Nickel catalysts supported on palygorskite for transformation of waste cooking oils into green diesel

Nickel catalysts supported on palygorskite of varying Ni content were synthesized following the deposition-precipitation method. The catalysts were characterized using various techniques and evaluated in a semi-batch reactor for the transformation of waste cooking oils (WCO) into green diesel at 310 degrees C and hydrogen pressure 40 bar. The nickel nanoparticles supported on palygorskite were proved to be very active. The conversion of the WCO was about 100%. The green diesel content of the liquid product depends mainly on the nickel surface exposed per gram of catalyst, following a volcano like trend and maximized (81.9 wt %) over the sample with 30 wt % Ni. Taking into account the very high ratio of WCO volume to catalyst mass (100 mL/g) and that the evaluation of the catalysts was performed under solvent free conditions, these results demonstrate the successful use of mineral palygorskite for developing promising natural catalysts for green diesel production.