Synthesis Of Fe₃O₄Loaded And Coated Mesoporous Carbon Nanoparticles And Their Applications In Adsorption

The Earth’s water resources are being increasingly contaminated along with therapid development of industry and agriculture, which poses a major environmentalhealth risk to humankind. Particularly, the effluents from textile plants containportions of dyes, which are deeply colored, low biodegradable and high toxic, havecreated great concerns for their removal from wastewater. In the field of water andwastewater treatment, adsorption technique has been proved to be most effective, withporous carbon as widely used adsorbent. However, it is quite troublesome to separatepowder carbon materials from liquid phase because of their small particle sizes.Magnetic nanomaterials could be assembled into other materials to constructmulticomponents, which are easily separated from the treated solution by the externalmagnetic field. Despite considerable progress in the synthesis of mesoporous carbon,there is still no reliable process of introduction of magnetic material into mesoporouscarbon while retaining their porous system. The low surface area and pore volumeresulted from the clogging of the pore space, amorphous pore wall of the mesoporousmaterials, complicated multistep synthetic process, low loadings of magneticcomposite restrict their applications to a great extent. To overcome the existedproblems, a simple synthesis of novel adsorbent materials with high surface area,large pore volume and strong magnetic responsiveness, which combine theadvantages of mesoporous carbon and magnetic nanoparticles, is desirable from theviewpoint of applications. Herein, we developed a facile “one-pot” synthesis routeand nano-casting method to prepare the magnetic mesoporous carbon materials.Themulticomponent possess excellent magnetic responsiveness which makes it facile tobe separated and recovered from wastewater.In this work, we prepared two kinds of magnetic mesoporous carbon materials,one is Fe₃O₄loaded mesoporous carbon, the other is core-shell structured magneticmesoporous carbon. Then adsorption properties of magnetic mesoporous carbonwere investigated in detail. The thesis includes two main parts:The first part: the magnetic loaded mesoporous carbon was prepared through afacile “one-pot” synthesis route by impregnating magnetic nanoparticle precursorswith the mesoporous carbon followed by in situ conversion of the precursors intomagnetic nanoparticles. The spherical magnetic mesoporous carbon was synthesizedby using ordered mesoporous carbon as the support, FeCl3.6H2O as the iron source,ethylene glycol as the reducing agent, sodium acetate as a mild precipitator. Thewell-designed microspheres had large surface area （741.8m²/g）, high open mesopore（⁴.3nm） and saturation magnetization of7.15emu/g, The as-prepared magneticmesoporous carbon material exhibited the excellent properties of mesoporousstructure and the magnetic responsiveness. It showed remarkably enhanced adsorptionrate, higher adsorption capacity and higher removal efficiency for pollutants fromaqueous solution and fast magnetic separation in wastewater treatment application.The second part: the magnetic mesoporous silica microspheres with asilica-coated magnetic core and ordered mesoporous silica shell was prepared through solvent evaporation self-assemply route. The component possessedsuperparamagnetism, and magnetization was2.24emu/g. Then the core-shellstructured magnetic mesoporous carbon composite was prepared through “hardtemplate” synthesis route by in situ polymerization and carbonation of sucrose withinthe mesopores of the magnetic mesoporous silica microspheres followed by chemicaletching with NaOH solution. The BET surface area for mesoporous carbon capsulesencapsulated with Fe₃O₄nanoparticles Fe₃O₄@MC is up to937.3m²/g, and the totalpore volume is about1.4cm3/g. The mesoporous structure of the carbon capsulesprovided the sufficient spaces that contribute to high adsorption capacities and fastadsorption rates to pollutants in aqueous media. Magnetic properties of thesynthesized material facile the fast separation by the external magnetic in wastewatertreatment application.