Co-pyrolysis characteristics and kinetics of electronic waste and macroalgae: A synergy study based on thermogravimetric analysis

Abstract

The study investigated the non-isothermal co-pyrolysis of Sargassum wightii (macroalgae) with electronic waste in the temperature range of 50–800 °C using a thermogravimetric analyser in an inert nitrogen atmosphere. Using the thermogravimetric analysis data, the synergistic influence of macroalgae on electronic waste and vice versa was evaluated by considering thermal decomposition behavior, the degree of thermal degradation and kinetics as evaluation criteria. The thermogravimetric analysis revealed the presence of three different decomposition stages (50–150, 150–550 and 550–800 °C) for all the samples and their blends. The second stage, which is considered as a major pyrolysis zone witnessed maximum weight loss in all the cases. While the decomposition of structural components can be attributed to the major weight loss with macroalgae, the thermal decomposition of polymeric fraction along with brominated and non-brominated epoxy resins could be the reason for weight loss with electronic waste in the second zone. The thermogravimetric data via isoconversional method was interpreted to evaluate the kinetic triplet for the co-pyrolysis process. The kinetic analysis indicated that the activation energy varied significantly with respect to the conversion in the range 0.1–0.8. Furthermore, the values obtained in this study for the kinetic parameters correspond to those reported in the literature. The synergistic impact of macroalgae on electronic waste and vice versa was clearly evident in terms of thermal degradation pattern, residues and reaction kinetics. The obtained thermodynamic and kinetic parameters demonstrated the co-pyrolysis of macroalgae and electronic waste as a potential pathway to harness bioenergy and ease the optimization of macroalgae co-pyrolysis with other similar feedstocks.