Application of Three Kinetic Models for the Prediction of Biomethane Yield of Combined Oxidative and Nanoparticle Additives Pretreated Xyris capensis

Abstract

Anaerobic digestion is a highly preferred technology for energy production and waste disposal because of its adaptability, sustainability, and environmental protection. Kinetic analysis is crucial in anaerobic digestion to represent biomethane production performance. However, the connection between the kinetic models and process parameters is not universal. This study investigates the performance of three kinetic models: first order, logistic, and Gompertz on the simulation of biomethane yield from oxidative pretreated and combined oxidative and Fe₃O₄ nanoparticle additive pretreated substrate. Xyris capensis was pretreated before anaerobic digestion. The cumulative biomethane released was used to simulate the digestion process using selected kinetic models. The results indicated that pretreatment conditions influence the performance of the models, and the cumulative biomethane yield of the single pretreated Xyris capensis fitted more accurately with the Gompertz model. In contrast, the total biomethane released from the combined pretreated feedstock best fits the logistic model. All the model’s performance metrics of lag phase (λ), correlation coefficient (R²) of 0.8269–0.9978, Root Mean Square Error (RMSE) of 3.0193–156.3094, AIC of 65.6708–175.1098, and %diff of 0.0329–4.7751, show acceptable values. Comparison along different pretreatment conditions using the performance metrics shows that the Gompertz model produced superior accuracy. This study has established the performance of kinetic models in simulating the biomethane release from varying pretreatment conditions and provides a scientific conceptualization for process optimization. This finding can be helpful in enhancing energy recovery that will support a decarbonization approach and can be investigated on a commercial scale.