Water recycling system based on adsorption by activated carbon synthesised from c. verum for space exploration; an estimated design

Abstract Water recycling is a crucial component of space flights. In this study, c.verum, a low-cost agricultural by-product abundant in Egypt, which was not utilized before for the preparation of porous carbons, and its ability for recycling water in space stations was estimated. The prepared samples show high porosity and surface area by physical activation. The influences of the pyrolysis temperature and activation hold-up time on the activated carbon’s porosity were studied. The BET surface area and the total pore volume of the prepared carbon were used as the criteria for selecting the optimum preparation parameters. The optimum temperature for pyrolysis was found to be at a temperature of 900°C, hold-up time of two-hour, a nitrogen flow rate of 150 cm3/min, and a heating rate of 10°C/min. However, the optimum activation conditions were at a temperature of 900°C, a CO2 flow rate of 150 cm3/min, a heating rate of 200C/min, and a hold-up time of 120 min. Equilibrium data is used for fitting to Freundlich, Langmuir, and Temkin isotherms models. The result revealed that the Langmuir model was the finest match for the equilibrium data, with an extreme monolayer adsorption capability of 12.37 mg/g at 25°C. The maximum monolayer adsorption capacity decreased with increasing temperature confirmed the exothermic character of the adsorption interaction.