Characterization of Schiff Base Modified MCM-41 Molecular Sieve for Adsorption of Lead Ions from Aqueous Solution / 分析化学

ABSTRACT

A new Schiff base modified MCM-41 molecular sieve(N-MCM-41)was synthesized via post-grafting method with 2-pyridine formaldehyde for efficient removal of lead ions(Pb2+)from aqueous solution.X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier transform-infrared(FT-IR)spectroscopy,thermogravimetric analysis(TGA),and X-ray photoelectron spectroscopy(XPS)were employed to characterize the structure,morphology,surface functional groups and chemical states of N-MCM-41.Moreover,the adsorption behavior of Pb2+by N-MCM-41 was systematically studied.Batch adsorption studies revealed that N-MCM-41 showed the maximal adsorption capacity of 101.3 mg/g at 45℃and pH=5.5 under the initial Pb2+ concentration of 80 mg/L after 180 min adsorption.The adsorption process conformed to the Langmuir isotherm model and the pseudo-second-order kinetics model.The adsorption of Pb2+by N-MCM-41 was a spontaneous and endothermic process.Adsorption mechanism analyses suggested that functional groups on N-MCM-41 had strong coordination ability with Pb2+to improve the adsorption capacity.The synthesized N-MCM-41 adsorbent exhibited excellent reusability in five regeneration cycles.Overall,this study showed that the N-MCM-41 had good application prospect to remove Pb2+ from aqueous solution.