Environmental performance of different sorbents used for direct air capture

• Main Authors: Fennell, P.S (Author), Leonzio, G. (Author), Mwabonje, O. (Author), Shah, N. (Author)
• Format: Article
• Language: English
• Published: Elsevier B.V. 2022
• Subjects: Adsorption; Air captures; Amine functionalized sorbent; Amine functionalized sorbents; Amine sorbent; Capture process; Carbon dioxide; Climate change; DAC; Direct air capture; Energy utilization; Environmental impact; Environmental management; Environmental performance; Environmental targets; Functionalized; Life cycle; Life cycle assessment; Metal organic frameworks; Metalorganic frameworks (MOFs); Organometallics; Silica gel; Sorbents; Sorption; Stringents
• Online Access: View Fulltext in Publisher

 Currently, conventional carbon dioxide (CO2) mitigation solutions may be insufficient to achieve the stringent environmental targets set for the coming decades. CO2 removal (CDR) technologies, such as direct air capture (DAC), capturing CO2 from the ambient air, are required. In this research, an independent life cycle assessment (LCA) of DAC adsorption systems based on three physisorbents (metal organic frameworks) and two chemisorbents (amine functionalized sorbents) is presented. These capture processes have been optimised by us in previous work. Results show that for the overall capture process, negative CO2 emissions are ensured by using a cellulose-based amine sorbent (cradle-to-gate) ensuring even the net removal of CO2 from the atmosphere (cradle-to-grave). Processes using physisorbents have poorer performances. Chemisorbents yield operating conditions allowing lower impacts on the environment. In 2050, these processes could reduce climate change but can generate other environmental impacts. With the aim to have better environmental performances of DAC systems, future research should be focused on improving the physical properties of sorbents such as the silica gel based amine sorbent to increase their capture capacities. If metal organic frameworks are to be used, it is necessary to drop their energy consumption (by increasing the loading) and the required mass of sorbent. © 2022 The Authors