Ferrate oxidation of bisphenol F and removal of oxidation products with ferrate resulted particles

Abstract

Bisphenol F (BPF) is used as bisphenol A (BPA) substitute in plastic products, and it has become an emerging environmental hormone. Herein, oxidation of BPF by ferrate [Fe(VI)] was explored. As solution pH varied from 6.5 to 10.0, reaction rate constant decreased from 2.0 × 103 M−1 s−1 to 1.2 × 102 M−1 s−1, and reaction ratio of ferrate with BPF was 3.33:1. Based on theoretical calculation, QSAR analysis and degradation product identification, it was found that C(14), C(4), C(11), and C(21) atoms of BPF molecular were electron rich and easy to be attacked by ferrate. Three possible pathways existed in the oxidation process of BPF by ferrate: hydroxylation pathway, bond-cleavage pathway, and coupling pathway. Total organic carbon (TOC) analysis showed that 8% of TOC was removed by ferrate oxidation [Fe(VI):BPF = 20:1], while 30% of TOC was adsorbed by ferrate resulted ferric particles. By analyzing particles formed by the self-decomposed ferrate and ferrate reacted with BPF with Fourier transform infrared spectroscopy (FTIR), it was found that the Fe-O peak red-shifted from 630 cm−1 to 605 cm−1, and OH stretch peak became broad and intense. These results indicated that complexation and hydrogen bond formed in the interaction of ferric particles with organics, and both physical adsorption and chemical adsorption participated in the removal of TOC with ferrate. Toxicity assessment and ECOSAR analysis showed that BPF had acute toxicity to P. phosphoreum, and coupling products were more toxic than their parent compound. Toxicity of oxidation products formed in oxidation by low molar ratio of ferrate [Fe(VI):BPF = 5:1] increased to 30%, while high molar ratio of ferrate [Fe(VI):BPF = 20:1] could effectively eliminate toxicity of BPF.