Dual-Functional Eu2+/3+-Complex@ZIF-67 Nanocatalyst Derived from a Green Reduction of Eu3+ Compound

Enhanced Selective Degradation of Pharmaceutical and Personal Care Products by β-Cyclodextrin-Decorated ZIF-67 Nanocomposites in Reclaimed Water

A peroxymonosulfate oxidation system was developed via modification of β-cyclodextrin (β-CD) on the surface of Fe2+-doped ZIF-67 (CD/Fe@ZIF-67) as an activator. The 99.7% carbamazepine, 91.3% bisphenol A (BPA), and 95.4% diclofenac (DCF) degradation efficiency were achieved within 10 min, 60, and 1 min, respectively. The hydrophobicity of these three pollutants is positively correlated with their adsorption kinetic constants by CD/Fe@ZIF-67 due to the introduction of β-CD. Scavenger experiments and electron spin resonance spectra confirmed that carbamazepine was preferentially oxidized by SO4•- [λ(SO4•-)(70.5%) > λ(•OH)(28.2%) > λ(O2•-)(1.3%)], where SO4•- and O2•- played dominant roles in the degradation of BPA [λ(SO4•-)(71.7%) > λ(O2•-)(22.8%) > λ(•OH)(5.5%)], and O2•- was responsible for DCF removal [λ(O2•-) = 93.2%]. Additionally, the particulate catalyst was immobilized in the shell side of a ceramic membrane in a membrane reactor for catalyst recovery. This reactor achieved nearly 100% removal efficiency under optimal conditions: 0.036 wt % catalyst loading, 0.5 mM peroxymonosulfate concentration, 1 L inflow, 10 mg/L initial carbamazepine concentration, and 0.012 L/min hydraulic retention time. In summary, this study elucidates the active role of β-CD in a polymetallic/peroxymonosulfate system and provides valuable insights into the development of effective oxidation methods for pharmaceutical and personal care products in wastewater.

Degradation of ciprofloxacin using hematite/MOF nanocomposite as a heterogeneous Fenton-like catalyst: A comparison of composite and core-shell structures

A novel strategy was described to fabricate hematite-MOF materials with morphologies (core-shell) and (composite) as an efficient peroxymonosulfate (PMS) activator for degrading ciprofloxacin (CIP) antibiotics. First, α-Fe₂O₃ nanoparticles (NPs) with a size distribution range of 80 nm were prepared by surfactant-assisted reflux method. Then, cobalt-based metal-organic framework (ZIF-67) was grown onto the α-Fe₂O₃ NPs with ultrasonic and solvothermal method, which can control the nanostructures morphology. The physicochemical properties of these nanostructures were probed by ATR-IR, WA-XRD, FESEM, VSM, TEM, and EDS spectroscopy. The results showed that all the added CIP (20 ppm) antibiotics were completely degraded in 30 min in the α-Fe₂O₃/ZIF-67 (0.10 g/L) and PMS (0.20 g/L) system with rate constant of 0.130 min^-1. To validate the merits of the α-Fe₂O₃/ZIF-67, α-Fe₂O₃@ZIF-67 core-shell nanostructures were also applied under similar conditions. The findings demonstrated that Co/Fe species within α-Fe₂O₃/ZIF-67 composite catalyzed PMS synergistically to the formation of the OH and SO₄^- and ¹O₂ for CIP degradation. Furthermore, α-Fe₂O₃/ZIF-67 showed good recyclability enabling facile separation of the catalyst from reaction mixtures using an external magnet. The current protocol can be a useful criterion in designing various Magnetic-MOF composites with controlled morphologies for environmental remediation.

Dinuclear helicate or mononuclear pincer lanthanide complexes from one ligand: stereo-controlled assembly and catalysis

By varying the metal/ligand ratio, either dinuclear triple helicate or mononuclear pincer can be stereo-selectively obtained from the same chiral ligand. Their catalytic properties have been demonstrated with the asymmetric FC alkylation reactions.