Biqin Chen,Yuxia Li,Jinghao Cao,Shenghui Liu,Ke Fan,Haixin Li
The existing TUF membranes often face challenges such as declining permeation flux and insufficient separation selectivity. This study proposes to improve the above problems by the synergistic effect of Mg–Al layered double hydroxide (LDH) and tannic acid (TA) etched metal–organic frameworks (MOFs): (1) TUF membranes with adjustable interlayer distances and multi-level mass transfer channels were constructed by doping LDH two-dimensional (2D) nanosheets; (2) TAZIF-L (Co) etched by TA was introduced. TA inhibited the swelling of LDH nanosheets through coordination and enhanced the interface binding between ZIF-L (Co) and the substrate, thereby suppressing its shedding. The results showed that TA can etch ZIF-L (Co), and the membrane prepared after etching has better selectivity and stability of dye/salt separation. Taking MTAZIF-0.02 as an example, the pure water flux was 88.23 L m −2 h −1 , which was 1.91 times that of MLDH. The removal rate of congo red (CR) solution was 92.56%. The NaCl rejection in methyl blue (MB)/NaCl solution was 10.88% and in CR/NaCl solution was 10.57%. This study provides an experimental basis for the construction of highly selective ultrafiltration membrane for the treatment of high concentration dye/salt wastewater.
Developing non-precious metal catalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is critical for Zn–air batteries. Herein, using NaCl and ammonium oxalate as templates to prepare a hierarchical porous Fe–N–C catalyst using an inorganic salt melting strategy is proposed. The prepared Fe–N–C-x catalysts have a hierarchical porous structure that increases the specific surface area, improves the exposure of a number of active sites and enhances the chance of contacting active sites. The structure change of a leaf-shaped zeolitic imidazolate framework (ZIF-L) during high-temperature pyrolysis was used to self-catalyze the growth of carbon nanotube structures, forming a structure of carbon nanotubes including Fe nanoparticles to provide additional active sites and reduce the aggregation of metal particles. From the perspective of economy and electrochemical performance, it is found that when the addition amount of NaCl and ammonium oxalate respectively is 2 g, the electrochemical performance of the ORR, OER and Zn–air batteries is better, and the preparation cost of the catalyst is more affordable. This strategy of forming hierarchical porous Fe–N–C catalysts by self-catalytic growth of Fe, N co-doped CNTs using inorganic salts provides a new design idea for the preparation of new hierarchical porous electrocatalysts.
Ming Qian,Lei Song,Zefan Huang,Xiucheng Hu,Yunpeng Bai,Yukun Chen,Na An,Haipeng Sun
Bacterial antibiotic resistance poses a global threat to public health, highlighting the urgent need for innovative antimicrobial strategies. Zinc-based nanomaterials have shown promise in antibacterial treatments but are often limited by their low antimicrobial efficiency and poor biocompatibility. In this study, we propose a synergistic antibacterial approach that utilizes the Trojan horse effect through nanocomposites. By exploiting bacterial dependence on Fe3+, we introduce Ga3+ as a substitute, disrupting bacterial growth from within. Utilizing a ZIF-L carrier to load indocyanine green (ICG), we achieve targeted delivery of ICG, which generates ROS under light irradiation, effectively eradicating methicillin-resistant Staphylococcus aureus biofilms. In addition, the combined application of Zn2+ and Ga3+ effectively inhibits the growth of Porphyromonas gingivalis, providing complementary synergistic damage to bacteria from the inside out. This combined approach, integrating Zn2+, the Trojan horse mechanism, and photodynamic therapy, offers a promising therapeutic strategy against bacterial antibiotic resistance.
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