One-Pot Facile Synthesis of Cerium-Doped TiO₂ Mesoporous Nanofibers Using Collagen Fiber As the Biotemplate and Its Application in Visible Light Photocatalysis

Cerium-doped TiO₂ (Ce_<i>x</i>/TiO₂) mesoporous nanofibers were prepared by one-pot facile synthesis method using collagen fiber as the biotemplate. The physicochemical properties of the as-prepared Ce_<i>x</i>/TiO₂ nanofibers were well characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N₂ adsorption–desorption isotherms, and UV–vis diffuse reflectance spectrum (UV–vis DRS). The visible light absorption ability and the band gap energy of the Ce_<i>x</i>/TiO₂ nanofibers could be adjusted by changing the doping amount of Ce. For example, when the mole ratio of Ce/Ti was fixed at 0.03, the absorbance wavelength of the Ce_0.03/TiO₂ reached 739 nm, and the corresponding band gap energy was obviously reduced to 1.678 eV. Photodegradation of Rhodamine B (RhB) was used as the probe reaction to evaluate the visible light photocatalytic activity of the Ce_<i>x</i>/TiO₂ nanofibers. Compared with the undoped TiO₂ nanofiber and commercial TiO₂ catalyst (Degussa P25), the Ce_<i>x</i>/TiO₂ nanofibers showed the excellent photocatalytic activity. Especially, the degradation degree of RhB using Ce_0.03/TiO₂ nanofiber reached 99.59% in 80 min, with corresponding TOC removal efficiency of 77.59%

Immobilization of <i>Saccharomyces cerevisiae</i> using polyethyleneimine grafted collagen fibre as support and investigations of its fermentation performance

<p>In the present investigation, an collagen fibre (CF), abundant natural biomass, was successfully grafted by polyethyleneimine (PEI). The resultant PEI grafted collagen fibre (CF-PEI) was employed as biocompatible and high cell loading support matrix for the immobilization of <i>Saccharomyces cerevisiae</i> cells. The as-prepared CF-PEI immobilized cells (CF-PEI-cell) exhibited high activity and stability for both batch and continuous fermentation. In batch fermentation, CF-PEI-cells showed enhanced stability as compared with other matrices supported cells, and produced an average ethanol concentration of 45.04 g/L with ethanol yield (<i>Y_P/S</i>) of 0.46 g/g and glucose conversion efficiency (η) of 90.4%. Continuous fermentation was operated stably in a down-flow trickling bed reactor charged with CF-PEI-cell for a total of 2 months. When the dilution rate was 0.16 1/h, the average ethanol productivity reached 7.18 g/(L h) with η of 88.94%. Further scanning electron microscopy observations confirmed that yeast cells can proliferate on the surface of CF-PEI during ethanol fermentation, which demonstrates that CF-PEI is indeed an ideal matrix for the immobilization of yeast cells.</p

Absorption and Reflection Contributions to the High Performance of Electromagnetic Waves Shielding Materials Fabricated by Compositing Leather Matrix with Metal Nanoparticles

Leather matrix (LM), a natural dielectric material, features a hierarchically suprafibrillar structure and abundant dipoles, which provides the possibility to dissipate electromagnetic waves (EW) energy via dipole relaxation combined with multiple diffuse reflections. Conventionally, metal-based materials are used as EW shielding materials due to that their high conductivity can reflect EW effectively. Herein, a lightweight and high-performance EW shielding composite with both absorption and reflection ability to EW was developed by coating metal nanoparticles (MNPs) onto LM. The as-prepared metal/LM membrane with only 4.58 wt % of coated MNPs showed excellent EW shielding effectiveness of ∼76.0 dB and specific shielding effectiveness of ∼200.0 dB cm³ g^–1 in the frequency range of 0.01–3.0 GHz, implying that more than 99.98% of EW was shielded. Further investigations indicated that the high shielding performances of the metal/LM membrane were attributed to the cooperative shielding mechanism between LM and the coating of MNPs

Synergistic Adsorption and In Situ Catalytic Conversion of SO₂ by Transformed Bimetal-Phenolic Functionalized Biomass

SO2 removal is critical to flue gas purification. However, based on performance and cost, materials under development are hardly adequate substitutes for active carbon-based materials. Here, we engineered biomass-derived nanostructured carbon nanofibers integrated with highly dispersed bimetallic Ti/CoOx nanoparticles through the thermal transition of metal-phenolic functionalized industrial leather wastes for synergistic SO2 adsorption and in situ catalytic conversion. The generation of surface-SO32– and peroxide species (O22–) by Ti/CoOx achieved catalytic conversion of adsorbed SO2 into value-added liquid H2SO4, which can be discharged from porous nanofibers. This approach can also avoid the accumulation of the adsorbed SO2, thereby achieving high desulfurization activity and a long operating life over 6000 min, preceding current state-of-the-art active carbon-based desulfurization materials. Combined with the techno-economic and carbon footprint analysis from 36 areas in China, we demonstrated an economically viable and scalable solution for real-world SO2 removal on the industrial scale