Development of CO2 adsorption materials from recycling spent tire char via orthogonal design: Optimal solution and thermodynamic evaluation

Abstract

This work uses chemical-physical activation to upgrade spent tire char for capturing CO2, and CO2 gas flow rate is the dominant factor of activation process based on the orthogonal experimental design. The final spent tire activated carbon with a specific surface area of 762.17 m2/g and a microporous pore volume of 0.23 cm3/g was obtained. The CO2 adsorption behavior can be described by the Langmuir and Freundlich models. The optimum spent tire-based activated carbon has the capacity to capture CO2 up to 1.42 mmol/g. It was also confirmed by Gibbs free energy change studies that the optimum spent tire-based activated carbon at less than 58.77 °C allows the CO2 adsorption reaction to proceed spontaneously. The excellent regenerability of the produced activated carbon material was demonstrated by the isosteric heat of adsorption. The process of CO2 adsorption was also confirmed as physical adsorption by various thermodynamic means. The spent tires recycling as CO2 adsorbent is a promising path which realizes the dual benefits of waste recycling and CO2 reduction.