Preparation Of Graphene Oxide/Silica Composite And It’s Adsorption Properties On Uranium (Ⅵ)

Wastewater containing uranium is intensely radioactive,causing serious damage to the ecological environment once discharged into water directly. The uptake of uranium by human beings would damage body organs, causing serious health problem. Therefore, it is urgent to find out a scientific and efficient uranium-containing wastewater treatment. Graphene oxide(GO) is a good adsorbent material and can be used to absorb a variety of heavy metal ions. Silica is a chemically stable, and has a multifunctional biocompatible material,Which can overcome the problem of aggregation prone when modified with graphene oxide as well as increase its surface area and the number of binding sites. Therefore, the effect of adsorption can be improved.Graphene oxide was prepared by Hummers. The synthesis of graphene oxide/silica composites(GOS) was fabricated using graphene oxide(GO), ethyl orthosilicate(TEOS) as the raw material, oxygen polyoxyethylene-polypropylene-polyoxyethylene(P123)as the surfactant,and SiO2 generated by hydrolyzing TEOS. Through a static test, different experimental parameters such as solution pH, adsorbent dose, initialconcentration and contact time were examined to investigate their effects on adsorption of uranium by GOS. The results are as follows:According to the static tests, p H has a great impact on adsorption of U(Ⅵ) by GOS, the optimum p H was 6 and the optimum dosage was 0.2g/L.it showed a rapid surface adsorption with a 92.69 percent of equilibrium capacity within 20 mins and the adsorption reached equilibrium within 120 mins. U(Ⅵ) concentration in the waste water of10 mg/L~20 mg/L, the treatment effect is best.Result of fitting analysis by isothermal adsorption models showed that the adsorption process fit well with the Freundlich isotherm model(R2≈1), indicating that adsorption of U(Ⅵ) by GOS ismultilayer adsorption.The kinetic fitting results show that the pseudo-second kinetic equation(R2≈1) can better describe the adsorption, which indicates that the adsorption process is chemisorption of speed control step.Through the study of the XRD characterization of GOS experiment that GO with SiO2 composite successfully. The result of FTIR, XRD and SEM indicate that GOS has good adsorption effect on U(Ⅵ), before and after adsorption, the structure of the GOS itself have not changed, the main adsorption mechanism exist ion exchange and complexing reaction.The use of HCl desorption solution 0.1mol/L adsorbed U(Ⅵ) of the GOS, after 4 cycles of adsorption-desorption-adsorption, desorption rate still reached more than 94%, indicating that the adsorbent gos has highre-use value. indicating that the adsorbent GOS has a high reuse value.