The untapped NH4+ in sewage has the potential to be recovered as fertilizer via the adsorption process. While zeolite-chitosan has demonstrated better performance in nutrient recovery compared to powder zeolite, research on mordenite-chitosan remains limited. Therefore, this study focused on the mordenite-chitosan for NH4+ recovery. Based on the characterization, the physicochemical properties of mordenite-chitosan closely resemble the mordenite. The addition of chitosan has increased the adsorption capacity of mordenite by 15%. The adsorption of NH4+ on mordenite-chitosan fitted well to the Langmuir linear model with an estimated adsorption capacity of 17.7 mg/g (R2 = 0.991). The positive entropy with an enthalpy value of 44.47 kJ/mol suggests a random organization of NH4+ ions, endothermic process, and ion-exchange. Mordenite-chitosan adhered well to the Thomas model, with NH4+ adsorption capacity of 17.97 mg/g, 6.14 mg/g, and 4.84 mg/g in synthetic sewage, influent, and effluent, respectively. Factors such as the negativity of the surface mordenite-chitosan, Si/Al ratio, and framework flexibility are likely to influence the NH4+ adsorption capacity. Overall, the ion-exchange property of mordenite-chitosan emerges as the main contributor to its efficacy in NH4+ recovery.