Structural and Optical Properties of Bi12NiO19 Sillenite Crystals: Application for the Removal of Basic Blue 41 from Wastewater

Abstract

This article covers the structural and optical property analysis of the sillenite Bi12NiO19 (BNO) in order to characterize a new catalyst that could be used for environmental applications. BNO crystals were produced by the combustion method using Polyvinylpyrrolidone as a combustion reagent. Different approaches were used to characterize the resulting catalyst. Starting with X-ray diffraction (XRD), the structure was refined from XRD data using the Rietveld method and then the structural form of this sillenite was illustrated for the first time. This catalyst has a space group of I23 with a lattice parameter of a = 10.24 Å. In addition, the special surface area (SSA) of BNO was determined by the Brunauer-Emmett-Teller (BET) method. It was found in the range between 14.56 and 20.56 cm2·g−1. Then, the morphology of the nanoparticles was visualized by Scanning Electron Microscope (SEM). For the optical properties of BNO, UV-VIS diffusion reflectance spectroscopy (DRS) was used, and a 2.1 eV optical bandgap was discovered. This sillenite′s narrow bandgap makes it an effective catalyst for environmental applications. The photocatalytic performance of the synthesized Bi12NiO19 was examined for the degradation of Basic blue 41. The degradation efficiency of BB41 achieved 98% within just 180 min at pH ~9 and with a catalyst dose of 1 g/L under visible irradiation. The relevant reaction mechanism and pathways were also proposed in this work.

Bismuth Sillenite Crystals as Recent Photocatalysts for Water Treatment and Energy Generation: A Critical Review

“…Figure 1 shows the crystal structure of the perfect Bi 12 MO 20 sillenite and local structure around the Bi and the M sites. The general structure of the BMO structure is described by a bismuth atom (Bi 3 • ) surrounded by eight oxygen atoms that share corners with other comparable polyhedra BiO 8 and tetravalent ions MO 4 that occur both at the cube center and on the corners of the cube [54][55][56][57][58][59][60]. There is a critical point of certain bismuth catalysts in the literature that was different from those reported and corresponds to the sillenite stoichiometric model.…”

“…There has recently been a surge in research on sillenite-phase semiconductors for various photocatalytic applications. Series of sillenite semiconductors Bi 12 CoO 20 [34], Bi 12 TiO 20 [25], Bi 12 NiO 19 [58], and Bi 12 ZnO 20 [32,70] were studied, and they showed high photoactivity against various kinds of pollutants. So, it was exciting to scan the literature and summarize recent works that dealt with sillenite crystals as photocatalysts for water treatment and environmental application.…”

“…Based on our recent research that dealt with the characterization and application of the sillenites Bi 12 TiO 20 (BTO), Bi 12 CoO 20 (BCO), Bi 12 ZnO 20 (BZO), and Bi 12 NiO 19 (BNO) for environmental applications, it is now feasible to compare their efficiency in terms of pollution removal. All those sillenites were synthesized by the sol-gel method, and the detailed method for each material can be found in the following works [25,34,58,70]. Cefixime (CFX) was chosen as the target pollutant since it was used in most of those works.…”

“…However, the sillenite BNO has shown a very low degradation efficiency for CFX, although it has given a very efficient degradation for Basic blue 41. The low efficiency of the sillenite BNO may be explained by the fact that BNO photodegradation can be enhanced in the basic condition [58]; however, CFX photodegradation is favored in the neutral medium of approximately 6 [25]; therefore, the two are incompatible. This phenomenon may be due to the surface charge of both the catalyst and the pollutant.…”

Visible-Light-Active Photocatalysts for Environmental Remediation and Organic Synthesis

“…Currently, this issue has collected six papers addressing the preparation and characterization of novel photocatalytic materials and their use in the visible (or solar) lightdriven photocatalytic removal of pollutants from liquid phases and in the inactivation of bacteria [1][2][3][4][5][6]. The photocatalytic efficiencies of Ag 3 PO 4 nanoparticles [2], Bi 12 NiO 19 sillenite crystals [3], g-C 3 N 4 /nanodiamond heterostructures [4], Ag/Cu 2 O [5], and activated carbon/TiO 2 [6] are shown. An improvement in photocatalytic activity toward the simultaneous removal of phenol and Cr(VI) under visible light is also evidenced by MoS 2 decorated on a g-C 3 N 4 heterostructure catalyst [1].…”