Industrial & Engineering Chemistry Research最新文献

The thermophysical properties of ionic liquids (ILs) are essential for CO₂ capture, yet their optimal modeling approach remains unclear due to complex intermolecular interactions. This work investigates the thermodynamic behavior of imidazolium-based ILs using the PC-SAFT equation in which ILs are modeled as electroneutral ion pairs with electrostatic interactions approximated by association or dipolar terms. Density, heat capacity, vapor pressure, and phase equilibria of IL-CO₂ and IL-water/ethanol are calculated to evaluate model performance. Three parametrization strategies based on different experimental data sets and four modeling schemes with 2 (011), 4 (022), and 10 (055) binding sites, as well as a polar nonassociating model, are examined. The results show that good performance requires simultaneously incorporating density, isobaric heat capacity, and vapor pressure in parameter fitting, and that increasing associating sites does not necessarily improve the accuracy. Analysis of association and dipolar contributions identified the 011 scheme as the most appropriate.

Facing limited lithium supply and rising demand, exploring diverse and economical lithium resources is key to easing pressure. Oilfield brine, with low land and freshwater use for lithium extraction, offers great potential. However, developing stable granular adsorbents with high adsorption capacity and selectivity for oilfield brine with an ultrahigh Na⁺/Li⁺ ratio is highly significant. Herein, hydrophilic polyacrylonitrile (PAN)/ Li_1.33Mn_1.67O₄ (LMO)-based granules were prepared by straightforward nonsolvent-induced phase separation. Meanwhile, polyethylenimine (PEI) was modified to PAN binder and the obtained PANP-LMO granules exhibit a highly interconnected three-dimensional network. The load capacity of LMO reached up to 87%, which was helpful for excellent adsorption performance. Notably, the adsorption capacity reached 17.4 mg/g. Moreover, PANP-LMO showed enhanced selectivity toward Li⁺ (distribution factor K_d = 15006 mL/g) over other coexisting cations, with a separation factor of α_Na^Li = 12695, α_Mg^Li = 5919, surpassing those of previously reported adsorbents. Theoretical calculations indicated that abundant amino groups from PEI effectively improved the selectivity of Li⁺ toward other cations. When used in Zhongyuan oilfield brine, the lithium adsorption efficiency was 98.7%, with the Na⁺/Li⁺ ratio descending to 4.5 from 2,316, the Mg²⁺/Li⁺ ratio descending to 0.1 from 19.5. This suggests that the adsorbent’s performance remained unaffected in the real brine with ultrahigh Mⁿ⁺/Li⁺ ratio. These findings collectively indicate that PANP-LMO granules could present a competitive option for industrial processes.

The growing demand for biodiesel has generated an excess of glycerol as a byproduct. Thus, catalytic conversion of glycerol into value-added products, such as glycerol carbonate (GC), is important. In the present study, Li₂ZrO₃ and different compositions of the lithium–sodium zirconate solid solution (Li_2–xNa_xZrO₃) were tested for GC production from glycerol and dimethyl carbonate transesterification reaction. All the ceramic chemical compositions were synthesized by solid-state reaction and fully characterized. Then, gas chromatography-mass spectroscopy was used to analyze the catalytic reaction products, using as initial and main material Li₂ZrO₃. For lithium zirconate, the best reaction conditions (80 °C and 180 min, using 10 mol % of catalyst and a reagents molar ratio of 1:1.5) evidenced a maximum glycerol conversion of 94.5%, with a yield and selectivity of 92.6 and 98%, respectively, toward glycerol carbonate formation. In addition, the kinetic parameters of this reaction, using Li₂ZrO₃ as the catalyst, were also investigated, revealing that the process followed a pseudo-first-order kinetic model, with an activation energy of 57.07 kJ mol^–1. Additionally, the associated thermodynamic parameters, including enthalpy, entropy, and Gibbs free energy, were also calculated. Based on lithium zirconate results, different Li_2–xNa_xZrO₃ solid solution compositions were catalytically analyzed under the same physicochemical conditions. Results evidenced that GC formation strongly depends on the Li/Na ratio, where optimal yield and selectivity values were achieved for mixed Li-rich compositions, while Na-rich samples promoted side reactions, mainly glycidol formation. Moreover, it was determined that Na addition mainly modified the kinetic behavior, rather than thermodynamic data. Overall, Li_2–xNa_xZrO₃, where (x ≥ 0.8), demonstrated good performance under moderate conditions, making them an attractive option for minimizing the costs associated with reagents and energy requirements.