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Separation of styrene from ethylbenzene is challenging because of their close boiling points and similar chemical characteristics. In this study, we utilized three ammonium-based deep eutectic solvents (DESs) with glycols as hydrogen bond donors to separate styrene from ethylbenzene via liquid-liquid extraction at room temperature and atmospheric pressure, with styrene concentration in the feed mixture ranging from (10 to 80) wt%. Consistency of the experimental data was ascertained by Othmer-Tobias and Hand correlations, and the NRTL binary interaction parameters were also validated for thermodynamic consistency. Distribution ratios of styrene were found to be comparable to that obtained using ionic liquids, although the selectivity values were much lower. The ternary liquid-liquid equilibria for the systems {ethylbenzene (1) + styrene (2) + DES (3)} were correlated with the NRTL model and predicted using the COSMO-RS approach. The average RMSD from the experimental data for NRTL correlation is 1.41% and for COSMO-RS prediction is 4.74%.

The separation of benzene and cyclohexane from their mixture is difficult to perform via conventional distillation because of their close boiling points. In this work, liquid-liquid extraction using ionic liquids (ILs) is suggested for this purpose and 16 cations and 13 anions were selected to form 208 possible ILs screened with the Conductor-like Screening Model for Real Solvents (COSMO-RS) module. The screening result was experimentally validated by liquid–liquid extraction using four of the top ranked ILs, namely 1-ethyl-3-methylimidazolium acetate ([C2mim][Ac]), 1-ethyl-3-methylimidazolium dicyanamide ([C2mim][N(CN)2]), 1-ethyl-3-methylimidazolium thiocyanate ([C2mim][SCN]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][Tf2N]). The ternary liquid–liquid equilibria for these ILs with benzene and cyclohexane were investigated at 25 °C and 1 atm with feed concentration of benzene ranging from 10 to 60 wt%. Good agreement was achieved between the tie-lines obtained from the COSMO-RS model and those obtained experimentally. The performance of ILs used in this study was compared with organic solvents, other ILs, and deep eutectic solvents reported in literature. The results of selectivity and distribution ratio confirmed that COSMO-RS was a reliable method for solvent screening and demonstrated the suitability of the selected ILs as extracting solvents. In all ternary systems, no IL was detected in the cyclohexane layer and the concentration of cyclohexane in the IL layer was very low. This observation indicated that there was minimum cross-contamination between the phases and therefore less energy will be required for the solvent recovery.

Separation of azeotropic mixtures is a topic of great industrial interest. In this work, liquid-liquid extraction using deep eutectic solvents (DESs) is explored to separate binary azeotropic mixtures of ethanol and n-hexane, n-heptane or n-octane. Ten DESs were screened using the COSMO-RS approach by predicting the activity coefficient at infinite dilution, γ∞ of ethanol and n-alkanes in each DES. Then, three DESs were selected for experimental validation where Tetrabutylammonium bromide/Levulinic acid (TBAB/LA) with a molar ratio (1:2) gave the best extractive performance for all systems. Ternary liquid-liquid extraction experiments were conducted at room temperature with this DES. It was found that the tie-lines of all systems have positive slopes, indicating that a small amount of solvent is required to extract ethanol. Moreover, the distribution ratio and selectivity values are all greater than unity and the DES was not detected in the raffinate phase which indicate minimal cross-contamination between extract and raffinate phases. Finally, COSMO-RS predictions of the ternary tie-lines were in excellent agreement with experimental data, with an average RMSD value of 1.65%. The experimental data were also successfully correlated with NRTL model with an average RMSD value of 1.50%.

The separation of benzene and cyclohexane is considered one of the most challenging processes in the petrochemical industry. For this study, 40 deep eutectic solvents (DESs) were screened by using the COSMO-RS model. The screening was achieved based on a comparison of selectivity, capacity, and the performance index, all derived from the activity coefficient at infinite dilution. In addition, the sigma σ-profile and σ-potential of each component were used to analyse the interactions between the different species during the extraction process. After screening, five DESs were selected for experimental validation. The liquid–liquid extraction process was conducted, and the ternary diagrams were plotted for the selected DESs at 25 °C under atmospheric pressure. The NRTL model was successfully employed to correlate the experimental tie lines. The results revealed that COSMO-RS was a useful tool for screening potential DESs qualitatively. In addition, observations revealed strong agreement between NRTL and the experiment results, with a root mean square deviation of less than unity for all systems. The findings showed that the selected DESs are feasible for use as extracting solvents for this separation, whereby in all systems no trace of DES was found in the cyclohexane layer.

This work investigates the use of deep eutectic solvents (DESs) to extract sulfur-based compounds from n-heptane as model diesel compounds. Four DESs were prepared by combining tetrabutylammonium bromide or methyltriphenylphosphonium bromide with ethylene glycol, triethylene glycol, or sulfolane. All DESs showed good ability to extract thiophene with the best extraction efficiency (35%) being observed for the sulfolane-based DES. The extraction efficiency can be further enhanced to reach 98% when five extraction cycles are performed. Moreover, the DESs were easily regenerated using rotary evaporation. In addition,1H NMR analysis is used to elucidate the extraction mechanism. Finally, the COSMO-RS model was used to predict the ternary tie lines for the studied systems and the NRTL model allowed, correlating the experimental data with an average root-mean-square deviation of

Selected types of deep eutectic solvents (DESs) were compared for designing CO 2 capturing process. Specifically, the typical absorption–desorption process is examined. A mathematical model based on Peng–Robinson equation of state was developed to estimate the CO 2 solubility and to determine the VLE conditions in the desorption unit. The comparison of the DES performance is based on the solvent requirement in the absorption unit and the temperature condition in the desorption unit. Ethanol amine based DES has shown the best performance when operating the absorber at 10 bar and the stripper at 1 bar. However, the simulation results indicate that in order to reduce the energy requirements in the regeneration process a large amount of solvent is needed. In fact, for 80% CO 2 recovery the solvent intake rate should be at least 5 times the flue gas flow rate. Finally, we have shown that (i) the desorption energy required with MEA based DESs is much lower compared to the classical MEA process and that (ii) the energy required for compression remains the most important drawback for a such process, especially at low CO 2 concentrations.

This work aimed to carry out an optimal investigation of the design and operation of a large capacity reverse osmosis (RO) desalination plant powered by wind energy. Different scenarios involving two design options, such as using storage tanks or batteries, and operation options, such as using variable or fixed feed pressure, were analyzed and optimized. In addition, another operation option, of using a fixed number of RO vessels or a varying number of active RO vessels, was also considered. It was found that an optimized plant using storage tanks can provide a less expensive water cost and a less complicated plant structure. Moreover, the use of a variable feed pressure can help in attenuating the disturbances incurred in the form of wind intermittency. Conversely, the use of fixed feed pressure and constantly supplied power per vessel can run the RO units smoothly, leading to a predictable production rate. However, this requires operating the plant on different active sets of vessels each hour, which mandates additional automatic control systems. The water cost when storage tanks are utilized can be as low as 7.42 $/m3, while it is around 19.7 $/m3 when a battery is used.