Polytetrafluoroethylene (PTFE) porous membranes are widely used for high-temperature filtration. The polytetrafluoroethylene nanofiber membranes for fine particulate filtration were prepared by sintering the precursor electrospun polytetrafluoroethylene/polyvinyl/boric acid alcohol composite membranes. The effects of PTFE/PVA mass ratio and sintering temperature on the morphology and properties of the prepared membranes were investigated to obtain the PTFE nanofibers with different diameters, and the film has been characterized by SEM, TG, XRD, FT-IR, and EDS, and the mechanical and hydrophobic properties of the membranes were also investigated. The PTFE nanofiber membranes after sintering had nanofiber and nanowire structures. Moreover, the membranes were tested in air filtration. The filtration efficiency and pressure drop were tested to evaluate the membrane permeability and separation properties. The results showed a high filtration efficiency (98%) and a low pressure drop (90 Pa) for 300 nm sodium chloride aerosol particles at a 30 L min⁻¹ airflow velocity and the hydrophobic membranes showed durable self-cleaning properties, which suggested that the PTFE nanofiber membranes were a promising candidate for high temperature filtration applications.

The immobilization of photocatalysts is considered an effective approach to solve the problem of the difficult recycling of powdered nanocatalysts after photocatalytic degradation. In this paper, tin dioxide/titanium dioxide (SnO₂/TiO₂) composite nanoparticles with excellent photodegradation performance and poly(vinylidene fluoride) (PVDF) resin were used as raw materials to prepare composite membranes for the catalytic degradation of rhodamine B (RhB) dye via a non-solvent-induced phase separation method. Specifically, the basic properties of SnO₂/TiO₂ composite nanoparticles were systematically analyzed, the photocatalytic performance of SnO₂/TiO₂/PVDF composite membranes was thoroughly investigated, and the photocatalytic mechanism has been revealed. Experimental results showed that the SnO₂/TiO₂ composite photocatalyst demonstrates a higher photocatalytic activity than the single photocatalyst with the SnO₂/TiO₂ composite comprising Sn/Ti in a molar ratio of 1 : 6, showing the highest photocatalytic performance. After SnO₂/TiO₂ composite particles were used as a kind of raw material for the production of PVDF membrane, the photocatalytic degradation rate of RhB by the SnO₂/TiO₂/PVDF composite membrane was as high as 91.84%. Moreover, ˙OH and h⁺ play a very important role in the whole photocatalytic degradation process. In summary, this paper will provide an effective guidance to improve the photocatalytic degradation of SnO₂/TiO₂/PVDF composite membranes, which will ultimately provide a broad potential application of photocatalysis in the field of water treatment.

Effective hemorrhage control becomes increasingly significant in today’s military and civilian trauma, while the topical hemostats currently available in market still have various disadvantages. In this study, three low molecular weight silk fibroins (LMSF) were prepared through hydrolysis of silk fibroin in a ternary solvent system of CaCl₂/H₂O/EtOH solution at different hydrolysis temperatures. Fourier transform infrared spectroscopy analysis showed that the content of β sheet structure in the LMSF decreased with the increase in hydrolysis temperature. The results of thromboelastographic and activated partial thromboplastin time methods showed that the LMSF hydrolyzed at 50 °C can significantly strengthen the coagulation in blood and activate the intrinsic pathway of coagulation cascade. In the murine hepatic injury model, the LMSF hydrolyzed at 50 °C can promote the blood clotting and decrease the blood loss and bleeding time. Based on these results, it can be suggested that the developed LMSF has the excellent hemostatic effect and may be a promising material in clinical hemostatic application.

This study reveals the first attempt to apply PTFE hollow fiber membranes for removing ultrafine particles in PM_2.5.

The anti-fouling performance of membranes is an important performance in the separation of oil/water. However, the membrane with anti-fouling performance will also have surface scaling phenomenon when it runs for a long time. Therefore, there is still a great demand for stain-resistant membranes with good self-cleaning ability and high flux recovery rate. Based on this, this paper firstly prepared a hydrophilic membrane with carboxyl group and carboxyl ion by blending poly(ethylene-alt-maleic anhydride) (PEMA) and polyvinylidene fluoride (PVDF), and then prepared a self-cleaning composite membrane by in situ mineralization of β-FeOOH particles on the surface of the membrane for efficient oil-in-water emulsion separation. A large number of –COOH/COO⁻ and β-FeOOH particles on the membrane surface make the composite membrane have strong hydrophilic properties (WCA = 20.34°) and underwater superoleophobicity (UOCA = 155.10°). These composite membranes have high separation efficiency (98.8%) and high flux (694.56 L m⁻² h⁻¹ bar⁻¹) for soybean oil-in-water emulsion. Importantly, the as-prepared membrane shows excellent flux recovery rate (over 99.93%) attributed to the robust photo-Fenton catalytic activity of β-FeOOH, and the β-FeOOH is chemically bonded to the as-prepared membrane, which makes the as-prepared membrane have good reusability. This work provides hope for the application of self-cleaning membranes in the construction of anti-fouling membranes for wastewater remediation.