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• Thermo-physical characteristics of ILs-amine hybrid solvent were studied for CO 2 capture. • The CO 2 absorption tests were conducted in hybrid media at 30 °C and 2 bar to 50 bar. • The viscosity of the samples does not change over the temperature range from 25 to 70 °C. • The hybrid solvent containing 10 wt% [bmim][TfO] exhibited highest CO 2 absorption kinetics. The thermo-physical characteristics of an ionic liquid-amine hybrid solvent were studied in this work as a result of its potential use in the CO 2 absorption process. The hybrid solvents were developed by mixing 30 wt% MDEA with ionic liquid at different concentrations of 5 wt%, 10 wt%, 15 wt% and 20 wt%. Three imidazolium-based ILs were investigated: 1-butyl-3-methylimidazolium dicyanamide [bmim][DCA], 1-butyl-3-methylimidazolium acetate [bmim][Ac] and 1-butyl-3-methylimidazolium trifluoromethanesulfonate [bmim][TfO. Aqueous ionic liquid-amine hybrid solvent's density, surface tension, refractive index, viscosity and were studied between 25 °C and 70 °C with a regular interval of 5 °C. Whereas the influence of temperature on viscosity is negligible beyond 65 °C and the influence of temperature changed certain physicochemical properties. Furthermore, high-pressure solubility tests were conducted at a fixed temperature of 30 °C to determine the solubility of CO 2 in hybrid media at pressures ranging from 2 bar to 50 bar. The results showed that the CO 2 solubility of the different ionic liquid-amine hybrid systems decreases in the following sequence: [bmim][TfO] + MDEA > [bmim][DCA] + MDEA > [bmim][Ac] + MDEA. It was also found out that the optimum concentration of ionic liquids in the solution is 10 wt%. The kinetics study of the hybrid solvents was studied as a function of concentration, and experimentally determined that 10 wt% [bmim][TfO] exhibited the fast CO 2 absorption kinetics. The kinetics performance study was further conducted as a function of pressure, and the highest absorption rate was recorded at 50 bar as expected. Overall, the addition of ionic liquids was verified to improve the CO 2 absorption and thus it was reported that ionic liquid-amine hybrid solvent is an auspicious solvent for CO 2 removal in the future. [ABSTRACT FROM AUTHOR]

Fig. Proposed mechanism of CN/BI 10.0. [Display omitted] • BI was incorporated within CN via molecular engineering (CN/BIx). • Endorsing charge transition dissociation and boosting the photocatalytic performance. • Superior sample CN/BI 10.0 demonstrate remarkable photocatalytic H 2 evolution and photoreduction of CO 2 respectively. • A dual synergetic mechanism of CN/BI 10.0 has been proposed. Due to a growing number of significant vitality and environmental issues, the standardized variation of carbon nitride (CN) for visible-light photocatalytic water splitting is an encouraging scientific topic. By revealing this, the functionalized monomer 2,6-dibromobenzimidazole (BI) was successfully embedded within the heptazine units of CN via a molecular engineering (Co-polymerization process) approach, and the as-synthesized product was named CN/BIx. Thereafter, as-synthesized materials were employed in the photocatalytic production of hydrogen (H 2) via water splitting and CO 2 reduction into CO under visible light irradiance (λ = 420 nm). Surprisingly, the substituent framework of CN, which was intimidated by the description of BI monomer, acted as a substitution reaction material and lubricated the electronic structure of CN by endorsing charge transition dissociation, which in turn boosted its photocatalytic performance under visible irradiation. The CN/BI 10.0 yields 62.8 mol of CO and 18.1 mol of H 2 for 4 h of the catalyzed reaction upon photooxidation under light irradiation, emphasizing the maximum photocatalytic performance with response to CO 2 +. Correspondingly, the H 2 evolution rate (HER) for bulk CN was estimated as 17.6 mol/h1, whereas it was approximated as 203.7 mol/h1 for CN/BI 10.0 , which is 10 times higher than that of CN. Such a phenomenon also predicts a substantial encroachment in the surface area, energy gap, and chemical properties, along with promotes the effective segregation of photoinduced charge separation from the valence band (VB) to the conduction band (CB) of CN, thereby, making it a good alternative for the photocatalytic water and CO 2 reduction reaction process. [ABSTRACT FROM AUTHOR]