Adsorptive Removal of Methyl Orange in Water Using PAN/PVP/CD-MOF Composite Beads

Cyclodextrin metal-organic frameworks (CD-MOFs) exhibit permanent porosity, which makes them an ideal adsorbent material. However, the instability of CD-MOFs in water limits their applications. To overcome this limitation, we encapsulated CD-MOFs in polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) polymeric support to produce PAN/PVP/CD-MOF composite beads. Batch adsorption studies were performed to remove methyl orange in water. The results showed that low CD-MOF and intermediate PAN and PVP loadings led to the highest dye sorption capacities. The optimized bead formulation of PAN = 4.10 wt.%, PVP = 3.07 wt.%, and CD-MOF = 2.00 wt.%, resulted in a sorption capacity of 6.56 ± 0.59 mg/g. Molecular modeling showed that the MO is adsorbed on the surface of the CD-MOF, with an adsorption energy of −292.55 kcal mol−1. Overall, this study demonstrated that PAN/PVP/CD-MOF composite beads could be an excellent adsorbent for textile dye removal in water.