Novel dragon fruit peel ash-derived solid catalyst for biodiesel production and PET waste recycling

Abstract

The present protocol demonstrates the development of an affordable methodology for synthesizing biodiesel and depolymerizing PET waste using dragon fruit (Hylocereus costaricensis or Hylocereus polyrhizus) peel ash derived solid catalyst. The reported catalytic process yielded 99 % biodiesel at room temperature in 5 h with 8 wt% catalyst amounts and 12 M equivalents of methanol, while requiring just 20 min of run time at an elevated temperature (65 °C). The reaction was found to be endothermic pseudo-first order reaction having activation energy of 56.36 kJ mol−1. Meanwhile, PET waste was depolymerized to bis(2-hydroxyethyl) terephthalate (BHET) in 1.5 h at 190 °C with 16 equivalents of ethylene glycol and 4 wt% of the catalyst, giving 84 % of the desired monomer. The developed catalyst and the resultant products are thoroughly characterized using a variety of techniques to determine the catalyst's chemical composition and to confirm the formation of the desired products.