Synthesis of a novel magnetic nano-zeolite and its application as an efficient heavy metal adsorbent

Abstract

A novel magnetic nano-zeolite (MNZ@MS) is successfully synthesized, characterized and applied to adsorp heavy metals from solution. In the synthesis of MNZ@MS, the fly ash magnetic sphere (MS) and [C18H37 (CH3)2-N+-(CH2)3 -N+-(CH3)2C18H37] Cl2 is used as carrier and directing agent, respectively. The characterization results of XRD, XRF, XPS and SEM demonstrate that the nano-scale (200–600 nm) Linde F(K) zeolite completely wraps the magnetic spherical fly ash particle, and the saturation magnetization value of MNZ@MS is around 17.7 emu g−1. MNZ@MS exhibits a favorable and efficient adsorption performances on heavy metals, and the maximum adsorption capacity of Cu, Cd and Pb on MNZ@MS is 59.9 mg g−1, 188 .6 mg g−1 and 909.1 mg g−1, respectively. The higher pH value in solution is more conducive to the adsorption process of heavy metals on MNZ@MS. The adsorption is a fast process, well represented by the pseudo-second-order model. Concerning the equilibrium behavior, Langmuir isotherm model are more suitable for describing the adsorption. Furthermore, in competitive adsorption system, the adsorption process of Pb is the most difficult to be interfered, and the order of adsorption advantage is Pb>Cu>Cd. MNZ@MS may be applied as a low-cost and efficient magnetic adsorbent for wastewater treatment to remove heavy metals.