Synthesis of novel Bi/Bi4O5Br2 via a UV light irradiation for decomposing the oil field pollutants

Plasmonic Bi promotes the construction of Z-scheme heterojunction for efficient oxygen molecule activation

Reactive oxygen species (ROS) are essential to photocatalytic degradation of antibiotics in water. In this work, we prepared Ag₃PO₄/Bi@Bi₄Ti₃O₁₂ by simple in-situ reduction method and precipitation method, which improves the ability to capture visible light and increases the activity of photoinduced molecular oxygen activation, resulting in reactive oxygen species (ROS) such as superoxide radicals (•O₂^-), hydroxyl radicals (•OH), and H₂O₂. The excellent TC degradation efficiency derive from the SPR effect of the metal Bi on the surface enhances the light absorption intensity, and development of a Z-scheme heterojunction between Ag₃PO₄ and Bi₄Ti₃O₁₂ promotes the activation of molecular oxygen. A possible photodegradation mechanism of the as-prepared photocatalyst was proposed. This work provides an insight perspective to the synthesis photocatalysts with molecular oxygen activation for environmental remediation.

Efficient photodegradation of cefixime catalyzed by a direct Z-scheme CQDs-BiOBr/CN composite: Performance, toxicity evaluation and photocatalytic mechanism

Development of low-cost, nontoxic, highly efficient performance photocatalyst for water pollution control engineering is critical for environmental remediation. In this contribution, a direct Z-scheme heterojunction based on C quantum dot (CQDs), bismuth oxybromide (BiOBr) and bulk graphitic carbon nitride (g-C₃N₄, CN) (CQDs-BiOBr/CN composite) with outstanding photocatalytic activity and good reusability is successfully fabricated though a hydrothermal procedure for cefixime antibiotic photodegradation. In particular, the CQDs-BiOBr/CN composite possess the best cefixime degradation effect, the degradation rate is about 92.82% within 120 min. The enhancement photocatalytic activity of CQDs-BiOBr/CN can be ascribed to the improved light-harvest ability, the excellent adsorption performance, the efficient charge transportation and separation capability. A possible degradation pathway of cefixime is proposed base on HPLC-MS. Toxicity experiments demonstrate that the antibiotic activity of cefixime is effectively deactivated after degradation process, and which is no toxic effect for Rye seeds in deionized water. The CQDs-BiOBr/CN also displays the excellent photoactivation activity towards Escherichia coli (E. coli). Reactive-species-trapping experiments show that hydroxyl radical (⋅OH) and superoxide radical (⋅O₂^-) are the active reactive species in the photodegradation process. The CQDs-BiOBr/CN composite demonstrate an effective potential practical application in antibiotic pollutants degradation from wastewater.

Citrate iron complex induced dramatically enhanced oxidation of atrazine with bimetallic Bi/Fe0: Reactivity, oxidation and mechanism

The oxidative degradation of atrazine (ATR) using bimetallic Bi/Fe⁰ nanoparticles cooperated with citric acid (CA) and sodium citrate (NaCA) without extra addition of H₂O₂ or another oxidant was conducted. Almost 73% of ATR was removed in Bi/Fe⁰+NaCA + CA buffer system in 3 h, and the bimetallic Bi/Fe⁰ performs high stability and long service life in the buffer system according to the results of cyclic degradation experiments. The citrate iron complex of Fe(II)[Cit]^- played the key role for the degradation process since it could quickly react with the generated H₂O₂ to produce free radicals in the Bi/Fe⁰+NaCA + CA system, which broadened the applicable pH range of the traditional Fenton reaction and promoted the oxidative degradation process of ATR. The possible degradation pathways of ATR were also investigated. In the Bi/Fe⁰+NaCA + CA buffer system, twelve kinds of ATR intermediate products were detected, of which the main products were dechlorination products and alkyl oxidative products. Due to the pH controllable of the Bi/Fe⁰+NaCA + CA system, it could reduce the acidity impact on the environment and makes the additional impact on the environment lower. Therefore, this work provides a new strategy for the degradation of ATR.