Recent advances in ionic liquids-based hybrid processes for CO2 capture and utilization.

CO2 capture and utilization (CCU) is an effective strategy to mitigate global warming. Absorption, adsorption and membranes are methods used for CO2 separation and capture, and various catalytic pathways have also been developed for CO2 utilization. Although widely researched and used in industry, these processes are energy-intensive and this challenge needs to be overcome. To realize further optimization, novel materials and processes are continuously being developed. New generation materials such as ionic liquids (ILs) have shown promising potential for cost-effective CO2 capture and utilization. This study reviews the current status of ILs-based solvents, adsorbents, membranes, catalysts and their hybrid processes for CO2 capture and utilization. The special properties of ILs are integrated into new materials through hybridization, which significantly improves the performance in the process of CCU.

Effects of different bicarbonate on spirulina in CO2 absorption and microalgae conversion hybrid system.

According to the characteristics of power plant flue gas emission and the requirements of reducing CO2 capture cost. CO2 absorption hybrid with microalgae conversion (CAMC) can avoid the challenges of heat consumption during absorbent desorption and nutrient consumption during microalgae culture. In this study, the bicarbonate solution (represents the products of CO2 absorption by Na2CO3 and K2CO3) is used as carbon source for mutagenic Spirulina platensis cultivation, and different concentrations of bicarbonate were set to explore the best carbon source. The results showed that NaHCO3 was a better medium for the CO2 absorption hybrid with microalgae conversion system, which was beneficial for the growth of mutagenic Spirulina, compared with K2CO3. When .3 mol/L NaHCO3 was added to the CO2 absorption hybrid with microalgae conversion system, the highest biomass dry weight, carbon fixation rate and carbon utilization efficiency were obtained, which were 2.24 g/L, 230.36 mg/L/d and 26.71%, respectively. In addition, .3 mol/L NaHCO3 was conducive to protein synthesis, reaching 1,625.68 mg/L. This study provided a feasible idea for power system to achieve carbon neutrality in the future.

Formation mechanisms of Caprolactam-tetraalkyl ammonium halide deep eutectic and its hydrate.

Deep eutectic solvents (DES) are generally composed of two or three cheap and safe components that are associated with each other via hydrogen bonds. The formation Caprolactam (CPL)-tetraalkyl ammonium halide (TAAX) DES and its hydrate were investigated using React IR. TAAX was introduced to CPL in the molten state at 353.15 K, the intermolecular H-N-C=O⋯H-N-C=O hydrogen bonds (CPL dimer) transfer to X-⋯H-N-C=O (CPL-TAAX DES). When water was added to CPL-TAAX DES, intermolecular X-⋯H-N-C=O⋯H-O-H hydrogen bonds appeared, and CPL-TAAX DES hydrate was formed. However, if the ratio of water exceeded the moral fraction of 0.61, CPL-TAAX DES hydrate turned into a CPL-TAAX aqueous solution. The CO (1660 cm-1) bonds were linearly correlated with hydrogen bonds number and TBAB amount in CPL-TBAB DES. When the molar fraction of CPL-TBAB DES was 0.39 to 0.78, the CO peak redshift has a better linear correlation with water. Halide anions and the alkyl chain length of TAAX have little influence on the redshifts and peak intensity of the CO peak.