Comparative Study on Adsorption of Cr(Ⅵ), Mn(Ⅶ), Pb(Ⅱ) and Cd(Ⅱ) from Aqueous Solution Using Cetylpyridinium Bromide-Modified Zeolite

摘要

The adsorption of Mn(VII), Cr(VI), Cd(II) and Pb(II) on cetyl-pyridinium bromide (CPB)-modified zeolite was investigated in both single-ion or multiple-ion aqueous systems, including the mode and mechanisms of adsorption. The surfaces and inner structures of both the CPB-modified and original zeolites were comprehensively characterized by infra-red spectroscopy (IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The adsorbent properties, including the zeta potentials of zeolites, were tested by a zeta nanosizer. Importantly, the results also demonstrate that the main mechanism of the adsorption of the heavy metal ions is electrostatic adsorption. The adsorption isotherms revealed that the adsorption capacity of CPB-modified zeolites for Mn(VII), Cd(II), Pb(II) and Cr(VI) fitted the Langmuir adsorption isothermal equation and pseudo-second-order kinetics.