Preparation method of particle size-controllable Fe3O4 nano-powder, and application of Fe3O4 nano-powder in oil-water separation

The invention discloses a preparation method of particle size-controllable Fe3O4 nano-powder, and an application of the Fe3O4 nano-powder in oil-water separation, and belongs to the technical fields of preparation of inorganic nano-powder materials and oil-water separation. The preparation method comprises the following steps: carrying out ultrasonic treatment on FeCl3.6H2O and mannitol in deionized water to realize complete dissolving, adjusting the pH value of the obtained solution by a NaOH solution, transferring the prepared solution into a reaction kettle, and carrying out a hydrothermal synthesis reaction to obtain the Fe3O4 nano-powder. The Fe3O4 nano-powder is added to an oil-water system, and the obtained system undergoes ultrasonic dispersing treatment, and stands or is magnetically separated to make Fe3O4 in the oil phase rapidly separated from the water phase. The Fe3O4 nano-powder is prepared through the hydrothermal technology by using iron chloride as an iron source and using mannitol as a redu