Development of a new formulation of air revitalization tablets in closed atmospheres using the Taguchi statistical method

In this study, a new formulation of KO2-based air revitalization tablets was developed to improve the performance of air regeneration equal to the man respiratory quotient, beneficial to use in life support systems. The effect of four additives, including Cu2Cl(OH)3, MnO2 (catalyst), LiOH (CO2 auxiliary absorbent), and CaSO4 (moisture absorbent), were investigated in 3 levels on the CO2 adsorption of the air revitalization tablets according to Taguchi's statistical approach. The ANOVA followed by Fisher’s test of the data revealed that an increase in the amount of Cu2Cl(OH)3 improves the CO2 adsorption and the final performance of the formulation. The CO2 adsorption of the optimum tablets was 50.83%, which is about 93%, and 43% higher than the KO2 tablets (26.25%) and the commercial tablets (35.42%), respectively. The BET and FE-SEM analysis of the commercial and optimized tablets indicated they have a mesoporous solid structure and a V-type adsorption isotherm. The BET-specific surface area before the adsorption process in the commercial and the newly produced sample was about 1.269 and 1.589 m2 g−1, respectively.