Preparation Of Mxene Supported Cobalt(Iron) Catalytic Materials And Their Removal Of Bisphenol A From Water

Degradation of organic micro-pollutants in water by nanocatalysts activated peroxymonosulfate（PMS）is a hot research topic in the field of water pollution.However,nanocatalysts are facing technical difficulties such as easy reunion and loss of active species,which lead to the reduction of their catalytic performance.Immobilization of nano-catalysts on supports can effectively solve this problem.In this paper,the preparation of two-dimensional layered titanium carbide（MXene）supported cobalt and iron catalysts and the degradation of bisphenol A（BPA）by PMS were studied.MXene with intercalation structure was prepared by etching aluminum titanium carbide（MAX）with hydrofluoric acid.The supported cobalt oxide（Co₃O₄）/MXene（CM-20%）and zero-valent iron（NZVI）/MXene（NM-0.1）composites were prepared by impregnation pyrolysis and chemical reduction,respectively.Characterization showed that the prepared composites had uniform particle size and good dispersion,and retained the layered structure of MXene.The degradation experiments of BPA showed that CM-20%and NM-0.1 had good catalytic activity,among which:（1）CM-20%/PMS system had high efficiency at pH=4-10,and pH=8 had the best efficiency,the removal rate of BPA could reach95%within 7 minutes;（2）NM-0.1/PMS system had high activity at pH=3-7,and BPA could be completely degraded within 20 minutes when pH=6.By calculating the activation energy of BPA degradation reaction,it was found that the catalytic degradation reaction was spontaneous,and the higher the temperature,the better the removal of BPA.The influence of coexisting anions on the catalytic performance and the performance of reuse was investigated.It was found that the presence of anions inhibited the degradation of BPA to varying degrees,and HCO₃^–had the most obvious inhibitory effect.CM-20%and NM-0.1 remained high catalytic activity after continuous recycling,and the loss rate of active species was very low,0.025 mg/L and 1.22mg/L,respectively.The results showed that the composites had good recyclability and stability.Ethanol and tert-butanol were used as free radical inhibitors to explore the mechanism of PMS degradation of BPA.Electron paramagnetic resonance experiment showed that sulfate radical(SO₄^·–)and hydroxyl radical（^·OH）existed simultaneously in the reaction,and SO₄^·–played a leading role.This paper provides a new research idea for inhibiting the agglomeration and loss of nanocatalysts,and expands the application of MXene in the field of environmental catalysis.