Use of biochar as a catalyst for biodiesel production

Abstract

The economic viability of biodiesel (BD) production is highly dependent on conversion techniques using inexpensive oil feedstocks. In this study, BD was synthesised by the thermally induced (non-catalytic) transesterification of oil extracted from camellia seed (42.23 wt% lipid content). The BD yield from the non-catalytic transesterification of camellia oil was higher than that from the alkali-catalysed process. The BD yield from the alkali-catalysed transesterification of camellia oil for 60 min was 84.1 wt%, whereas that from the non-catalytic process for ≤ 1 min at 360 ˚C was 93.5 wt%. To realise a virtuous circle in the production of BD, this study sought a strategic way to valorise oil-extracted biomass waste (lignocellulose-based). Specifically, this study sought a method for valorising biochar as an effective catalyst, hypothesizing that earth alkaline metals finely dispersed within the porous structure of biochar would effectively enhance catalytic capability. The BD yield in the presence of camellia biochar was 92.4 wt% (saturated at ≥ 240 ˚C). Thus, the reaction kinetics for the transesterification of camellia oil over camellia biochar was catalytically accelerated. Such efforts provide opportunities to enhance economic viability and realise the concept of a sustainable cycle in BD production.