Fabrication of visible-light induced fluorine doped bismuth oxide (Bi2O3-xFx) photocatalyst in degrading textile dyes from wastewater
Chakraborty Ak, Shumaila Razzaque, Md Ahsanul Haque, Afroza Akter, Sumon Ganguli, Md. Nazrul Islam, Alam S.M. Nur, Md Abdus Sabur
Abstract
Discharge of unused and untreated dye effluents into the environment by the textile industries is a major issue. In this wastewater, the methylene blue (MB) and methyl orange (MO) remain in a dissolved state along with various pollutants at different levels. To remove these dyes, visible light (λ ≥ 420 nm) active F (fluorine) doped bismuth oxide (Bi2O3-xFx) photocatalyst was synthesized through facile sol-gel method utilizing bismuth oxide (Bi2O3) and hydrofluoric acid (HF). Bi2O3-xFx demonstrated enhanced photocatalytic activity to decompose methylene blue (MB) and methyl orange (MO) under visible light. The F content in Bi2O3-xFx composite was optimized to 0.94 atom % with respect to organics decomposition. The study showed that enhanced photocatalytic activity of Bi2O3-xFx was ascribed due to participation of photo-induced electron (e¯)-hole (h+) in photocatalysis. The existence of hole (h+) and the generated °OH radical was experimentally confirmed in aqueous medium. The formation mechanism of these reactive species was explained on the basis of relative energy band position of Bi2O3-xFx and a detail photocatalytic decomposition reaction mechanism was proposed.