Synthesis of a novel Si-N-S flame retardant and its application on cotton cellulose biomacromolecule.

A novel flame retardant containing Si, N, and S elements, ((2-(triethoxysilyl)ethyl)thio)ethan-1-amine hydrochloride (TETEA), was synthesized via a click reaction and characterized using nuclear magnetic resonance spectroscopy (NMR) and fourier transform infrared spectroscopy (FTIR). Subsequently, the flame-retardant cotton fabric was fabricated by sol-gel method. The results indicated that TETEA was successfully loaded on cotton fabric and formed a uniform protective layer on the surface of cotton fabric, exhibiting excellent flame retardancy. The flame-retardant cotton fabric achieved limiting oxygen index (LOI) of 28.3 % and passed vertical combustion test without after-flame or afterglow time at TETEA concentration of 500 g/L. Thermogravimetric analysis revealed that the residual carbon content of the flame-retardant cotton fabric was much higher than that of the control under air and N2 conditions. Besides, the flame-retardant cotton fabric was not ignited in cone calorimeter test with an external heat flux of 35 kW/m2. The peak heat release rate and the total heat release decreased from 133.4 kW/m2 to 25.8 kW/m2 and from 26.46 MJ/m2 to 17.96 MJ/m2, respectively. This phosphorus-free flame retardant offers a simplified synthesis process without adverse environmental impacts, opening up a new avenue for the development environmentally friendly flame retardants compared to traditional alternatives.

Preparation of BiOCl/Bi2WO6 Photocatalyst for Efficient Fixation on Cotton Fabric: Applications in UV Shielding and Self-Cleaning Performances.

In this work, a visible-light-driven BiOCl/Bi2WO6 photocatalyst was obtained via a facile hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), ultraviolet/visible light diffuse reflection spectroscopy (UV/Vis), and photocurrent (PC). BiOCl/Bi2WO6 was modified with (3-chloro-2-hydroxypropyl) trimethyl ammonium chloride to obtain the cationized BiOCl/Bi2WO6. Cotton fabric was pretreated with sodium hydroxide (NaOH) and sodium chloroacetate solution to obtain carboxymethylated cotton fabric, which was further reacted with cationized BiOCl/Bi2WO6 to achieve finished cotton fabric. The cotton fabrics were characterized by Fourier-transform infrared spectroscopy (FT-IR), XRD, SEM, and EDS. The photocatalytic activity of the BiOCl/Bi2WO6 photocatalyst and cotton fabrics was assessed by photocatalytic degradation of MB (methylene blue) solution under simulated visible light. The self-cleaning property of cotton fabrics was evaluated by removing MB solution and red-wine stains. Results revealed that the coated cotton fabrics exhibited appreciable photocatalytic and self-cleaning performance. In addition, anti-UV studies showed that the finished cotton fabrics had remarkable UV blocking properties in the UVA and UVB regions. Therefore, the finished cotton fabric with BiOCl/Bi2WO6 can provide a framework for the development of multifunctional textiles.

Crystalline phase regulation of anatase-rutile TiO2 for the enhancement of photocatalytic activity.

Biphasic TiO2 with adjustable crystalline phases was prepared by the hydrothermal-calcination method assisted by nitric acid (HNO3) and hydrogen peroxide (H2O2), using potassium titanate oxalate (K2TiO(C2O4)2) as the titanium source. The influences of H2O2 volume on anatase and rutile contents and photocatalytic activity of biphasic TiO2 were investigated and the photocatalytic mechanism was explored. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and specific surface area (BET) were employed to characterize crystal structure, physical morphology, absorbable light, chemical composition, specific surface area and pore size distribution. The photocatalytic degradation efficiency towards a methylene blue (MB) solution under xenon light was tested, and the photocatalytic stability of the sample was investigated by photocatalytic cycle experiments. The prepared biphasic TiO2 was nanorod-shaped and had a large specific surface area. The results showed the anatase TiO2 content increased and the photocatalytic efficiency was enhanced as the H2O2 volume solution increased. Among the catalysts, the biphasic TiO2 prepared with 30 mL of H2O2 had the best photocatalytic effect and could entirely degrade the MB solution after 30 minutes under irradiation. After three repeated degradations, the photocatalytic degradation rate was still estimated to be as high as 95%. It is expected that the work will provide new insights into fabricating heterophase junctions of TiO2 for environmental remediation.

Big-leaf hydrangea-like Bi2S3-BiOBr sensitized TiO2 nanotube arrays with enhanced photoelectrocatalytic performance.

TiO2 nanoparticles as solar cells and photocatalysts caused extensive attention in solar energy utilization and environment remediation due to the high photoelectrochemical performance. We demonstrated a novel approach to fabricate big-leaf hydrangea-like Bi2S3-BiOBr self-assembled by superthin nanosheets on TiO2 nanotube arrays (TiO2 NTs/B2S3-BiOBr). Results indicated that the Bi2S3-BiOBr co-sensitization showed higher photoelectric conversion efficiency than the single Bi2S3 or BiOBr sensitization. More remarkably, TiO2 NTs/B2S3-BiOBr showed excellent photoelectrocatalytic (PEC) removal of MB, MO, RhB and Cr(VI). The remarkable PEC performance could be attributed to the strong visible light absorption and effective electron transportation at the interface of TiO2/B2S3-BiOBr. The high photoelectrochemical performances indicate that the TiO2 NTs/B2S3-BiOBr could work as potential photoelectric materials for large-scale applications in the photoelectrochemical energy conversion and pollutant removal.