Modification of NiW/Al₂O₃ Bimetallic Catalysts by ZSM-5, HY Zeolite, and Amorphous Silica Additions for Heavy Gas Oil (HGO) Hydrotreating

Sarwan Sarwan (Department of Chemistry, Faculty of Science and Technology, Syarif Hidayatullah State Islamic University Jakarta)
Isalmi Aziz (Department of Chemistry, Faculty of Science and Technology, Syarif Hidayatullah State Islamic University Jakarta)
Wawan Rustyawan (Technology Innovation & Implementation, PT. Pertamina)
Fuady Hanief (Technology Innovation & Implementation, PT. Pertamina)
Nurhasni Nurhasni (Department of Chemistry, Faculty of Science and Technology, Syarif Hidayatullah State Islamic University Jakarta)
Siti Nurbayti (Department of Chemistry, Faculty of Science and Technology, Syarif Hidayatullah State Islamic University Jakarta)
Yulyani Nur Azizah (Department of Chemistry, Faculty of Science and Technology, Syarif Hidayatullah State Islamic University Jakarta)

VALENSI
Jurnal Kimia VALENSI, Volume 12, No. 1, May 2026

The NiW/γ-Al₂O₃ bimetallic catalyst is widely used in the hydrotreating of heavy gas oil (HGO) fractions to remove impurities, particularly sulfur-containing compounds (hydrodesulfurization, HDS) and polycyclic aromatic hydrocarbons (hydrodearomatization, HDA). The incorporation of additives into the alumina support can enhance catalytic activity by increasing surface acidity and improving textural properties. This study aims to synthesize, characterize, and evaluate the performance of NiW/γ-Al₂O₃ catalysts modified with zeolitic (ZSM-5 and HY zeolite) and amorphous silica additives on HDS and HDA of HGO. Catalysts were prepared via the wet impregnation method using supports containing 3 wt% additive. Among the synthesized materials, the NiW/γ-Al₂O₃ catalyst incorporating ZSM-5 exhibited the highest crystallinity, with metal loadings of 4.960 wt% Ni and 16.269 wt% W. This catalyst showed a surface area of 153.415 m²/g, a pore diameter of 116.643 Å, and a total acidity of 0.496 mmol/g. Hydrotreating evaluation demonstrated that the ZSM-5–modified NiW/γ-Al₂O₃ catalyst yielded a product with 4.50 ppm sulfur (99.96% HDS conversion) and 10.66% aromatics (54.10% HDA conversion) at 360 oC.