Oxidative removal of bisphenol A using zero valent aluminum–acid system

Bisphenol A (BPA), a controversial endocrine disruptor, is ubiquitous in the aquatic environment. In this study, the oxidative degradation of BPA and its mechanism using zero valent aluminum (ZVAl)–acid system under air-equilibrated conditions was investigated. Under pH <3.5 acidic conditions, ZVAl demonstrated an excellent capacity to remove BPA. More than 75% of BPA was eliminated within 12 h in pH 1.5 reaction solutions initially containing 4.0 g/L aluminum and 2.0 mg/L BPA at 25 ± 1 °C. The removal of BPA was further accelerated with increasing aluminum loadings. Higher temperature and lower initial pH also facilitated BPA removal. The addition of Fe2+ into the ZVAl–acid system significantly accelerated the reaction likely due to the enhancing transformation of H2O2 to HO via Fenton reaction. Furthermore, the primary products or intermediates including monohydroxylated BPA, hydroquinone, 2-(4-hydroxyphenyl)propane and 4-isopropenylphenol, were identified and a possible reaction scheme was proposed. The remarkable capacity of the ZVAl–acid system in removing BPA displays its potential application in the treatment of organic compound–contaminated water.

Research highlights
► The zero valent aluminum–acid system possesses a relatively high oxidative capacity in removing aqueous BPA.
► Acidic conditions (pH < 3.0) facilitate the reaction.
► Ferrous ion (Fe2+) accelerates the reaction.
► Humic acid suppresses the reaction.