal dosages and solution pH for a complete and optimized removal of NOx and SOx also being less energy-intensive. For a scrubbing solution under acid-induced conditions (pH = 3), the retrieved results show that the NaClO2 molar dosage needed for a complete simultaneous removal results 3.6 times greater than the total NOx concentration in the flue-gas. This allows an interesting reduction of 83 % in oxidant consumption and a water-saving of 70 % with respect to the same process applied to the simultaneous NOx absorption but without altering the solution pH. Overall, the results confirm the enhancing role exerted by euchlorine deriving from chlorite acidification and sulfur dioxide presence in the flue-gas
“Rimozione di metalli pesanti da soluzioni acquose mediante adsorbimento su carboni attivi”
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