Preparation of MgX/Al2O3-Y sorbent for highly efficient simultaneous removal of hydrogen fluoride and hydrogen chloride under low-temperature environment

In this study, a series of Mg-modified γ-Al2O3 sorbents have been introduced to simultaneously remove HCl and HF in a low-temperature environment. These sorbents were prepared by impregnation, and the effects of Mg loading amount and calcination temperature on the performance of the sorbent were investigated. The optimal sorbent (modified by 15 wt% Mg and calcined at 400℃, Mg15/Al2O3-400) exhibited the highest adsorption capacity of all the sorbents tested, 37.89 mg(HF)•gsorbent−1 and 34.54 mg(HCl)•gsorbent−1, respectively. Taking into account an excellent HF(HCl) capacity of the Mg15/Al2O3-400, these sorbents are very promising HF(HCl)sorbents usable in a low-temperature environment. The role of MgO loaded on γ-Al2O3 was investigated by Brunauer−Emmet−Teller (BET) method, X-ray diffractometer (XRD), scanning electron microscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of CO2 (CO2-TPD), and thermogravimetric analysis (TG-DTG). The results revealed that MgO acted as a ‘leading role’ to promote the adsorption activity of the sorbents. BET analysis demonstrated that the Mg modification process did not seriously change the pore type of the γ-Al2O3. CO2-TPD results revealed that the calcination temperature will significantly affect the number and strength of the basic sites on the surface of the sorbent. In addition, XRD and XPS analysis indicated that the consumption of MgO and the accumulation of reaction products on the surface and pores are the main reasons for the deactivation of the sorbent.