Supported lithium hydroxide for carbon dioxide adsorption in water-saturated environments

Experimental, RSM modelling, and DFT simulation of CO2 adsorption on Modified activated carbon with LiOH

This research investigates the enhancement of CO2 adsorption capacity through the use of modified activated carbon (AC) with LiOH, focusing on operational conditions and adsorbent properties. Response Surface Methodology (RSM) is employed to optimize process parameters for maximizing CO2 adsorption capacity. The study considers temperature, pressure, LiOH concentration for modification, and adsorbent weight as independent variables across five levels. Analysis of Variance reveals that LiOH concentration, adsorbent quantity, pressure, and temperature significantly influence CO2 adsorption. Optimal values for temperature (30°C), pressure (9 bar), LiOH concentration (0.5 mol/L), and adsorbent weight (0.5 g) result in a maximal CO2 adsorption capacity of 154.90 mg/g. Equilibrium adsorption capacity is utilized for modeling, with the Freundlich model proving suitable for CO2 adsorption on LiOH-AC. Kinetic modeling indicates the second-order model's suitability for temperatures of 30 °C and 50 °C, while the Elovich model fits temperatures of 70 °C and 90 °C. Thermodynamic modeling at the optimized conditions (303 K and 6 bar) yields ∆H, ∆S, and ∆G values of adsorption as 12.258 kJ/mol, - 0.017 kJ/mol·K, and - 7.031 kJ/mol, respectively. Furthermore, structural considerations of AC are discussed alongside modeling and simulation, presenting the adsorption rate of CO2 and the binding energy index based on Density Functional Theory (DFT).

CO2 Capture Membrane for Long-Cycle Lithium-Air Battery

Lithium-air batteries (LABs) have attracted extensive attention due to their ultra-high energy density. At present, most LABs are operated in pure oxygen (O₂) since carbon dioxide (CO₂) under ambient air will participate in the battery reaction and generate an irreversible by-product of lithium carbonate (Li₂CO₃), which will seriously affect the performance of the battery. Here, to solve this problem, we propose to prepare a CO₂ capture membrane (CCM) by loading activated carbon encapsulated with lithium hydroxide (LiOH@AC) onto activated carbon fiber felt (ACFF). The effect of the LiOH@AC loading amount on ACFF has been carefully investigated, and CCM has an ultra-high CO₂ adsorption performance (137 cm³ g^-1) and excellent O₂ transmission performance by loading 80 wt% LiOH@AC onto ACFF. The optimized CCM is further applied as a paster on the outside of the LAB. As a result, the specific capacity performance of LAB displays a sharp increase from 27,948 to 36,252 mAh g^-1, and the cycle time is extended from 220 h to 310 h operating in a 4% CO₂ concentration environment. The concept of carbon capture paster opens a simple and direct way for LABs operating in the atmosphere.

Reinvestigations of the Li2O–Al2O3 system. Part I: LiAlO2 and Li3AlO3

Reinvestigations of the Li2O–Al2O3 system focused on the synthesis and properties of LiAlO2 and Li3AlO3 phases have been performed with the help of XRD and IR measuring techniques and Li2CO3, LiOH·H2O, Al2O3-sl., α-Al2O3, Al(NO3)3·9H2O and boehmite as reactants. Results of investigations have shown the formation of α-, β-, and γ- polymorphs of LiAlO2. It was found that only the use of LiOH·H2O as a reactant yields to β-LiAlO2 as a reaction product. On the other hand, it was proved that Li3AlO3 does not form in the Li2O–Al2O3 system. A new method for the synthesis of α-LiAlO2 was developed, consisting in grinding the mixture of Li2CO3 and Al(NO3)3·9H2O and heating the obtained paste at the temperature range of 400–600 °C. The IR spectroscopy was used to characterize obtained phases.