Degradation Of Tetrabromobisphenol A In Sulfate Radical Based Oxidation Processes

Tetrabromobisphenol A(TBBPA)is a brominated flame retardant(BFR)widely applied in the manufacture of paper,textiles,plastics,electronics and upholstered furniture.Due to its intensive use and high persistency.TBBPA is found in carious environmental matrices such as air conditioning filter dust,water,sediments and organisms.TBBPA is an endocrine disruptor and shows negative effects to mammals and human beings,inducing cytotoxicity,hepatotoxicity,nephrotoxicity and neurotoxicity.Therefore,proper treatment of TBBPA contaminated water and soil is required in order to decrease associated environment risks.Sulfate radical(SO4·-)generated by heat activated persulfate or Co2+ catalyzed peroxymonosulfate was employed to degrade brominated flame retardant tetrabromobisphenol A(TBBPA).Experimental results showed TBBPA can be oxidized rapidly in either of above SO4·--based oxidation processes and the degradation rate was positively correlated with the concentration of each reactant.Radical.scavenging tests using ethanol and t-butanol as probes revealed that SO4·-was the dominant oxidizing species and the second-rate-constant for reaction of sulfate radical with TBBPA was determined to be 3.49 ×1010 M-1 s-1 by conpetition kinetics method.Degradation efficiency was adversely affected by the presence of humic acid and bicarbonate.Based on brominated intermediates and products identified by liquid chromatography-mass spectrometry and calculated frontier electron densities of TBBPA,phenolic moieties in the TBBPA structure were reactive sites for SO4·-reaction and TBBPA transformation was most likely initialized by electron ion.Furthermore,transformation of bromine was a1so investigated in Co2+PMS oxidation process.Experimental results showed tribromophenol and several brominated disinfection by-products(Br-DBPs)with bromoform and momobrominated acetic acid were yielded.The presence of humic acid(HA)retard the release of Br-but enhance the formation of Br-DBPs.Therefore,removal of bromide-containing organic compounds in sulfate radical-based oxidation may pose toxicological risks to human health and this risk may be even more obvious in practical application.