Ionic liquid grafted polyethersulfone nanofibrous membrane as recyclable adsorbent with simultaneous dye, heavy metal removal and antibacterial property

Abstract

In view of the harmfulness of the pollutants in wastewater to both human being and environment, it is urgent to develop a multifunctional polymer adsorbent that can remove dyes, heavy metals and bacteria simultaneously. Herein, ionic liquid (IL) grafted Polyethersulfone (PES) (PES-g-IL) nanofibrous membranes (NFMs) were prepared by combining radiation induced grafting method and electrospinning strategy. The adsorption behavior, antibacterial property as well as reusability were examined for the obtained NFMs. It was found that the PES-g-IL NFMs exhibited excellent adsorption ability for heavy metal ions and dyes as well as good recyclability. The adsorption capacity for anionic dyes Congo Red (CR) and heavy metal ions (Cd(II)) reached 120.3 and 187.3 mg/g, respectively. The adsorption mechanism of CR was proved to be the electrostatic interaction between the NFMs and CR, while the adsorption of Cd(II) was driven by the complex between the nitrogen atoms on the imidazolium ring of the grafted ionic liquid and Cd(II). According to the adsorption kinetics, the adsorption of CR and Cd(II) was well fitted by the pseudo-second-order kinetic equation, indicating that the adsorption process was controlled by multiple steps. By calculating the thermodynamic parameters, it is indicated that the adsorption of CR and Cd(II) was a spontaneous physical adsorption process. In addition, PES-g-IL NFMs had excellent antibacterial ability. The killing rate of E. coli. was close to 99%. Given the above advantages, the PES-g-IL NFMs showed great potential in wastewater treatment.