Solar Photocatalytic Degradation of Trace Organic Pollutants in Water by Bi(0)-Doped Bismuth Oxyhalide Thin Films

Abstract

Herein, we demonstrate the fabrication of Bi(0)-doped bismuth oxyhalide solid solution films for the removal of trace organic pollutants (TrOPs) in water. With the advantage of a viscous AlOOH sol, very high loadings (75 wt %) of bismuth oxyhalides were embedded within the thin films and calcined at 500 °C to develop porous alumina composite coatings. Various concentrations of Bi(0) doping were tested for their photocatalytic activity. Seven TrOPs including iopromide (IPRM), iohexol (IHX), iopamidol (IPMD), sulfamethoxazole (SMX), carbamazepine, venlafaxine, and bezafibrate (BZF) were selected for this study based on their occurrence and detection in effluents and surface waters worldwide. In all tests, with the exception of IPRM, 3% Bi(0)-doped BiOCl 0.875 Br 0.125 showed highest activity, which can be attributed to its unique, highly organized, and compact morphology besides its well-matched energy band positions. Although IPMD, IHX, IPRM, and SMX are susceptible to photolysis, still the photocatalytic activity significantly augmented the removal of all tested compounds. In addition, analysis of the surface charge excluded electrostatic interactions and confirmed the ion-exchange adsorption mechanism for the high degradation rate of BZF in the presence of bismuth oxyhalides.

Boosting Photocatalytic Activity Using Carbon Nitride Based 2D/2D van der Waals Heterojunctions

“…To surmount the drawback of unfavorable redox potential and stability of BiOI and BiOBr, the BiOCl with a wide indirect band gap and relatively more resilient nature seems to be a good replacement. Introducing the oxygen vacancies or Bi(0) doping in the BiOCl nanosheets was found to improve the photocatalytic performance significantly due to increased visible absorption and formation of subgap energy levels. , The performance can be further improved by making a 2D/2D vdW heterojunction . Wang et al synthesized an oxygen vacancy-rich ultrathin g-C 3 N 4 /BiOCl 2D/2D heterojunction using polyvinylpyrrolidone (PVP) which displayed excellent photocatalytic degradation performance for 4-chlorophenol (4-CP) and bisphenol A (BPA) degradation (Figure ).…”

Hydrothermal synthesis of BiOBr and BiOBr/CNT composites, their photocatalytic activity and the importance of early Bi6O6(OH)3(NO3)3·1.5H2O formation

“…BiOBr is now widely used as photocatalysts in degrading pollutants including dyes such as (Methyl Orange, Rhodamine B, Methylene Blue, etc.) [12,44,45], phenols [46], some phenolic compounds [3], and for some pesticides [47]. These are among the best choices when it comes to visible light photocatalytic activity due to its high photocorrosion stability and high photoactivity [48], its good chemical stability and non-toxicity [49], and the low probability of charge carrier recombination [50].…”

Visible-Light-Active Iodide-Doped BiOBr Coatings for Sustainable Infrastructure

“…Chloride- and iodide-doped BiOBr materials have been reported as promising photocatalysts for applications involving organic pollutant decomposition, photoelectrochemical biosensors, or carbon dioxide (CO 2 ) reduction . Most of these materials, however, have been produced in powder form from hydro/solvothermal methods, ,, which poses a challenge for scale-up and commercialization.…”

“…19−22 crystal structures and compositions, with Cl − and Br − or Br − and I − showing similar ionic radii (Cl − = 1.67 Å, Br − = 1.82 Å, and I − = 2.06 Å), 23 allowing for the continuous adjustment of band structures upon doping with minimum formation of detrimental crystal defects. 24 Chloride-and iodide-doped BiOBr materials have been reported as promising photocatalysts for applications involving organic pollutant decomposition, 25 photoelectrochemical biosensors, 26 or carbon dioxide (CO 2 ) reduction. 27 Most of these materials, however, have been produced in powder form from hydro/solvothermal methods, 20,28,29 which poses a challenge for scale-up and commercialization.…”