Preparation of coal fly ash derived metal organic frameworks and their carbon derivatives

In this study, a new strategy for preparing metal organic frameworks (MOFs) using coal fly ash (CFA) as a metal feedstock is introduced. Aluminium and other metal species were leached out from CFA using sulfuric acid and reacted with fumaric acid following a procedure that had been optimized to mimic Aluminium fumarate MOF (Al-FumMOF). Despite the presence of different metals in the synthesis solution, the prepared coal fly ash derived MOF (CFA-FumMOF) exhibited almost similar characteristics to Al-FumMOF synthesized using commercial chemicals. In this case, the surface area of 1236 m²/g was obtained for CFA-FumMOF, whereas that of Al-FumMOF was 1266 m²/g. For pore enhancement, the prepared CFA-FumMOF was subjected to direct carbonization and resulted in improved surface area (i.e. increase from 1236 m²/g to 2017 m²/g). The developed innovative strategy of using CFA leachate in MOF synthesis has the potential for lowering the cost of producing MOFs as well as create a new route for value-addition of the waste CFA for many applications.