Overview of Activity Coefficient of Thiophene at Infinite Dilution in Ionic Liquids and their Modeling Using COSMO-RS

Ionic liquids (ILs) gained a lot of attention, from both academe and industry, as alternative liquids for different types of applications. Chemical and physical characteristics can be designed with the large availability of cation and anions. Experimental measurement of all these systems is not practically feasible, hence requiring the use of a computational predictive model study. This work evaluates the prediction of the activity coefficient (γ_<i>s</i>^∞) at infinite dilution in several classes of ILs using the conductor-like screening model for real solvents (COSMO-RS), a model based on unimolecular quantum chemistry calculations. Comparison of the experimental γ_<i>s</i>^∞ value with COSMO-RS predicted data is carried out, and absolute average relative deviation was determined to be 24.1%, indicating that the COSMO-RS model presents a reliable prediction to determine γ_<i>s</i>^∞ in a wide range of ILs. The observation also confirms that polarizability of ILs plays a crucial role in their interaction with thiophene. With respect to cation impact, it is more evident to state that γ_<i>s</i>^∞ decreases with increasing the cation size. The results shown here help in understanding of IL–thiophene interactions. The effect of various structural features of ILs on γ_<i>s</i>^∞ can be observed, which aids in the development of various steps for the design of most suitable ILs with improved interaction with thiophene

Investigation of the Thermophysical Properties of AMPS-Based Aprotic Ionic Liquids for Potential Application in CO₂ Sorption Processes

The thermophysical properties such as density, refractive index, and viscosity of five aprotic ILs bearing imidazolium (1-ethyl-3-methylimidazolium [emim], 1-butyl-3-methylimidazolium [bmim], 1-benzyl-3-methylimidazolium [bnmim]), pyrrolidinium (1-butyl-1methylpyrrolidinium [bmpyr]), and pyridinium (<i>N</i>-butylpyridinium [bpyn]) cations with 2-acryloamido-2-methylpropanesulfonate [AMPS] anion were studied, and their effect on CO₂ solubility was explored. The density and viscosity were determined within the temperature range of (293.15 to 363.15) K at atmospheric pressure, while refractive indices were measured within the temperature range of (288.15 to 333.15) K. Among imidazolium cations, increasing the side chain length resulted in increased refractive index and viscosity with a corresponding decrease in density. In the presented ILs, [emim]­[AMPS] showed the highest density and least viscosity over the entire temperature range and an enhanced CO₂ dissolution of 0.40 mole fraction at 1 MPa was observed at 298.15 K. Moreover, the Henry’s constant of [emim]­[AMPS] was determined to be 1.957 MPa which was 49.5, 65.5, 21, and 53% less than [bmim]­[AMPS], [bnmim]­[AMPS], [bmpyr]­[AMPS], and [bpyn]­[AMPS], respectively. The present study provides a better understanding of the structure–activity relationship between CO₂ sorption and physicochemical properties of studied ILs

Improving the Sulfurophobicity of the NiS-Doping CoS Electrocatalyst Boosts the Low-Energy-Consumption Sulfide Oxidation Reaction Process

Producing sulfur from a sulfide oxidation reaction (SOR)-based technique using sulfide aqueous solution has attracted considerable attention due to its ecofriendliness. This study demonstrates that NiS-doped cobalt sulfide NiS-CoS-supported NiCo alloy foam can deliver the SOR with superior electrocatalytic activity and robust stability compared to reported non-noble metal-based catalysts. Only 0.34 V vs RHE is required to drive a current density of 100 mA cm–2 for the SOR. According to the experiment, the catalyst exhibits a unique sulfurophobicity feature because of the weak interaction between sulfur and the transition metal sulfide (low affinity for elemental sulfur), preventing electrode corrosion during the SOR process. More impressively, the chain-growth mechanism of the SOR from short- to long-chain polysulfides was revealed by combining electrochemical and spectroscopic in situ methods, such as in situ ultraviolet–visible and Raman. It is also demonstrated that electrons can transfer straight from the sulfion (S2–) to the active site on the anode surface during the low-energy-consumption SOR process. This work provides new insight into simultaneous energy-saving hydrogen production and high-value-added S recovery from sulfide-containing wastewater