| Fly ash(FA)is a kind of solid waste produced by coal-fired power plants,which is mainly used in construction and agriculture with limited added value after classification and grading.In view of the above problems,this paper classifies and resource fly ash by modifying the surface of fly ash and then coating the functional materials,and prepares fly ash-based functional composite materials with good application prospects,so as to achieve the purpose of "classification resource utilization" of fly ash.(1)Design of ZnO/FA composites.The fly ash removed by magnetic beads was modified by phase change deposition to adjust the whiteness of the fly ash.A new ZnO/FA composite material was successfully prepared from hydrochloric acid modified fly ash with Ba(OH)2 and ZnSO4 as coating agents.The samples were characterized by XRD,FT-IR,particle size analyzer and BET.The results show that ZnO was coated on the surface of acid pickled and calcined fly ash by single factor test and orthogonal test,and the optimum process conditions were determined.The whiteness of fly ash increased from 34.7%ISO to 74.7%ISO,which greatly improved the whiteness value of fly ash.ZnO/FA composites are expected to be used in the packing field.(2)PANI@FAB/Ni composites.Electromagnetic microwave absorption materials were prepared by polymerizing PANI on the surface interface of FAB and Ni,and the mechanism of multi-component magneto-electric cooperative loss was studied.The PANI@FAB/Ni composite was successfully synthesized by interfacial polymerization of magnetic fly ash beads modified by silane coupling agent and nickel powder.XRD,FT-IR,SEM,VSM and NVA were used to investigate the structure,composition,morphology,magnetic properties and electromagnetic parameters of the composites in detail.The results show that PANI@FAB/Ni has the minimum reflectivity at 5.52 GHz.When the thickness is 5.48 mm,the RL value is-67.07 dB,the effective absorption bandwidth is 4.24 GHz,almost covering the Ku band(12～18 GHz),and the thickness is only 1.98 mm.Compared with PANI@FAB and PANI@Ni,the electromagnetic microwave absorption performance of PANI@FAB/Ni is obviously improved.The PANI@FAB/Ni’s excellent microwave absorption performance is attributed to the synergistic effect of dielectric loss and magnetic loss.A new type of electromagnetic absorbing material made from fly ash magnetic beads has broad commercial prospects.(3)Design of N-TiO2/FA composites.Nitrogen doping was designed in the demulsification process of nano titanium dioxide sol,and the surface of fly ash was modified under negative temperature gradient.Nitrogen doped titanium dioxide solar catalyst was prepared to explore the performance of solar catalytic industrial organic wastewater.The synthesized products were characterized by SEM,XRD,FT-IR and UV-Vis DRS,and the photocatalytic degradation of rhodamine B by visible light was tested.The results show that when the mass ratio of TiO2 to fly ash is 1:1 and the addition amount of urea is 0.5 g,the prepared N-TiO2/FA photocatalyst has a good degradation effect on rhodamine B under visible light.The degradation process can degrade 96.98%in 180 min,and the degradation process is consistent with the first-order kinetic model.The recycling for 6 times still has good stability and repeatability.This method provides a functional application scheme for high value-added resource fly ash,and has a good application prospect.To sum up,according to the characteristics of fly ash,three different fly ash-based functional composites were prepared by interface functionalized design method,which not only classified and resourced utilization of fly ash,but also greatly improved its added value,and had a good application prospect in different fields.Figure 44 table 12 reference 106... |
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