Grain-like bismuth-rich bismuth/bismuth oxychlorides intra-heterojunction: Efficacious solar-light-driven photodegradation of fluoroquinolone antibiotics and 2-level factorial approach

Oxygen-rich bismuth oxybromide nanosheets coupled with Ag2O as Z-scheme nano-heterostructured plasmonic photocatalyst: Solar light-activated photodegradation of dye pollutants

In this research to enhance the photocatalytic activity of Bi₂₄O₃₁Br₁₀, precipitation fabrication of the Z-scheme heterojunction with Ag-Ag₂O has been investigated. The characterizations were carried out by XRD, FESEM, TEM, EDX, BET-BJH, DRS and pH_pzc analyzes. The Ag-Ag₂O/Bi₂₄O₃₁Br₁₀ Z-scheme heterojunction nanophotocatalyst with weighted ratio of 3:1 exhibited the wide absorption in the visible light region and displayed the high photocatalytic activity for the photodegradation of acid orange 7 (96.5%, 94.1% and 90% for 10, 20 and 60 mg/L, respectively after 120 min) and eosin yellow (for 10 mg/L: 81.5%) compared to the other composites and pure Bi₂₄O₃₁Br₁₀ and Ag-Ag₂O samples. The highly enhanced photocatalytic activity of Ag-Ag₂O/Bi₂₄O₃₁Br₁₀ (3:1) was assigned to the surface plasmon resonance effect of silver nanoparticles, high solar-light-response and the structure of Z-scheme heterojunction, which effectively reduces the recombination of the photogenerated charge carriers. Moreover Ag-Ag₂O/Bi₂₄O₃₁Br₁₀(3:1) Z-scheme heterojunction nanophotocatalyst exhibited the good photocatalytic activity even after 4 runs.

Sunlight-activated 3D-mesoporous-flowerlike Cl-Br bismuth oxides nanosheet solid solution: In situ EG-thermal-sonication synthesis with excellent photodecomposition of ciprofloxacin

In this research, a group of BiOX (Cl:Br) nanosheet solid solution with various Cl/Br molar ratios have been fabricated using a facile one-pot in-situ thermal-sonication method. The crystal phases structure, elemental composition, morphology, specific surface area and optical features of as-synthesized photocatalyst were explored by XRD, EDX, FESEM, HRTEM, AFM, BET-BJH, and DRS techniques. The photocatalytic activity of nanophotocatalysts was investigated by photodegradation of ciprofloxacin as a model pharmaceutical pollutant under simulated solar light illumination. The scavenging effect was studied by using tTriethanolamine and 2-propanol to evaluate the roles of holes and hydroxyl radicals as main active species. All the samples showed higher photocatalytic activity compared to pristine BiOCl and BiOBr. Among the solid solutions, BiOX (Cl:Br = 1:3)-U sample exhibited excellent photocatalytic performance by 100% degradation efficiency of ciprofloxacin within 120 min. The outstanding photocatalytic activity of BiOX (Cl:Br = 1:3)-U might be ascribed to the large specific surface area, suitable morphology and band gap, effective separation of the photo-generated electron-hole pairs and the existence of the meso-size pores in structure. Moreover, results demonstrated that the presence of ultrasound irradiations and generated microjets during the synthesis step could appreciably improve the photocatalytic performance. After 4 cycles, there was no significant change in photocatalytic activity that confirms the high stability of BiOX (Cl:Br = 1:3)-U mesoporous nanophotocatalyst. Besides, the influence of operating parameters on the degradation efficiency and the possible photocatalytic mechanism was examined.

Influence of fuel type and microwave combustion on in-situ fabrication of BimOnBrz mixed-phase nanostructured photocatalyst: Effective sun-light photo-response ability in tetracycline degradation

In this research, Bi_mO_nBr_z nanophotocatalysts were fabricated using various fuels such as ethylene glycol, propylene glycol and glycerol to investigate the effect of fuel types on the photocatalytic activity and structure. Moreover, the influence of conventional and microwave combustion was investigated. Results of XRD, EDX, BET-BJH, FESEM, TEM and DRS techniques illustrated that the simultaneous use of the glycerol and microwave irradiation was leaded to the synthesis of Bi_mO_nBr_z nanophotocatalyst with unique characteristics; which consists of 26 % BiOBr and 74 % Bi₂₄O₃₁Br₁₀. The photocatalytic performance of this sample was investigated in the photo-decomposition of the tetracycline antibiotic under a light source that was simulated as the solar light. The results of reactor test showed the highest photo-degradation efficiency (98.9 %) of tetracycline over this nanophotocatalyst. In addition, in order to appraise the effects of operational variables on the photocatalytic process efficiency the tetracycline concentration, initial pH of polluted solution and dosage of photocatalyst were changed. Moreover, the re-used of the optimum photocatalyst was evaluated. Finally, a mechanism for the photocatalytic decomposition of the antibiotic was suggested.