Synthesis Of Magnetic Modified Coal-bearing Kaolinite Composites And Their Adsorption Properties

In recent years, a large number of dye wastewater are being discarged into ecosystem, and cause serious water-pollution and damages to living beings. Therefore, dye wastewater treatments have attracted much attention. Coal-bearing kaolinite is going to has many tiny small pores after a series of activation treatment, and thus has a larger specific surface area. Owing to its large specific surface area, the activated coal-bearing kaolinite has a strong adsorption ability, and can be applied to waste water treatment as an adsorbent. However, the problem is that the fine powder coal-bearing kaolinite cannot be efficiently recovered from treated water by traditional methods such as filtration and centrifugation because of their small particle size. But, in this case, if the coal-bearing kaolinite possesses magnetic properties, it can be readily separated from the treated water with an external magnetic field, which can not only overcome the problem of recovery, but also can prevent the treated water from secondary pollution. With this goal in mind, in this study, the magnetic y-Fe2O3/activated coal-bearing kaolinite composite composite was synthesized and their adsorption properties were studied. Although the y-Fe2O3/activated coal-bearing kaolinite has a high adsorption ability for cationic dyes, but it has a relatively adsorption capacity for anionic dyes. In the present study, TiO2/y-Fe2O3-activated coal-bearing kaolinite composite was synthesized and it was used for the adsorption of different dyes in order to overcome above mentioned problem.1. Magnetic y-FeO3/activated coal-bearing kaolinite nanocomposite was synthesized by thermal decomposition method using Fe-urea complex and activated coal-bearing kaolinite as raw materials. The synthesized composite was characterized using X-ray diffraction, X-ray photoelectron spectroscopy, N2 adsorption-desorption, and vibrating sample magnetometer. In addition, the adsorption abilities of the magnetic composite for dyes were investigated. The results show that the magnetic composite material has a mesoporous structure with a specific surface area of 99.4 m2/g and possesses ferromagnetic characteristics with a maximum magnetization of 12.5 emu/g. The maximum adsorption capacity of the composite for malachite green, methylene blue and crystal violet has been measured to be 85.5,50.0 and 15.3 mg/g, respectively, and the adsorption of three dyes fit well with the pseudo-second-order model and langmuir adsorption isotherm model; and, after adsorption, the magnetic composite can be easily separated from the treated water by using a magnet.2. TiO2/y-Fe2O3-activated coal-bearing kaolinite composite was synthesized from titanium sulfate, and y-Fe2O3/activated coal-bearing kaolinite by hydrothermal method. The composite is characterized by X-ray diffraction, N2 adsorption-desorption, and vibrating sample magnetometer. In addition, the adsorption performance of composite for Congo red, weak acid dark blue and methylene blue were investigated. The results show that the synthesized sample has a mesoporous structure with specific surface area of 198 m2/g and possesses ferromagnetic characteristics with a maximum saturation magnetization of 6 emu/g. The maximum adsorption capacity of Congo red, weak acid dark blue and methylene blue was determined to be 102.0,86.2 and 122.0 mg/g, respectively. The adsorption behavior of these dyes on the composite can be well described by the pseudo-second-order kinetics equation and the langmuir adsorption isotherm model.