Research on the removal of heavy metal ions in water by magnetically modified zeolite

Zeolite has many advantages such as outstanding ion exchange performance, large specific surface area and uniform pores in the field of wastewater treatment. However, zeolites are difficult to separate from complex industrial wastewater systems. Magnetically modified zeolite (MMZ) composites with both magnetic and adsorption properties were synthesized by attaching Fe 3 O 4 to the surface of Na-zeolite by chemical co-precipitation. MMZ can be better adsorbed from wastewater by permanent magnets for reuse. The structure, morphology and magnetic properties of MMZ were characterized. Compared with Na-zeolite, the structure of MMZ has no obvious change, Fe 3 O 4 is evenly coated on the surface of the zeolite matrix, the specific surface area is greatly increased, and the magnetism is sufficient to attract the permanent magnet. The adsorption efficiency of MMZ for Pb 2+ , Cd 2+ , and Cu 2+ in simulated wastewater was largely dependent on pH. According to the Langmuir and Freundlich isotherms to fit the equilibrium data, the maximum monolayer saturated adsorption capacities of the three ions are 83.20 mg/g, 30.58 mg/g and 16.16 mg/g, respectively, which are greatly improved compared with the samples before modification. Therefore, MMZ is an adsorbent with good adsorption performance and easy to be recycled and reused.