Preparation of expanded graphite loaded with zinc oxide and its decolorizing performance for dye

Author(s): Xiuyan Pang, Ruinian Lin, Xin Su

Expanded graphite (EG) loaded with Zinc oxide (ZnO/EG) was prepared with 50 mesh natural graphite as raw materials, KMnO4 as the oxidant, H2SO4 as intercalation reagent and ZnSO4 as the secondary intercalation agent.Whenmass ratio of C:KMnO4:H2SO4(98%):ZnSO4·H2Ois controlled as 1.0:0.35:5.0:0.4, H2SO4 diluted to 80%before reaction; and the reaction lasts 40 min at 30 ºC, ZnO/EG with an expanded volume of 420 mL·g-1 is obtained when the graphite intercalation compound is expanded at 950 ºC. X-ray diffraction analysis shows that ZnO on ZnO/EG is in the form of hexagonal crystal system. Decolorization kinetics and thermodynamics of ZnO/EG for Auramine lake yellow O were investigated. Kinetic research results show the decolorization process can be described with the pseudo second-order kinetic model. Thermodynamics research results show the decolorization isothermforAuramine lake yellowO is type I. Decolorization property of ZnO/EG under ultraviolet radiation is higher than either adsorption decolorization of EG or the ultraviolet radiation decolorization of ZnO. Increase of solution ionic strength is of benefit to improve the decolorization capacity of ZnO/EG.

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