Application of a Response Surface Method for the Optimization of the Hydrothermal Synthesis of Magnetic NiCo2O4 Desulfurization Catalytic Powders

Abstract

In this study, nickel cobaltate (NiCo2O4) powders are employed as a catalyst in conjunction with persulfate for the development of a catalytic oxidation system to enhance fuel desulfurization. The hydrothermal synthesis conditions of NiCo2O4 powders, which significantly influenced the desulfurization efficiency, were optimized using a response surface methodology with a Box–Behnken design. These conditions were ranked in the following order: calcination temperature > hydrothermal temperature > calcination time > hydrothermal time. Through the optimization process, the ideal preparation conditions were determined as follows: a hydrothermal temperature of 143 °C, hydrothermal time of 6.1 h, calcination temperature of 330 °C, and calcination time of 3.7 h. Under these optimized conditions, the predicted desulfurization rate was approximately 85.8%. The experimental results closely matched the prediction, yielding a desulfurization rate of around 84%, with a minimal error of only 2.1%. To characterize the NiCo2O4 powders prepared under the optimal conditions, XRD, SEM, and TEM analyses were conducted. The analysis revealed that the microscopic morphology of NiCo2O4 exhibited a rectangular sheet structure, with an average particle size of 20 nm. Additionally, fan-shaped NiCo2O4 particles were observed as a result of linear and bundle agglomerations. Thus, this work is innovative in its ability to synthesize nano-catalysts using hydrothermal synthesis in a controllable manner and establishing a correlation between the hydrothermal synthesis conditions and catalytic activity.

Optimization of Desulfurization Process via Choline Phosphotungstate Coupled with Persulfate Using Response Surface Methodology

“…However, its use is limited by its instability, strong corrosiveness, and high cost. In earlier studies [12][13][14], our team employed peroxymonosulfate as an alternative oxidant in conjunction with cobalt-based ionic liquid catalysts, achieving highly efficient desulfurization. Peroxymonosulfate stands out for its potent oxidative strength, minimal corrosiveness, affordability, and exceptional stability as a solid salt.…”