Enhanced mechanical stability with hierarchical porosity of activated carbon pellets realized through the use of combined polymer binders

Activated carbon (AC) is a promising absorbent feasible for use in the removal of various pollutants from wastewater. From a practical standpoint, AC must be in a bulk form such as granules or pellets with a well-developed porous internal architecture. Sufficient mechanical stability is also important to secure functionality and durability of this material. The fabrication of the granules and pellets usually requires the addition of a binder to provide mechanical stability of the bulk, thus highlighting the importance of the proper selection of the binder. In this study, to realize better binder compositions, a combination of polymer binders was used and the effects of such combination were investigated using polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP). As a result, the following promising binder composition is suggested: PVA:PVP = 3:7 in wt.%. The optimized composition exhibited 146% higher compressive strength and showed superior agitation resistance, with a total binder content of 10 wt.% compared to commercial AC pellets. Moreover, the mixed binder provided good hierarchical porosity, enhancing the permeability of fluids in potential filter applications.