Facile synthesis of novel Co3O4-Bi2O3 catalysts and their catalytic activity on bisphenol A by peroxymonosulfate activation

- A novel Co3O4-Bi2O3 catalyst prepared via a facile microwave-assistant method.
- The calcination temperature has significant influence on the catalyst activity.
- Co3O4-Bi2O3 catalyst shows high degradation efficiency and TOC removal for BPA.
- SO4− on the surface-bound plays a dominant role in the BPA degradation process.
- The catalytic oxidation proceeds efficiently over a pH ranging from 3.0 to 9.0.

A novel Co3O4-Bi2O3 catalyst was synthesized by a microwave-assisted co-precipitation method and systematically characterized with multifarious techniques to investigate its crystallinity, morphology and chemical state of Co3O4-Bi2O3. The catalytic activity of Co3O4-Bi2O3 in peroxymonosulfate (PMS) activation was assessed through bisphenol A (BPA) degradation. The results indicated that the catalyst synthesized by microwave irradiation and calcination treatment of 200 °C exhibited good stability, high catalytic activity and mineralization percentage of BPA degradation under a broad pH range in the Co3O4-Bi2O3/PMS system. The BPA degradation in aqueous solution of 20 mg·L−1 reached almost 100% within 30 min by using 0.3 g·L−1 of catalyst and [PMS]/[BPA] = 5 at pH ranging from 3.0-9.0. The activation energy (Ea = 50.59 kJ·mol−1) was calculated under different reaction temperatures, indicating that the catalytic reaction occurred easily in the Co3O4-Bi2O3/PMS/BPA system. According to the characterizations of catalyst, as well as the dissolving and trapping studies, it was illustrated that BPA molecules were degraded mainly by the surface-bound SO4− radicals. At the same time, the increase of cobalt (III) content was caused by the catalytic reaction between PMS and cobalt (II) on the surface of catalyst. Overall, the study could lay groundwork toward the catalyst-activated peroxymonosulfate-based oxidation system in wastewater treatment.

Schematic representation of degradation of BPA with Co3O4-Bi2O3 by PMS activation in Co3O4-Bi2O3/PMS system.107