BiOCl/TiO₂/diatomite composites with enhanced visible-light photocatalytic activity for the degradation of rhodamine B

Abstract

A BiOCl/TiO2/diatomite (BTD) composite was synthesized via a modified sol–gel method and precipitation/calcination method for application as a photocatalyst and shows promise for degradation of organic pollutants in wastewater upon visible-light irradiation. In the composite, diatomite was used as a carrier to support a layer of titanium dioxide (TiO2) nanoparticles and bismuth oxychloride (BiOCl) nanosheets. The results show that TiO2 nanoparticles and BiOCl nanosheets uniformly cover the surface of diatomite and bring TiO2 and BiOCl into close proximity. Rhodamine B was used as the target degradation product and visible light (λ > 400 nm) was used as the light source for the evaluation of the photocatalytic properties of the prepared BTD composite. The results show that the catalytic performance of the BTD composite under visible-light irradiation is much higher than that of TiO2 or BiOCl alone. When the molar ratio of BiOCl to TiO2 is 1:1 and the calcination temperature is 400 °C, the composite was found to exhibit the best catalytic effect. Through the study of the photocatalytic mechanism, it is shown that the strong visible-light photocatalytic activity of the BTD composite results mainly from the quick migration of photoelectrons from the conduction band of TiO2/diatomite to the surface of BiOCl, which promotes the separation effect and reduces the recombination rate of the photoelectron–hole pair. Due to the excellent catalytic performance, the BTD composite shows great potential for wide application in the field of sewage treatment driven by solar energy.

A novel carbon nanotube–magnesium oxide composite with excellent recyclability to efficiently activate peroxymonosulfate for Rhodamine B degradation

“…where C 0 is the initial RhB concentration, C t is the RhB concentration at time t in the PMS&CNTs/MgO system, and k obs is the pseudo-first-order constant (min -1 ) [21].…”

High-Efficiency Catalysis of Peroxymonosulfate by MgO for the Degradation of Organic Pollutants

“…This result is surprisingly like previous catalytic experiments ( Figure S8) and XPS results (Figure 7), so it is further determined that oxygen vacancy in the MgO surface is the key factor for MgO-catalyzing PMS. Optical investigations can reveal very useful information to understand the physical properties of materials [23,49]; as a result, photoluminescence spectroscopy (PL) of three kinds of MgO with different particle sizes are given in Figure 8. With an excitation wavelength of 325 nm, the PL spectra exhibit an intrinsic emission peak at 372 nm, a purple emission resulted from adsorbed oxygen species centered around 400 nm, and two blue emission around 454 and 469 nm, which are attributed to the oxygen vacancy (F center) [50,51].…”

Highly Efficient Photo-Degradation of Gaseous Organic Pollutants Catalyzed by Diatomite-Supported Titanium Dioxide

“…He, Luo, and Yu synthesized microdisk-like g-C 3 N 4 /diatomite composites utilized for the removal of methylene blue (MB) from MB/MO or MB/RhB mixed dyes [37]. Numerous other studies in this area have also been conducted [38][39][40][41]. The present study focuses on the removal of organic pollutants, the results of which will provide an exciting reference in the area of pollutant degradation.…”