DEBROMINATION OF TETRABROMOBISPHENOL A (TBBPA) WITH AN ENVIRONMENTALLY FRIENDLY OXIDANT - FERRATE (VI)

Brominated flame retardants (BFRs) have been extensively applied in plastics and textiles to inhibit the ignition of these combustible materials. Of the most widely used BFRs, tetrabromobisphenol A [4,4-isopropyl-idenebis(2,6-dibromophenol), TBBPA] accounts for nearly 50% of the BFR products in the market, and has been frequently identified in the aquatic environment. Because TBBPA possesses a chemical structure similar to steroid hormones, its endocrine-disrupting effects on the ecosystem and public health are of increasing concern. In this study, bench-scale batch tests were conducted to study the debromination of TBBPA using an environmentally friendly oxidant, namely, ferrate (Fe(VI)), and evaluate the effects of certain key experimental parameters on TBBPA degradation. The factors tested included initial TBBPA concentrations (1.0 – 20.0 mg/L), Fe(VI) dose (2.0 – 20.0 mg/L as Fe), initial pH (5.5 - 9.0), and reaction time (30 min – 24 hours). TBBPA debromination was confirmed by the release of bromide ions and elevated solution pH. Under all the experimental conditions, Fe(VI) oxidation of TBBPA exhibited a pseudo–second-order reaction pattern (R²= 0.99). Generally, higher Fe(VI) dose and lower pH favored TBBPA degradation. At pH 5.5 and 20.0 mg/L Fe(VI), more than 85% of 20.0 mg/L TBBPA was debrominated within 5 hours. The encouraging preliminary results indicate that Fe(VI) has a strong potential to effectively treat TBBPA contaminated water.