Adsorption experiments were carried out under dynamic conditions for the removal of phosphine (PH3) in nitrogen on a fixed bed of 5A molecular sieve. The experiments were conducted to characterize the breakthrough characteristics of PH3 in the fixed bed under different operating conditions, including bed temperature, bed mass, and initial PH3 concentration. A mathematical model was developed to predict the breakthrough profiles of PH3 during adsorption on the 5A molecular sieve. The model was successfully validated with the observed experimental breakthrough data, showing that the adsorption capacity increases with decreasing temperature and with rising phosphine concentration in the gas mixture. The study showed the potential application of 5A molecular sieve in controlling PH3 emission.