Activation Of Peroxymonosulfate By Prussian Blue Analogue And Its Derivative For Degradation Of Bisphenol A

The technology of persulfate activation based Fenton-like reactions,a kind of advanced oxidation processes developed in recent years,has attracted wide attention due to its ability to in situ generate highly reactive sulfate radicals and hydroxyl radicals and degrade organic pollutants efficiently.Developing efficient and environmentally friendly Fenton-like catalysts and exploring the mechanism of Fenton-like reactions deeply are the focuses in this field currently.This study investigated the application and mechanism of Co-Fe Prussian blue analogue（Co-Fe PBA）and Prussian blue’s derivative of magnetic graphene encapsulated Fe nanoparticles（Fe@NC）in peroxymonosulfate（PMS）activation based Fenton-like reaction for the removal of organic pollutant bisphenol A（BPA）,and in the first time studied the effect of different spin states of cobalt on the sulfate radical-mediated Fenton-like activity.The contents of this study are as follows:（1）Co-Fe PBA was developed as a Fenton-like catalyst to activate PMS for the degradation of BPA with high performance(k=0.0852 min^-1).Co^II in the Co-Fe PBA was identified as the reaction active site mainly by X-ray photoelectron spectroscopy and M?ssbauer techniques.The theoretical calculation indicated that the longer oxygen-oxygen bond of SO₄-OH in PMS（HSO₅^-）adsorbed on the Co-Fe PBA surface makes PMS more easily generate sulfate radicals for degradation of BPA.（2）The effect of the spin state of cobalt on the PMS activation activity was studied first time by M?ssbauer spectroscopy in connection with the theoretical calculation.By comparing the PMS activation performances of Co（high spin）-Co（low spin）PBA,Co（high spin）-Fe PBA,Fe-Co（low spin）PBA and precursor K₃[Co（low spin）（CN）₆],it was found that high-spin cobalt has excellent activity of PMS activation.Theoretical calculations illustrated that facilitated electron transfer,high adsorption energy and low energy barrier for PMS activation catalyzed by high-spin cobalt ions are the main contributors for their excellent activities of PMS activation.This study is important for exploring the relationship between the electronic structure of the catalysts and their sulfate radical-mediated Fenton-like activity.（3）By heating and acidizing the precursor Prussian blue（PB）,Fe@NC has been successfully prepared as an excellent Fenton-like catalyst for PMS activation(k=0.3039 min^-1)with magnetic separation ability.M?ssbauer spectroscopy and X-ray photoelectron spectroscopy showed that the high performance of Fe@NC could be ascribed as its large specific surface area and the high content of pyrrolic nitrogen and zero-valent iron sites.The electron spin-resonance spectroscopy identified that the reactive species were singlet oxygen,sulfate radicals and hydroxyl radicals during the Fenton-like reaction catalyzed by Fe@NC.