Effect of metal addition of Cu, Ni, and Fe on swelling Zeolit Alam Lampung (ZAL) to present amphoteric features on Cu-Ni-Fe/ZAL swelling

The main challenge in using Zeolit Alam Lampung (ZAL) as a catalyst lies in controlling its acidic nature which is influenced by the content of alkali metals, alkaline earth metals, transition metals, and Si/Al ratio. Controlling by reducing and adding metals with higher acidity is necessary. This research involved two stages: ZAL Swelling formation followed by adding Cu, Ni, and Fe metals to make a Cu-Ni-Fe/ZAL Swelling catalyst. The acid distribution analysis using the NH₃-TPD profile test showed that the Cu-Ni-Fe/ZAL swelling catalyst exhibited higher Lewis-type acidity and more uniform distribution compared to Brønsted acid. The addition of Cu, Ni, and Fe metals can modify the acidity strength of ZAL Swelling to form Cu-Ni-Fe/ZAL Swelling catalysts with Lewis and Brønsted sites at lower temperatures (120–550 °C) compared to ZAL Swelling (120–750 °C). This gives an idea about the optimization of the arrangement of Lewis and Bronsted acid sites to present amphoteric features.