Montmorillonite-supported zero-valent iron nanoparticles (nZVImontmorillonite) were prepared by liquid-phase reduction under ambient atmosphere. Transmission electron microscope images indicated that the presence of montmorillonite decreased the aggregation and the size of iron nanoparticles. A portion of the gaps in the supporting material was filled with nanoparticles. Irregular angular shaped shells were also observed. X-ray diffraction indicated that the reduction rate had a substantial effect on the morphology and size of nanoparticles. nZVI-montmorillonite showed higher adsorption capacity for Zn(II) (9.9038 mg/g) compared to nZVI (9.4190 mg/g), montmorillonite (1.8835 mg/g), and zero-valent iron powder (5.8568 mg/g). The material can be used for several repeated applications.