Pyrolysis of cigarette butts as a sustainable strategy to recover triacetin for low-cost and efficient biodiesel production

The high cost of biodiesel production is the main barrier to its commercialization. Addition of triacetin as an oxygenated additive to biodiesel is one of the most profitable solutions to augment its combustion propensity if it is extracted from a sustainable and cheap source and processed properly. Cigarette butts (CBs) are very rich in triacetin and are characterized by high sustainability, hence, they are probable to help to realize the concept of this strategy. Within this framework, this research aims to recover triacetin from CBs using pyrolysis treatment as an eco-friendly solution. The experiments were carried out in a 200 g reactor at different reaction temperatures (650, 700, and 750 degrees C) to obtain optimal conditions that yield the largest abundance of triacetin in the pyrolysis oil. The gases generated during the entire decomposition process were observed using an instantaneous gas analyser. The effect of reaction temperature on the yield and composition of oil and char products was also investigated using GC/MS, SEM-EDX, and FTIR. It was found that the reaction temperature had no significant impact on the yield of pyrolysis products which was estimated in the ranges of 38-39.5 wt% (oil), 25.7-27.7 wt% (char), and 33-36.4 wt% (gas). However, the biggest quantity of triacetin (43%) was synthesized at 750 degrees C accompanied by a gaseous product consisting mainly of CO2 (11.6%), CO (8%), H2 (4.6%), and CH4 (2%). The composite char product with a porous structure was very rich in calcium (upto 32 wt%) in the form of debris (at 650 degrees C) and flakes (at 750 degrees C) with a pore size smaller than 1 & mu;m. This study experimentally proved that the pyrolysis process has a high potential to dispose of CBs and can be used as a sustainable source of triacetin recovery.