Synthesis of MIL-53(Al) metal-organic framework from aluminium-lined multi-layered packaging materials and polyethylene terephthalate bottles

Abstract

A promising approach towards the synthesis of metal-organic frameworks (MOFs) is the use of precursors that can be extracted from waste materials found in landfills. In this work, we explore a combination of two waste materials for Al-based MOF synthesis. Aluminium sulphate was successfully derived from Poly-Al pellets obtained from multi-layered packaging materials. Terephthalic acid (BDC) was obtained from polyethylene terephthalate (PET) waste bottles. Both precursors were employed as metal and organic linker sources, respectively to synthesise MIL-53(Al). The results are compared with those of corresponding MOFs synthesised from commercial precursors and partly waste precursors. The study revealed that the structural properties of MIL-53(Al) synthesised from the two waste materials are comparable to those obtained when the MOF is synthesised using commercial sources of precursors or partly waste precursors. The MOFs were highly crystalline and stable up to 500°C. An improvement was observed in the surface area of the MOF when synthesised from complete waste (1588 m2/g) as opposed to partly waste (1323 and 1197 m2/g) and commercial precursors (1468 m2/g). Although hydrogen adsorption capacity of the synthesised MOF materials was low at low pressures (< 0.5 wt% at 1 bar and 77 K), attributable to the narrow pore form of MIL-53(Al), this work demonstrates an approach to waste management while producing high-value materials for various applications.