Phototransformation of tetrabromobisphenol A in saline water under simulated sunlight irradiation.

The widespread use of halogenated flame retardants in recent years has led to the accumulation of TBBPA in water, which may cause potential harm to living organisms. The phototransformation of the flame retardant TBBPA in alkaline saline water under simulated sunlight irradiation was investigated. The effects of abiotic factors such as the initial concentration of TBBPA, chloride ion concentration, solution pH, inorganic anions and cations, dissolved organic matter (DOM) were studied. The results showed that the phototransformation rate of TBBPA accelerated with the decrease of the initial concentration of TBBPA, the increase of chloride ion concentration and solution pH. The scavenging experiments showed that •OH, 1O2, O2•- and 3TBBPA* all participated in the phototransformation of TBBPA. The presence of NO3-, CO32-, SO42-, Mg2+, Ca2+, Fe3+ and fulvic acid (FA) all inhibited the phototransformation of TBBPA in the present study. The phototransformation products of TBBPA were detected by liquid chromatography-mass spectrometry (LC-MS), and the phototransformation pathways were proposed. This is the first report on the photo-induced generation of halogen exchange products from TBBPA in saline solutions, which will contribute to a better understanding of the environmental behavior and risks of BFRs in water.

Lead release and species transformation of commercial minium pigments in aqueous phase under UV-irradiation.

This study reports the lead ions release and species transformation of minium pigment under UV-irradiation in aqueous phase. The effects of fulvic acid (FA) and pH on lead ions release were investigated. Lower pH and higher FA concentration facilitate the release of lead ions. During photoreaction, electron donors (FA) are provided to scavenge photogenerated holes and enhance the charge separation, leading to the increased lead ions release. When significant amounts of FA exist in the water, they will complex with the released lead ions preferentially. Then, lead ions react with CO2 and proton resulting in the formation of insoluble Pb3(CO3)2(OH)2 after FA consumed. Correspondingly, the dissolved lead ion concentration in water showed a trend of increasing first and then decreasing. Based upon characterization and experimental results, lead ions release and lead species transformation mechanisms of minium were eventually speculated. This research is helpful for better understanding the environmental behavior and risk of semiconductor pigments in natural water.