Synthesis And Chromium Ion Adsorption Properties Of Magnetite Nanostructure (hollow) Microspheres And Its Composite Materials

With the continuous development of China’s industrialization level, the resulting environmental issuesare worsening, which had been faced by developed countries. Especially, industrial wastewater fromfactories, which is directly discharged to the surrounding environment, is to become the biggest hiddendangers of the environment. Therefore, the treatment of industrial waste water has always been the focus ofenvironmental protection departments and relevant technical staff. Wherein, for the human body, the heavymetal ions in the effluent will not only has a high toxicity and ease of the absorbent but also can beenriched in vivo through the food chain. So, for scientists, looking for an efficient, cheap, simple approachto governance of heavy metal ions in wastewater is most urgent subject.For a long time, the people through a variety of physical and chemical principles and chemicalmanipulation techniques pioneered the treatment of a variety of heavy metal ions. Even, plant andmicrobial have been used to absorb heavy metal ions in wastewater. So far, adsorption received extensiveattention for the treatment of heavy metal ions. In this method, the heavy metal ions are separated from thewastewater by an adsorbent, so as to achieve the purpose of purifying water body. For general adsorbents, itis difficult to be separated from the waste, which limits the scope of its application in actual operation. Bythe control of an external magnetic field, magnetic adsorbents can be separated from the waste out, and it iseasily to solve the problem of the material separated from the solution. Therefore, the magnetic adsorbentbecomes the most promising of adsorbent in the field of heavy metal ions adsorption.In this paper, iron oxide materials as a research object. Using a new method, the iron oxide hollowmicrospheres have been synthesized, and the formation mechanism of the hollow ball has been studied indetail. Through a series of adsorption experiments, we have comprehensively investigated the adsorptioncharacteristics of the iron oxide hollow microspheres for chromium ions. In addition, glucose as carbonsource, we successfully synthesized carbon-coated iron oxide core-shell microspheres by hydrothermal, andthe main contents are as follows:1. With the dodecyl benzene sulfonate (SDBS) micelles formed in the glycol solution for soft template,we synthesized iron oxide hollow microspheres by solvothermal. By scanning electron microscopy (SEM),transmission electron microscopy (TEM), under different experimental conditions, we get a differentproduct and explore the formation mechanism of the iron oxide hollow sphere, and thus proposed micellesassisted Ostwald ripening mechanism. Potassium dichromate as hexavalent chromium source, syntheticiron oxide hollow microspheres as adsorbents, we study the adsorption properties of iron oxide hollowmicrospheres for hexavalent chromium ions at room temperature. By studying the adsorption isotherms ofthe Langmuir and Freundlich models, it is found that the chromium adsorption of the hollow microspheresis a bidirectional adsorption behavior, and the maximum adsorption capacity reached180mg/g. UsingX-ray diffraction (XRD), X-ray photoelectron energy dispersive spectroscopy (XPS) for further study, theresults show that the adsorption mechanism of iron oxide hollow microspheres for hexavalent chromiumions is a physical and chemical processes. 2. Based on the above studies, synthetic iron oxide hollow microspheres has great adsorption capacityof chromium ions, but further studies have shown that their recycling capacity is not high due to theadsorbent adsorption mechanism for the physical and chemical processes. In addition, their surfaces arealso susceptible to extreme environmental impact. On the basis of previous experiments, synthetic ironoxide solid ball as the core, glucose as carbon source, we synthesized carbon-coated iron oxide core-shellmicrospheres by hydrothermal. Through the regulation of the experimental parameters, the thickness of thecarbon layer achieve adjustable. Under extreme conditions, the carbon layer is a high stability, and providesprotection for the solid ball, which makes magnetite avoid the impact of the external environment. Inaddition, carbon layer contains a lot of groups, which can contribute to drug uptake and heavy metaladsorption. So, there will be a great application prospects in the field of heavy metal ions adsorbed.