Single-step extraction–esterification process to produce biodiesel from palm oil mill effluent (POME) using microwave heating: a circular economy approach to making use of a difficult waste product

This investigation explores single-step biodiesel synthesis using palm oil mill effluent (POME) as a feedstock. Normally considered a waste product from the extraction process of palm oil, POME treatment is difficult and can cause significant environmental pollution if discharged directly into watercourses. Fatty acids (FAs) present in POME were extracted and subsequently esterified in situ to FA methyl esters (FAME) suitable for use as biodiesel. The process of simultaneous extraction and esterification was performed under microwave irradiation in a sealed vessel, which has been shown to reduce both time of reaction and energy use considerably in other reactions. The simultaneous extraction and esterification result in an 89% yield of biodiesel from the available FAs in the POME solids. The facile separation of biodiesel products from the reaction mixture augments the process and here presented is a potential route to making economic use of this difficult feedstock.