Theoretical Foundations of Chemical Engineering最新文献

A technology is proposed for processing of apatite concentrates by decomposition by phosphoric acid at 20°C in the presence of a sulfonic cation-exchange resin, defluorination of the obtained phosphoric acid, desorption of the sorbed cations with concentrated solutions of alkali metal salts, sequential hydrolytic precipitation of the thorium-enriched impurity cake and nonradioactive concentrate of carbonates of rare-earth and alkaline-earth elements, and regeneration of the sulfonic cation cation-exchange resin from the Na⁺ form to the H⁺ form. It is shown that the technology is also applicable for the processing of apatite concentrate with a high content of rare-earth elements and strontium. The technology ensures the recovery of all valuable components into commercial products while minimizing the consumption of reagents and energy, the amount of generated waste, and the environmental pollution.

Kinetic Monte Carlo modeling was employed as a powerful tool to kinetically investigate of ibuprofen removal by direct ozonation (O₃ alone) and heterogeneous catalytic ozonation (graphene oxide and graphene oxide loaded with Fe₃O₄). The kinetic mechanisms and the values of rate constants for each step of the suggested mechanisms were found by Monte Carlo simulation. The graphene oxide loaded with Fe₃O₄ displays a significant role as a heterogeneous catalyst in the ozonation of ibuprofen by enhancing the reactivity of ibuprofen drug and O₃ on the graphene oxide surface. Optimized values of catalysts and O₃ were attained through obtaining the effect of initial O₃ and catalyst amounts on the rate of ibuprofen elimination utilizing kinetic Monte Carlo simulation. The simulation outcomes of the present investigation demonstrate satisfactory agreement with the experimental ozonation data for the systems above.

Data on the crystallization of the basic magma and its intrachamber and intrapocket (deep-seated) differentiations are given. Problems of the genesis of stratiform anorthosites are considered.

The present investigation pertains to a theoretical study of mathematical model for methane steam reforming in membrane reactor, by simulating the operating variables of the reactor for high hydrogen yield and methane conversion. Basically, it deals with the development of the mathematical model of a fluidized bed Auto thermal membrane reactor (without integrated O₂ perm-selective membranes), by using the mass balance macroscopically. Model is validated with the available experimental data in the literature and was found that the prediction from the models is in excellent agreement with the experimental values, with a maximum deviation of –12 to +13% and –12 to +1.8% for methane gas conversion and hydrogen yield, respectively. Finally, it investigates the effect of operating variables namely, reactor pressure, temperature, and steam to methane ratio (SMR) and permeates side pressure, on the methane gas conversion and hydrogen. The prediction reveals that the hydrogen yield and methane conversion increases with increase in reactor temperature and pressure whereas decreases with increase in SMR and permeate side pressure.

The oxidative dehydropolycondensation of aniline production waste with up to 30 wt % free aniline with ammonium persulfate or potassium bichromate has been studied. The effects of the component ratio and synthesis conditions on the product yield were examined. The product composition was analyzed by IR spectroscopy. The polymers obtained from potassium bichromate were shown to be characterized by electric conductivity.

An earthquake-resistant brick of M150–M175 grade is obtained from a low-alumina (Al₂O₃) < 15%) fusible clay and a high-alumina (Al₂O₃ > 60%) nanotechnogenic aluminoalkaline sludge. The use of the aluminoalkaline sludge even in the amount of 20% enhances the performance characteristics of the ceramic brick to the M125 grade; the optimum amount of the aluminoalkaline sludge to be used is at most 30%. The crystallization of hematite, anorthite, diopside, and crystobalite is observed when the temperature of burning of the ceramic samples is 1000°C. The increase in the burning temperature to 1050°C results in no specific changes, except for an increase in the content of crystobalite, anorthite, glass phase, and diopside. A further increase in the temperature of burning of the aseismic brick to 1100°C favors the emergence of mullite, which increases the main physicomechanical and chemical characteristics of the aseismic brick.

In this work, the [2 + 2] cycloaddition of fullerenes with the carcinogen BaPe was examined using the DFT method, with the aim of inhibiting the carcinogenic process of the latter. The increase in the electrophilic character of the reagents by the functionalization with electron-withdrawing groups was shown. By the functionalization of C₆₀, an increase in the dipole moment and consequently in the solubility of these reagents was shown. Also, a significant improvement in this solubility for these reagents by the [2 + 2] cycloaddition with BaPe increasing the dipole moment was noted. The most favored electrophilic-nucleophilic interaction between C2 and C3 has been rationalized. In the gaseous phase, very asynchronous concerted mechanisms by functionalization were demonstrated for this type of fullerene cycloaddition. In addition, an insufficiency of the calculations for the prediction of the inhibition of the mutagenic process by forming the C₆₀CONH₂–2.5BaPe complex (the major product) was noted and therefore the inclusion of the effects of biological solvent (water) was mandatory. In the presence of water, a significant decrease in the activation barriers and reaction energies compared to those of the gaseous phase was shown, therefore, a kinetic and thermodynamic preference of the C₆₀CONH₂–2.5BaPe complex from this cycloaddition, is deduced.