Liang Zhang,Jing Wang,Xinyi Ren,Wentao Zhang,Tianshu Zhang,Xinnan Liu,Ting Du,Tao Li,Jianlong Wang
The excessive accumulation of toxic copper species makes it imperative to develop smart dual-functional materials for the simultaneous removal and detection of Cu(II) in drinking water. In this work, novel core–shell NH2-MIL-101(Al)@ZIF-8 nanoflowers were successfully fabricated via an internal extended growth mode under the regulation of polyvinylpyrrolidone (PVP) to achieve this goal. Benefiting from the specific affinity of imidazole nitrogen in ZIF-8 toward Cu(II), the resultant NH2-MIL-101(Al)@ZIF-8 shows high adsorption capacity (526.74 mg g−1). Moreover, the fluorescence of NH2-MIL-101(Al) shows a Cu(II)-dependent change, causing this composite to possess superior selective/sensitive detection with a broad linear range (1.5–625 μM) and a low detection limit (0.17 μM) for Cu(II). Specifically, the hybrid MOF@MOF structure provides greater sensitivity as compared to the individual constituent (pristine NH2-MIL-101(Al)) and the mixed state, which is ascribed to the rational optimization of the smart adsorbent based on the following two aspects. (i) The synergistic effect of the core–shell nanostructure improves the preconcentration ability at the interface between single MOFs. (ii) The existence of the three-dimensional hierarchical nanoflower architecture (structure optimization) accelerates the mass transport and sculpts the final composite with enhanced adsorption and detection ability. These indicate that the smart NH2-MIL-101(Al)@ZIF-8 nanoflower could be an excellent candidate for the synchronous remediation and selective detection of Cu(II) in aqueous systems, which could be potentially useful in wastewater treatment and water quality monitoring.
Intelligent films are essential for real-time monitoring of food spoilage. However, the application is often limited by challenges such as hydrophilicity and color instability. In this study, two high hydrophobic bilayer indicators based on sodium alginate-polyvinyl alcohol/chitosan-zein with alizarin grafted onto ZIF-8 carrier (AL@ZIF-8) were fabricated using the casting method and electrospinning, respectively. Molecular docking simulations confirmed the successful grafting of AL@ZIF-8 onto the film substrates. The performance of films was compared and the effectiveness in monitoring freshness indicators was evaluated. The cast film had a precisely controlled thickness due to self-assembly performance, resulting in superior mechanical properties (TS = 10.64 MPa, EB = 43.764 %). In comparison, the nanofiber films demonstrated higher UV-blocking ability (ΔE < 4), faster spoilage response, and greater safety (Cell viability >80 %). Importantly, the nanofiber films exhibited higher sensitivity in monitoring beef freshness, with a color change pattern strongly correlating with spoilage (R 2 = 0.8976).
A Zn dosage-mediated thermal reconstruction strategy was proposed to fabricate LDH@ZIF derived catalyst. • Moderate Zn addition achieves uniformly dispersed ZnCo 2 O 4 spinel. • Optimized LZ-0.2 removes levofloxacin rapidly through multiple ROS pathways involving 1 O 2 . • The catalyst realizes stable 144 h continuous degradation in fixed-bed reactor. Peroxymonosulfate-based advanced oxidation processes (PMS-AOPs) are effective for refractory antibiotic removal, yet conventional layered double hydroxide (LDH) catalysts often suffer from lamellar collapse, active site aggregation and poor pore accessibility after calcination. Herein, a series of LDH(Co/Al)@ZIF-8 derived catalysts (LZ-x) were prepared through the growth of ZIF-8 on LDH(Co/Al), followed by pyrolysis, for PMS activation and levofloxacin (LFX) degradation. Regulating the Zn dosage controlled ZIF-8 growth and the subsequent thermal reconstruction of the hybrid precursor. Among them, LZ-0.2 exhibited an open hierarchical architecture and the highest catalytic activity, achieving 95.11% LFX removal within 5 min with a k obs of 0.576 min −1 . In addition, structural characterization indicated that an appropriate Zn dosage favored the formation and dispersion of ZnCo 2 O 4 -containing spinel domains within the porous nanosheet architecture. Meanwhile, mechanistic investigations supported a hybrid radical/non-radical oxidation pathway involving 1 O 2 , •OH, SO 4 •- and • O 2 − . Additionally, the LZ-0.2 + PMS system maintained effective performance in various real water matrices and stable fixed-bed operation for 144 h in hospital wastewater, with low Co and Zn leaching. Moreover, phytotoxicity, antibacterial activity, and zebrafish developmental toxicity were reduced after treatment. This work highlights Zn-dosage regulation as an effective strategy for directing the thermal reconstruction of LDH@MOF derived catalysts for efficient PMS activation and antibiotic abatement.
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