Investigation on the photocatalytic degradation properties of BiOX on carbendazim and its mechanism

Abstract

Bismuth Oxyhalide (BiOX, X = Cl, Br, I) has been widely used in water purification, environmental remediation and other fields due to its special layered structure and good photocatalytic performance. In this work, BiOCl, BiOBr and BiOI photocatalysts were successfully synthesized by a simple solvothermal method and first applied to the mineralization and degradation of carbendazim (CBZ). The degradation performance of BiOX to CBZ was studied under different light sources and different pH conditions. And the influence mechanism of the degradation performance of the three catalysts were revealed by analyzing the structure, morphology, specific surface area, optical performance, energy band structure, and electronic density of state of the materials. The results showed that, under the irradiation of metal halide lamp, the photocatalytic activity of BiOBr was the best when the pH was at 7. The degradation efficiency reached 99 % after 3 h and more than 90 % CBZ molecules could be mineralized. The BiOBr catalyst had good stability in four cycles. Furthermore, it was found that the main active species were h + and ⋅O 2 À in the photodegradation process by free radical trapping experiment. Based on the density functional theory (DFT) calculation, it was demonstrated that different halogen atoms had different density of state contribution intensity in atomic orbitals, different band gap width and different light response capabilities by the analysis of its energy band structure and partial wave density of state (PDOS), resulting in different photocatalytic performance under different energy light irradiation.

Shining a light on fungicide- water: enhanced photocatalytic degradation using the CoTiO3/CaTiO3 nanocomposite and experimental and theoretical viewpoints on improved intervalence charge transfer from O2− to Ti4+ and from Co2+ to Ti4+ ions and spatial charge transfer

“…Its molecular structure is stable in various environments, including water, wastewater, soil, crops, and food. 4 The breakdown of other fungicides, such as thiophanate methyl and benzimidazole, could produce carbendazim. 5 CBZ has toxic effects on humans, animals, and plants, 6 such as DNA damage, 7 reproduction and developmental defects, 8,9 and neuro-, 10 liver and kidney toxicity.…”

“…Among these methods, semiconductor photocatalytic technology has become an essential solution to remediate environmental pollution. 17–21 However, there are few catalyst systems available for the photocatalytic degradation of CBZ, and only composite materials such as Fe/TiO 2 , 22 BiOX, 4 Gd 2 (WO 4 ) 3 , 23 Gd 2 S 2 /NRGO, 24 Cu 2 O/ZnO@PET, 25 and Bi 2 S 3 /BiFeO 3 15 are currently available. Therefore, expanding the diversity and effectiveness of photocatalysts suitable for this reaction is the current challenge.…”

Fabrication of high photocatalytic activity photocatalysts with TiO2 supported on lamellar BiOCl

“…The layered arrangement prevents the recombination of photogenerated charge carriers through internal electric fields produced between the halogen and [Bi-O-O-Bi] layers. Moreover, it diminishes the surface trapping of photogenerated carriers due to the low-dangling bonds resulting from covalently bonded layers [13]. Because of their unique energy band configurations, electrons are able to migrate from the conduction band of BiOCl to that of TiO 2 .…”