Biodiesel Upgrading to Renewable Diesel over Nickel Supported on Natural Mordenite Catalysts

In the present work the valorization of natural mordenite as a catalyst support was investigated. Natural mordenite of Greek origin was activated by acid treatment with an aqueous solution of HCl. This treatment led to a material with a high specific surface area (156 m(2) g(-1)). Ni catalysts (10 wt % Ni) supported on activated mordenite were synthesized by incipient wetness impregnation (IWI), wet impregnation (WI), infiltration (INF), and deposition-precipitation (DP). They were evaluated for the biodiesel upgrading into renewable diesel via hydrotreatment. DP was proven to be the most effective preparation method. In fact, an almost total conversion of biodiesel and production of the highest amount of green diesel (14 wt % of the liquid product) was achieved over the catalyst prepared by DP. Its high efficiency was attributed to its enhanced specific surface area, better nickel dispersion (smaller size of crystallites), and the smaller amount of carbon deposits on its surface compared to the other catalysts of this series. When the DP method was adopted, nickel catalysts supported on activated mordenite were synthesized varying active phase loading in the range 10-30 wt %. The catalyst with the maximum nickel loading exhibited high specific surface area and the highest Ni surface area as well as a balanced population of weak and strong acid sites. These characteristics resulted in the highest efficiency for green diesel production (25 wt % of the liquid product) among the catalysts studied.

Automated summary

In this study, natural mordenite was activated by acid treatment to serve as a catalyst support for Ni catalysts. The catalysts synthesized using the deposition-precipitation method showed the highest efficiency in biodiesel upgrading, with almost complete conversion and production of the highest amount of green diesel. This was attributed to enhanced specific surface area, better nickel dispersion, and reduced carbon deposits on the catalyst surface.