Applied Basic Research Of Porous Material Derived From Iron Tailings

One crucial measure for achieving sustainable development is to enhance the level of solid waste recycling.Iron tailings,as a type of industrial solid waste with vast reserves,are stored in tailings ponds for extended periods.This not only occupies land resources,but also poses serious security risks and environmental pollution.Efficient processing and utilization of iron tailings is a viable approach to conserving energy,safeguarding the environment,and enhancing economic benefits.A diverse range of methods have been developed for utilizing iron tailings The comprehensive utilization of iron tailings in our country,especially its high-value,remains low.Porous materials,as important functional materials,play a crucial role in various fields such as environment,energy,construction and chemical industry.Particularly in environmental governance and sustainable development,there are of great significance.The high-silicon iron tailings with large stock were utilized as raw materials in this study.By taking advantage of their main components and structural properties that contain quartz and hematite,a series of porous materials have been constructed by various physical and chemical methods to realize efficient value-added utilization of iron tailings resources.The application prospect of several porous materials in the environmental field is explored in order to achieve sustainable development.（1）Well-ordered mesoporous silica materials with a BET surface area of 1915 m²/g and pore volume of 1.32 cm³/g were successfully synthesized from iron tailings using an innovative room-temperature synthesis method.A pretreatment process consisting of acid leaching and hydrothermal alkaline reaction was essential for the successful utilization of iron tailings as a source of silicon.Acid leaching and alkali treatment changed the coordination structure of iron and silicon elements in iron tailings,thereby facilitating the fabrication of porous silicon materials.The mesoporous material was composed of amorphous silica,and the structural units were mainly（Si O）₃≡Si–O–H（Q³）,（Si O）₃≡Si–O–Si≡（Q⁴）and a small amount of（Si O）₂=Si=（OH）₂（Q²）,indicating that the material possessed a stable silicon structure,and contained active silicon hydroxyl groups,which was conducive to functional modification and application of the material.The mesoporous silicon materials of iron tailings prepared by room temperature synthesis could provide the same quality or even better than that of traditional organosilane.The adsorption of organic pollutants by mesoporous silicon materials showed that MB and Rh B could be adsorbed well.The adsorption mechanism showed that the adsorption was mainly caused by electrostatic attraction and hydrogen bonding.（2）Fe-containing mesoporous silica materials（MFS）with high specific surface area,uniform pore size,dispersed iron sites and oxygen vacancy were prepared by one-step hydrothermal method,which realized effective utilization of all components of iron tailings.Scattered iron sites exposed more active sites,oxygen vacancy accelerates interfacial electron transfer,and MFS exhibited good light response and lower electron transfer impedance under visible light,which promoted the activation of persulfate（PMS）.Performance experiments showed that MFS showed good photocatalytic performance for Orange II after repeated use for 5times in a wide p H range.Degradation tests with tap water and Xiangjiang River water confirmed its practical application.MFS was also effective in removing a variety of organic contaminants,including Rh B,MB,CR and TC.The degradation mechanism showed that free radicals（including sulfate radicals（·SO₄^-）,hydroxyl radicals（·OH）and superoxide radicals（·O₂^-））and non-free radicals（singlet oxygen（¹O₂））played a key role in the degradation of pollutants.（3）The porous electrospun membranes of iron tailings（EF-iron tailings）were synthesized by anchoring iron tailings in electrostatic spinning fibers（EF）.The introduction of electrospinning technology made the catalyst easy to recover,and the introduction of iron tailings provided the active material,so that the catalyst had the ability to activate PMS.During the reaction,visible light accelerated the electron transfer between high and low iron,which was conducive to the activation of PMS.The experimental results showed that EF-iron tailings had good photocatalytic performance and stable reuse for organic pollutants.Degradation mechanism showed that in EF-iron tailings/PMS/vis system,the main active substance was hydroxyl radical（·OH）,superoxide radical（·O₂^-）and singlet oxygen（¹O₂）.The potential application value of EF-iron tailings was determined through the evaluation of its application in natural water.（4）Porous iron tailings/biochar composite（FPC）was prepared by a simple semi-isolated air calcination process using iron tailings and pine sawdust as raw materials.The results showed that the synergistic interaction between biochar and iron tailings could increase the light absorption intensity in the visible region and make more efficient use of sunlight.The surface of the prepared FPC contained abundant oxygen-containing functional groups and iron sites,and FPC had the structure of defective carbon and graphitized carbon,which helped to improve the electron transfer of the material under light and promote the reoxidation between Fe（III）/Fe（II）in the material,thus effectively activating PMS.The experimental results showed that the material has good photocatalytic performance against organic pollutants and stable reusability.The degradation mechanism showed that the main active substances were hydroxyl radical（·OH）,sulfate radical（·SO₄^-）,superoxide radical（·O₂^-）and singlet oxygen（¹O₂）,and hole（h⁺）was also directly involved in the degradation process.FPC was a kind of magnetic photocatalyst with good recyclability and stability.Based on the composition and structural characteristics of iron tailings,this paper realizes the development and application of porous materials of iron tailings source through structural modification and design optimization.It not only provides a possible solution to the problem of iron tailings solid waste,but also provides a new idea for the development and design of multiphase catalyst,and realizes the development of solid waste treatment of organic pollutants wastewater.It is of great significance to the sustainable development of economy and environment.Figures 88,Tables 37,References 231.