The current work aimed to investigate the removal mechanism of NH4+ from wastewater treatment plant effluent (WWTPE) onto the zeolite in the plug-flow column reactor (PFCR). The adsorption process was optimised as a function of length (2–15), time (0.5–202 min), and accumulation (0.05–2.4 mg/g) using response surface methodology (RSM). The optimal operating parameters for the adsorption were recorded after 134.89 min with 1.52 mg/L of zeolite with 6.685 cm of the column length where the predicted and actual removal was 99.79 vs. 98.00% of NH4+ from WWTPE. The bed depth service time (BDST), Thomas, and Yoon-Nelson models were used to explain the adsorption behaviour. In contrast, the mass transfer factor (MTF) model was carried out to determine the internal and external removal mechanism. The findings revealed that PFCR exhibited an efficiency for removing NH4+ from WWTPE. The dynamic adsorption behaviour was satisfactorily described by the BDST, Thomas, and Yoon-Nelson models. These findings confirmed that the empirical models had verified the suitable of PFCR for removing NH4+ from WWTPE.
