Synthesis And Water Treatment Application Of3D Micro-and Nano-Iron Oxide

With the rapid growth of economy, dye wastewater from textile and dyeingindustry and heavy metal pollution from industrial production have become the mainsource of water pollution. In order to solve the serious pollution problems caused bythe dye wastewater and heavy metal pollution effectively, it is of great significance todevelop a wastewater treatment material for the protection of water resources andwater pollution governance. As the most stable iron oxide under external environment,the3D α-Fe2O3has wide potential applications in waste-water treatment. The key pointto adsorption capacities lies in the high specific surface area and the porous structure ofα-Fe2O3nanomaterials. Thus, the preparation of α-Fe2O3with various morphologiesand high surface area draws considerable attentions.Flower-like α-Fe2O3microspheres were successfully synthesized with thedifferent reaction system through a facile high-temperature solution method. Then, theflower-like α-Fe2O3was applied to wastewater treatment, examined its adsorptionof chromium ion (VI) and Congo red dye.(1) A facile, economical, and environment-friendly method was used for thelarge-scale synthesis of porous flower-like α-Fe2O3microstructures with diameter ofabout1.5μm. In this reaction system,2mL of ethylenediamine served as alkali source,and the reaction needed only30min for reflux in ethylene glycol system. It was foundthat the size and morphology of the products were greatly influenced by the amount ofEDA, EG, and refluxing time, and a possible growth mechanism of such flower-likeshape was proposed based on the controlled experiments. The α-Fe2O3microflowersshowed good adsorption performances with maximum removal capacities of212mg/gfor Congo red and14.7mg/g for Cr(VI) in waste-water treatment. The samples obtained from controlled experiments were also tested for the adsorption capacities,and the dates were188,191.2,107.6and210.1mg/g respectively.(2) Novel flower-like hematite microstructures composed of many porousnanosheets were synthesized by a PVP-assisted process (2.5g), and urea (2.7g) servedas alkali source, and the reaction needed6h for reflux in urea system. The shape washighly dependent on the dosage of PVP and reaction time, respectively. Because of thehigh specific surface area and porous structure, the Novel flower-like α-Fe2O3showedexcellent adsorption performances with maximum removal capacities of628.9mg/gfor Congo red and25.1mg/g for Cr(VI) in waste-water treatment. And the adsorptiondata were better fitted by Langmuir models.