International Journal of Chemical Kinetics最新文献

n-Dodecane, a key component in diesel and aviation fuel, is commonly used to simulate real-world diesel and aviation fuels (Jet-A and Chinese RP-3). Since existing n-dodecane kinetic mechanisms may not fully address the complexities of aromatics formation during combustion, this study proposes a mechanism that not only extends the capability of predicting 16 light-weight aromatics but also provides a compact size with improved accuracy in predicting combustion characteristics. Using a two-step reduction method involving path flux analysis (PFA) and artificial neural network (ANN) without tuning kinetic parameters, the newly constructed mechanism consisting of 155 species and 827 reactions is coupled with a 2-D computational fluid dynamics (CFD) model of a laminar diffusion flame that well reproduces experimentally measured centerline profiles of flame temperature, aromatics and soot volume fraction in combustion of methane doped with n-dodecane. From the results obtained by CFD, we investigate the effect of n-dodecane on the spatial distributions of aromatics and reaction pathways, which have not been analyzed in previous literature.

In this work, we study the characterization of raw clay extracted from Jbel Lahbib Region of Tetouan in the north of Morocco, and organo-modified clay by a cationic surfactant hexadecyltrimethylammonium bromide (CJL + HDTMA). In addition, we evaluate their potential to remove organic pollutants (methyl orange, MO) in aqueous solutions by means of the absorption techniques. All samples were characterized by XRD, FTIR, SEM-EDAX, TGA, BET, and zeta potential. The XRD results show that the principal peak d001 moved from $��14.7�$ to $��23�$ Åfor the modified clay, the specific surface area of the raw and modified clay is 68.28 and 1.47 m²/g, respectively. Furthermore, these results confirm the success of this modification. With raw clay extracted from Jbel Lehbib (CJL), the maximum adsorption capacity of MO is pH-dependent. Consequently, the MO adsorption is favored in the high acidic pH range. The adsorption kinetics of MO on both clays revealed that the equilibrium is rapidly obtained. Moreover, it is shown that the experimental data for MO adsorption on the two materials best fit the pseudo-second-order kinetic model. The adsorption isotherms indicate that the Sips and Temkin models correctly describe the adsorption of MO on the raw with experimental maximum adsorption value of 40.9 and 66.65 mg/g for raw and modified (CJL), respectively. The energy obtained from D-R model (6.9 KJ/mol for raw clay and 12.86 KJ/mol for modified clay) suggested that process is dominated by physisorption for raw clay and chemisorption for modified clay. Besides, the thermodynamic study revealed that MO adsorption by crude clay is exothermic ($��\Delta �H^{\circ }�=�-�2.39�$ KJ/mol), physical, and spontaneous.

The sulfuric acid decomposition reactor is a key component of the iodine-sulfur thermochemical cycle process. The design of the sulfuric acid decomposition reactor requires excellent corrosion resistance and mechanical strength performance. In this work, a patented reactor on a pilot scale was scaled up to an industrial scale. A plant equipment design for an industrial-scale reactor was performed. Based on an integrated inherent safety design approach, it was determined that the optimal thickness was 110 mm, and the design passed all stress analysis tests. With a minimum targeted hydrogen production rate of 1000 kg/h, the process design yielded a reactor with a diameter of 7 m and a height of 30 m, while silicon carbide was chosen as the construction material. The scaled-up reactor was dynamically simulated in MATLAB. Simulink demonstrated that both the reactor temperature and product flow rates successfully produced a stable response within 1.8 and 4 h of operation, respectively.

This work aims to valorize pine cones powder (PCP), an agricultural waste, as a bioadsorbent for the removal of a cationic dye, Rhodamine B (RhB), and hexavalent chromium Cr(VI) from an aqueous solution. The adsorbent was characterized by scanning electron microscopy (SEM), Fourier-transformed infrared (FTIR), and X-ray diffractometer (XRD) spectroscopy. Adsorption studies were carried out in a batch mode under different operating parameters like initial solution pH (2–11), adsorbent dosage (0.025–0.6 g), initial contaminant concentration (20–100 mg/L), temperature (283–328K), contact time (0–120 min), and ionic strength (NaCl, MgCl₂, CuSO₄, Na₂SO₄, and FeCl₃). The optimum conditions for adsorption for Cr(VI) were; ([Cr(VI)] = 30 mg/L, pH = 2, adsorbent dose = 1.5 g/L, T = 25°C), and for RhB: ([RhB] = 30 mg/L, pH = 4.6, adsorbent dose = 4 g/L, T = 25°C). Under these conditions, the maximum adsorption capacities reached were 19.861 and 6.565 mg/g, for Cr(VI) and RhB, respectively. The inhibiting effect of the studied salts on RhB dye and metal ion removal is as follows: FeCl₃ > CuSO₄> MgCl₂> Na₂SO₄> NaCl. The Freundlich isotherm described the best the adsorption of Cr (VI) and RhB onto PCP, since it gave the highest R² values (R² ≥ 0.983) associated with the lowest error values (χ², RMSE, and Δq). The calculated Dubinin–Radushkevich mean energy (E) is less than 8 kJ/mol. It is 3.391 kJ/mol for Cr(VI) and 2.310 kJ/mol for RhB sorption, respectively, confirming the physical character of adsorption onto PCP sorbent. Experimental data for Cr(VI) and RhB ion adsorption onto PCP, fitted well the pseudo-second-order kinetic model (R² ≥ 0.997). According to the thermodynamic analysis, the retention of Cr(VI) and RhB followed a physisorption, endothermic, and spontaneous process at all temperatures for Cr(VI), and at higher temperatures for RhB dye. These results suggest that raw PCP may be envisaged as a promising biosorbent for water remediation without the need of costly heat and activation processes as a cheap and sustainable adsorption process.