Abstract: A nitrogen removal granular material (MZ) was prepared from modified zeolite with the addition of polyvinyl alcohol (PVA) and sodium bicarbonate (NaHCO₃). The effects of dosage and initial pH on the adsorption performance of ammonium nitrogen (NH₄⁺-N) were systematically investigated. The results showed that the NH₄⁺-N removal rate of MZ reached 94.0% at an MZ dosage of 5 g/L and an initial pH of 7. The adsorption process of NH₄⁺-N on MZ fitted well with the pseudo-second-order kinetic model and Freundlich adsorption isotherm model. The adsorption was jointly controlled by liquid film diffusion and intraparticle diffusion, with a saturated adsorption capacity of 8.4701 mg/g for NH₄⁺-N. Four common coexisting cations exhibited inhibitory effects on NH₄⁺-N adsorption by MZ, following the order of K⁺ > Na⁺ > Ca²⁺ > Mg²⁺ After five regeneration cycles, MZ still retained an NH₄⁺-N removal efficiency of over 80%. Combined with material characterization results, the adsorption of NH₄⁺-N on MZ was predominantly governed by chemical adsorption via ion exchange, while physical adsorption played a secondary role.