Diamine functionalized volcanic tuff: a promising CO2 adsorbent

Abstract

Background: Greenhouse gases, especially CO2, are primary factors for global warming and CO2 emissions continue to increase annually. Many legislations and agreements have been made to decrease, or at least stabilize, CO2 concentrations in the atmosphere. Moreover, promising CO2 capture technologies, such as adsorption using solid sorbents, have been developed and shown high CO2 adsorption capacity. Results: Volcanic tuff, a natural pozzolanic material, was evaluated as a solid CO2 adsorbent in this study. Following pre-treatment of the volcanic tuff with HCl solution, CO2 adsorption experiments were conducted by thermogravimetric analysis (TGA). Diamine functionalization of the volcanic tuff was carried out using amine based compounds with different chain lengths, including ethylenediamine, 1,4-diaminobutane and 1,6-diaminohexane. The CO2 adsorption capacity of the volcanic tuff was significantly enhanced in the presence of 1,6-diaminohexane. Maximum CO2 adsorption capacity was determined to be 42.94 mg g−1 with 70 wt% 1,6-diaminohexane loading. The CO2 adsorption capacity of the 1,6-diaminohexane functionalized volcanic tuff decreased with increasing temperature, which was an indication of exothermic adsorption. Adsorption–desorption cycles revealed that the 1,6-diaminohexane functionalized volcanic tuff was a reusable CO2 adsorbent with high stability. Conclusion: The results show that the low cost, eco-friendly, and highly stable diamine functionalized volcanic tuff can be considered a promising adsorbent for CO2 capture. © 2023 Society of Chemical Industry (SCI). © 2023 Society of Chemical Industry (SCI).