Abstract:
Tetrabromobisphenol A (TBBPA) is widely used as a brominated flame retardant in construction materials and electronic products. Due to a large amount of applications, TBBPA was detected in wastewater treatment plants and various environmental medias such as air, soil and river sediments. It is harmful to the environment and causes serious issues to human healthy because of its toxicity. However, the removal of TBBPA by photolysis as well as its degradation mechanism is rarely reported. In this paper, the influence of pH, initial concentration of TBBPA, temperature and structural analogues on photolysis of TBBPA was studied. Acute toxicity change during photolysis was investigated as well. Finally, the degradation pathway of TBBPA under UV was proposed through the determination of photolysis intermediates by GC-MS. The photolysis of TBBPA follows first-order kinetic process and the rate constant of photolysis reaction under basic condition is controlled by the quantum yield (
Φ). Under the same reaction conditions, the rate constant of photolysis reaction decreases with the increasing of initial TBBPA concentration and phenol concentration, while it increases with temperature. The direct photolysis can't reduce acute toxicity effectively because of the toxicity of intemediates after photolysis. GC-MS results show that the cleavage of
β-bond (bond between isopropyl and benzene ring) and C-Br bond of tetrabromobisphenol A is involved during the photolysis under ultraviolet light. The main intermediates include 2,6-dibromophenol and 2,4-dibromo-4-isopropyl-phenol.