Synthesis and Application of Porous Kaolin-Based ZSM-5 in the Petrochemical Industry

Zeolites are advanced chemical materials that play a significant role in many petrochemical applications. In recent years, research interest in improving and enhancing the effectiveness of ZSM-5 as a catalyst has grown immensely. In particular, finding cheaper, environmentally friendly alternative starting materials for the synthesis of ZSM-5 has gained much attention. Kaolin has been widely investigated as a zeolite precursor as it comprises the required constituents for an aluminosilicate zeolite material; ubiquitous nature and its benefit in synthesising zeolites are well known as an inexpensive way of obtaining catalysts. This chapter deals with the factors affecting ZSM-5 synthesis when utilising a kaolin precursor. The effects of kaolin crystallinity, kaolinite content and synthesis parameters on ZSM-5 formation and its physicochemical properties are discussed. The potential of kaolin-based ZSM-5 as an oligomerisation catalyst is investigated. Pure, crystalline ZSM-5 could be successfully synthesised from a kaolin precursor. Physicochemical properties such as morphology, porosity and acidity are affected by the kaolin precursor and optimum synthesis conditions are required for synthesis of ZSM-5 from particular kaolin. Kaolin-based ZSM-5 catalyst showed good activity and selectivity to valuable fuel range hydrocarbons

Synthesis, Characterization, and Catalytic Activity of Nickel Sulfided Catalysts for the Dehydrogenation of Propane: Effect of Sulfiding Agent and Sulfidation Temperature

The effect of sulfiding agent and sulfidation temperature on nickel catalysts supported on MgAl2O4 were investigated for propane dehydrogenation. The catalysts were prepared by reduction of NiO/MgAl2O4, followed by sulfidation using (NH4)2SO4 (S1), (NH4)2S (S2), and DMSO (S3) as sulfiding agents. The catalysts were sulfided at 200 °C, 400 °C, and 550 °C to form Ni/MgAl2O4-Sx-y, where x and y represent the sulfiding agent and sulfidation temperature, respectively. Physiochemical properties of the catalysts were characterized by XRD, BET, SEM, TEM, and TGA to investigate the type of nickel-sulfur species, surface area, morphology, particle size, and stability of the catalysts. Structural and textural properties revealed that the anion present on the sulfiding agent as well as the sulfidation temperature affect both the type and the strength of the Ni-S species. For the S1 catalysts, the SO42− ion interacted with the support to form MgSO4, while the S2− ion on the S2 and S3 catalysts was responsible for the formation of the Ni3S2 phase. The sulfidation temperature contributed to the %S present on each catalyst. Although the catalysts sulfided by S3 contained the least %S, Ni/MgAl2O4-S3-550 displayed the best catalytic performance as a result of the higher particle dispersion and stronger Ni-S interaction compared to S1 and S2 catalysts