Surface-fluorinated TiO2 (F-TiO2) particles was synthesized by a simple fluorosilanization method to serve as a visible-light photocatalyst for rapid degradation of Rhodamine B (RhB) dyes. The fluroalkylsilane (FAS-17) was covalently immobilized on the TiO2 particles via robust Si–O bonds. The changes in surface properties of the F-TiO2 particles were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and zeta potential measurements. The optical property of the F-TiO2 particles was determined by UV-visible spectroscopy. Upon the fluorination modification, the zeta potential of TiO2 particles switched from positive to negative, whilst the optical property of bulk TiO2 particles remained almost unchanged. Photodegradation experimental results demonstrated that zwitterionic RhB dyes were more favorably adsorbed on F-TiO2 rather than on the Ti(IV) sites of the pristine TiO2, and that the photodegradation reaction of RhB on F-TiO2 proceeded much faster than that on the pristine TiO2. However, the adsorption and photodegradation rate of anionic methyl orange (MO) dyes did not show an obvious change on F-TiO2. These results suggested that the molecular structure of dyes played a key role in visible-light photodegradation reactions on F-TiO2 particles. Positive-charged diethylamine groups of RhB molecular structures were postulated to promote the adsorption of RhB dyes on the surface of F-TiO2 particles, thus leading to easy electron injection and induction of rapid photodegradation under visible-light illumination.
Maiping Yang,Weiqu Liu,Chi Jiang,Sha He,Yankun Xie,Zhengfang Wang
The purpose of this paper is to propose a facile, green and low-cost approach of the preparation of superhydrophobic cotton textiles, which can be fabricated with fluorinated TiO 2 sols via a sol-gel method. The coating was prepared with TiO 2 sols catalyzed with acetic acid, then modified by poly(Hexafluorobutyl methacrylate) (PHFBMA) which was synthesized by free radical polymerization. The wettability, surface morphology and chemical composition of pristine and modified cotton fabrics were investigated. The modified fabric presents a high contact angle reached up to 152.5°. The successful incorporation of fluorinated TiO 2 nanoparticles into cotton fabric was verified by the above measurements results. Additionally, the chemical stability of the coated fabric has been tested by immersing in different pH solutions and organic solvents, demonstrating the outstanding water repellency of the fabric. Furthermore, the treated cotton fabric shows excellent self-cleaning properties, which makes it an ideal material for large-scaled industrial applications in various conditions.
Zihao Hong,Ziyi Yuan,Zhiyu Liu,Raphael Semiat,J. Paul Chen
Membrane distillation (MD) is a thermal-based membrane separation process driven by vapor pressure differences generated by temperature differences, and has great potential for applications in desalination, wastewater treatment, and resource recovery. However, during long-term operation, wetting and fouling lead to deteriorated permeate quality and treatment efficiency. Herein, we developed a surface modification method for the polyvinylidene difluoride (PVDF) membrane to improve the antifouling and antiwetting ability without sacrificing permeability. This method imparts superhydrophobic properties to the PVDF membrane by depositing fluorinated TiO2 nanoparticles (NPs) on its surface. The modified PVDF membrane exhibited a higher water contact angle (WCA, 157.4°) and an ultralow water sliding angle (WSA, 2.1°), indicating successful superhydrophobic modification. The modified PVDF membrane possessed superior resistance against fouling and wetting. In 150-h operation of direct contact membrane distillation, it exhibited robust performance in treating a hypersaline solution (100 g/L NaCl) containing foulants (50 mg/L humic acid). The results also verified that the TiO2 layer was firmly attached to the membrane surface. Our study demonstrates that this surface modification approach can effectively improve the membrane performance of the MD process for treatment of high-salinity solution containing foulants.
In order to tailor the surface properties of propellants to meet the requirements of progressive burning and anti-erosion performance of propellant for high loading density tank guns, the surface migration and enrichment effects of fluorinated TiO 2 nanocomposite additives with low surface energy toward the air/solid interface of propellants were investigated. Fluorinated TiO 2 nanocomposites were prepared by emulsion polymerization and characterized by FT-IR spectroscopy, TEM, and TGA to obtain the information of chemical groups, morphology, and thermal stability. The propellant samples containing the fluorinated TiO 2 nanocomposite additives were manufactured by an extrusion process. The migration effect of the fluorinated TiO 2 nanocomposite additives was observed by SEM and X-ray energy dispersive analysis. The influence factors on the migration and enrichment properties of fluorinated TiO 2 nanocomposite additives in propellants were discussed. The results showed that there exists a gradient distribution of fluorine element in the additive modified propellants, indicating a significant surface enrichment of fluorinated groups inside the propellants. The composition of propellants and the chain structure of fluoropolymer also have a significant influence on the migration and enrichment properties of fluorinated TiO 2 nanocomposite additives in propellants. This study can bring forward the research of smart construction of slowing burning and anti-wear layers in the propellants.
危险品化学品经营许可证（带存储）