•TiO2/chrysotile-based silica nanofiber composites are synthesized for the first time.•TiO2 nanoparticles are well dispersed on the surface of SiO2 nanofibers without agglomeration.•The diameters of the TiO2 nanoparticles in the composites are less than 10 nm.•TiO2/SiO2 nanofiber composites show high photocatalytic activity.TiO2/chrysotile-based silica nanofibers composites (TiO2/SiO2NFs) were synthesized for the first time via a modified sol-gel method combining layer self-assembly procedure. In the composite, TiO2 nanoparticles are anatase structured and evenly dispersed without agglomeration on the surface of SiO2NFs in the form of monolayer. Compared to the commercial TiO2 (P25) and TiO2 prepared by similar sol-gel method, the TiO2/SiO2NFs composite exhibits much higher photocatalytic activity. The SiO2NFs in the composite not only provide a large adsorption capacity substrate, but also make TiO2 particles formed a well-dispersed monolayer to provide larger photocatalytic reaction surface area, resulting in the significantly increasing of photocatalytic activity. It is also found the TiO2/SiO2NFs prepared under 800 °C exhibits best photocatalytic activity due to the relatively optimum anatase crystalline phase fraction and crystallinity.

Chrysotile nanofibers, which are derived from the natural mineral chrysotile, are a promising reinforcement material used to improve the mechanical properties of composite films, causing minimal reduction in visible transparency. The fabricated films were characterized through scanning electron microscopy, atomic force microscopy, and UV–Vis spectroscopy. Results showed that the composite films exhibited high luminous transmittance at fiber contents ranging from 10 wt.% to 40 wt.%, with an average transparency above 75%. Transparency showed low sensitivity to the nanofiber content of the composite films and was dependent on refractive index difference between the nanofiber and the resin. The refractive index distribution of the resins ranged from 1.496 to 1.619, the resin matched better with nanofiber the obtained composites got higher transparency. The composite film exhibited the highest transparency of approximately 85%, with transparency loss less than 5%, under equal refractive index between the chrysotile nanofiber and the resin. This study illustrates that the high transparency of the composite film mainly resulted from the reduction of Rayleigh scattering effect.

•A flexible and transparent film is prepared from chrysotile nanofibres.•The nanofibre sheet is sandwiched by two layers of cured resin.•The nanocomposite films display excellent transparency with about 85% transmittance.•The addition of nanofibres improves the mechanical strength of cured resin greatly.In the present study, chrysotile nanofibres, obtained from physicochemical dispersion of natural chrysotile, were used to prepare nanofibre sheets by vacuum filtration. As-prepared sheets were then impregnated by UV-curable resin and cured by ultraviolet light to fabricate the flexible and transparent nanocomposite films. Observed from SEM, the transparent films showed a smooth surface and a typical sandwich structure in cross section, viz. nanofibre sheet filled with resin was sandwiched by two layers of resin. XRD patterns indicated the amorphous nature of cured resin and characteristic crystallographic structure of chrysotile in nanocomposite films. Though the nanofibre sheets were white in colour, and nanofibre contents in nanocomposites were as much as 43.4 wt%, the nanocomposite films displayed an excellent optical transparency with about 85% light transmittance in the visible light range. Tensile tests showed that the addition of nanofibres resulted in a great improvement in mechanical strength of the nanocomposite films; with the increase of nanofibre contents, the modulus and tensile strength of nanocomposite films increased gradually.Photos show the experimental phenomenon. The white nanofibre sheets can be written or printed like paper, and it's very interested that the handwriting is clearly visible from the front and back of the transparent films prepared from nanofibre sheets by vacuum impregnation and UV curing. This phenomenon can be attributed to the increase of transparency of film, which results from the replacement of air interstices in nanofibre sheet by resin with higher refractive index. Visible light can pass easily through the transparent film without obvious loss, but can be apparently adsorbed and scattered by ink particles that adhered to nanofibres and embedded in resin.

This paper presents an objective study on the utilization of stone coal vanadium slag in preparing cement clinker. The hydrates and hydration mechanism of this cement were analyzed and studied by means of the hydration heat analysis, X-ray diffraction (XRD) and the differential thermal gravity (DTG) analysis. The results of experiments show that the hydration mechanism is similar to ordinary Portland cement. The hydration process can be divided into five stages: (I) initial period; (II) induction period; (III) acceleration period; (IV) deceleration period; (V) final period And the hydrates are basically the same as Portland cement, mainly containing the calcium silicate hydrates (C-S-H), ettringite (AFt), portlandite (CH). It is proved that stone coal vanadium slag can be used as siliceous materials to prepare cement clinker Furthermore, the addition of fine materials such as the waste and fly ash can accelerate cement hydration, which is the result of giving rise to water-to-cementitious ratio. On the other hand, the fine materials may provide the crystal nucleus for hydrates such as portlandite. Using the waste and fly ash to replace part of clinker can prepare series of cement, whose compositions and physical properties are fully complied with the requirements of national standard, and bring huge ecological and economic benefits.

•Preparation of nepheline by alkali-hydrothermal process was proposed.•The adsorption process of fluoride well matched the Langmuir isotherm model.•The maximum adsorption capacity was 189 mg/g, far superior than major adsorbents.•The adsorption process followed a pseudo-second order rate law.A direct alkali-hydrothermal induced transformation process was adopted to prepare nepheline from raw kaolinite (shortened form RK in this paper) and NaOH solution in this paper. Structure and morphology characterizations of the synthetic product showed that the nepheline possessed high degree of crystallinity and uniform surface morphology. Specific surface area of nepheline is 18 m2/g, with a point of zero charge at around pH 5.0–5.5. The fluoride (F− ions) adsorption by the synthetic nepheline (shortened form SN in this paper) from aqueous solution was also investigated under different experimental conditions. The adsorption process well matched the Langmuir isotherm model with an amazing maximum adsorption capacity of 183 mg/g at 323 K. The thermodynamic parameters (ΔG0, ΔH0, and ΔS0) for adsorption on SN were also determined from the temperature dependence. The adsorption capacities of fluoride on SN increased with increasing of temperature and initial concentration. Initial pH value also had influence on adsorption process. Adsorption of fluoride was rapidly increased in 5–60 min and thereafter increased slowly to reach the equilibrium in about 90–180 min under all conditions. The adsorption followed a pseudo-second order rate law.