Influence of Natural Mordenite Activation Mode on Its Efficiency as Support of Nickel Catalysts for Biodiesel Upgrading to Renewable Diesel

In the present work, natural mordenite originated from volcanic soils in Greek islands, activated using HCl solution and HCl solution followed by NaOH solution, was used as support for preparing two metallic nickel catalysts (30 wt.% Ni). The catalysts were thoroughly characterized (XRF, N-2 adsorption-desorption, SEM, XRD, TEM, H-2-TPR, NH3-TPD) and evaluated for biodiesel upgrading to green (renewable) diesel. Double activation of natural mordenite optimized its supporting characteristics, finally resulting in a supported nickel catalyst with (i) enhanced specific surface area (124 m(2) g(-1)) and enhanced mean pore diameter (14 nm) facilitating mass transfer; (ii) easier nickel phase reduction; (iii) enhanced Ni-0 dispersion and thus high active surface; (iv) balanced population of moderate and strong acid sites; (v) resistance to sintering; and (vi) low coke formation. Over the corresponding catalyst, the production of a liquid consisting of 94 wt.% renewable diesel was achieved, after 9 h of reaction at 350 degrees C and 40 bar H-2 pressure, in a semi-batch reactor under solvent-free conditions.

Automated summary

In this study, activated natural mordenite was used as a support to prepare two metallic nickel catalysts for the production of green diesel from biodiesel. The optimized mordenite support exhibited enhanced surface area and pore size, ease of nickel reduction, high active surface, balanced distribution of acid sites, resistance to sintering, and low coke formation. The catalyst achieved a liquid product consisting of 94 wt.% renewable diesel after 9 hours of reaction at 350°C and 40 bar H-2 pressure under solvent-free conditions.