Cu₂O/N–TiO₂ was achieved through a two-step route by deposition of CuO on Degussa P25 TiO₂ using a wet impregnation method and then treatment with N₂/Ar plasma. The morphology, composition, and structure of the prepared catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR). XRD spectra indicated that neither the low-content copper oxides nor the plasma treatment changed the crystalline phase of TiO₂. XPS results indicated the transformation of Cu species from CuO to Cu₂O and the doping of N after plasma treatment. EPR spectra confirmed the formation of Ti³⁺ that was also induced by plasma treatment. TEM analysis revealed that the well crystallized Cu₂O nanoparticles, existed with sizes of ∼3 nm, dispersed uniformly on the surface of TiO₂. As for the optical absorption curves obtained by UV-vis absorption spectroscopy, an extended absorption edge of Cu₂O/N–TiO₂ was confirmed compared with that of TiO₂ and CuO/TiO₂. In addition, the photodegradation efficiency of methyl orange (MO) solutions over Cu₂O/N–TiO₂ were markedly enhanced under both the visible and full-spectrum light irradiation in comparison with TiO₂ and CuO/TiO₂. The mechanism of photocatalytic reaction over Cu₂O/N–TiO₂ corresponding to UV and visible light irradiation was discussed.

Melt-blown nonwoven materials have demonstrated significant advancements in a multitude of industrial sectors, mainly due to their high production efficiency, extensive specific surface area, and narrow aperture. The demand for melt-blown nonwoven materials has increased further in recent time, particularly in the wake of the novel coronavirus (COVID-19) pandemic. Polypropylene (PP) is extensively used in production and research due to its low cost, low weight, and easy processing, and the melt-blown materials made from it share similar characteristics. We systematically summarize the research advancements of melt-blown nonwoven technology and applications of PP-based melt-blown materials over the last few years. First, the principles and processes of melt-blown nonwoven that govern the production of micro/nano fibers are described. Then the raw materials and process technology of melt-blown are reviewed. After these, we highlight the use of PP-based melt-blown materials in key fields, including media filtration, oil–water separation, heavy metal ions removal, organic pollutants removal and battery separator. Finally, we summary and suggest some potential future research directions of melt-blown nonwoven technology and PP-based melt-blown materials.

The role of F⁻ in the corrosion of stainless steel at the stage of occluded cell corrosion in a mixture of chloride, fluoride, and sulfate ions was investigated. A simulated occluded corrosion cell was designed using an elaborate simulated rust layer. Composite electrodes were used to monitor the variation of the concentration of ions, pH, and dissolved oxygen of the occluded solution. The results show that the influence of F⁻ on the corrosion of 304 stainless steel, in the occluded cell corrosion stage, is concentration dependent. When the F⁻/Cl⁻ ratio is higher than 2, the corrosion can be significantly suppressed. Analyses showed that the corrosion inhibition effect could be attributed to the migration of F⁻ to the occluded cell, which can reduce the migration of Cl⁻, dampen the decrease in pH, and react with metal ions to form semi-soluble products. Meanwhile, the influence of F⁻ on the corrosion process was also verified using drilled stainless steel specimens, demonstrating the practicality and validity of the simulated occluded cell corrosion model.

In this study, the plasma graft polymerization technique was used to graft glycidyl methacrylate (GMA) onto polypropylene (PP) melt-blown fibers, which were subsequently aminated with N-methyl-D-glucamine (NMDG) by a ring-opening reaction, resulting in the formation of a boron adsorbent denoted as PP-g-GMA-NMDG. The optimal conditions for GMA concentration, grafting time, grafting temperature, and the quantity of NMDG were determined using both single factor testing and orthogonal testing. These experiments determined the optimal process conditions to achieve a high boron adsorption capacity of PP-g-GMA-NMDG. Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersion spectrum analysis (EDS), and water contact angle measurements were performed to characterize the prepared adsorbent. Boron adsorption experiments were carried out to investigate the effects of pH, time, temperature, and boron concentration on the boron adsorption capacity of PP-g-GMA-NMDG. The adsorption isotherms and kinetics of PP-g-GMA-NMDG for boron were also studied. The results demonstrated that the adsorption process followed a pseudo-second-order kinetic model and a Langmuir isothermal model. At a pH of 6, the maximum saturation adsorption capacity of PP-g-GMA-NMDG for boron was 18.03 ± 1 mg/g. In addition, PP-g-GMA-NMDG also showed excellent selectivity for the adsorption of boron in the presence of other cations, such as Na⁺, Mg²⁺, and Ca²⁺, PP-g-GMA-NMDG, and exhibited excellent selectivity towards boron adsorption. These results indicated that the technique of preparing PP-g-GMA-NMDG is both viable and environmentally benign. The PP-g-GMA-NMDG that was made has better qualities than other similar adsorbents. It has a high adsorption capacity, great selectivity, reliable repeatability, and easy recovery. These advantages indicated that the adsorbents have significant potential for widespread application in the separation of boron in water.