Synthesis, characterization of nanostructured sulfated Zirconia@silica catalyst using green chemistry and its catalytic application in one pot isomerization of n-alkane

Nano structured sulfated zirconium-sillicon binary oxides were synthesized in different mole-ratios of Zr4±:Si4±, 2:1 (SZS-1), 1:1 (SZS-2) and 1:2 (SZS-3), by a simple precipitation chemical method using green chemistry. The preparation of the catalysts from rice husk that is a waste product is highly exclusive and unique. Evaluation of these catalysts was carried out in a batch reaction system at normal temperature and pressure as well as at high temperature –flow-reactor during the isomerization of n-hexane, n-heptane and n-octane to their corresponding branched isomers. The best performing catalyst (SZS-2) was characterized by TEM, SEM, AFM, FTIR, TG-DTA, BET and small angle XRD. The super acidity of the catalyst was measured by performing ammonia-TPD. From this end, the SZS-2 contains nano particles of ~ 20 nm, presenting an amorphous nature and having no definite surface morphology.  Catalyst evaluation and characterization allowed proposing a reaction mechanism, elucidating a probable role of Bronsted and Lewis acid sites on the studied reaction-catalyst. This catalyst can be effectively used in future to enhance the efficiency of petroleum

Toward the industrial exploitation of the oxidative dehydrogenation of ethane over a NiO-SnO2-based catalyst : regime, parametric sensitivity, and optimization analysis

An industrial-scale catalytic reactor for ethylene productionviathe oxidative dehydrogenation of ethane (ODH-C-2) over ahighly active and selective SnO2-NiO-based catalyst isinvestigated using a pseudo-heterogeneous reactor model (describingboth the gas and solid phase and making use of effective kinetic andtransport coefficients). More particularly, the dominant phenomenaat the micro- and macroscale in a packed-bed reactor configurationwith a low tube-to-particle diameter ratio (d (t)/d (p)) are assessed. First, therelevance of kinetics and transport phenomena on the reactor performanceis determined. The evaluation of the corresponding characteristictimes demonstrated that axial mass dispersion and axial heat transferconduction exert a negligible impact on the concentration and temperatureprofiles obtained in the reactor. Fluid dynamics as well as radialconductive heat transfer mechanisms, on the other hand, must be accountedfor in order to have an accurate simulation of the profiles aroundthe hot spot position. A sensitivity analysis allowed assessing theimpact of the operating conditions on the performance of the industrial-scalereactor. Temperature and concentration, mainly around the hot spot,are highly sensitive to the inlet particle Reynolds number (Re-p), the coolant temperature, and the inlet concentration ofethane and oxygen. Finally, a multi-parametric sensitivity analysiswas used to identify the safety operating window leading to the optimalmacroscopic performance of the reactor: a coolant temperature between410 and 440 & DEG;C, an inlet concentration of ethane from 2 to 4mol %, an inlet concentration of oxygen from 10 to 14 mol %, and aRe(p) from 620 to 1000. Thus, the engineering analysis ledto the development of the most simplified yet comprehensive pseudo-heterogeneousmodel with reduced computational costs, which can be used with confidencein future studies for the industrial implementation of the ODH-C-2 catalytic reaction concept

Cadmium(II), Lead(II) and Copper(II) biosorption on Baker’s yeast (Saccharomyces cerevesiae)

© 2015 American Society of Civil Engineers. The biosorption properties of ethylenediaminetetraacetate (EDTA)-treated biomass of baker's yeast (Saccharomyces cerevisiae) are studied for the removal of Cadmium(Cd), Lead(Pb), and Copper(Cu) from artificially prepared industrial wastewater. The metal ions are chosen for biosorption studies with regard to their availability in industry and potential pollution impact. The optimum biosorption capacity of these metal ions on the biomass is obtained at pH 5. It is observed that the sorption capacity of EDTA-treated biomass increases when the initial concentration of the metal ions is increased. Both Langmuir and Freundlich isotherm models are used to fit experimental biosorption equilibrium data. The maximum biosorption capacity as determined via the Langmuir isotherm is 32.26, 200.0, and 17.24 mg/g for Cd(II), Pb(II), and Cu(II) ions, respectively. The kinetics of biosorption is studied using both pseudo first order and pseudo second order models. Based on a linear regression correlation coefficient, pseudo second order metal uptake rate kinetics is found to give the best fit.status: publishe