Layered Double Hydroxide for Carbon dioxide mitigation from Bitumen and formation of Carbonic acid: A Step toward Achieving Greener Pavements

Abstract

ABSTRACT Carbon dioxide (CO2) emission in light of global climate change has become a burgeoning issue across several disciplines. In the transportation sector, which is a leading cause of global emissions, greenhouse gases emitted from bitumen are a significant issue. This paper aims to add to the existing literature on the use of nanoparticles in reducing CO2 emissions from bitumen. The use of layered double hydroxides (LDHs) has been investigated in this paper to evaluate the degree of their impact in reducing carbon dioxide (CO2) emissions from bitumen. To reduce the emission of CO2 from bitumen (VG 20), Calcium Aluminum Nitrate layered double hydroxide (Ca−Al−NO3 LDH) nanocomposite was synthesized, and characterized by powder XRD, FTIR, SEM, and TEM. The synthesized LDH was then checked for its efficiency for the reduction of CO2 emission in the laboratory by a simple experiment. To minimize the CO2 emission from bitumen, the LDH was applied to VG 20 grade of bitumen. Remarkably, the synthesized LDH derivatives due to their lamellar structure showed high potential for CO2 reduction at 120–160°C from bitumen at the hour of adaptable asphalt development. This was accomplished by converting the emitted carbon dioxide (CO2) into carbonic acid (H2CO3) due to the proton transfer from hydroxyl (-OH) group of the LDH. From this study, it was observed that the best reduction of CO2 without altering the fundamental properties of the bitumen was achieved at a 6% dosage of the additive (LDH) in bitumen. This alluring property of Ca−Al−NO3 layered double hydroxide (LDH) for CO2 removal from bitumen (VG 20) at high temperatures (up to 160°C) during the manufacture of flexible pavement has been reported in this study. This article, therefore, presents a novel approach of utilizing the CO2 adsorption capacity of LDHs to reduce the CO2 emissions from bitumen and addresses the worldwide challenge, to decrease the emission of carbon dioxide from fossil fuels or their derivatives.