Removal
of Metal Ions from Water Using Poly(MMA-<i>co</i>-MA)/Modified-Fe<sub>3</sub>O<sub>4</sub> Magnetic Nanocomposite:
Isotherm and Kinetic Study
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Abstract
Magnetic
Fe<sub>3</sub>O<sub>4</sub> nanoparticles were synthesized,
surface modified with an amino-terminated silane coupling agent, 3-aminopropyltrimethoxysilane
(APTMS), and characterized by Fourier transform infrared spectroscopy
(FT-IR), field scanning electron microscopy (FESEM), and X-ray diffraction
(XRD). A copolymer of methyl methacrylate (MMA) and maleic anhydride
(MA), poly(MMA-<i>co</i>-MA), was synthesized by radical
polymerization and transformed into magnetic nanocomposite (MNC) by
chemical immobilization of APTMS-Fe<sub>3</sub>O<sub>4</sub> with
the anhydride groups of poly(MMA-<i>co</i>-MA) chains. The
MNC was characterized by FT-IR, XRD, FESEM, TEM, and atomic force
microscopy (AFM) and used for the removal of metal ions from water.
Various factors influencing adsorption capacity such as contact time,
absorbent dosage, pH, and initial concentration of ions were investigated.
The adsorption kinetics showed a pseudo-second-order rate law, indicating
chemical sorption as the rate-limiting step mechanism. Sorption of
metal ions to MNC agreed well with the Langmuir adsorption model with
the maximum adsorption capacity of 90.09, 90.91, 109.89, and 111.11
mg g<sup>–1</sup> for Co<sup>2+</sup>, Cr<sup>3+</sup>, Zn<sup>2+</sup>, and Cd<sup>2+</sup>, respectively