Characterization of TiO2 and an as-prepared TiO2/SiO2 composite and their photocatalytic performance for the reduction of low-concentration N-NO3− in water

Abstract

Excessive N-NO 3water pollution has become a widespread and serious problem that threatens human and ecosystem health. Here, a TiO 2 /SiO 2 composite photocatalyst was prepared via the sol-gel/hydrothermal method. TiO 2 and TiO 2 /SiO 2 were characterized by X-ray diffraction (XRD), UV-Vis differential reflectance spectroscopy (DRS), Fourier infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Afterward, the photocatalytic performance of TiO 2 and TiO 2 /SiO 2 to reduce low nitrate concentrations (30 mgN•L -1 ) under UV light were evaluated and the effects of different factors on this process were investigated, after which the reaction conditions were optimized. Removal rates of up to 99.93% were achieved at a hole scavenger (formic acid) concentration of 0.6 mL•L -1 , a CO 2 flow rate of 0.1 m 3 •h -1 , and a TiO 2 concentration of 0.9 g•L -1 . In contrast, TiO 2 /SiO 2 at a 1.4 g•L -1 concentration and a TiO 2 load rate of 40% achieved a removal rate of 83.48%,But with more than 98% of nitrogen generation rate.NO 2and NH 4 + were the minor products, whereas N 2 was the main product.

Enhancement of dielectric properties of acrylic resin elastomer‐based composites with SiO2 loaded carbon nanotubes

“…Determining whether SiO 2 is successfully loaded on CNT can be verified through basic characterization methods. In Figure 1A, the peaks at 3441 and 1641 cm −1 in the FT‐IR spectrum of the CNT correspond to OH stretching and mixed vibrations, respectively, probably attributed to the physical absorption of H 2 O molecules by the CNT owing to its large surface area and porous structure 14 . However, the OH absorption peaks at 3436 and 1636 cm −1 in the FT‐IR spectrum of SiO 2 @CNT show a significant redshift, which is possibly explained by the SiOH vibrations on the surface of the prepared SiO 2 nanoparticles 15 .…”