Advanced mixed-linker UiO-66 MOFs as high-performance functional materials for removing emerging contaminants: DFT-guided design and real wastewater validation

Abstract

The persistent contamination of aquatic environments by emerging organic pollutants (EOPs) such as bisphenol A (BPA) and tetracycline (TC) poses significant threats to ecosystems and human health. Herein, we report a computationally guided strategy for designing mixed-linker metal–organic frameworks (ML-MOFs) with enhanced selectivity toward BPA and TC removal. By systematically incorporating amino-functionalized and pyridine-functionalized terephthalic acid linkers alongside conventional BDC linkers into UiO-66 topology, we engineered ML-MOFs with tailored binding sites. Density functional theory (DFT) calculations revealed that amino- and pyridine-functionalized linkers strengthen pollutant binding through π–π stacking, hydrogen bonding, and electrostatic interactions, with adsorption energies of −89.4 kJ mol⁻¹ (BPA) and −102.7 kJ mol⁻¹ (TC), significantly exceeding those of parent UiO-66 (−52.3 and −61.8 kJ mol⁻¹, respectively). The optimized ML-MOF (UiO-66-NH₂/Py, 1 : 1 : 2 BDC : NH₂–BDC : Py–BDC ratio) demonstrated exceptional adsorption capacities of 385 mg g⁻¹ for BPA and 428 mg g⁻¹ for TC, outperforming commercial adsorbents (activated carbon: 156 mg per g BPA and189 mg per g TC). X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) analyses validated the computational predictions of specific binding mechanisms. Remarkably, the ML-MOF retained >92% capacity after five regeneration cycles and exhibited minimal capacity loss (≤15%) in industrial wastewater matrices. Competitive adsorption studies and column breakthrough experiments confirmed practical applicability. This synergistic computational–experimental approach provides a robust framework for rational MOF design targeting persistent environmental contaminants.