Synthesis of a nanostructured pillar MOF with high adsorption capacity towards antibiotics pollutants from aqueous solution

In this study, various sonochemical conditions were applied to prepare the microsheets, nanosheets and nanoflowers of a metal-organic framework (MOF; [Zn₆(IDC)₄(OH)₂(Hprz)₂]_n) that is composed of Zn(II) cations coordinated with the linear N-donor piperazine (prz) and rigid planar imidazole-4,5-dicarboxylate (H₃IDC) ligands. The PXRD patterns approved purity of the samples and the FT-IR spectra related the detected bonds and functional groups to [Zn₆(IDC)₄(OH)₂(Hprz)₂]_n crystals. The morphological results indicated that any changes in the synthesis conditions can affect nucleation and morphology of the nanostructures. The prepared MOF nanosheets and nanoflowers (with particle size average of 95 and 116 nm, respectively) were employed to adsorb the ampicillin, amoxicillin and cloxacillin antibiotics. Then, the MOFs were calcined at 550 ℃ and atmospheric pressure to produce ZnO nanoparticles and the resultant nanoparticles were adopted to photodegrade the antibiotics. These nanoparticles can photodegrade 37% of the amoxicillin compounds within 180 min. Among the examined samples, the nanoflowers demonstrated the highest adsorption capacity by eliminating 92.5%, 88% and 89% of the antibiotic molecules from the 60-ppm amoxicillin, ampicillin and cloxacillin solutions, respectively. Also, these nanoflowers are thermally stable up to 365 ℃. The associated adsorption process was found to follow pseudo-first-order kinetics, in the case of amoxicillin.