Magnetic nickel chrysotile nanotubes tethered with pH-sensitive poly (methacrylic acid) brushes for Cu(II) adsorption

Magnetic nickel chrysotile nanotubes (NCNTs) tailored with poly(methacrylic acid) (PMAA) brushes have been synthesized by surface-initiated atom transfer radical polymerization as a novel canonic nanosorbent for Cu(II) ions removal in aqueous solutions. Batch adsorption experiments are conducted to determine the effect of solution pH and coexisted ions on the adsorption capacity, sorption kinetics, adsorption isotherms, thermodynamics of Cu(II) adsorption of the as-synthesized magnetic PMAA-grafted NCNTs. Adsorption kinetics of magnetic nanosorbents are verified to be consistent with a pseudo-second-order (PSO) kinetic model and to be evidently affected by mass transfer process. The Langmuir-fitted maximum adsorption capacity of Cu(II) ions is as high as 1.40 mmol.g(-1) (circa 89.0 mg.g(-1)) at solution pH 5.0 and 25 degrees C with the initial Cu(II) concentration of 20-100 mg.L-1. The desorption results demonstrate good regenerability, stability and easy separation of the magnetic PMAA-grafted NCNTs for repeated use. (C) 2018 Elsevier B.V. All rights reserved.