SiO2-coated magnetic graphene oxide modified with polypyrrole-polythiophene: A novel and efficient nanocomposite for solid phase extraction of trace amounts of heavy metals.
The synthesis of a novel nanocomposite comprised of SiO2-coated magnetic graphene oxide modified with a pyrrole-thiophene (mGO/SiO2@coPPy-Th) copolymer is reported in the present work. The nanocomposite was applied for the fast magnetic solid phase extraction (MSPE) of trace levels of copper, lead, chromium, zinc and cadmium from water and agricultural samples. The nanocomposite was prepared in three steps: (1) decoration of graphene oxide sheets with magnetite nanoparticles thorough a facile one-step chemical reaction strategy; (2) chemical grafting by a silica layer to obtain high stability in acidic solutions; and (3) surface modification by coPPy-Th via simultaneous oxidation polymerization of pyrrole and thiophene in the presence of mGO/SiO2composite. The nanocomposite was subsequently characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and vibrating sample magnetometry (VSM) techniques. Several important experimental variables that could affect MSPE performance, including the pH of the sample, sorption time, sorbent dosage, eluent type and its concentration, eluent volume and elution time, were investigated and optimized. Under optimal conditions, the limits of detection for the target heavy metals ranged from 0.15 to 0.65μgL-1. The maximum sorption capacity of the mGO/SiO2@coPPy-Th nanocomposite was 201, 230, 125, 98 and 80mgg-1for Cu(II), Pb(II), Zn(II), Cr(III) and Cd(II), respectively. Finally, the feasibility of the proposed method was investigated for the extraction and determination of the target metals from real matrices.
Department of Chemistry, Tarbiat Modares University, Tehran, Iran.
Karam
K
Molaei
Chemical Injuries Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Electronic address: h.bagheri82@gmail.com.
Hasan
H
Bagheri
Faculty of Chemistry, Shahid Beheshti University, G.C., Evin, Tehran, Iran.
Ali Akbar
AA
Asgharinezhad
Faculty of Chemistry, Shahid Beheshti University, G.C., Evin, Tehran, Iran.
Homeira
H
Ebrahimzadeh
Department of Chemistry, Razi University, Kermanshah, Iran.
Mojtaba
M
Shamsipur
Graphene oxide; Heavy metal ions; Magnetic solid phase extraction; Nanocomposite; Pyrrole-thiophene copolymers