Preparation Of γ-Fe₂O₃/Graphene Nanocomposites And Study On The Adsorption Of DFS And SMX In Water

Adsorption method is considered to have a very good application prospect in the removal of pharmaceuticals and personal care products（PPCPs）, and other organic pollutants aspect because of its simple operation, difficult to produce secondary pollution, pollutant removal efficiency higher advantages. And the efficient adsorbent with good reusability and easy preparation method is the key to adsorption. Therefore, based on the new material grapheme which has great adsorption properties, this paper improves its preparation method and prepares further γ-Fe₂O₃/graphene nano magnetic composite material as adsorbent which adsorbs the organic pollutants in water to change its difficulty in separating and recycling.This paper first prepares graphene by improving the oxidation reduction method, and observes and analyzes the morphology and structure of the adsorbent through the TEM, AFM, FTIR and XRD tests. The result shows that the experiment prepared the graphene which thickness was around 1.46 nm and lamella was homogeneous and kept a variety of surface functional groups and active site successfully. To study the graphene adsorption effect using the methylene blue, the experimental results show that the elevation of temperature improved the adsorption and the maximum adsorption quantity increased with the elevation of temperature. The decolorization rate increased with p H increasing and the higher the initial concentration the more obviously of the impact. The main reason may be electrostatic interactions between adsorbent and adsorbate is enhanced in alkaline conditions. Decolorization rate decreased with the increase of initial concentration, but the adsorption capacity was increased. Adsorption reached balanced after around 180 min, and the reaction accorded with quasi level 2 dynamic model and adsorption isotherm was in line with the Langmuir isotherm adsorption model.On this basis, to solve the shortcomings of graphene in separation, this paper uses the improved method of in situ growth to prepare γ-Fe₂O₃/graphene nano magnetic materials and analyzes composite material performance improvements through analyzing the structure characterization. The magnetic particles grown on the material have a saturation magnetization of 3.8emu/g, which make it easy separation and recovery. This paper uses the typical PPCPs contaminants diclofenac sodium and sulfamethoxazole as example to study improved magnetic graphene adsorption efficiency of emerging organic pollutants in water. Experimental results show that with the increase of p H and initial concentration of contaminant the removal efficiency decreased significantly. When p H≤5, adsorption removal was better, but the adsorption capacity increased with the concentration of pollutants increasing. The reaction rate was quickly. It closed to the adsorption equilibrium only after 5 minutes, and the removal rate could reach 80% or more. Reactions accorded with pseudo-second order kinetic model. And the adsorption isotherm model fit more in line with Freundlich adsorption model. Mechanistic studies suggest that hydrogen bonding and electrostatic interactions are the main driving force of adsorption. The iron oxide not only strengthen the effect of adsorption, make the adsorbents magnetic separation but also lead to surface rich in oxygen-containing functional groups. It can be seen that the adsorption capacity of the unit mass or per unit area magnetic graphene are many times higher than other different materials by comparison. And the adsorption removal of magnetic graphene was still more than 80% after 6 times circulation. In the background of the Songhua River water, the adsorption experiments effect was still able to maintain about 80% of the similar beaker experiments. And the adsorption was quickly. It achieved the purpose of this project which is preparing efficient adsorbents.