Use of Magnetic Activated Carbon to Increase CO2 Absorption Capacity of Alkali-Activated Slag

Abstract In this study, magnetic activated carbon (MAC, nano- Fe 3 O 4 loaded activated carbon) was used to assist alkali activated slag to capture CO 2 from the air. Fresh alkali activated slag slurry containing MAC was exposed to an external magnetic field, the MAC particles were attracted and moved to the surface of the specimen, forming a CO 2 capture layer. The characteristics of MAC and the influence of magnetic induced movement of MAC on alkali activated slag were studied. The results show that: (1) MAC has higher pore volume and higher CO 2 adsorption capacity than activated carbon. (2) Higher external magnetic field intensity and higher water/binder ratio result in the higher content of MAC at the outer layer of the specimen. (3) The magnetic induced movement of activated carbon increases the pore volume of alkali activated slag. (4) In an environment with CO 2 concentration of 660 ± 10 ppm , MAC distributed on specimen surfaces significantly increases the CO 2 absorption capacity and compressive strength of alkali activated slag.