The Effects of pH and Chelating Agent on Synthesis and Characterization of Ni Mo/γ- Alumina Nanocatalyst for Heavy Oil Hydrodesulfurization

In this research, various organic additives (as a chelating agent) were used to prepare NiMo/ 𝛾-Al2O3 bimetallic catalysts. Then effects of additives and pH variation were studied on textural properties, morphology and size of nanocatalyst particles, interaction, and loading of active metals on a support. Additionally, this research evaluated the activity of catalysts and compared them with commercial and catalysts in the absence of additives. The metal oxide nanoparticles were prepared and impregnated on 𝛾-Al2O3 in-situ by using the wetness impregnation method, under conditions 60°C and calcination temperature 520°C. The supported nanocatalyst was calcined to remove the volatile materials and gases. The catalysts were characterized by TPR, BET, BJH, AAS, FT-IR, SEM, and XRD. The prepared nanocatalyst displayed the enhanced catalytic activity for the heavy oil hydrodesulfurization (HDS) containing 21 g/L sulfur. At the acidic pH, the activity of the catalyst was promoted by using EDTA compound as a chelating agent. The sulfur content of the feed was decreased up to 2 g/L at 380°C, 60 bar, and LHSV 1.5h-1 showing an efficient catalyst with the conversion of 90.47%.