Study On Removal Of Pb ~ Sup> 2 + And Cd ^{2 +} In Water By Modified Graphene Modified Chitosan And Cyclodextrin

Since its industrialization, water pollution, especially heavy metal water pollution, has become a storm in the process of China’s economic reform and development that can not be bypassed. Particularly in the last twenty years, heavy metal contamination of water emerge in endlessly. It has different levels of pollution in the country’s major rivers and lakes. There are several processing methods to takcle heavy metal pollution, adsorption method is famous for its low cost and high efficiency. In the context of this, the use of independent synthesis of the adsorbent material for water of Pb2+,Cd2+ removal are studied.With the modified Hummers method prepared Graphene oxide (GO), and use a modified chitosan and β- cyclodextrin obtain two composites of graphene oxide/ chitosan (GO-CS) and graphene oxide/cyclodextrin (GO-CD). The adsorbent materials of surface functional groups, topography and others are characterized by infrared spectroscopy (FTIR), Raman spectroscopy (Raman), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and other means. The results show that the functional groups of modified material increases, and adsorption sites increases too.The prepared adsorbents are used for the adsorption uptake of Pb2+ and Cd2+. The waste water intial pH, adsorption time, dosage of adsorbent and other factors are investigated. Within the scope of the pH value of 1-7, GO, GO-CS and GO-CD this three kinds of materials for the adsorption of Pb2+ and Cd2+ capacity increases with the increasing of pH. pH=7, the optimal conditions for GO adsorption of Cd2+ and Pb2+ are: 30 min,60 min, and 0.4 mg/mL; which GO-CS are 120 min and 0.2 mg/mL; GO-CD are 60 min,80 min and 0.2 mg/mL,0.4 mg/mL. The adsorption of heavy metal ions by three kinds of adsorbents is in accordance with the quasi two order kinetic equation, indicating that the adsorption process is mainly dominated by the chemical reaction. Isothermal adsorption experiment results show that the GO, GO-CS and GO-CD adsorption behavior is in line with the Freundlich isothermal adsorption model. Compared with the traditional adsorption materials, the composite materials have a dominant position in the adsorption capacity and adsorption efficiency. Three kinds of materials for regenerative adsorption Cd2+ experiments show that the GO and GO-CD for using adsorption capacity can reach 80% of the initial after five cycles, while GO-CS adsorption capacity tendency decline tendency from 0.64 mmol/g to 0.18 mmol/g.In this paper, the adsorption behavior of the material is qualitatively studied by energy spectrum and infrared spectrum, and the adsorption mechanism is also discussed preliminarily. Infrared results show that the adsorption material is mainly on the surface of the oxygen containing functional groups and amino groups involved in the coordination of heavy metal ions.