Sustainable Synthesis of MOF/Biopolymer Macrostructures: Cellulose Nanofiber-Supported Copper Benzene-1,4-dicarboxylate/Carboxymethyl Cellulose Beads

Metal-organic frameworks (MOFs) are highly effective materials for environmental cleanup, but their small size limits industrial scalability. MOF-based macroscopic architectures offer a solution allowing for their practical use. This study presents a sustainable, scalable method for the in-situ growth of copper benzene-1,4-dicarboxylate (Cu-BDC) MOF on carboxymethyl cellulose (CMC) beads. A 2% w/v CMC solution with aniline and 1,4-benzenedicarboxylic acid (H2BDC) was dropped into a copper nitrate solution. Cellulose nanofibers (CNFs) were also added to this CMC solution to assess their effects. The resulting beads, sized 1.87±0.16 mm, featured gyrification-like folds with 488.78±1.19 nm Cu-BDC spherical protrusions. Aniline was crucial in forming the folds and spherical protrusions. The presence of CNFs enhanced the beads' mechanical and thermal strength, although higher concentrations of CNFs (>1%) hindered the growth of MOFs. This method offers a viable pathway for scaling MOFs for practical industrial applications.