Chiang Mai Journal of Science

     MIL-53(Al), a flexible metal-organic framework, was synthesized by a facile method through a water-based method at room temperature, aligning with the principles of green chemistry. The objective was to investigate its effectiveness in removing pharmaceuticals and personal care products (PPCPs), specifically focusing on oxytetracycline (OTC). Our findings revealed that MIL-53(Al) possesses a structure with both micropores and mesopores, with a specific surface area of 916 m²/g. MIL-53(Al) notably exhibited a higher OTC adsorption capacity than commercially available powder activated carbon (PAC). The adsorption kinetics followed a pseudo-second-order model, while the Langmuir model accurately described the experimental isotherms for OTC adsorption. MIL-53(Al) outperformed previously reported MOF-based adsorbents with a maximum of 1005 mg/g capacity at pH 7. The flexible structure induces a breathing effect that significantly improves intraparticle diffusion for OTC, contributing to its adsorption efficiency. The adsorption of OTC was influenced by the solution pH, the acid dissociation constants of OTC, and the charged surface of the adsorbent. Pore filling, hydrogen bonding, π-π interaction, electrostatic interaction, and hydrophobic interaction were all associated with the adsorptive interaction between OTC and MIL-53(Al). The MIL-53(Al) also demonstrated good regeneration and reuse, with just a little decreased adsorption capacity after three reuse cycles. These findings indicate that green material MIL-53(Al) has the potential to be an effective adsorbent for removing OTC from water matrices.