Structural Design,Catalytic Performance And Mechanism Study Of Nanoporous Metal-based Materials For Peroxymonosulfate Activation

Wastewater treatment is closely related to human health,so it is widely concerned worldwide.Advanced oxidation processes（AOPs）is a widely accepted technology to solve the problem of wastewater pollution.The nanoporous metal and its metal oxide synthesized by the dealloying strategy is to remove the active elements from the alloy precursors,thus retaining the relatively inert components with the structure of the bicontinuous ligament-channel network.Nanoporous metal synthesized by dealloying has the advantages of high porosity,high surface area and good conductivity,which make it widely applicable in energy storage and conversion,surface enhanced Raman scattering and environmental remediation.Therefore,the dealloyed nano-porous metal materials have been used as catalysts for advanced oxidation and photocatalytic degradation.In this thesis,the non-toxic and inexpensive nano-porous copper（np-Cu）and nano-porous copper composite ferric oxide（np-Cu-Fe）catalysts were synthesized by dealloying method,which can be used as the catalyst of peroxomonosulfate（PMS）to efficiently degrade organic pollutants in sewage.The specific research mainly includes the following two aspects:1.Structural design,catalytic performance and mechanism study of np-Cu catalyst.The np-Cu was prepared by dealloying Al-Cu alloy as precursor.By adjusting the dealloying conditions,a Cu network with a trace amount of Cu₂O on the surface was obtained,showing the structural characteristics of double continuous ligament-channel.Compared with commercial Cu⁰and Cu₂O nanoparticles or similar materials prepared by liquid method,np-Cu has excellent catalytic performance in activating PMS to degrade bisphenol A（BPA）.The unique structure of np-Cu provides more active sites and pathways for mass transfer.In addition,the Cu network has good conductivity,which is conducive to electron transfer,and the Cu ligament has rich low coordination sites,which is conducive to the interaction with PMS.With the help of simulated sunlight,light and PMS work together to greatly improve the photochemical oxidation efficiency.In chemical oxidation,hydroxyl radical（·OH）and sulfate radical(SO₄^·-)play a major role,while in photochemical reaction,·OH,SO₄^·-and singlet oxygen（¹O₂）dominate the decomposition of BPA.2.Structural design,catalytic performance and mechanism study of np-Cu-Fe catalyst.Nanoporous Cu/Fe₃O₄heterostructure with rich oxygen vacancies was designed using Al-Cu-Fe alloy as precursor.The morphology of nano-porous Cu network,the valence of Fe and the concentration of oxygen defects can be controlled by changing the conditions of dealloying,such as the composition of precursor,dealloying time,additives and dealloying atmosphere.The dual-continuous ligament-channel structure,Cu-O-Fe interface and oxygen defects are beneficial to improve the catalytic activity of nano-porous Cu/Fe₃O₄activated PMS,such as 100%BPA（10 ppm）can be degraded within 3 min.The catalyst has good anti-interference ability and excellent catalytic efficiency under the conditions of wide p H range and coexistence of anions/organic matter.In this reaction system,¹O₂replaces·OH and SO₄^·-to dominate the degradation of BPA.