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  • Eco-friendly polyvinyl alco...
    Dai, Hongjie; Huang, Yue; Huang, Huihua

    Carbohydrate polymers, 04/2018, Letnik: 185
    Journal Article

    Display omitted •Eco-friendly PVA/CMC hydrogels reinforced with GO and bentonite were prepared.•Introducing GO and bentonite promoted formation of porous structure of hydrogels.•Improving swelling, thermal stability and MB adsorption by introducing two fillers.•MB adsorption was well fitted by Langmuir isotherm and pseudo-second-order model.•The hydrogels displayed good pH sensitivity and reusability for MB adsorption. Eco-friendly polyvinyl alcohol/carboxymethyl cellulose (isolated from pineapple peel) hydrogels reinforced with graphene oxide and bentonite were prepared as efficient adsorbents for methylene blue (MB). The structure and morphology of the prepared hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). Introducing graphene oxide and bentonite into the hydrogels evidently enhanced the thermal stability, swelling ability and MB adsorption capacity. The effects of initial concentration of MB, pH, contact time and temperature on MB adsorption capacity of the prepared hydrogels were investigated. Adsorption kinetics and equilibrium adsorption isotherm fitted pseudo-second-order kinetic model and Langmuir isotherm model well, respectively. After introducing graphene oxide and bentonite into the hydrogels, the maximum adsorption capacity calculated from the Langmuir isotherm model reached 172.14 mg/g at 30 °C, obviously higher than the hydrogels prepared without these additions (83.33 mg/g). Furthermore, all the prepared hydrogels also displayed good reusability for the efficient removal of MB. Consequently, the prepared hydrogels could be served as eco-friendly, stable, efficient and reusable adsorbents for anionic dyes in wastewater treatment.