Effective parameters of Mo recovery from spent homogeneous nanocatalyst in slurry phase hydroconversion processes

Molybdenum sulfide nanoparticles have an important role in catalytic behavior of hydroconversion catalyst. The extraction of Mo is a crucial issue because of great consumption, environmental regulations, high cost and depletion of high grades resources. In this work, Plackett-Burman design as a screening method is used to analyze the effects of six variables with the intent to increase the efficiency of molybdenum recovery from homogenous nanocatalysts in the slurry phase hydroconversion processes. These variables consist of leaching temperature, oxidation temperature, leaching time, oxidation time, hydrogen peroxide concentration, and ammonium carbonate concentration. This design offers the significant role of parameters that determining optimum recovery conditions for achieving the cost-efficient, shorter duration and more environmentally friendly process. The results show that the leaching time, hydrogen peroxide concentration, and ammonium carbonate concentration are effective parameters on molybdenum concentration with a degree of confidence of 95%. Based on the obtained results, the influences of leaching and oxidation temperatures and oxidation time were negligible. A linear model was obtained to predict operation conditions by effective parameters for estimating recovery. The maximum recovery is achieved at minimum leaching time (20 min), minimum hydrogen peroxide concentration (10 vol %) and maximum ammonium carbonate concentration (7 wt %).