The determination of point zero charge (PZC) of Al2O3-MgO mixed oxides

A series of Al₂O₃-MgO mixed oxides with different loading of MgO (5, 10, 15 and 20 wt% with respect to Al₂O₃) were prepared by wet impregnation method. The synthesized Al₂O₃-MgO mixed oxides samples were characterized with different analytical techniques such as X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray (FESEM-EDAX), Fourior Transform Infrared (FTIR) and BET methods. The point of zero charge of mixed oxides was also determined by salt addition method to explore the effects of MgO of PZC of pure alumina. The results showed the addition of MgO loading increased the PZC of alumina. Moreover, it was noted that the PZC of synthesized mixed oxides with different MgO contents varied between the PZCs of pure oxides of Al₂O₃ and MgO. The characterization techniques further showed that MgO is well dispersed on the surface of γ-Al₂O₃ and structure of alumina changed only at high loading of MgO.