Ultrahigh adsorption and singlet-oxygen mediated degradation for efficient synergetic removal of bisphenol A by a stable zirconium-porphyrin metal-organic framework

Abstract

Bisphenol A (BPA), one of 23 most important endocrine disrupting chemicals, was efficiently removed and sequentially photodegraded by a zirconium-porphyrin metal-organic framework (MOF) catalyst under visible light for water treatment. Well control of photodegradation allows the kinetic separation of adsorption step and photodegradation step. Ultrahigh adsorption uptake of 487.69 ± 8.37 mg g-1 is observed, while efficient photodegradation could be observed within 20 min at the rate of 0.004 mg min-1. The synergetic effect boosts the photocatalytic efficiency and confirms that the catalysis happens inside the MOF pores other than in the solution phase. Furthermore, the mechanism was elucidated by diverse control experiments, such as in the conditions of 1O2 scavenger, in darkness and with the changes of light sensitizing ligands. It confirmed that BPA was oxidized by the 1O2 which was generated from porphyrin ligand within MOFs under visible-light. The excellent reusability and wide range of suitable pH range make the Zr-porphyrin MOFs practical for the photocatalytic water treatment processes.