Nitrate removal from aqueous solutions with sodium alginate/quaternary branched polyethylenimine/carboxylated multi-wall carbon nanotube

Abstract One concern in recent years is increasing the amount of nitrate in drinking water. This study investigated nitrate adsorption using sodium alginate/quaternary branched polyethylenimine /carboxylated multi-wall carbon nanotube nanocomposite beads. The structure of nanocomposite beads was characterized with Field emission scanning electron microscopy images (FE-SEM), Energy dispersive X-ray mapping (EDX), X-ray diffraction spectroscopy (XRD), Fourier transform-infrared spectroscopy (FT-IR), and Thermogravimetric analysis (TGA). Several experiments were performed to optimize adsorption conditions, adsorption isotherms, kinetics, and reusability of the synthesized nanocomposite beads. Temkin and Freundlich isotherms, and the pseudo-first-order kinetic model, provided the best fit for the experimental adsorption data. Under optimal conditions, the nitrate removal efficiency was 72%. The results demonstrated that the introduced nanocomposite beads are pH-stable, have low-cost preparation, are recyclable at least for twelve adsorption-desorption cycles, and are safe.