Adsorption removal of basic nitrogen from benzene feedstock for ethylbenzene unit using HZSM-5 zeolite

To solve the problem of excessive basic nitrogen compounds in the benzene feedstock of ethylbenzene unit, the adsorption performance of HZSM-5 zeolite, activated clay and waste fluid catalytic cracking catalyst as absorbents was systematically investigated. The structural features, morphological characteristics, and physicochemical properties of the adsorbents were characterized by a combination of analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), low-temperature nitrogen adsorption-desorption, and ammonia temperature-programmed desorption (NH3-TPD). The correlation between the adsorption performance and material structure was also established. Results show that HZSM-5 zeolite exhibits highest adsorption capacity and removal efficiency for basic nitrogen. After treatment with HZSM-5 zeolite, the residual basic nitrogen concentration in the raw benzene feedstock was reduced to 0.08 mg/kg, meeting the industrial specification. The structure-activity relationship analyses reveal that the adsorption performance is positively correlated with the specific surface area of the adsorbent, while acidity is not the dominant influencing factor. Breakthrough experiments confirm that the adsorption kinetics follow the Boltzmann model. This research aligns with the trends of green chemistry and sustainable development, demonstrates good potential for industrial application, and provides new insights for adsorbent design.